Water temperatures fluctuate in time and space, creating diverse thermal regimes on river networks. Temporal variability in these thermal landscapes has important biological and ecological consequences because of nonlinearities in physiological reactions; spatial diversity in thermal landscapes provides aquatic organisms with options to maximize growth and survival. However, human activities and climate change threaten to alter the dynamics of riverine thermal regimes. New data and tools can identify particular facets of the thermal landscape that describe ecological and management concerns and that are linked to human actions. The emerging complexity of thermal landscapes demands innovations in communication, opens the door to exciting research opportunities on the human impacts to and biological consequences of thermal variability, suggests improvements in monitoring programs to better capture empirical patterns, provides a framework for suites of actions to restore and protect the natural processes that drive thermal complexity, and indicates opportunities for better managing thermal landscapes.
Managers make decisions regarding if and how to remove dams in spite of uncertainty surrounding physical and ecological responses, and stakeholders often raise concerns about certain negative effects, regardless of whether these concerns are warranted at a particular site. We used a dam-removal science database supplemented with other information sources to explore seven frequently raised concerns, herein Common Management Concerns (CMCs). We investigate the occurrence of these concerns and the contributing biophysical controls. The CMCs addressed are the following: degree and rate of reservoir sediment erosion, excessive channel incision upstream of reservoirs, downstream sediment aggradation, elevated downstream turbidity, drawdown impacts on local water infrastructure, colonization of reservoir sediments by nonnative plants, and expansion of invasive fish. Biophysical controls emerged for some of the concerns, providing managers with information to assess whether a given concern is likely to occur at a site. To fully assess CMC risk, managers should concurrently evaluate site conditions and identify the ecosystem or human uses that will be negatively affected if the biophysical phenomenon producing the CMC occurs. We show how many CMCs have one or more controls in common, facilitating the identification of multiple risks at a site, and demonstrate why CMC risks should be considered in the context of other factors such as natural watershed variability and disturbance history.
This volume presents findings on, and implications for, wildlife conservation in the tropical forests in Garo Hills of Meghalaya state in the North East India. A companion volume presented the findings on forest fragmentation due to practice of slash and burn agriculture in the region. Both of the volumes summarize work completed over more than a decade on characterizing conditions of tropical forests in the Garo Hills of western Meghalaya State of North East India. The work has led to innovations in use of remote sensing information and tools and to suggestions for designing a protected area network for wildlife conservation planning in the region. This volume is a synthesis and compilation of findings on wildlife habitats and conservation in fragmented tropical forests, from a long-term (1996-2012) research and application project initially entitled "Management of Forests in India for Biological Diversity and Forest Productivity - A New Perspective."
Thermal regimes of forested headwater streams control the growth and distribution of various aquatic organisms. In a western Oregon, USA, case study we examined: (1) forested headwater stream temperature variability in space and time; (2) relationships between stream temperature patterns and weather, above-stream canopy cover, and geomorphic attributes; and (3) the predictive ability of a regional stream temperature model to account for headwater stream temperature heterogeneity. Stream temperature observations were collected at 48 sites within a 128-ha managed forest in western Oregon during 2012 and 2013. Headwater stream temperatures showed the greatest spatial variability during summer (range up to 10 °C) and during cold and dry winter periods (range up to 7.5 °C), but showed less spatial variability during spring, fall and wet winter periods (range between 2 and 5 °C). Distinct thermal regimes among sites were identified; however, geomorphic attributes typically used in regional stream temperature models were not good predictors of thermal variability at headwater scales. A regional stream temperature model captured the mode of mean August temperatures observed across the study area, but overpredicted temperatures for a quarter of the sites by up to 2.8 °C. This study indicates considerable spatial thermal variability may occur at scales not resolved by regional stream temperature models. Recognizing this sub-landscape variability may be important when predicting distributions of aquatic organisms and their habitat under climate and environment change scenarios.
The home range is one of the most frequently sought-after characteristics of an animal’s behavior and ecology. However, most techniques for evaluating home ranges were developed before GPS collar technology. We use VHF and GPS location data collected in tandem on Pacific marten (Martes caurina) to determine the minimum length of time in which frequent GPS locations defined their annual home ranges. We fitted VHF transmitters to 38 individuals, collecting data for an average of 19.9 (8.7) months. We collected data using micro-GