Wildlife and Climate Change

Overview

There are a number of ways that climate change is beginning to impact wildlife. Temperature increases and changes in precipitation can directly affect species depending on their physiology and tolerance of environmental changes. Climate change can also alter a species' food supply or its reproductive timing, indirectly affecting its fitness. Understanding these interactions is an important step in developing management strategies to help species survive the changing climate.

Read through the accompanying pages to learn more about different wildlife responses to climate change.

Related pages: Biodiversity, Aquatic Ecosystems

Overview

There are a number of ways that climate change is beginning to impact wildlife. Temperature increases and changes in precipitation can directly affect species depending on their physiology and tolerance of environmental changes. Climate change can also alter a species' food supply or its reproductive timing, indirectly affecting its fitness. Understanding these interactions is an important step in developing management strategies to help species survive the changing climate.

Read through the accompanying pages to learn more about different wildlife responses to climate change.

Related pages: Biodiversity, Aquatic Ecosystems

Amphibians and Climate Change

D. Olson

Topics Horizontal Tabs

Synthesis

Synthesis

Preparers

Deanna H. Olson, Pacific Northwest Research Station; Daniel Saenz, Southern Research Station

An archived version of this topic paper is available.

Issues

Several factors contribute to the vulnerability of amphibians to the projected effects of climate change. First consider that for over 20 years, amphibians have been globally recognized as declining (1). Today, they are among the leading taxonomic groups threatened with losses: about 1/3 of amphibian species are already at risk of extinction (2, 3). Leading threat factors include habitat loss, disease, invasive species, overexploitation, and chemical pollution. Next, consider their basic biology. Amphibians have been heralded as Canaries in the Coal Mine, being sentinels of a host of environmental changes due to their biphasic life style with life stages relying on both aquatic and terrestrial systems, their moist permeable skin which is a sensitive respiratory organ, and their central position in food webs. The scenario becomes even more complex when multiple threats affect single populations and the synergistic effects of threats together may become more potent than the simple sum of those parts. Now, adding the effects of climate change to this cocktail of multiple threats and climate-sensitive life history modes is worrisome indeed.

Numerous researchers have considered the adverse effects of climate change on amphibians and found differing results (4-13) suggesting that risks vary among taxa. Dispersal-limited or rare species may have restricted movements and may not be able to shift their distribution to accommodate changes in the locations of suitable habitat. In contrast, species with continental distributions may have innate resiliency to a broad swath of conditions, and have better adaptive capacity to survive as a whole. Amphibian species with narrow tolerances for temperature and moisture regimes may be at heightened risk. Amphibians that rely on certain habitat types may be at most risk, for example those found in ephemeral ponds and streams which may dry before the annual reproductive cycle is complete. Regions projected to have increasing fluctuations in climate conditions may experience reproductive "bust" years, or episodic mass mortality (14).

  • Salamander

    The salamander Rhyacotriton variegatus occurs in small headwater streams in the Pacific Northwest, where water flows may be at risk of changing in some areas. Credit: William P. Leonard.

  • Windmill and solar-powered pump

    Maintaining pond water levels for species at risk is one example of a climate adaptation strategy. Here, a windmill and solar-powered pump is used. Credit: Bruce Christman.

  • Cascades Frog

    The Cascades Frog, Rana cascadae, breeds in ephemeral ponds in the Cascade Range of the Pacific Northwest; these habitats are vulnerable to drying out early in warm, dry years. Credit: William P. Leonard.

  • Northern Cricket frog

    The Northern Cricket frog, Acris crepitans can be found throughout the eastern U.S. Severe declines have been reported for the species, though no single cause for the decline has been identified. Credit: Dan Saenz.

  • Coastal-plain Toads

    Coastal-plain Toads, Incilius nebulifer, are found on coastal plain from western Mississippi to northern Mexico. This species breeds in ephemeral ponds and appears to be associated with disturbed and urban habitats. Credit: Dan Saenz.

Likely Changes

Knowing that climate change predictions vary considerably with geographic locations, that there is uncertainty tied to all climate change models, and amphibians are an extremely diverse taxon -a single or simple answer of how amphibians are likely to respond to climate change is not possible. Several types of likely changes may prove to be lethal to amphibians: altered hydroperiods; altered seasons and phenology (cyclical timing of events); increased incidence of severe storms and storm surge; rise in sea level; fluctuating weather conditions; and warmer, drier conditions (e.g., 14-24).

Hydroperiod refers to the timing of water availability. Water retention in streams and ponds is particularly important for amphibians breeding in temporary, ephemeral, or vernal ponds and intermittent or discontinuously flowing streams. Many taxa are already experiencing occasional early drying of their habitats, with mass mortality of eggs, tadpoles, and metamorphosing animals resulting (25). Some of these habitats are also important foraging habitats or dispersal ‘stepping stones’, so altered hydroperiods can have negative effects outside of reproductive losses. Another side effect of changed hydroperiod could be increased exposure to predators. For example, if shorelines recede then amphibian refugia may be lost and fish, bird or mammal predators may gain access to newly exposed amphibian prey.

Phenology refers to the timing of life cycle events such as breeding and overwintering. Each plant and animal species has its own phenological patterns associated with local climatic conditions. Climate change may result in shifts in phenology, especially for species that breed early or late in the season. A shift to earlier breeding may leave amphibians exposed to fluctuating weather conditions. For example, a warm spell in late winter followed by a cold storm after breeding can freeze animals. A deep freeze may penetrate below the ground surface to affect animals emerging in spring, or overwintering hibernacula in winter. Also, survival of annual recruits may be tied to their size at metamorphosis, which may depend upon when breeding occurs. Furthermore, if the synchrony of communities (the timing of breeding or other activities) becomes offset, there may be altered interactions with predator and prey species or increased exposure to disease and invasive species. Lastly, generally warmer, drier conditions can cause moist microhabitats to become too dry and unsuitable for native amphibians. This may especially affect leaf litter or other refugia on the ground surface.

Options for Management

A recent paper on "Engineering a future for amphibians with climate change" (14, 26, 27) discusses a variety of adaptation management approaches. These approaches are discussed briefly below, and focus on tools that we may use to safeguard habitat conditions for vulnerable amphibian populations.

Manipulation of hydroperiod or moisture regimes at sites is a dominant tool in the land manager’s repertoire to mitigate the effects of climate change on any wildlife group. This can be implemented by a variety of methods, including: irrigation, site excavation, vegetation management, riparian buffer creation, down wood recruitment, and litter supplementation. Novel engineered approaches include installation of solar-powered water pumps to retain water levels of ponds, and installation of sprinkler systems to retain surface moisture. Consideration of climate during landscape management planning may result in incorporation of hill-shaded refugia in protected habitat areas (29) and designation of linkage areas for connectivity among habitats (30, 31). Using logs as dispersal conduits, and forest thinning to ameliorate dry conditions are being trialed in case studies. A new "hot topic" of research is investigating the effects of alternative forest management practices on microclimate, and specifically tying these effects to certain metrics of biodiversity such as moisture sensitive amphibians (32). Policies directed at vulnerable site protection, such as riparian reserves (14), are likely the most pro-active management option that has multiple-site implications.

If stop-gap measures are needed for rare species faced with extinction, the more costly methods of Reintroduction, Relocation, Translocation, and Headstarting (RRTH) may be considered. In the United States, numerous RRTH projects are underway for amphibians and reptiles (28). Captive breeding and RRTH programs are also managed by Zoos and Aquariums, with the international program Amphibian Ark being the most notable.

References

  1. Blaustein, A.R.;Wake, D.B. 1990. Declining amphibian populations: A global phenomenon? Trends in Ecology and Evolution. 5:203-204.
  2. Stuart, S.N.; Chanson, J.S.; Cox, N.A.; Young, B.E.; Rodrigues, A.S.L.; Fischman, D.L.; Waller, R.W. 2004. Status and trends of amphibian declines and extinctions worldwide. Science. 306:1783-1786.
  3. Hoffmann, M.; Hilton-Taylor, C. et al. 2010. The impact of conservation on the status of the world's vertebrates. Science. 330:1503-1509.
  4. Corn, P.S. 2005. Climate change and amphibians. Animal Biodiversity and Conservation. 28:59–67.
  5. Carey, C.; Alexander, M.A. 2003. Climate change and amphibian declines: is there a link? Diversity and Distributions. 9:111-121.
  6. Araujo, M.B.; Thuiller, W.; Pearson, R.G. 2006. Climate warming and the decline of amphibians and reptiles in Europe. Journal of Biogeography. 33:1712-1728.
  7. Reading, C. J. 1998. The effect of winter temperatures on the timing of breeding activity in the common toad Bufo bufo. Oecologia. 117:469-475.
  8. Wake, D.B. 2007. Climate change implicated in amphibian and lizard declines. PNAS. 104:8201-8202.
  9. Laurance, W.F. 2008. Global warming and amphibian extinctions in eastern Australia. Australia Ecology. 33: 1-9.
  10. Blaustein, A.R.; Walls, S.C.; Bancroft, B.A.; Lawler, J.J.; Searle, C.L. ; Gervasi, S. S. 2010. Direct and indirect effects of climate change on amphibian populations. Diversity. 2:281-313.
  11. Lawler, J.J.; Shafer, S.L.; Bancroft, B.A.; Blaustein, A.R. 2009. Projected climate impacts for the amphibians of the Western Hemisphere. Conservation Biology. 24:38-50.
  12. Milanovich, J.R.; Peterman, W.E.; Nibbelink, N.P.; Maerz, J.C. 2010. Predicted loss of salamander diversity hotspot as a consequence of projected global climate change. PLoS ONE. 5(8):1-10.
  13. McCallum, M.L. 2010. Future climate change spells catastrophe for Blanchard's cricket frog, Acris blanchardii (Amphibia: Anura: Hylidae) [pdf]. Acta Herpetologica. 5:119-130.
  14. Shoo, L. P.; Olson, D.H. et al. 2011. Engineering a future for amphibians under climate change. Journal of Applied Ecology. 48: 487-492.
  15. Beebee, T.J.C. 1995. Amphibian Breeding and Climate. Nature. 374:219-220.
  16. Blaustein, A.R., L.K. Belden, D.H. Olson, D.M. Green, T.L. Root, and J.M. Kiesecker. 2001. Amphibian breeding and climate change. Conservation Biology. 15:1804-1809.
  17. Daszak, P.; Scott, D.E.; Kilpatrick, A.M.; Faggioni, C.; Gibbons, J.W.; Porter, D. 2005. Amphibian population declines at Savannah River site are linked to climate, not chytridiomycosis. Ecology. 86:3232-3237.
  18. Saenz, D.; Fitzgerald, L.A.; Baum, K.A.; Conner, R.N. 2006. Abiotic correlates of anuran calling phenology: the importance of rain, temperature, and season. Herpetological Monographs. 20(1): 64-82.
  19. Trauth, J.B.; Trauth, S.E.; Johnson, R.L. 2006. Best management practices and drought combine to silence the Illinois chorus frog in Arkansas. Wildlife Society Bulletin. 34:514-518.
  20. Schriever, T.A.; Ramspott, J.; Crother, B.I.; Fontenot, C.L. 2009. Effects of hurricanes Ivan, Katrina, and Rita on a southeastern Louisiana herpetofauna. Wetlands. 29:112-122.
  21. Gunzburger, M.S.; Hughes, W.B.; Barichivich, W.J.; Staiger, J.S. 2010. Hurricane storm surge and amphibian communities in coastal wetlands of northwestern Florida. Wetlands Ecology and Management. 18:651-663.
  22. Donnelly M.A.; Crump, M. L. 1998. Potential effects of climate change on two
    Neotropical amphibian assemblages. Climatic Change. 39:541-561.
  23. Pounds, J. A.; Crump, M.L. 1994. Amphibian declines and climate disturbance: The case of the golden toad and the harlequin frog. Conservation Biology. 8:72-85.
  24. Pounds, J. A.; Fogden, M.P.L.; Campbell, J.H. 1999. Biological response to climate change on a tropical mountain. Nature. 398:611-615.
  25. Blaustein, A.R.; Olson, D.H. 1991. Amphibian population declines. Science 253:1467.
  26. Olson, D.H. 2011. Brochure on climate change and amphibians and reptiles. Available at: http://parcplace.org/images/stories/ClimateChangeFlyer.pdf
  27. Olson, D.H. 2011. Showcase of herpetofaunal climate change adaptation management tools. Available at: http://parcplace.org/images/stories/ClimateChangeShowcase.pdf
  28. Olson, D.H. 2011. Compilation of Relocation, Reintroduction, Translocation, and Headstarting (RRTH) projects for herpetofauna. Available at: http://parcplace.org/news-a-events/242-rrth.html
  29. Suzuki, N.; Olson, D.H.; Reilly, E.C. 2008. Developing landscape habitat models for rare amphibians with small geographic ranges: a case study of Siskiyou Mountains salamander in the western USA. Biodiversity and Conservation. 17:2197-2218.
  30. Olson, D.H.; Burnett, K.M. 2009. Design and management of linkage areas across headwater drainages to conserve biodiversity in forest ecosystems. Forest Ecology and Management. 258S: S117-S126.
  31. Olson, D.H.; Burnett, K.M. 2013. Geometry of forest landscape connectivity: pathways for persistence. In: Anderson, P.D.; Ronnenberg, K.L., eds. Density management in the 21st century: west side story. Gen. Tech. Rep. PNW-GTR-880. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: 220–238.
  32. Olson, D.H.; Anderson, P.D.; Frissell, C.A.; Welsh, H.H.Jr.; Bradford, D.F. 2007. Biodiversity management approaches for stream riparian areas: Perspectives for Pacific Northwest headwater forests, microclimate and amphibians. Forest Ecology and Management. 246(1):81-107.

How to cite

Olson, D.H.; Saenz, D. 2013. Climate Change and Amphibians. (March, 2013). U.S.
Department of Agriculture, Forest Service, Climate Change Resource Center. www.fs.usda.gov/ccrc/topics/wildlife/amphibians/

 
Research

Research

Ongoing research on amphibians by US Forest Service scientists includes the following topics that relate to climate and climate change:

Climate Change and Herpetofauna
Climate change is expected to affect amphibians through a number of direct and indirect mechanisms. This project focuses on examining several of these mechanisms, as well as potential management responses, including:

  • "Shrinking heads hypothesis" - How do forested headwater streams respond to low water years? Do riparian buffers mitigate shrinking heads effects?
  • Over-ridge connectivity designs for forested amphibians.
  • Climate associations of the amphibian chytrid fungus.
  • Long-term monitoring of anuran breeding dates in the Cascade Range.

Contact: Dede Olson

Climate and breeding phenology of anuran species in Texas
Changing weather patterns from global climate change could be a contributing factor in declining frog populations, particularly for species that rely on ephemeral water sources, like some of those in eastern Texas. Scientists in Nacogdoches, TX are currently studying the effects of rainfall and temperature on the breeding activities of 13 different species of frogs in eastern Texas. Information from the research will make it possible to predict potential effects of a changing climate on frog populations.
Contact: Dan Saenz

Impacts of year-year variations of precipitation (snowpack and rainfall) on amphibian recruitment and survival
This study explores the link between the changes in water availability -- including complete pond drying -- and the abundance and recruitment of mountain yellow-legged frog in Dusy Basin , Kings Canyon National Park , California , USA . We propose using the low-snowpack years (1999, 2002, 2004) as comparative case studies to predict future effects of climate change on aquatic habitat availability and amphibian abundance and survival.
Contact: Kathleen Matthews

The Effects of Climate Change on Terrestrial Birds of North America

By Korall (Own work) GFDL (http://www.gnu.org/copyleft/fdl.html)

Topics Horizontal Tabs

Synthesis

Synthesis

Preparers

David King, U.S. Forest Service, Northern Research Station Center for Research on Ecosystem Change, University of Massachusetts; Deborah M. Finch, U.S. Forest Service, Rocky Mountain Research Station, Grassland, Shrubland, and Desert Ecosystems Program.

An archived version of this topic page is available

Issues

A discussion of avian responses to climate change is of interest for a number of reasons. First, because birds are relatively easy to identify and measure and their responses to environmental perturbation are relatively well known, they are useful as indicators of ecological change (1). Furthermore, birds are of conservation interest in their own right. Bird populations face global conservation challenges, with 1 in 8 species facing a high risk of extinction in the near future according to a recent report (2). Finally, birds perform significant ecosystem services with consequences for human health and well-being, including pest control, sanitation, seed dispersal and pollination (3).

  • The gray jay

    The gray jay is a montane and boreal specialist, and could be particularly sensitive to climate change because it caches food using frozen spit. Credit: Bill DeLuca

  • the greater sage grouse

    Climate can interact with other factors to threaten the sagebrush habitat needed several species, such as the greater sage grouse. Credit: USFWS Pacific Southwest Region.

  • Decline of bird species associated with spruce-fir habitat

    Recent declines of bird species that are associated with spruce-fir habitat on the White Mountain National Forest highlight concerns about montane bird species under climate change. Credit: Bill DeLuca.

  • cheatgrass

    Invasive plants like cheatgrass can harm birds that are dependent on sagebrush habitat by altering fire behavior in those ecosystems. These interactions can be exacerbated by climate change. Credit: Robin Tausch.

Likely Changes

Research on birds has shown that climate change affects birds both directly and indirectly. The distributions of birds are closely associated with both winter and summer temperatures, and increased temperatures due to climate change may directly affect birds by forcing them to use more energy for thermoregulation. This can disrupt their maintenance (the energy needed by organisms to maintain their basal levels of activity and condition) , reproduction, timing of breeding and migration, and reduce survival or fitness (4). Birds may respond to these costs by shifting their ranges over time to areas with more suitable thermal conditions, but habitat and other resources may be insufficient or unsuitable for their needs (5).

Generally speaking, global temperatures decrease with increased latitude and elevation, so a fundamental prediction of climate scientists is that species will shift towards the poles and upward in elevation (6; 7). Long-term changes in North American bird distributions show clear evidence of latitudinal shifts, with many species shifting their geographic distributions northwards over the past few decades (8, 9). Elevational shifts have also been reported in long-term datasets, and these shifts appear to implicate changes in precipitation as well as temperature. In the Sierra Nevada mountains, data show that the majority of species ranges have shifted upwards in elevation since the 1940s, with some bird species more closely associated with temperature shifts and others with changes in precipitation (10).

Climate-related shifts in species distribution along latitudinal and elevation gradients have important implications for conservation. If shifts in temperature take place at a more rapid rate than vegetation responses, or occur beyond the boundaries of suitable potential vegetation, then bird populations could be forced into areas of marginal habitat where they are likely to experience decreased survival and reproduction (4). With elevational shifts, the area available for species to colonize as ranges shift upwards also decreases with elevation (11). For this reason, montane species are considered to be especially vulnerable to climate change. This concern is highlighted by recent evidence of declines of montane spruce-fir indicator species on the White Mountain National Forest, including the threatened Bicknell’s Thrush (Catharus bicknelli; 12). Analyses of these same data also show an upward shift of bird species from lower forest areas into montane forest, which is consistent with general observed patterns that show middle elevation species shifting upwards (13).

In contrast to expectations, DeLuca (13) also reported that the montane spruce-fir bird species that occupy the forests nearest tree line are actually shifting downwards in elevation. This might at first seem like a cause for optimism, since there is more area at lower elevations, and thus montane bird ranges would not be constricted at the lower end of an elevational gradient. A more detailed analysis however indicates that lower elevations are marginal habitats for montane birds where they experience lower pairing and nesting success, and therefore lower reproductive success. These results demonstrate some important aspects of climate change research: they contradict the prevailing paradigm that species will respond to climate change by shifting their ranges towards higher elevations, and they highlight the necessity of considering aspects of fitness as well as the distribution of organisms in relation to climate change, because shifts might not be adaptive.

In addition to these direct effects, increased temperatures associated with climate change have the potential to cause a myriad of indirect effects.. One of the most widely reported is the de-synchronization of migrant bird reproduction with food resources. Many bird species synchronize their nesting cycle so the period of maximum food requirements of the young coincides with the maximum food availability (14). In the case of migratory birds, which comprise the majority of species and individuals in many temperate ecosystems, their departures from winter areas are related to photoperiod, whereas the availability of their largely insect food resources is affected by plant phenology. Since plant phenology is related to climate and is advancing in most regions, migratory bird species are in some cases arriving and therefore breeding too late to keep pace with the timing of their food supply (15).

Other indirect effects are mediated by changes in the types and timing of disturbance. In parts of the western U.S., climate change is manifested by drought conditions that increase the frequency and severity of wildfires. These disturbances can impact birds directly by destroying nests and altering habitats. For example, in the Great Basin the effects of drought on fire regimes is compounded by the invasion of cheatgrass (Bromus tectorum), an exotic species introduced from Eurasia. Cheatgrass is more flammable than native grasses, and as drought conditions increase, fire frequency and severity increases and plant species adapted for less severe fire regimes are replaced by cheatgrass, which further increases extreme fire behavior. The synergistic effects of climate, fire and invasion are blamed for loss and fragmentation of big sagebrush habitats needed by sagebrush obligates like sage thrasher (Oreoscoptes montanus) sage sparrow (Amphispiza belli), and greater sage-grouse (Centrocercus urophasianus), a candidate species for listing under the Endangered Species Act (16). West Nile virus models also show climate’s influence in this region, predicting disease spread to more western locations and states. This could impact vulnerable birds like the greater sage-grouse, which withdraws during droughts to water sources where it can be infected by mosquitos potentially carrying the virus. Finally, studies of high elevation birds in Arizona show that lower snowpack associated with climate change allows greater access to montane areas by elk, and recent declines in several species of migratory songbirds could be the result of decreased reproductive success resulting from habitat degradation from over-browsing (17).

There have been dramatic changes in global climate before, however the current challenge to species and ecosystems from climate is not only the degree of change but the rate. Rapid changes in environmental conditions are likely to exceed the ability of many bird species to adapt via natural selection (18). This concern has led to increased interest in identifying species characteristics associated with vulnerability to climate change (19). In addition to the examples presented above showing that montane and western grassland species are negatively affected, analyses of data from the Breeding Bird Survey are underway to determine whether traits like migratory status, clutch size or geographic range affect the vulnerability of bird species to climate change, as indicated by elevational and latitudinal shifts in their distributions (20). Because responses to climate change are largely species-specific it is expected that species will recombine into novel communities, which could present additional challenges as species are exposed to predators or competitors for whom they have no evolved defenses (21).

Management Options

Strategies to mitigate the impacts of climate change on bird populations include maintaining the resilience of their habitats by reducing compound stressors that potentially interact with climate change and magnify its impact. The effect of cheatgrass on fire regimes mentioned above is an example that illustrates the potential compounding effects of invasives. Other examples include habitat fragmentation and pollution. Where necessary, habitat resilience can be increased through active management, which can maintain robust growth and reproduction of native plants to mitigate the impacts of drought, heat stress and other climate-related effects (22). Other strategies to mitigate the effects of climate change include increasing the area of protected lands to include greater representation of habitat refugia, where species are predicted to be buffered from the effects of climate change because of site characteristics. Establishing and maintaining habitat connectivity among preserves and along elevational and latitudinal gradients by establishing corridors or networks of preserves could also facilitate shifts by climate-sensitive species (23).

Projects are underway nationwide to enhance resiliency through habitat improvement of ecosystems considered susceptible to climate change. For example, the Central Appalachian Spruce Restoration Initiative is a multi-partner collaboration of individuals and organizations who share the common goal of restoring the red spruce-northern hardwood ecosystem across the high elevation landscapes of Central Appalachia. The US Forest Service is a key player in this initiative, and recent accomplishments include planting, silvicultural treatments and removal of exotic species to enhance spruce regeneration, as well as reforestation and habitat acquisition to reduce fragmentation. These efforts will help priority species within this threatened ecosystem to withstand the effects of climate change or shift their range to track suitable climate conditions. Similar practices are being embraced by National Forests in their forest plan revisions. For example, the Kaibab National Forest in Arizona implements fuels control treatments and mechanical thinnings in an attempt to reduce the risk of pest and disease outbreaks and catastrophic wildfire, all of which are expected to increase with continued climate change.

References

  1. Niemi, G. J.; McDonald, M. E. 2004. Application of Ecological Indicators. Annual Review of Ecology, Evolution, and Systematics. 35: 89-111.
  2. Vie, J.-C., Hilton-Taylor, C.; Stuart, S.N. (eds.) (2009). Wildlife in a Changing World - An Analysis of the 2008 IUCN Red List of Threatened Species. Gland, Switzerland: IUCN. 180 pp.
  3. Sekercioglu, C.H; Daily, G.C; Ehrlich, P.R. 2004. Ecosystem consequences of bird declines. Proceedings of the National Academy of Sciences of the United States of America. 101:18042-18047.
  4. Crick, H. Q. P. 2004. The impact of climate change on birds. Ibis. 146:48-56.
  5. Devictor, V.; Julliard, R.; Couvet, D.; Jiguet, F. 2008. Birds are tracking climate warming, but not fast enough. Proceedings of the Royal Society B. 275: 2743-2748.
  6. Rodenhouse, N. L.; Matthews, S. N.; McFarland, K. P.; Lambert, J. D.; Iverson, L. R.; Prasad, A.; Sillett, T. S.; Holmes, R. T. 2008. Potential effects of climate change on birds of the Northeast. Mitigation and adaptation strategies for global change 13:517-540.
  7. Matthews, S.N.; Iverson, L. R.; Prasad, A. M.; Peters, M. P. 2011. Changes in potential habitat of 147 North American breeding bird species in response to redistribution of trees and climate following predicted climate change. Ecography. 34: 933-945.
  8. Hitch, A. T.;Leberg, P. L. 2007. Breeding distributions of North American bird species moving north as a result of climate change. Conservation Biology. 21:1523-1739.
  9. LaSorte, F. A.; Thompson, F. R. III. 2007. Poleward shifts in winter ranges of North American birds. Ecology. 88:1803-1812.
  10. Tingley, M. W.; Monahan, W. B.; Beissinger, S. R.; Moritz, C. 2009. Birds track their Grinnellian niche through a century of climate change. Proceedings of the National Academy of Sciences. 106:19637-19643.
  11. Sekercioglu, C.H.; Schneider, S.H.; Fay, J.P.; Loarie, S.R. 2008. Climate Change, Elevational Range Shifts, and Bird Extinctions. Conservation Biology. 22: 140-150.
  12. King, D. I.; Lambert, J. D.; Buonaccorsi, J. P.; Prout, L. S. 2008. Avian population trends in the vulnerable montane forests of the Northern Appalachians, USA. Biodiversity and Conservation. 17:2691-2700.
  13. DeLuca, W.V. 2012. Ecology and conservation of the high elevation forest avian community in northeastern North America. Doctoral Dissertation, University of Massachusetts, Amherst.
  14. Visser, M.E.; Holleman, L.J.M.; Gienapp, P. 2006. Shifts in caterpillar biomass phenology due to climate change and its impact on the breeding biology of an insectivorous bird. Oecologia. 147: 164-172.
  15. Both, C.; Visser, M.E. 2001. Adjustment to climate change is constrained by arrival date in a long-distance migrant bird. Nature.411: 296-298.
  16. Finch, D. M. 2012. Climate change in grasslands, shrublands, and deserts of the interior American West: a review and needs assessment. Gen. Tech. Rep. RMRS-GTR-285. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 139 p.
  17. Auer, S. K.; Martin, T. E. 2013. Climate change has indirect effects on resource use and overlap among coexisting bird species with negative consequences for their reproductive success. Global Change Biology. 19:411-419.
  18. Visser, M.E. 2008. Keeping up with a warming world; assessing the rate of adaptation to climate change. Proceedings of the Royal Society B. 275: 649-659.
  19. Cormont, A.; Vos, C.C.; van Turnhout, C.A.M.; Foppen, R.P.B.; ter Braak, C.J.F. 2011. Using life-history traits to explain bird population responses to increasing weather variability. Climate Research. 49: 59-71.
  20. Auer and King, In review
  21. Lurgi, M.; Lopez, B. C.; Montoya, J. M. 2012. Novel communities from climate change. Philosphical Transactions of the Royal Society B. 367:2913-2922.
  22. Millar, C. I.; Stephenson, N. L.;Stephens, S. L. 2007. Climate change and forests of the future: managing in the face of uncertainty. Ecological Applications. 17:2145-2151.
  23. Mawdsley, J.R.; O'Malley, R.; Ojima, D.S. 2009. A review of climate‐change adaptation strategies for wildlife management and biodiversity conservation. Conservation Biology. 23: 1080-1089.

How to cite

King, D.; Finch, D.M. 2013. The Effects of Climate Change on Terrestrial Birds of North America. (June, 2013). U.S. Department of Agriculture, Forest Service, Climate Change Resource Center. www.fs.usda.gov/ccrc/topics/wildlife/birds

Reading
Research

Research

Modeling potential future habitats for trees and birds in the eastern U.S.
Our group, the Landscape Change Research Group, from Delaware, OH lab of the Northern Research Station, have been modeling potential changes in suitable habitat for trees and birds of the eastern US. These maps are available online at www.nrs.fs.fed.us/atlas. We also look at dispersal potentials through another modeling toolset, and work with modification factors to understand more about the factors not readily modeled.
Contact: Louis Iverson

Pacific Northwest Wildlife Habitat
RMRS scientists are collaborating with scientists from the Pacific Northwest Station and the University of Washington to develop methods to generate forested landscapes given climate change. These landscapes will be linked to multi-scale wildlife habitat models currently under development at RMRS.
Contact: Sam Cushman

Predicting the Effects of Climate Change on Avian Abundance
Using a longterm dataset (27+ years), researchers are examining the effect of weather patterns on avian abundance at the San Joaquin Experimental Range, an oak woodland savanna in California, to reveal potential climate change effects on demography and identify species at risk.
Contact: Kathryn Purcell, Sylvia Mori

The Effects of Climate Change on Mammals

K. Marcinkowski

Topics Horizontal Tabs

Synthesis

Synthesis

Preparers

Kevin S. McKelvey, Rocky Mountain Research Station, Missoula MT; Roger W. Perry, Southern Research Station, Hot Springs, AR; L. Scott Mills, University of Montana, Missoula MT.

An archived version of this topic paper is available.

Issues

Climate change is expected to impact most parts of an ecosystem, and mammals are no exception. Some mammals have very specific climatic adaptations, such as requirements for snow, sea ice, or temperatures within a narrow range for hibernation. Some have distributions that are dependent on climate. Most mammals will not be able to avoid the effects of climate change, with both positive and negative effects possible. Mammals generally utilize a variety of often disjunct resources. They need places to hide, eat, drink, and breed, and in many cases these places are distinct and may change seasonally. Thus there are many opportunities for climate change to disrupt mammalian life histories. In general they will not be able to effectively hide in microhabitats; in contrast many plants can persist as rare endemics long after the climate has changed. Most mammals are also highly mobile and, compared to perennial plants, have relatively short (generally < 20 yrs) life spans. Thus, if climates become unsuitable, mammalian response can be expected to be rapid.

Mammals play dominant roles in many systems. They make up most of the terrestrial large-bodied predators in North America, and these large, high-trophic mammals have significant impacts on the ecosystems they inhabit. For example, gray wolf introduction in Yellowstone National Park has reduced the northern elk herd to approximately 1/3 of its former size (1, Figure 1), which has initiated a cascade of ecological effects (2, 3). Rodents and lagomorphs (hares, pikas, and rabbits) are the primary prey for many mammalian, avian, and reptilian predators and rodents can affect the composition of vegetative communities through seed predation (4). Small terrestrial mammals, including rodents and insectivores (shrews), typically comprise the largest and most diverse group of mammals in many ecosystems (e. g. 5); thus, most of the changes in mammal abundances and distributions resulting from climate change are expected to be in this group (e. g. 6). Additionally rodents host many diseases that can affect us. Many tick- and flea-borne diseases that infect humans, including Lyme disease, Rocky Mountain spotted tick fever, Tularemia, plague, and Ehrlichiosis are carried by rodents or rodents serve as the reservoir hosts (7); the prevalence of these diseases is often strongly linked to population size (e.g., 8, 9). Thus, changes in mammal communities will have profound impacts on ecosystems and may directly affect human societies.

  • Endangered Indiana bats hibernating in a cave

    Endangered Indiana bats hibernating in a cave. Credit: Roger Perry, USFS.

  • White hare in a brown background

    Hares may be particularly vulnerable to predators when their coloration does not match the background. Changes in the timing of snow cover could affect their survival. Credit: L. Scott Mills et al., PNAS Early Edition (2013)

  • Pika

    Pikas appear dependent both on moist and cool summer conditions and winter snow. Climate-related stressors may playing a role in pika declines in the Great Basin over the last decades. Copyright photograph courtesy Jim Jacobson.

Likely Changes

The effects of climate changes on mammals can sometimes be ascertained directly through the study of their biology and physiology. For example, once it is understood that wolverines require snow to den (10, 11) and persistent spring snow defines the southern extent of their range (11), the likely effects of reduced snowpack are straightforward (12). There is no evidence that wolverines will be able to persist in areas that lose their snow as a consequence of climate change. For most mammals, however, climate broadly defines their ecological niche. Therefore for many species, future distributions are estimated by correlating climatic factors with their current ranges and projecting these models into the future (e. g. 13). Here we examine 3 species that illustrate some of the myriad of ways that climate is likely to affect mammals.

Research

The Indiana bat (encounters with diseases)
The Indiana bat (Myotis sodalis) presents an example of how changing climates and introduction of exotic organisms can together threaten the persistence of native mammal species. The Indiana bat, (listed as federally endangered in 1967), ranges throughout the northeastern, midwestern, and parts of the southeastern U.S. During winter, Indiana bats hibernate in caves and mines within a narrow thermal range (3.0-7.2°C; 14). The most important hibernation sites occur primarily in the Midwest and Southeast (15). Currently, most of these important sites are exterior to the area affected by white nose syndrome (WNS), a lethal disease caused by an imported European fungus (16). Climate change predictions suggest the summer range of Indiana Bats may move north and east (17). This would move them closer to the areas most affected by WNS; the disease has resulted in the death of approximately 72% of the Indiana bats that hibernate in the Northeast since 2006-2007 (18).

The snowshoe hare (snow dependency)
The snowshoe hare (Lepus americanus) is a small lagomorph well- adapted to seasonally snowy environments. Its range includes most of Alaska and Canada, with montane extensions as far south as California and New Mexico in the western U.S. and West Virginia in the eastern U.S. It has oversized rear paws leading to low foot loadings (19, Figure 4.3), and seasonally changes its pelage from mostly brown to white. Snowshoe hares are typically killed by predators (as opposed to dying of starvation, old age, etc.; 20). Thus, predator avoidance is a critical aspect of snowshoe-hare behavior (21). Hares may be particularly vulnerable when their coloration does not match the background-a white hare on a brown background is more visible to predators (22). The period when the landscape is predictably snow covered is extremely sensitive to climate (23, 24). With climate change, spring snowmelt is predicted to occur earlier (23, 22) and snow cover lost sooner (25) in areas inhabited by the snowshoe hare. Hare pelage change has limited plasticity in the rate of the spring white-to-brown molt, but both initiation dates of color change and the rate of the fall brown-to-white molt are fixed; unless the timing of coat color change can be modified by natural selection, the reduced snowpack will increase periods of mismatch by 3 - 8 times (22).

The American pika (sensitivity to temperature and water-balance stresses, perhaps mediated by vegetation)
The pika (Ochotona princeps) is a small lagomorph that often inhabits alpine areas in the western U. S. In the Great Basin, pika habitat occurs as small islands near the tops of mountains. Pikas appear dependent both on moist and cool summer conditions and winter snow (26). Historically and during the 20th century, pikas have reacted to climate changes by moving upslope or becoming locally extirpated when the weather becomes hot and dry (26). In the Great Basin, sites of pika extirpation (1994-2008; 27) were generally hotter in the summer and more frequently very cold in the winter than sites where pika persisted - warming led to the removal of insulating snow causing nighttime winter temperatures to plummet (27). Winter snowpack not only insulates pikas during cold snaps, but also may provide water longer into the summer season, when plant senescence at drier sites occurs earlier in the year, which eliminates water availability for pika. Analyses suggest that both chronic stresses (average temperature during all of summer, snowpack and growing-season precipitation), acute (hot and cold) temperature stresses, and vegetation productivity may all be playing a role in pika declines in the Basin over the last decades.

Options for Management

Managing lands or species in the face of climate change requires an acknowledgement of both the range of different effects and the high levels of uncertainty involved in local projections. Additionally, projections are for climate, not weather. As such, they produce long-term averages. Organisms, including mammals, generally respond to weather events that deviate from the average such as droughts, extreme or unusual cold or heat, and storms. Thus, the weather that organisms actually respond to will be inferred from relatively broad-scale climate projections. Additional uncertainties exist in predicting mammalian responses to changing climate. Unforeseen opportunities and stressors can be expected-white nose syndrome, for example, was discovered in 2006 (16). However, these uncertainties do not preclude active management to conserve mammals, they simply change the nature of that management. Many approaches are generically beneficial for native species, and are particularly beneficial given climate change. These include:

  1. Maintain and if possible improve landscape connectivity.
  2. Reduce stresses on current populations and habitats.
  3. Maintain or improve current habitat for specific species.
  4. Manage to maintain landscape diversity.
  5. Monitor change.

A connected landscape allows mammals to seek appropriate habitats and prevents the negative consequences of small isolated populations, such as increased extinction risks and lower fitness. Negative effects of climate change can be ameliorated by reducing other human-caused stressors (e.g. invasive species, development, overharvest). With higher fitness across habitats, organisms may be able to persist in what was formerly "sink" habitat*, both increasing overall population size and range and increasing adaptive potential. Similarly, habitat improvement will help maintain a large, healthy population, which may improve its likelihood of persistence. Diverse landscapes increase overall resilience and provide opportunities for adaptation. Lastly, because climate change will lead to many unexpected ecological effects, systems must be in place to rapidly identify and monitor these effects and facilitate appropriate management responses.

* Sink habitat =habitat that is currently occupied, but where populations cannot persist without external subsidies from organisms that emigrate from better quality areas.

References

  1. Ripple, W. J.; Painter, L. E.; Beschta, R. L.; Gates, C.C. 2010. Wolves, elk, bison, and secondary trophic cascades in Yellowstone National Park [pdf]. The Open Ecology Journal. 3:31-37.
  2. Fortin, D.; Beyer, H. L.; Boyce, M. S.; Smith, D. W.; Duchesne, T.; Mao, J.S. 2005. Wolves influence elk movements: behavior shapes a trophic cascade in Yellowstone National Park. Ecology. 86:1320-1330.
  3. Beyer, H. L.; Merrill, E. H.; Varley, N.; Boyce, M.S. 2007. Willow on Yellowstone's Northern Range: Evidence for a Trophic Cascade? Ecological Applications. 17: 1563-1571
  4. Maron, J.L.; Pearson, D.E.; Potter, T.; Ortega, Y.K. 2012. Seed size and provenance mediate the joint effects of disturbance and seed predation on community assembly. Journal of Ecology. 100:1492-1500.
  5. Trani, M.K.; Ford, W.M.; Chapman, B.R., eds. 2007. The Land Manager's Guide to Mammals of the South. Durham, NC: The Nature Conservancy; Atlanta, GA: U.S. Forest Service. 546 p.
  6. Burns, C.E.; Johnson, K.M.; Schmitz, O.J. 2003. Global climate change and mammalian species diversity in U.S. national parks. Proceedings of the National Academy of Sciences. 100:11474-11477.
  7. Gubler, D.J.; Reiter, P.; Ebi, K.L.; Yap, W.; Nasci, R.; Patz, J.A. 2001. Climate variability and changes in the United States: Potential impacts on vector- and rodent-borne diseases. Environmental Health Perspectives. 109:223-233.
  8. Mills, J.N.; Ksiazek, T.G.; Peters, C.J.; Childs, J.E. 1999. Long-term studies of hantavirus reservoir populations in the southwestern United States: A synthesis. Emerging Infectious Diseases. 5:135-142.
  9. Kuenzi, A.J.; Morrison, M.L.; Madhav, N.K.; Mills, J.N. 2007. Brush mouse (Peromyscus boylii) population dynamics and hantavirus infection during a warm, drought period in southern Arizona. Journal of Wildlife Diseases. 43:675-683.
  10. Magoun, A.J.; Copeland, J.P. 1998. Characteristics of wolverine reproductive den sites. Journal of Wildlife Management. 62:1313-1320.
  11. Copeland, J.P.; McKelvey, K.S.; Aubry, K.B.; Landa, A.; Persson, J.; Inman, R.M.; Krebs, J.; Lofroth, E.; Golden,H.; Squires, J.R.; Magoun, A.; Schwartz, M.K.; Wilmot, J.; Copeland, C.L.; Yates, R.E.; Kojola, I.; May, R. 2010. The bioclimatic envelope of the wolverine: Do climatic constraints limit their geographic distribution? Canadian Journal of Zoology. 88:233-246.
  12. McKelvey, K.S.; Copeland, J.P.; Schwartz, M.K.; Littell, J.S.; Aubry, K.B.; Squires, J.R.; Parks, S.A.; Elsner, M.M.; Mauger, G.S. 2011. Climate change predicted to shift wolverine distributions, connectivity, and dispersal corridors. Ecological Applications. 21: 2882-2897.
  13. Levinsky, I.; Skov, F.; Svenning, J.-C.; Rahbek, C. 2007. Potential impacts of climate change on the distributions and diversity patterns of European mammals. Biodiversity Conservation. 16:3803-3816.
  14. Tuttle, M.D.; Kennedy, J. 2002. Thermal requirements during hibernation. In: Kurta, A.; Kennedy, J., eds. The Indiana Bats: Biology and management of an Endangered Species. Austin, TX: Bat Conservation international. 68-78.
  15. U.S. Fish and Wildlife Service (USFWS). 2007. Indiana Bat (Myotis sodalis) Draft Recovery Plan: First Revision. Fort Snelling, MN: U.S. Fish and Wildlife Service. 45 pp. (available at http://www.fws.gov/midwest/Endangered/mammals/inba/inba_drftrecpln16ap07.html).
  16. Warnecke, L.; Turner J. M.; Bollinger, T. K.; Lorch, J. M.; Misra, V.; Cryan, P. M.; Wibbelt, G.; Blehert, D. S.; Willis, C. K. R. 2012. Inoculation of bats with European Geomyces destructans supports the novel pathogen hypothesis for the origin of white-nose syndrome. Proceedings of National Academy of Science.
  17. Loeb, S.C., Winters, E. In press. Summer maternity range of Indiana Bats. In: Perry, R.W.; Franzreb, K.E.; Loeb, S.C.; Saenz, D.; Rudolph, D.C. Climate Change and Wildlife in the Southern United States: Potential Effects and Management Options. Asheville, NC: USDA Forest Service, Southern Research Station.
  18. Turner, G.G.; Reeder, D.M.; Coleman, J.T.H. 2011. A five-year assessment of mortality and geographic spread of White-nose Syndrome in North American bats and a look to the future. Bat Research News. 52:13-27.
  19. Buskirk, S.W.; Ruggiero, L. F.; Krebs, C.J. 2000. Habitat fragmentation and interspecific competition: implications for lynx conservation. In: Ruggiero, L. F.; Aubry, K. B.; Buskirk, S. W.; Koehler, G. M.; Krebs, C.J.; McKelvey, K. S.; Squires, J.R., eds. Ecology and conservation of lynx in the United States. Boulder, CO: University Press of Colorado. 83-100.
  20. Hodges, K. E. 2000. Ecology of snowshoe hares in southern boreal and montane forests. In: Ruggiero, L. F.; Aubry, K. B.; Buskirk, S. W.; Koehler, G. M.; Krebs, C.J.; McKelvey, K. S.; Squires, J.R., eds. Ecology and conservation of lynx in the United States. Boulder, CO: University Press of Colorado. 163-206
  21. Griffin, P.C.; Griffin, S.C.; Waroquiers, C.; Mills, S.L. 2005. Mortality by moonlight: predation risk and the snowshoe hare. Behavioral Ecology. 16:938-944.
  22. Mills, L.S.; Zimova, M.; Oyler, J.; Running, S.; Abatzoglou, J.; Lukacs, P. 2013. Camouflage mismatch in seasonal coat color due to decreased snow duration. Proceedings of the National Academy of Science. Early Edition.
  23. Stewart, I.T.; Cayan, D.R.; Dettinger, M.D. 2004. Changes in snowmelt runoff timing in western North America under a “business as usual” climate change scenario. Climatic Change. 62: 217-232.
  24. Mote P.W.; Hamlet, A.F.; Clark, M.P.; Lettenmaier, D.P. 2005. Declining mountain snowpack in western North America. Bulletin of the American Meteorological Society. 86:39-49.
  25. Salathe, E.P. Jr.; Steed, R.; Mass, C. F.; Zahn, P.H. 2008. A high-resolution climate model for the U.S. Pacific Northwest: mesoscale feedbacks and local responses to climate change. Journal of Climate. 21:5708-5726.
  26. Beever, E.A.; Ray, C.; Wilkening, J. L.; Brussard, P.F.; Mote, P.W. 2011. Contemporary climate change alters the pace and drivers of extinction. Global Change Biology. 17, 2054-2070.
  27. Beever, E.A.; Ray, C.; Mote, P.W.; Wilkening, J.L. 2010. Testing alternative models of climate-mediated extirpations. Ecological Applications. 20:164-178.

How to cite

McKelvey, K.S.; Perry, R.W.; Mills, L.S. 2013. The Effects of Climate Change on Mammals. U.S. Department of Agriculture, Forest Service, Climate Change Resource Center. www.fs.usda.gov/ccrc/topics/wildlife/mammals

Reading
Research

Research

In addition to the examples presented in the synthesis, the following are research projects taking place in the Forest Service.

Canada Lynx
RMRS scientists are currently developing landscape-level habitat relationships for Canada lynx. These relationships include direct links to environmental variables such as temperature and snow cover, as well as indirect links such as forest type. These models can be linked to future projections of forested landscapes, snow cover, and temperature. To predict the specific effects of climate change on lynx RMRS scientists are cooperating with other scientists in the development habitat projections.
Contact: John Squires

Climate Change and Wildlife Habitat
An analysis of potential national effects of climate change on wildlife habitat is being addressed by RMRS scientists through the estimation of an index of climate change stress to terrestrial biodiversity in order to identify regional hotspots of climate change impacts. This research focuses on management strategies for climate change in the states' Wildlife Action Plans.
Contact: Linda Joyce, Curt Flather

Pacific Northwest Wildlife Habitat
RMRS scientists are collaborating with scientists from the Pacific Northwest Station and the University of Washington to develop methods to generate forested landscapes given climate change. These landscapes will be linked to multi-scale wildlife habitat models currently under development at RMRS.
Contact: Sam Cushman

Wolverines and Climate Constraints
RMRS scientists have shown that historical wolverine distribution was highly correlated with persistent snow. Genetic analysis reinforced these understandings and showed that the occurrence patterns had been present for at least 2,000 years. Wolverine's snow association is likely due to the location of reproductive dens in snow. We are currently collaborating with Scandinavian scientists to ascertain whether European wolverines are also snow-dependent when denning. Additionally we are working with the University of Montana and and the USGS to project snow patterns into the future and determine the likely effects of snow cover changes on wolverines.
Contact: Kevin McKelvey

Reptiles and Climate Change

L. Jones

Topics Horizontal Tabs

Synthesis

Synthesis

Preparers

Deanna H. Olson, Pacific Northwest Research Station; Daniel Saenz, Southern Research Station

An archived version of this topic paper is available.

Issues

Many reptiles are highly sensitive to the altered temperatures that may result from climate change due to their ectothermy which requires that they rely on ambient environmental temperatures to maintain critical physiological processes.  Due to the variety of snakes, lizards, crocodilians, and turtles in our world (traditionally classified as reptiles), and because climate change data and projections vary with location, it will be important to consider each species and location separately when considering the potential effects of altered climate on these animals. 

In temperate zones, lizards are thought to be highly vulnerable to climate change (1-7). Their reproduction is closely tied to narrow windows of time in the spring and summer when suitable temperature and moisture regimes are available for critical natural history activities, such as foraging and mating. Altered weather conditions during these seasons may result in frequently recurring "bust" years of reproductive failure. Other climate effects on lizard survival include mortality associated with warm spells in winter (8), interacting effects of altered vegetation communities, fire regimes and invasive species (9), and potentially disease (10).
Snakes are very closely related to lizards, and these effects may hold true for them as well.  Just as with lizards, new studies illustrate species differences:  climatic niche models suggest that some rattlesnakes may have smaller ranges (11); while ratsnakes have increased activities due to warmer night temperatures (12).

Climate change concerns for turtles and crocodilians are three-fold. First, these mostly aquatic species may encounter altered habitats and increased habitat fragmentation with altered climate. In this regard they share many concerns with amphibians, such as sensitivity to changes in water availability and its’ thermal properties. Second, turtles and alligators have temperature-sensitive sex determination: cooler temperatures may produce nests of only males; warmer temperatures may produce nests of only females. Temperature changes in a local area may have the effect of altering the sex ratios of populations - potentially affecting future reproduction and over time compromising their evolutionary fitness (13). Third, coastal species such as the American Alligator and Crocodile are susceptible to an increasing frequency or intensity of storms caused by increases in ocean temperatures. Storm surges can displace or drown animals, and dehydrate them by salt water intrusion into freshwater habitats (14). Because the United States is a biodiversity hotspot for turtles, and turtle conservation issues are multi-faceted, concern for climate change projections relative to rare turtle species is a specific concern (15).

  • Mississippi stream channel completely dried out during a drought

    The Mississippi stream channel pictured here dried out completely during a drought. Such changes in stream flow quantity and timing are expected to occur more often as climate changes. Credit: Susan Adams.

  • flowchart showing Climate change affects temperature and precipitation patterns

    Climate change affects temperature and precipitation patterns, which regulate many ecological processes in aquatic ecosystems. Solid arrows indicate direct responses. Credit: Center for Climate and Energy Solutions.

  • Jackson Prairie Crayfish

    Changing water temperatures and rainfall patterns may pose challenges for certain species. The Jackson Prairie Crayfish (Procambarus barbiger) is native to a limited area in the southern U.S., making it particularly vulnerable. Credit: Chris Lukhaup.

  • riparian buffers

    Maintaining or re-creating high quality habitat for native species, for example riparian buffers, woody debris, and stable banks, could help some warmwater species withstand the effects of climate change. Credit: Chris Lukhaup.

Likely Changes

The highest biodiversity of reptiles in the United States is in the southern states, in desert and subtropical ecosystems. The northern distributions are constrained by latitude, with species richness dropping considerably as you go north. North boundaries of species ranges are often marginal habitats due to climate factors such as cool temperatures and weather variation.  Altered thermal niches (4, 5) for reptiles in these zones due to climate change will be important to track. Briefly, to understand thermal niches, consider that there is a time-window during the day when there are suitable temperatures for reptile activities. It appears that this time-window is becoming smaller as climate changes are apparent in both tropical and temperate zone regions, reducing the activity times of reptiles, affecting their reproduction and survival. Although habitat may be marching northward or into mountains for some species, for other species, increased weather variation may alter the frequency or intensity of boom-bust reproductive cycles and cohort survival. Examples follow.

In Oregon, variable spring weather has been shown to narrow the time window of suitable breeding conditions for the Common Side-blotched Lizard, Uta stansburiana, with reproductive bust years being reported (6, 7). In Mexico, a study reported that 12% of local lizard populations have been lost since 1975, with evidence that these losses are associated with climate change altering thermal niches (4). In Alberta, Canada, the Greater Short-horned Lizard, Phrynosoma hernandesi, overwinter survival relies on persistent snow cover to retain animals in insulated hibernation: lizards become active during warm spells in winter, and then they can be ‘caught out’ and die when it snows again (8). In contrast, ratsnake thermal niches may be expanding with more warmer nights (12).

Vulnerability assessments and predictions of how habitat distributions will change abound for many taxa. Looming questions are where will suitable habitats occur in the future, and will organisms be able to get there?  In our human-altered world, roads and urban-rural development are new hurdles to dispersing reptiles, added to a variety of natural geographic barriers. In Spain, the northward expansion of lizard ranges coincident with changing climate has been tracked over about a 50 year period, with geographic barriers including the Pyrenees Mountains now posing dispersal limitations (3).

Options for Management

For reptiles, management is of paramount concern to maintain and restore existing habitats, augment acreages of intact habitat blocks, and adapt management actions to reduce environmental stressors (see regional Habitat Management Guidelines at: www.parcplace.org). Because microclimates can be readily manipulated with local land management activities, people can actively engineer a future for some of these organisms, especially when their environments are already highly altered due to human activities.

Invasive plant species and most human disturbances can alter local- to landscape-scale habitats and microclimates, which can have consequent effects on reptiles. Non-native vegetation may have different physical structure and cover, hindering reptile daily activities, and subsequently altering critical life history functions and reptile survival, and negatively influencing dynamics of interacting communities. Open habitat management may be needed to forestall encroaching vegetation, especially non-native plants, or to mitigate human disturbance (e.g., agricultural or energy development). Meadow shrub and tree control may be needed to retain sun-exposure. Riparian buffers may retain near-water refugia.  For turtles or other water-dependent reptiles, manipulation of hydroperiod at sites by site excavation and riparian buffer management are considerations.  Substrate management may be needed for several types of reptiles: rock outcrops and talus are complex refugia for lizards and snakes and may need protection or augmentation; rocky pond edges provide basking sites and antipredation refugia for turtles. Some species need specific substrate types, or rely on existing burrows created by other animals; these need consideration if climate change alters landscape-scale habitat distribution. Traditionally used snake hibernacula may need special protection. Management measures taken to maintain natural fire regimes and control invasive plants might also benefit reptiles. Altered fire regimes may change refugia, reduce cover and expose animals to heightened predation, and invasive plants may exacerbate climate-linked fire patterns.

Managers can facilitate the movement of reptiles by providing corridors between needed habitats that support complex reptile life histories:  breeding, foraging, overwintering, anti-predation, and basking habitats can all differ. Corridors between overwintering hibernacula and foraging areas, or between upland nesting sites and aquatic breeding sites are a particular concern because these can be inadvertently affected by roads or development. Considerations include: 1) extension of riparian corridors along safe upland dispersal routes; 2) creating barriers to dispersal along unsafe routes, such as along roads or into disturbed areas; 3) road-crossing culverts that may require dry as well as wetted channel areas; 4) management of surface rock or burrow availability and connectivity. 

If stop-gap measures are needed for rare species faced with extinction, the more costly methods of Reintroduction, Relocation, Translocation, and Headstarting (RRTH) may be considered. In the United States, numerous RRTH projects are underway for reptiles (16), such as the captive propagation and reintroduction of Eastern Indigo Snakes (http://www.oriannesociety.org/). Broad-scale policies directed at vulnerable site protections warrant consideration.

References

  1. Araujo, M.B.; Thuiller, W.; Pearson, R.G. 2006. Climate warming and the decline of amphibians and reptiles in Europe. Journal of Biogeography. 33:1712-1728.
  2. Wake, D.B. 2007. Climate change implicated in amphibian and lizard declines. PNAS 104:8201-8202.
  3. Moreno-Rueda, G.; Pleguezuelos, J.M.; Pizarro, M.; Montori, A. 2011. Northward shifts of the distribution of Spanish reptiles in association with climate change. Conservation Biology. 26:278-283.
  4. Sinervo, B. et al. 2010. Erosion of lizard diversity by climate change and altered thermal niches. Science. 328:894-899.
  5. Huey, R.; Losos, J.; Moritz, C. 2010. Are lizards toast? Science. 328:832-833.
  6. Zani, P.A. 2005. Life-history strategies near the limits of persistence: winter survivorship and spring reproduction in the common side-blotched lizard (Uta stansburiana) in eastern Oregon. Journal of Herpetology. 39:166-169.
  7. Zani, P.A.; Rollyson, M. 2011. The effects of climate modes on growing-season length and timing of reproduction in the Pacific Northwest as revealed by biophysical modeling of lizards. The American Midland Naturalist. 165: 372-388.
  8. Alberta Conservation Association. 2010. Reptiles of Alberta. 12 p. Available at http://www.ab-conservation.com/go/default/assets/File/Publications/Brochures/ACA_Reptiles_of_Alberta_WR_2010_v2.pdf, accessed 22 November 2011.
  9. Newbold, T.A.S. 2005. Desert horned lizard (Phrynosoma platyrhinos) locomotor performance: the influence of cheatgrass (Bromus tectorum). Southwestern Naturalist. 50:17-23.
  10. Scholnick, D.A.; Manivanh, R.V.; Savenkova, O.D.; Bates, T.G.; McAlexander, S.L. 2010. Impact of malarial infection on metabolism and thermoregulation in the Fence Lizards Sceloporus occidentalis from Oregon. Journal of Herpetology. 44:634-640.
  11. Lawing, A.M.; Polly, P.D. 2011. Pleistocene climate, phylogeny, and climate envelope models: An integrative approach to better understand species' response to climate change. PLoS ONE. 6(12): e28554.
  12. Weatherhead, P.J.; Sperry, J.H.; Carfagno, G.L.F.; Blouin-Demers, G. 2012. Latitudinal variation in thermal ecology of North American ratsnakes and its implications for the effect of climate warming on snakes. Journal of Thermal Biology. 37:273-281.
  13. Gibbons, J.W.; Scott, D.E.; Ryan, J.; Buhlmann, K.A.; Tuberville, T.D.; Metts B.S.; Greene, J.L.; Mills, T.; Leiden, Y.; Poppy, S; Winne, C.T. 2000. The global declines of reptiles, Deja vu amphibians. BioScience 50:653-666.
  14. Schriever, T.A.; Ramspott, J.; Crother, B.I.; Fontenot, C.L. 2009. Effects of hurricanes Ivan, Katrina, and Rita on a southeastern Louisiana herpetofauna. Wetlands. 29:112-122.
  15. Kiester, A.R.; Olson, D.H. 2011. Prime time for turtle conservation. Herpetological Review. 42:198-204.
  16. Olson, D.H. 2011. Compilation of Relocation, Reintroduction, Translocation, and Headstarting (RRTH) projects for herpetofauna. Available at: http://parcplace.org/news-a-events/242-rrth.html

How to cite

Olson, D.H.; Saenz, D. 2013. Climate Change and Reptiles. (March, 2013).
U.S. Department of Agriculture, Forest Service, Climate Change Resource Center. www.fs.usda.gov/ccrc/topics/wildlife/reptiles/

Reading
Research

Research

Ongoing research on reptiles by US Forest Service scientists includes the following topics that relate to reptiles and climate change:

Climate Change and Reptile Habitat in the northwestern U.S.
Understanding reptile distributions and how they might be affected by climate change help guide the management of these species. Research activities include:

  • Modeling landscape-scale factors including climate metrics associated with northwestern reptile distributions.
  • Examining potential habitat ‘hot spots’ for reptiles in coastal Oregon mesic forests.

Contact: Dede Olson

Conservation of the Louisiana Pine Snake
One of North America’s rarest reptiles, the Louisiana pine snake, may require extra assistance to persist under climate change. Scientists with the Southern Research station are developing an RRTH (relocation, reintroduction, translocation, headstarting) project for these reptiles.
Contact: Dan Saenz

Effects of climate change and other factors on a lizard community in an ecotone in southeastern Arizona.  
Lizards are expected to be an early warning system of impending change in vegetation communities, and a useful tool in predicting adaptive management needs. This study is conducted in the area with the highest diversity of lizards in the USA, situated at an ecotone between two deserts and a mountain range. Changes in the lizard community are expected sooner in this ecotone than in distinct habitat types, and are also expected to precede observed changes in vegetation.
Contact: Lawrence L.  C. Jones

Section

Overview

Overview

There are a number of ways that climate change is beginning to impact wildlife. Temperature increases and changes in precipitation can directly affect species depending on their physiology and tolerance of environmental changes. Climate change can also alter a species' food supply or its reproductive timing, indirectly affecting its fitness. Understanding these interactions is an important step in developing management strategies to help species survive the changing climate.

Read through the accompanying pages to learn more about different wildlife responses to climate change.

Related pages: Biodiversity, Aquatic Ecosystems

Overview

There are a number of ways that climate change is beginning to impact wildlife. Temperature increases and changes in precipitation can directly affect species depending on their physiology and tolerance of environmental changes. Climate change can also alter a species' food supply or its reproductive timing, indirectly affecting its fitness. Understanding these interactions is an important step in developing management strategies to help species survive the changing climate.

Read through the accompanying pages to learn more about different wildlife responses to climate change.

Related pages: Biodiversity, Aquatic Ecosystems

Amphibians

Amphibians and Climate Change

D. Olson

Topics Horizontal Tabs

Synthesis

Synthesis

Preparers

Deanna H. Olson, Pacific Northwest Research Station; Daniel Saenz, Southern Research Station

An archived version of this topic paper is available.

Issues

Several factors contribute to the vulnerability of amphibians to the projected effects of climate change. First consider that for over 20 years, amphibians have been globally recognized as declining (1). Today, they are among the leading taxonomic groups threatened with losses: about 1/3 of amphibian species are already at risk of extinction (2, 3). Leading threat factors include habitat loss, disease, invasive species, overexploitation, and chemical pollution. Next, consider their basic biology. Amphibians have been heralded as Canaries in the Coal Mine, being sentinels of a host of environmental changes due to their biphasic life style with life stages relying on both aquatic and terrestrial systems, their moist permeable skin which is a sensitive respiratory organ, and their central position in food webs. The scenario becomes even more complex when multiple threats affect single populations and the synergistic effects of threats together may become more potent than the simple sum of those parts. Now, adding the effects of climate change to this cocktail of multiple threats and climate-sensitive life history modes is worrisome indeed.

Numerous researchers have considered the adverse effects of climate change on amphibians and found differing results (4-13) suggesting that risks vary among taxa. Dispersal-limited or rare species may have restricted movements and may not be able to shift their distribution to accommodate changes in the locations of suitable habitat. In contrast, species with continental distributions may have innate resiliency to a broad swath of conditions, and have better adaptive capacity to survive as a whole. Amphibian species with narrow tolerances for temperature and moisture regimes may be at heightened risk. Amphibians that rely on certain habitat types may be at most risk, for example those found in ephemeral ponds and streams which may dry before the annual reproductive cycle is complete. Regions projected to have increasing fluctuations in climate conditions may experience reproductive "bust" years, or episodic mass mortality (14).

  • Salamander

    The salamander Rhyacotriton variegatus occurs in small headwater streams in the Pacific Northwest, where water flows may be at risk of changing in some areas. Credit: William P. Leonard.

  • Windmill and solar-powered pump

    Maintaining pond water levels for species at risk is one example of a climate adaptation strategy. Here, a windmill and solar-powered pump is used. Credit: Bruce Christman.

  • Cascades Frog

    The Cascades Frog, Rana cascadae, breeds in ephemeral ponds in the Cascade Range of the Pacific Northwest; these habitats are vulnerable to drying out early in warm, dry years. Credit: William P. Leonard.

  • Northern Cricket frog

    The Northern Cricket frog, Acris crepitans can be found throughout the eastern U.S. Severe declines have been reported for the species, though no single cause for the decline has been identified. Credit: Dan Saenz.

  • Coastal-plain Toads

    Coastal-plain Toads, Incilius nebulifer, are found on coastal plain from western Mississippi to northern Mexico. This species breeds in ephemeral ponds and appears to be associated with disturbed and urban habitats. Credit: Dan Saenz.

Likely Changes

Knowing that climate change predictions vary considerably with geographic locations, that there is uncertainty tied to all climate change models, and amphibians are an extremely diverse taxon -a single or simple answer of how amphibians are likely to respond to climate change is not possible. Several types of likely changes may prove to be lethal to amphibians: altered hydroperiods; altered seasons and phenology (cyclical timing of events); increased incidence of severe storms and storm surge; rise in sea level; fluctuating weather conditions; and warmer, drier conditions (e.g., 14-24).

Hydroperiod refers to the timing of water availability. Water retention in streams and ponds is particularly important for amphibians breeding in temporary, ephemeral, or vernal ponds and intermittent or discontinuously flowing streams. Many taxa are already experiencing occasional early drying of their habitats, with mass mortality of eggs, tadpoles, and metamorphosing animals resulting (25). Some of these habitats are also important foraging habitats or dispersal ‘stepping stones’, so altered hydroperiods can have negative effects outside of reproductive losses. Another side effect of changed hydroperiod could be increased exposure to predators. For example, if shorelines recede then amphibian refugia may be lost and fish, bird or mammal predators may gain access to newly exposed amphibian prey.

Phenology refers to the timing of life cycle events such as breeding and overwintering. Each plant and animal species has its own phenological patterns associated with local climatic conditions. Climate change may result in shifts in phenology, especially for species that breed early or late in the season. A shift to earlier breeding may leave amphibians exposed to fluctuating weather conditions. For example, a warm spell in late winter followed by a cold storm after breeding can freeze animals. A deep freeze may penetrate below the ground surface to affect animals emerging in spring, or overwintering hibernacula in winter. Also, survival of annual recruits may be tied to their size at metamorphosis, which may depend upon when breeding occurs. Furthermore, if the synchrony of communities (the timing of breeding or other activities) becomes offset, there may be altered interactions with predator and prey species or increased exposure to disease and invasive species. Lastly, generally warmer, drier conditions can cause moist microhabitats to become too dry and unsuitable for native amphibians. This may especially affect leaf litter or other refugia on the ground surface.

Options for Management

A recent paper on "Engineering a future for amphibians with climate change" (14, 26, 27) discusses a variety of adaptation management approaches. These approaches are discussed briefly below, and focus on tools that we may use to safeguard habitat conditions for vulnerable amphibian populations.

Manipulation of hydroperiod or moisture regimes at sites is a dominant tool in the land manager’s repertoire to mitigate the effects of climate change on any wildlife group. This can be implemented by a variety of methods, including: irrigation, site excavation, vegetation management, riparian buffer creation, down wood recruitment, and litter supplementation. Novel engineered approaches include installation of solar-powered water pumps to retain water levels of ponds, and installation of sprinkler systems to retain surface moisture. Consideration of climate during landscape management planning may result in incorporation of hill-shaded refugia in protected habitat areas (29) and designation of linkage areas for connectivity among habitats (30, 31). Using logs as dispersal conduits, and forest thinning to ameliorate dry conditions are being trialed in case studies. A new "hot topic" of research is investigating the effects of alternative forest management practices on microclimate, and specifically tying these effects to certain metrics of biodiversity such as moisture sensitive amphibians (32). Policies directed at vulnerable site protection, such as riparian reserves (14), are likely the most pro-active management option that has multiple-site implications.

If stop-gap measures are needed for rare species faced with extinction, the more costly methods of Reintroduction, Relocation, Translocation, and Headstarting (RRTH) may be considered. In the United States, numerous RRTH projects are underway for amphibians and reptiles (28). Captive breeding and RRTH programs are also managed by Zoos and Aquariums, with the international program Amphibian Ark being the most notable.

References

  1. Blaustein, A.R.;Wake, D.B. 1990. Declining amphibian populations: A global phenomenon? Trends in Ecology and Evolution. 5:203-204.
  2. Stuart, S.N.; Chanson, J.S.; Cox, N.A.; Young, B.E.; Rodrigues, A.S.L.; Fischman, D.L.; Waller, R.W. 2004. Status and trends of amphibian declines and extinctions worldwide. Science. 306:1783-1786.
  3. Hoffmann, M.; Hilton-Taylor, C. et al. 2010. The impact of conservation on the status of the world's vertebrates. Science. 330:1503-1509.
  4. Corn, P.S. 2005. Climate change and amphibians. Animal Biodiversity and Conservation. 28:59–67.
  5. Carey, C.; Alexander, M.A. 2003. Climate change and amphibian declines: is there a link? Diversity and Distributions. 9:111-121.
  6. Araujo, M.B.; Thuiller, W.; Pearson, R.G. 2006. Climate warming and the decline of amphibians and reptiles in Europe. Journal of Biogeography. 33:1712-1728.
  7. Reading, C. J. 1998. The effect of winter temperatures on the timing of breeding activity in the common toad Bufo bufo. Oecologia. 117:469-475.
  8. Wake, D.B. 2007. Climate change implicated in amphibian and lizard declines. PNAS. 104:8201-8202.
  9. Laurance, W.F. 2008. Global warming and amphibian extinctions in eastern Australia. Australia Ecology. 33: 1-9.
  10. Blaustein, A.R.; Walls, S.C.; Bancroft, B.A.; Lawler, J.J.; Searle, C.L. ; Gervasi, S. S. 2010. Direct and indirect effects of climate change on amphibian populations. Diversity. 2:281-313.
  11. Lawler, J.J.; Shafer, S.L.; Bancroft, B.A.; Blaustein, A.R. 2009. Projected climate impacts for the amphibians of the Western Hemisphere. Conservation Biology. 24:38-50.
  12. Milanovich, J.R.; Peterman, W.E.; Nibbelink, N.P.; Maerz, J.C. 2010. Predicted loss of salamander diversity hotspot as a consequence of projected global climate change. PLoS ONE. 5(8):1-10.
  13. McCallum, M.L. 2010. Future climate change spells catastrophe for Blanchard's cricket frog, Acris blanchardii (Amphibia: Anura: Hylidae) [pdf]. Acta Herpetologica. 5:119-130.
  14. Shoo, L. P.; Olson, D.H. et al. 2011. Engineering a future for amphibians under climate change. Journal of Applied Ecology. 48: 487-492.
  15. Beebee, T.J.C. 1995. Amphibian Breeding and Climate. Nature. 374:219-220.
  16. Blaustein, A.R., L.K. Belden, D.H. Olson, D.M. Green, T.L. Root, and J.M. Kiesecker. 2001. Amphibian breeding and climate change. Conservation Biology. 15:1804-1809.
  17. Daszak, P.; Scott, D.E.; Kilpatrick, A.M.; Faggioni, C.; Gibbons, J.W.; Porter, D. 2005. Amphibian population declines at Savannah River site are linked to climate, not chytridiomycosis. Ecology. 86:3232-3237.
  18. Saenz, D.; Fitzgerald, L.A.; Baum, K.A.; Conner, R.N. 2006. Abiotic correlates of anuran calling phenology: the importance of rain, temperature, and season. Herpetological Monographs. 20(1): 64-82.
  19. Trauth, J.B.; Trauth, S.E.; Johnson, R.L. 2006. Best management practices and drought combine to silence the Illinois chorus frog in Arkansas. Wildlife Society Bulletin. 34:514-518.
  20. Schriever, T.A.; Ramspott, J.; Crother, B.I.; Fontenot, C.L. 2009. Effects of hurricanes Ivan, Katrina, and Rita on a southeastern Louisiana herpetofauna. Wetlands. 29:112-122.
  21. Gunzburger, M.S.; Hughes, W.B.; Barichivich, W.J.; Staiger, J.S. 2010. Hurricane storm surge and amphibian communities in coastal wetlands of northwestern Florida. Wetlands Ecology and Management. 18:651-663.
  22. Donnelly M.A.; Crump, M. L. 1998. Potential effects of climate change on two
    Neotropical amphibian assemblages. Climatic Change. 39:541-561.
  23. Pounds, J. A.; Crump, M.L. 1994. Amphibian declines and climate disturbance: The case of the golden toad and the harlequin frog. Conservation Biology. 8:72-85.
  24. Pounds, J. A.; Fogden, M.P.L.; Campbell, J.H. 1999. Biological response to climate change on a tropical mountain. Nature. 398:611-615.
  25. Blaustein, A.R.; Olson, D.H. 1991. Amphibian population declines. Science 253:1467.
  26. Olson, D.H. 2011. Brochure on climate change and amphibians and reptiles. Available at: http://parcplace.org/images/stories/ClimateChangeFlyer.pdf
  27. Olson, D.H. 2011. Showcase of herpetofaunal climate change adaptation management tools. Available at: http://parcplace.org/images/stories/ClimateChangeShowcase.pdf
  28. Olson, D.H. 2011. Compilation of Relocation, Reintroduction, Translocation, and Headstarting (RRTH) projects for herpetofauna. Available at: http://parcplace.org/news-a-events/242-rrth.html
  29. Suzuki, N.; Olson, D.H.; Reilly, E.C. 2008. Developing landscape habitat models for rare amphibians with small geographic ranges: a case study of Siskiyou Mountains salamander in the western USA. Biodiversity and Conservation. 17:2197-2218.
  30. Olson, D.H.; Burnett, K.M. 2009. Design and management of linkage areas across headwater drainages to conserve biodiversity in forest ecosystems. Forest Ecology and Management. 258S: S117-S126.
  31. Olson, D.H.; Burnett, K.M. 2013. Geometry of forest landscape connectivity: pathways for persistence. In: Anderson, P.D.; Ronnenberg, K.L., eds. Density management in the 21st century: west side story. Gen. Tech. Rep. PNW-GTR-880. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: 220–238.
  32. Olson, D.H.; Anderson, P.D.; Frissell, C.A.; Welsh, H.H.Jr.; Bradford, D.F. 2007. Biodiversity management approaches for stream riparian areas: Perspectives for Pacific Northwest headwater forests, microclimate and amphibians. Forest Ecology and Management. 246(1):81-107.

How to cite

Olson, D.H.; Saenz, D. 2013. Climate Change and Amphibians. (March, 2013). U.S.
Department of Agriculture, Forest Service, Climate Change Resource Center. www.fs.usda.gov/ccrc/topics/wildlife/amphibians/

 
Research

Research

Ongoing research on amphibians by US Forest Service scientists includes the following topics that relate to climate and climate change:

Climate Change and Herpetofauna
Climate change is expected to affect amphibians through a number of direct and indirect mechanisms. This project focuses on examining several of these mechanisms, as well as potential management responses, including:

  • "Shrinking heads hypothesis" - How do forested headwater streams respond to low water years? Do riparian buffers mitigate shrinking heads effects?
  • Over-ridge connectivity designs for forested amphibians.
  • Climate associations of the amphibian chytrid fungus.
  • Long-term monitoring of anuran breeding dates in the Cascade Range.

Contact: Dede Olson

Climate and breeding phenology of anuran species in Texas
Changing weather patterns from global climate change could be a contributing factor in declining frog populations, particularly for species that rely on ephemeral water sources, like some of those in eastern Texas. Scientists in Nacogdoches, TX are currently studying the effects of rainfall and temperature on the breeding activities of 13 different species of frogs in eastern Texas. Information from the research will make it possible to predict potential effects of a changing climate on frog populations.
Contact: Dan Saenz

Impacts of year-year variations of precipitation (snowpack and rainfall) on amphibian recruitment and survival
This study explores the link between the changes in water availability -- including complete pond drying -- and the abundance and recruitment of mountain yellow-legged frog in Dusy Basin , Kings Canyon National Park , California , USA . We propose using the low-snowpack years (1999, 2002, 2004) as comparative case studies to predict future effects of climate change on aquatic habitat availability and amphibian abundance and survival.
Contact: Kathleen Matthews

Birds

The Effects of Climate Change on Terrestrial Birds of North America

By Korall (Own work) GFDL (http://www.gnu.org/copyleft/fdl.html)

Topics Horizontal Tabs

Synthesis

Synthesis

Preparers

David King, U.S. Forest Service, Northern Research Station Center for Research on Ecosystem Change, University of Massachusetts; Deborah M. Finch, U.S. Forest Service, Rocky Mountain Research Station, Grassland, Shrubland, and Desert Ecosystems Program.

An archived version of this topic page is available

Issues

A discussion of avian responses to climate change is of interest for a number of reasons. First, because birds are relatively easy to identify and measure and their responses to environmental perturbation are relatively well known, they are useful as indicators of ecological change (1). Furthermore, birds are of conservation interest in their own right. Bird populations face global conservation challenges, with 1 in 8 species facing a high risk of extinction in the near future according to a recent report (2). Finally, birds perform significant ecosystem services with consequences for human health and well-being, including pest control, sanitation, seed dispersal and pollination (3).

  • The gray jay

    The gray jay is a montane and boreal specialist, and could be particularly sensitive to climate change because it caches food using frozen spit. Credit: Bill DeLuca

  • the greater sage grouse

    Climate can interact with other factors to threaten the sagebrush habitat needed several species, such as the greater sage grouse. Credit: USFWS Pacific Southwest Region.

  • Decline of bird species associated with spruce-fir habitat

    Recent declines of bird species that are associated with spruce-fir habitat on the White Mountain National Forest highlight concerns about montane bird species under climate change. Credit: Bill DeLuca.

  • cheatgrass

    Invasive plants like cheatgrass can harm birds that are dependent on sagebrush habitat by altering fire behavior in those ecosystems. These interactions can be exacerbated by climate change. Credit: Robin Tausch.

Likely Changes

Research on birds has shown that climate change affects birds both directly and indirectly. The distributions of birds are closely associated with both winter and summer temperatures, and increased temperatures due to climate change may directly affect birds by forcing them to use more energy for thermoregulation. This can disrupt their maintenance (the energy needed by organisms to maintain their basal levels of activity and condition) , reproduction, timing of breeding and migration, and reduce survival or fitness (4). Birds may respond to these costs by shifting their ranges over time to areas with more suitable thermal conditions, but habitat and other resources may be insufficient or unsuitable for their needs (5).

Generally speaking, global temperatures decrease with increased latitude and elevation, so a fundamental prediction of climate scientists is that species will shift towards the poles and upward in elevation (6; 7). Long-term changes in North American bird distributions show clear evidence of latitudinal shifts, with many species shifting their geographic distributions northwards over the past few decades (8, 9). Elevational shifts have also been reported in long-term datasets, and these shifts appear to implicate changes in precipitation as well as temperature. In the Sierra Nevada mountains, data show that the majority of species ranges have shifted upwards in elevation since the 1940s, with some bird species more closely associated with temperature shifts and others with changes in precipitation (10).

Climate-related shifts in species distribution along latitudinal and elevation gradients have important implications for conservation. If shifts in temperature take place at a more rapid rate than vegetation responses, or occur beyond the boundaries of suitable potential vegetation, then bird populations could be forced into areas of marginal habitat where they are likely to experience decreased survival and reproduction (4). With elevational shifts, the area available for species to colonize as ranges shift upwards also decreases with elevation (11). For this reason, montane species are considered to be especially vulnerable to climate change. This concern is highlighted by recent evidence of declines of montane spruce-fir indicator species on the White Mountain National Forest, including the threatened Bicknell’s Thrush (Catharus bicknelli; 12). Analyses of these same data also show an upward shift of bird species from lower forest areas into montane forest, which is consistent with general observed patterns that show middle elevation species shifting upwards (13).

In contrast to expectations, DeLuca (13) also reported that the montane spruce-fir bird species that occupy the forests nearest tree line are actually shifting downwards in elevation. This might at first seem like a cause for optimism, since there is more area at lower elevations, and thus montane bird ranges would not be constricted at the lower end of an elevational gradient. A more detailed analysis however indicates that lower elevations are marginal habitats for montane birds where they experience lower pairing and nesting success, and therefore lower reproductive success. These results demonstrate some important aspects of climate change research: they contradict the prevailing paradigm that species will respond to climate change by shifting their ranges towards higher elevations, and they highlight the necessity of considering aspects of fitness as well as the distribution of organisms in relation to climate change, because shifts might not be adaptive.

In addition to these direct effects, increased temperatures associated with climate change have the potential to cause a myriad of indirect effects.. One of the most widely reported is the de-synchronization of migrant bird reproduction with food resources. Many bird species synchronize their nesting cycle so the period of maximum food requirements of the young coincides with the maximum food availability (14). In the case of migratory birds, which comprise the majority of species and individuals in many temperate ecosystems, their departures from winter areas are related to photoperiod, whereas the availability of their largely insect food resources is affected by plant phenology. Since plant phenology is related to climate and is advancing in most regions, migratory bird species are in some cases arriving and therefore breeding too late to keep pace with the timing of their food supply (15).

Other indirect effects are mediated by changes in the types and timing of disturbance. In parts of the western U.S., climate change is manifested by drought conditions that increase the frequency and severity of wildfires. These disturbances can impact birds directly by destroying nests and altering habitats. For example, in the Great Basin the effects of drought on fire regimes is compounded by the invasion of cheatgrass (Bromus tectorum), an exotic species introduced from Eurasia. Cheatgrass is more flammable than native grasses, and as drought conditions increase, fire frequency and severity increases and plant species adapted for less severe fire regimes are replaced by cheatgrass, which further increases extreme fire behavior. The synergistic effects of climate, fire and invasion are blamed for loss and fragmentation of big sagebrush habitats needed by sagebrush obligates like sage thrasher (Oreoscoptes montanus) sage sparrow (Amphispiza belli), and greater sage-grouse (Centrocercus urophasianus), a candidate species for listing under the Endangered Species Act (16). West Nile virus models also show climate’s influence in this region, predicting disease spread to more western locations and states. This could impact vulnerable birds like the greater sage-grouse, which withdraws during droughts to water sources where it can be infected by mosquitos potentially carrying the virus. Finally, studies of high elevation birds in Arizona show that lower snowpack associated with climate change allows greater access to montane areas by elk, and recent declines in several species of migratory songbirds could be the result of decreased reproductive success resulting from habitat degradation from over-browsing (17).

There have been dramatic changes in global climate before, however the current challenge to species and ecosystems from climate is not only the degree of change but the rate. Rapid changes in environmental conditions are likely to exceed the ability of many bird species to adapt via natural selection (18). This concern has led to increased interest in identifying species characteristics associated with vulnerability to climate change (19). In addition to the examples presented above showing that montane and western grassland species are negatively affected, analyses of data from the Breeding Bird Survey are underway to determine whether traits like migratory status, clutch size or geographic range affect the vulnerability of bird species to climate change, as indicated by elevational and latitudinal shifts in their distributions (20). Because responses to climate change are largely species-specific it is expected that species will recombine into novel communities, which could present additional challenges as species are exposed to predators or competitors for whom they have no evolved defenses (21).

Management Options

Strategies to mitigate the impacts of climate change on bird populations include maintaining the resilience of their habitats by reducing compound stressors that potentially interact with climate change and magnify its impact. The effect of cheatgrass on fire regimes mentioned above is an example that illustrates the potential compounding effects of invasives. Other examples include habitat fragmentation and pollution. Where necessary, habitat resilience can be increased through active management, which can maintain robust growth and reproduction of native plants to mitigate the impacts of drought, heat stress and other climate-related effects (22). Other strategies to mitigate the effects of climate change include increasing the area of protected lands to include greater representation of habitat refugia, where species are predicted to be buffered from the effects of climate change because of site characteristics. Establishing and maintaining habitat connectivity among preserves and along elevational and latitudinal gradients by establishing corridors or networks of preserves could also facilitate shifts by climate-sensitive species (23).

Projects are underway nationwide to enhance resiliency through habitat improvement of ecosystems considered susceptible to climate change. For example, the Central Appalachian Spruce Restoration Initiative is a multi-partner collaboration of individuals and organizations who share the common goal of restoring the red spruce-northern hardwood ecosystem across the high elevation landscapes of Central Appalachia. The US Forest Service is a key player in this initiative, and recent accomplishments include planting, silvicultural treatments and removal of exotic species to enhance spruce regeneration, as well as reforestation and habitat acquisition to reduce fragmentation. These efforts will help priority species within this threatened ecosystem to withstand the effects of climate change or shift their range to track suitable climate conditions. Similar practices are being embraced by National Forests in their forest plan revisions. For example, the Kaibab National Forest in Arizona implements fuels control treatments and mechanical thinnings in an attempt to reduce the risk of pest and disease outbreaks and catastrophic wildfire, all of which are expected to increase with continued climate change.

References

  1. Niemi, G. J.; McDonald, M. E. 2004. Application of Ecological Indicators. Annual Review of Ecology, Evolution, and Systematics. 35: 89-111.
  2. Vie, J.-C., Hilton-Taylor, C.; Stuart, S.N. (eds.) (2009). Wildlife in a Changing World - An Analysis of the 2008 IUCN Red List of Threatened Species. Gland, Switzerland: IUCN. 180 pp.
  3. Sekercioglu, C.H; Daily, G.C; Ehrlich, P.R. 2004. Ecosystem consequences of bird declines. Proceedings of the National Academy of Sciences of the United States of America. 101:18042-18047.
  4. Crick, H. Q. P. 2004. The impact of climate change on birds. Ibis. 146:48-56.
  5. Devictor, V.; Julliard, R.; Couvet, D.; Jiguet, F. 2008. Birds are tracking climate warming, but not fast enough. Proceedings of the Royal Society B. 275: 2743-2748.
  6. Rodenhouse, N. L.; Matthews, S. N.; McFarland, K. P.; Lambert, J. D.; Iverson, L. R.; Prasad, A.; Sillett, T. S.; Holmes, R. T. 2008. Potential effects of climate change on birds of the Northeast. Mitigation and adaptation strategies for global change 13:517-540.
  7. Matthews, S.N.; Iverson, L. R.; Prasad, A. M.; Peters, M. P. 2011. Changes in potential habitat of 147 North American breeding bird species in response to redistribution of trees and climate following predicted climate change. Ecography. 34: 933-945.
  8. Hitch, A. T.;Leberg, P. L. 2007. Breeding distributions of North American bird species moving north as a result of climate change. Conservation Biology. 21:1523-1739.
  9. LaSorte, F. A.; Thompson, F. R. III. 2007. Poleward shifts in winter ranges of North American birds. Ecology. 88:1803-1812.
  10. Tingley, M. W.; Monahan, W. B.; Beissinger, S. R.; Moritz, C. 2009. Birds track their Grinnellian niche through a century of climate change. Proceedings of the National Academy of Sciences. 106:19637-19643.
  11. Sekercioglu, C.H.; Schneider, S.H.; Fay, J.P.; Loarie, S.R. 2008. Climate Change, Elevational Range Shifts, and Bird Extinctions. Conservation Biology. 22: 140-150.
  12. King, D. I.; Lambert, J. D.; Buonaccorsi, J. P.; Prout, L. S. 2008. Avian population trends in the vulnerable montane forests of the Northern Appalachians, USA. Biodiversity and Conservation. 17:2691-2700.
  13. DeLuca, W.V. 2012. Ecology and conservation of the high elevation forest avian community in northeastern North America. Doctoral Dissertation, University of Massachusetts, Amherst.
  14. Visser, M.E.; Holleman, L.J.M.; Gienapp, P. 2006. Shifts in caterpillar biomass phenology due to climate change and its impact on the breeding biology of an insectivorous bird. Oecologia. 147: 164-172.
  15. Both, C.; Visser, M.E. 2001. Adjustment to climate change is constrained by arrival date in a long-distance migrant bird. Nature.411: 296-298.
  16. Finch, D. M. 2012. Climate change in grasslands, shrublands, and deserts of the interior American West: a review and needs assessment. Gen. Tech. Rep. RMRS-GTR-285. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 139 p.
  17. Auer, S. K.; Martin, T. E. 2013. Climate change has indirect effects on resource use and overlap among coexisting bird species with negative consequences for their reproductive success. Global Change Biology. 19:411-419.
  18. Visser, M.E. 2008. Keeping up with a warming world; assessing the rate of adaptation to climate change. Proceedings of the Royal Society B. 275: 649-659.
  19. Cormont, A.; Vos, C.C.; van Turnhout, C.A.M.; Foppen, R.P.B.; ter Braak, C.J.F. 2011. Using life-history traits to explain bird population responses to increasing weather variability. Climate Research. 49: 59-71.
  20. Auer and King, In review
  21. Lurgi, M.; Lopez, B. C.; Montoya, J. M. 2012. Novel communities from climate change. Philosphical Transactions of the Royal Society B. 367:2913-2922.
  22. Millar, C. I.; Stephenson, N. L.;Stephens, S. L. 2007. Climate change and forests of the future: managing in the face of uncertainty. Ecological Applications. 17:2145-2151.
  23. Mawdsley, J.R.; O'Malley, R.; Ojima, D.S. 2009. A review of climate‐change adaptation strategies for wildlife management and biodiversity conservation. Conservation Biology. 23: 1080-1089.

How to cite

King, D.; Finch, D.M. 2013. The Effects of Climate Change on Terrestrial Birds of North America. (June, 2013). U.S. Department of Agriculture, Forest Service, Climate Change Resource Center. www.fs.usda.gov/ccrc/topics/wildlife/birds

Reading
Research

Research

Modeling potential future habitats for trees and birds in the eastern U.S.
Our group, the Landscape Change Research Group, from Delaware, OH lab of the Northern Research Station, have been modeling potential changes in suitable habitat for trees and birds of the eastern US. These maps are available online at www.nrs.fs.fed.us/atlas. We also look at dispersal potentials through another modeling toolset, and work with modification factors to understand more about the factors not readily modeled.
Contact: Louis Iverson

Pacific Northwest Wildlife Habitat
RMRS scientists are collaborating with scientists from the Pacific Northwest Station and the University of Washington to develop methods to generate forested landscapes given climate change. These landscapes will be linked to multi-scale wildlife habitat models currently under development at RMRS.
Contact: Sam Cushman

Predicting the Effects of Climate Change on Avian Abundance
Using a longterm dataset (27+ years), researchers are examining the effect of weather patterns on avian abundance at the San Joaquin Experimental Range, an oak woodland savanna in California, to reveal potential climate change effects on demography and identify species at risk.
Contact: Kathryn Purcell, Sylvia Mori

Mammals

The Effects of Climate Change on Mammals

K. Marcinkowski

Topics Horizontal Tabs

Synthesis

Synthesis

Preparers

Kevin S. McKelvey, Rocky Mountain Research Station, Missoula MT; Roger W. Perry, Southern Research Station, Hot Springs, AR; L. Scott Mills, University of Montana, Missoula MT.

An archived version of this topic paper is available.

Issues

Climate change is expected to impact most parts of an ecosystem, and mammals are no exception. Some mammals have very specific climatic adaptations, such as requirements for snow, sea ice, or temperatures within a narrow range for hibernation. Some have distributions that are dependent on climate. Most mammals will not be able to avoid the effects of climate change, with both positive and negative effects possible. Mammals generally utilize a variety of often disjunct resources. They need places to hide, eat, drink, and breed, and in many cases these places are distinct and may change seasonally. Thus there are many opportunities for climate change to disrupt mammalian life histories. In general they will not be able to effectively hide in microhabitats; in contrast many plants can persist as rare endemics long after the climate has changed. Most mammals are also highly mobile and, compared to perennial plants, have relatively short (generally < 20 yrs) life spans. Thus, if climates become unsuitable, mammalian response can be expected to be rapid.

Mammals play dominant roles in many systems. They make up most of the terrestrial large-bodied predators in North America, and these large, high-trophic mammals have significant impacts on the ecosystems they inhabit. For example, gray wolf introduction in Yellowstone National Park has reduced the northern elk herd to approximately 1/3 of its former size (1, Figure 1), which has initiated a cascade of ecological effects (2, 3). Rodents and lagomorphs (hares, pikas, and rabbits) are the primary prey for many mammalian, avian, and reptilian predators and rodents can affect the composition of vegetative communities through seed predation (4). Small terrestrial mammals, including rodents and insectivores (shrews), typically comprise the largest and most diverse group of mammals in many ecosystems (e. g. 5); thus, most of the changes in mammal abundances and distributions resulting from climate change are expected to be in this group (e. g. 6). Additionally rodents host many diseases that can affect us. Many tick- and flea-borne diseases that infect humans, including Lyme disease, Rocky Mountain spotted tick fever, Tularemia, plague, and Ehrlichiosis are carried by rodents or rodents serve as the reservoir hosts (7); the prevalence of these diseases is often strongly linked to population size (e.g., 8, 9). Thus, changes in mammal communities will have profound impacts on ecosystems and may directly affect human societies.

  • Endangered Indiana bats hibernating in a cave

    Endangered Indiana bats hibernating in a cave. Credit: Roger Perry, USFS.

  • White hare in a brown background

    Hares may be particularly vulnerable to predators when their coloration does not match the background. Changes in the timing of snow cover could affect their survival. Credit: L. Scott Mills et al., PNAS Early Edition (2013)

  • Pika

    Pikas appear dependent both on moist and cool summer conditions and winter snow. Climate-related stressors may playing a role in pika declines in the Great Basin over the last decades. Copyright photograph courtesy Jim Jacobson.

Likely Changes

The effects of climate changes on mammals can sometimes be ascertained directly through the study of their biology and physiology. For example, once it is understood that wolverines require snow to den (10, 11) and persistent spring snow defines the southern extent of their range (11), the likely effects of reduced snowpack are straightforward (12). There is no evidence that wolverines will be able to persist in areas that lose their snow as a consequence of climate change. For most mammals, however, climate broadly defines their ecological niche. Therefore for many species, future distributions are estimated by correlating climatic factors with their current ranges and projecting these models into the future (e. g. 13). Here we examine 3 species that illustrate some of the myriad of ways that climate is likely to affect mammals.

Research

The Indiana bat (encounters with diseases)
The Indiana bat (Myotis sodalis) presents an example of how changing climates and introduction of exotic organisms can together threaten the persistence of native mammal species. The Indiana bat, (listed as federally endangered in 1967), ranges throughout the northeastern, midwestern, and parts of the southeastern U.S. During winter, Indiana bats hibernate in caves and mines within a narrow thermal range (3.0-7.2°C; 14). The most important hibernation sites occur primarily in the Midwest and Southeast (15). Currently, most of these important sites are exterior to the area affected by white nose syndrome (WNS), a lethal disease caused by an imported European fungus (16). Climate change predictions suggest the summer range of Indiana Bats may move north and east (17). This would move them closer to the areas most affected by WNS; the disease has resulted in the death of approximately 72% of the Indiana bats that hibernate in the Northeast since 2006-2007 (18).

The snowshoe hare (snow dependency)
The snowshoe hare (Lepus americanus) is a small lagomorph well- adapted to seasonally snowy environments. Its range includes most of Alaska and Canada, with montane extensions as far south as California and New Mexico in the western U.S. and West Virginia in the eastern U.S. It has oversized rear paws leading to low foot loadings (19, Figure 4.3), and seasonally changes its pelage from mostly brown to white. Snowshoe hares are typically killed by predators (as opposed to dying of starvation, old age, etc.; 20). Thus, predator avoidance is a critical aspect of snowshoe-hare behavior (21). Hares may be particularly vulnerable when their coloration does not match the background-a white hare on a brown background is more visible to predators (22). The period when the landscape is predictably snow covered is extremely sensitive to climate (23, 24). With climate change, spring snowmelt is predicted to occur earlier (23, 22) and snow cover lost sooner (25) in areas inhabited by the snowshoe hare. Hare pelage change has limited plasticity in the rate of the spring white-to-brown molt, but both initiation dates of color change and the rate of the fall brown-to-white molt are fixed; unless the timing of coat color change can be modified by natural selection, the reduced snowpack will increase periods of mismatch by 3 - 8 times (22).

The American pika (sensitivity to temperature and water-balance stresses, perhaps mediated by vegetation)
The pika (Ochotona princeps) is a small lagomorph that often inhabits alpine areas in the western U. S. In the Great Basin, pika habitat occurs as small islands near the tops of mountains. Pikas appear dependent both on moist and cool summer conditions and winter snow (26). Historically and during the 20th century, pikas have reacted to climate changes by moving upslope or becoming locally extirpated when the weather becomes hot and dry (26). In the Great Basin, sites of pika extirpation (1994-2008; 27) were generally hotter in the summer and more frequently very cold in the winter than sites where pika persisted - warming led to the removal of insulating snow causing nighttime winter temperatures to plummet (27). Winter snowpack not only insulates pikas during cold snaps, but also may provide water longer into the summer season, when plant senescence at drier sites occurs earlier in the year, which eliminates water availability for pika. Analyses suggest that both chronic stresses (average temperature during all of summer, snowpack and growing-season precipitation), acute (hot and cold) temperature stresses, and vegetation productivity may all be playing a role in pika declines in the Basin over the last decades.

Options for Management

Managing lands or species in the face of climate change requires an acknowledgement of both the range of different effects and the high levels of uncertainty involved in local projections. Additionally, projections are for climate, not weather. As such, they produce long-term averages. Organisms, including mammals, generally respond to weather events that deviate from the average such as droughts, extreme or unusual cold or heat, and storms. Thus, the weather that organisms actually respond to will be inferred from relatively broad-scale climate projections. Additional uncertainties exist in predicting mammalian responses to changing climate. Unforeseen opportunities and stressors can be expected-white nose syndrome, for example, was discovered in 2006 (16). However, these uncertainties do not preclude active management to conserve mammals, they simply change the nature of that management. Many approaches are generically beneficial for native species, and are particularly beneficial given climate change. These include:

  1. Maintain and if possible improve landscape connectivity.
  2. Reduce stresses on current populations and habitats.
  3. Maintain or improve current habitat for specific species.
  4. Manage to maintain landscape diversity.
  5. Monitor change.

A connected landscape allows mammals to seek appropriate habitats and prevents the negative consequences of small isolated populations, such as increased extinction risks and lower fitness. Negative effects of climate change can be ameliorated by reducing other human-caused stressors (e.g. invasive species, development, overharvest). With higher fitness across habitats, organisms may be able to persist in what was formerly "sink" habitat*, both increasing overall population size and range and increasing adaptive potential. Similarly, habitat improvement will help maintain a large, healthy population, which may improve its likelihood of persistence. Diverse landscapes increase overall resilience and provide opportunities for adaptation. Lastly, because climate change will lead to many unexpected ecological effects, systems must be in place to rapidly identify and monitor these effects and facilitate appropriate management responses.

* Sink habitat =habitat that is currently occupied, but where populations cannot persist without external subsidies from organisms that emigrate from better quality areas.

References

  1. Ripple, W. J.; Painter, L. E.; Beschta, R. L.; Gates, C.C. 2010. Wolves, elk, bison, and secondary trophic cascades in Yellowstone National Park [pdf]. The Open Ecology Journal. 3:31-37.
  2. Fortin, D.; Beyer, H. L.; Boyce, M. S.; Smith, D. W.; Duchesne, T.; Mao, J.S. 2005. Wolves influence elk movements: behavior shapes a trophic cascade in Yellowstone National Park. Ecology. 86:1320-1330.
  3. Beyer, H. L.; Merrill, E. H.; Varley, N.; Boyce, M.S. 2007. Willow on Yellowstone's Northern Range: Evidence for a Trophic Cascade? Ecological Applications. 17: 1563-1571
  4. Maron, J.L.; Pearson, D.E.; Potter, T.; Ortega, Y.K. 2012. Seed size and provenance mediate the joint effects of disturbance and seed predation on community assembly. Journal of Ecology. 100:1492-1500.
  5. Trani, M.K.; Ford, W.M.; Chapman, B.R., eds. 2007. The Land Manager's Guide to Mammals of the South. Durham, NC: The Nature Conservancy; Atlanta, GA: U.S. Forest Service. 546 p.
  6. Burns, C.E.; Johnson, K.M.; Schmitz, O.J. 2003. Global climate change and mammalian species diversity in U.S. national parks. Proceedings of the National Academy of Sciences. 100:11474-11477.
  7. Gubler, D.J.; Reiter, P.; Ebi, K.L.; Yap, W.; Nasci, R.; Patz, J.A. 2001. Climate variability and changes in the United States: Potential impacts on vector- and rodent-borne diseases. Environmental Health Perspectives. 109:223-233.
  8. Mills, J.N.; Ksiazek, T.G.; Peters, C.J.; Childs, J.E. 1999. Long-term studies of hantavirus reservoir populations in the southwestern United States: A synthesis. Emerging Infectious Diseases. 5:135-142.
  9. Kuenzi, A.J.; Morrison, M.L.; Madhav, N.K.; Mills, J.N. 2007. Brush mouse (Peromyscus boylii) population dynamics and hantavirus infection during a warm, drought period in southern Arizona. Journal of Wildlife Diseases. 43:675-683.
  10. Magoun, A.J.; Copeland, J.P. 1998. Characteristics of wolverine reproductive den sites. Journal of Wildlife Management. 62:1313-1320.
  11. Copeland, J.P.; McKelvey, K.S.; Aubry, K.B.; Landa, A.; Persson, J.; Inman, R.M.; Krebs, J.; Lofroth, E.; Golden,H.; Squires, J.R.; Magoun, A.; Schwartz, M.K.; Wilmot, J.; Copeland, C.L.; Yates, R.E.; Kojola, I.; May, R. 2010. The bioclimatic envelope of the wolverine: Do climatic constraints limit their geographic distribution? Canadian Journal of Zoology. 88:233-246.
  12. McKelvey, K.S.; Copeland, J.P.; Schwartz, M.K.; Littell, J.S.; Aubry, K.B.; Squires, J.R.; Parks, S.A.; Elsner, M.M.; Mauger, G.S. 2011. Climate change predicted to shift wolverine distributions, connectivity, and dispersal corridors. Ecological Applications. 21: 2882-2897.
  13. Levinsky, I.; Skov, F.; Svenning, J.-C.; Rahbek, C. 2007. Potential impacts of climate change on the distributions and diversity patterns of European mammals. Biodiversity Conservation. 16:3803-3816.
  14. Tuttle, M.D.; Kennedy, J. 2002. Thermal requirements during hibernation. In: Kurta, A.; Kennedy, J., eds. The Indiana Bats: Biology and management of an Endangered Species. Austin, TX: Bat Conservation international. 68-78.
  15. U.S. Fish and Wildlife Service (USFWS). 2007. Indiana Bat (Myotis sodalis) Draft Recovery Plan: First Revision. Fort Snelling, MN: U.S. Fish and Wildlife Service. 45 pp. (available at http://www.fws.gov/midwest/Endangered/mammals/inba/inba_drftrecpln16ap07.html).
  16. Warnecke, L.; Turner J. M.; Bollinger, T. K.; Lorch, J. M.; Misra, V.; Cryan, P. M.; Wibbelt, G.; Blehert, D. S.; Willis, C. K. R. 2012. Inoculation of bats with European Geomyces destructans supports the novel pathogen hypothesis for the origin of white-nose syndrome. Proceedings of National Academy of Science.
  17. Loeb, S.C., Winters, E. In press. Summer maternity range of Indiana Bats. In: Perry, R.W.; Franzreb, K.E.; Loeb, S.C.; Saenz, D.; Rudolph, D.C. Climate Change and Wildlife in the Southern United States: Potential Effects and Management Options. Asheville, NC: USDA Forest Service, Southern Research Station.
  18. Turner, G.G.; Reeder, D.M.; Coleman, J.T.H. 2011. A five-year assessment of mortality and geographic spread of White-nose Syndrome in North American bats and a look to the future. Bat Research News. 52:13-27.
  19. Buskirk, S.W.; Ruggiero, L. F.; Krebs, C.J. 2000. Habitat fragmentation and interspecific competition: implications for lynx conservation. In: Ruggiero, L. F.; Aubry, K. B.; Buskirk, S. W.; Koehler, G. M.; Krebs, C.J.; McKelvey, K. S.; Squires, J.R., eds. Ecology and conservation of lynx in the United States. Boulder, CO: University Press of Colorado. 83-100.
  20. Hodges, K. E. 2000. Ecology of snowshoe hares in southern boreal and montane forests. In: Ruggiero, L. F.; Aubry, K. B.; Buskirk, S. W.; Koehler, G. M.; Krebs, C.J.; McKelvey, K. S.; Squires, J.R., eds. Ecology and conservation of lynx in the United States. Boulder, CO: University Press of Colorado. 163-206
  21. Griffin, P.C.; Griffin, S.C.; Waroquiers, C.; Mills, S.L. 2005. Mortality by moonlight: predation risk and the snowshoe hare. Behavioral Ecology. 16:938-944.
  22. Mills, L.S.; Zimova, M.; Oyler, J.; Running, S.; Abatzoglou, J.; Lukacs, P. 2013. Camouflage mismatch in seasonal coat color due to decreased snow duration. Proceedings of the National Academy of Science. Early Edition.
  23. Stewart, I.T.; Cayan, D.R.; Dettinger, M.D. 2004. Changes in snowmelt runoff timing in western North America under a “business as usual” climate change scenario. Climatic Change. 62: 217-232.
  24. Mote P.W.; Hamlet, A.F.; Clark, M.P.; Lettenmaier, D.P. 2005. Declining mountain snowpack in western North America. Bulletin of the American Meteorological Society. 86:39-49.
  25. Salathe, E.P. Jr.; Steed, R.; Mass, C. F.; Zahn, P.H. 2008. A high-resolution climate model for the U.S. Pacific Northwest: mesoscale feedbacks and local responses to climate change. Journal of Climate. 21:5708-5726.
  26. Beever, E.A.; Ray, C.; Wilkening, J. L.; Brussard, P.F.; Mote, P.W. 2011. Contemporary climate change alters the pace and drivers of extinction. Global Change Biology. 17, 2054-2070.
  27. Beever, E.A.; Ray, C.; Mote, P.W.; Wilkening, J.L. 2010. Testing alternative models of climate-mediated extirpations. Ecological Applications. 20:164-178.

How to cite

McKelvey, K.S.; Perry, R.W.; Mills, L.S. 2013. The Effects of Climate Change on Mammals. U.S. Department of Agriculture, Forest Service, Climate Change Resource Center. www.fs.usda.gov/ccrc/topics/wildlife/mammals

Reading
Research

Research

In addition to the examples presented in the synthesis, the following are research projects taking place in the Forest Service.

Canada Lynx
RMRS scientists are currently developing landscape-level habitat relationships for Canada lynx. These relationships include direct links to environmental variables such as temperature and snow cover, as well as indirect links such as forest type. These models can be linked to future projections of forested landscapes, snow cover, and temperature. To predict the specific effects of climate change on lynx RMRS scientists are cooperating with other scientists in the development habitat projections.
Contact: John Squires

Climate Change and Wildlife Habitat
An analysis of potential national effects of climate change on wildlife habitat is being addressed by RMRS scientists through the estimation of an index of climate change stress to terrestrial biodiversity in order to identify regional hotspots of climate change impacts. This research focuses on management strategies for climate change in the states' Wildlife Action Plans.
Contact: Linda Joyce, Curt Flather

Pacific Northwest Wildlife Habitat
RMRS scientists are collaborating with scientists from the Pacific Northwest Station and the University of Washington to develop methods to generate forested landscapes given climate change. These landscapes will be linked to multi-scale wildlife habitat models currently under development at RMRS.
Contact: Sam Cushman

Wolverines and Climate Constraints
RMRS scientists have shown that historical wolverine distribution was highly correlated with persistent snow. Genetic analysis reinforced these understandings and showed that the occurrence patterns had been present for at least 2,000 years. Wolverine's snow association is likely due to the location of reproductive dens in snow. We are currently collaborating with Scandinavian scientists to ascertain whether European wolverines are also snow-dependent when denning. Additionally we are working with the University of Montana and and the USGS to project snow patterns into the future and determine the likely effects of snow cover changes on wolverines.
Contact: Kevin McKelvey

Reptiles

Reptiles and Climate Change

L. Jones

Topics Horizontal Tabs

Synthesis

Synthesis

Preparers

Deanna H. Olson, Pacific Northwest Research Station; Daniel Saenz, Southern Research Station

An archived version of this topic paper is available.

Issues

Many reptiles are highly sensitive to the altered temperatures that may result from climate change due to their ectothermy which requires that they rely on ambient environmental temperatures to maintain critical physiological processes.  Due to the variety of snakes, lizards, crocodilians, and turtles in our world (traditionally classified as reptiles), and because climate change data and projections vary with location, it will be important to consider each species and location separately when considering the potential effects of altered climate on these animals. 

In temperate zones, lizards are thought to be highly vulnerable to climate change (1-7). Their reproduction is closely tied to narrow windows of time in the spring and summer when suitable temperature and moisture regimes are available for critical natural history activities, such as foraging and mating. Altered weather conditions during these seasons may result in frequently recurring "bust" years of reproductive failure. Other climate effects on lizard survival include mortality associated with warm spells in winter (8), interacting effects of altered vegetation communities, fire regimes and invasive species (9), and potentially disease (10).
Snakes are very closely related to lizards, and these effects may hold true for them as well.  Just as with lizards, new studies illustrate species differences:  climatic niche models suggest that some rattlesnakes may have smaller ranges (11); while ratsnakes have increased activities due to warmer night temperatures (12).

Climate change concerns for turtles and crocodilians are three-fold. First, these mostly aquatic species may encounter altered habitats and increased habitat fragmentation with altered climate. In this regard they share many concerns with amphibians, such as sensitivity to changes in water availability and its’ thermal properties. Second, turtles and alligators have temperature-sensitive sex determination: cooler temperatures may produce nests of only males; warmer temperatures may produce nests of only females. Temperature changes in a local area may have the effect of altering the sex ratios of populations - potentially affecting future reproduction and over time compromising their evolutionary fitness (13). Third, coastal species such as the American Alligator and Crocodile are susceptible to an increasing frequency or intensity of storms caused by increases in ocean temperatures. Storm surges can displace or drown animals, and dehydrate them by salt water intrusion into freshwater habitats (14). Because the United States is a biodiversity hotspot for turtles, and turtle conservation issues are multi-faceted, concern for climate change projections relative to rare turtle species is a specific concern (15).

  • Mississippi stream channel completely dried out during a drought

    The Mississippi stream channel pictured here dried out completely during a drought. Such changes in stream flow quantity and timing are expected to occur more often as climate changes. Credit: Susan Adams.

  • flowchart showing Climate change affects temperature and precipitation patterns

    Climate change affects temperature and precipitation patterns, which regulate many ecological processes in aquatic ecosystems. Solid arrows indicate direct responses. Credit: Center for Climate and Energy Solutions.

  • Jackson Prairie Crayfish

    Changing water temperatures and rainfall patterns may pose challenges for certain species. The Jackson Prairie Crayfish (Procambarus barbiger) is native to a limited area in the southern U.S., making it particularly vulnerable. Credit: Chris Lukhaup.

  • riparian buffers

    Maintaining or re-creating high quality habitat for native species, for example riparian buffers, woody debris, and stable banks, could help some warmwater species withstand the effects of climate change. Credit: Chris Lukhaup.

Likely Changes

The highest biodiversity of reptiles in the United States is in the southern states, in desert and subtropical ecosystems. The northern distributions are constrained by latitude, with species richness dropping considerably as you go north. North boundaries of species ranges are often marginal habitats due to climate factors such as cool temperatures and weather variation.  Altered thermal niches (4, 5) for reptiles in these zones due to climate change will be important to track. Briefly, to understand thermal niches, consider that there is a time-window during the day when there are suitable temperatures for reptile activities. It appears that this time-window is becoming smaller as climate changes are apparent in both tropical and temperate zone regions, reducing the activity times of reptiles, affecting their reproduction and survival. Although habitat may be marching northward or into mountains for some species, for other species, increased weather variation may alter the frequency or intensity of boom-bust reproductive cycles and cohort survival. Examples follow.

In Oregon, variable spring weather has been shown to narrow the time window of suitable breeding conditions for the Common Side-blotched Lizard, Uta stansburiana, with reproductive bust years being reported (6, 7). In Mexico, a study reported that 12% of local lizard populations have been lost since 1975, with evidence that these losses are associated with climate change altering thermal niches (4). In Alberta, Canada, the Greater Short-horned Lizard, Phrynosoma hernandesi, overwinter survival relies on persistent snow cover to retain animals in insulated hibernation: lizards become active during warm spells in winter, and then they can be ‘caught out’ and die when it snows again (8). In contrast, ratsnake thermal niches may be expanding with more warmer nights (12).

Vulnerability assessments and predictions of how habitat distributions will change abound for many taxa. Looming questions are where will suitable habitats occur in the future, and will organisms be able to get there?  In our human-altered world, roads and urban-rural development are new hurdles to dispersing reptiles, added to a variety of natural geographic barriers. In Spain, the northward expansion of lizard ranges coincident with changing climate has been tracked over about a 50 year period, with geographic barriers including the Pyrenees Mountains now posing dispersal limitations (3).

Options for Management

For reptiles, management is of paramount concern to maintain and restore existing habitats, augment acreages of intact habitat blocks, and adapt management actions to reduce environmental stressors (see regional Habitat Management Guidelines at: www.parcplace.org). Because microclimates can be readily manipulated with local land management activities, people can actively engineer a future for some of these organisms, especially when their environments are already highly altered due to human activities.

Invasive plant species and most human disturbances can alter local- to landscape-scale habitats and microclimates, which can have consequent effects on reptiles. Non-native vegetation may have different physical structure and cover, hindering reptile daily activities, and subsequently altering critical life history functions and reptile survival, and negatively influencing dynamics of interacting communities. Open habitat management may be needed to forestall encroaching vegetation, especially non-native plants, or to mitigate human disturbance (e.g., agricultural or energy development). Meadow shrub and tree control may be needed to retain sun-exposure. Riparian buffers may retain near-water refugia.  For turtles or other water-dependent reptiles, manipulation of hydroperiod at sites by site excavation and riparian buffer management are considerations.  Substrate management may be needed for several types of reptiles: rock outcrops and talus are complex refugia for lizards and snakes and may need protection or augmentation; rocky pond edges provide basking sites and antipredation refugia for turtles. Some species need specific substrate types, or rely on existing burrows created by other animals; these need consideration if climate change alters landscape-scale habitat distribution. Traditionally used snake hibernacula may need special protection. Management measures taken to maintain natural fire regimes and control invasive plants might also benefit reptiles. Altered fire regimes may change refugia, reduce cover and expose animals to heightened predation, and invasive plants may exacerbate climate-linked fire patterns.

Managers can facilitate the movement of reptiles by providing corridors between needed habitats that support complex reptile life histories:  breeding, foraging, overwintering, anti-predation, and basking habitats can all differ. Corridors between overwintering hibernacula and foraging areas, or between upland nesting sites and aquatic breeding sites are a particular concern because these can be inadvertently affected by roads or development. Considerations include: 1) extension of riparian corridors along safe upland dispersal routes; 2) creating barriers to dispersal along unsafe routes, such as along roads or into disturbed areas; 3) road-crossing culverts that may require dry as well as wetted channel areas; 4) management of surface rock or burrow availability and connectivity. 

If stop-gap measures are needed for rare species faced with extinction, the more costly methods of Reintroduction, Relocation, Translocation, and Headstarting (RRTH) may be considered. In the United States, numerous RRTH projects are underway for reptiles (16), such as the captive propagation and reintroduction of Eastern Indigo Snakes (http://www.oriannesociety.org/). Broad-scale policies directed at vulnerable site protections warrant consideration.

References

  1. Araujo, M.B.; Thuiller, W.; Pearson, R.G. 2006. Climate warming and the decline of amphibians and reptiles in Europe. Journal of Biogeography. 33:1712-1728.
  2. Wake, D.B. 2007. Climate change implicated in amphibian and lizard declines. PNAS 104:8201-8202.
  3. Moreno-Rueda, G.; Pleguezuelos, J.M.; Pizarro, M.; Montori, A. 2011. Northward shifts of the distribution of Spanish reptiles in association with climate change. Conservation Biology. 26:278-283.
  4. Sinervo, B. et al. 2010. Erosion of lizard diversity by climate change and altered thermal niches. Science. 328:894-899.
  5. Huey, R.; Losos, J.; Moritz, C. 2010. Are lizards toast? Science. 328:832-833.
  6. Zani, P.A. 2005. Life-history strategies near the limits of persistence: winter survivorship and spring reproduction in the common side-blotched lizard (Uta stansburiana) in eastern Oregon. Journal of Herpetology. 39:166-169.
  7. Zani, P.A.; Rollyson, M. 2011. The effects of climate modes on growing-season length and timing of reproduction in the Pacific Northwest as revealed by biophysical modeling of lizards. The American Midland Naturalist. 165: 372-388.
  8. Alberta Conservation Association. 2010. Reptiles of Alberta. 12 p. Available at http://www.ab-conservation.com/go/default/assets/File/Publications/Brochures/ACA_Reptiles_of_Alberta_WR_2010_v2.pdf, accessed 22 November 2011.
  9. Newbold, T.A.S. 2005. Desert horned lizard (Phrynosoma platyrhinos) locomotor performance: the influence of cheatgrass (Bromus tectorum). Southwestern Naturalist. 50:17-23.
  10. Scholnick, D.A.; Manivanh, R.V.; Savenkova, O.D.; Bates, T.G.; McAlexander, S.L. 2010. Impact of malarial infection on metabolism and thermoregulation in the Fence Lizards Sceloporus occidentalis from Oregon. Journal of Herpetology. 44:634-640.
  11. Lawing, A.M.; Polly, P.D. 2011. Pleistocene climate, phylogeny, and climate envelope models: An integrative approach to better understand species' response to climate change. PLoS ONE. 6(12): e28554.
  12. Weatherhead, P.J.; Sperry, J.H.; Carfagno, G.L.F.; Blouin-Demers, G. 2012. Latitudinal variation in thermal ecology of North American ratsnakes and its implications for the effect of climate warming on snakes. Journal of Thermal Biology. 37:273-281.
  13. Gibbons, J.W.; Scott, D.E.; Ryan, J.; Buhlmann, K.A.; Tuberville, T.D.; Metts B.S.; Greene, J.L.; Mills, T.; Leiden, Y.; Poppy, S; Winne, C.T. 2000. The global declines of reptiles, Deja vu amphibians. BioScience 50:653-666.
  14. Schriever, T.A.; Ramspott, J.; Crother, B.I.; Fontenot, C.L. 2009. Effects of hurricanes Ivan, Katrina, and Rita on a southeastern Louisiana herpetofauna. Wetlands. 29:112-122.
  15. Kiester, A.R.; Olson, D.H. 2011. Prime time for turtle conservation. Herpetological Review. 42:198-204.
  16. Olson, D.H. 2011. Compilation of Relocation, Reintroduction, Translocation, and Headstarting (RRTH) projects for herpetofauna. Available at: http://parcplace.org/news-a-events/242-rrth.html

How to cite

Olson, D.H.; Saenz, D. 2013. Climate Change and Reptiles. (March, 2013).
U.S. Department of Agriculture, Forest Service, Climate Change Resource Center. www.fs.usda.gov/ccrc/topics/wildlife/reptiles/

Reading
Research

Research

Ongoing research on reptiles by US Forest Service scientists includes the following topics that relate to reptiles and climate change:

Climate Change and Reptile Habitat in the northwestern U.S.
Understanding reptile distributions and how they might be affected by climate change help guide the management of these species. Research activities include:

  • Modeling landscape-scale factors including climate metrics associated with northwestern reptile distributions.
  • Examining potential habitat ‘hot spots’ for reptiles in coastal Oregon mesic forests.

Contact: Dede Olson

Conservation of the Louisiana Pine Snake
One of North America’s rarest reptiles, the Louisiana pine snake, may require extra assistance to persist under climate change. Scientists with the Southern Research station are developing an RRTH (relocation, reintroduction, translocation, headstarting) project for these reptiles.
Contact: Dan Saenz

Effects of climate change and other factors on a lizard community in an ecotone in southeastern Arizona.  
Lizards are expected to be an early warning system of impending change in vegetation communities, and a useful tool in predicting adaptive management needs. This study is conducted in the area with the highest diversity of lizards in the USA, situated at an ecotone between two deserts and a mountain range. Changes in the lizard community are expected sooner in this ecotone than in distinct habitat types, and are also expected to precede observed changes in vegetation.
Contact: Lawrence L.  C. Jones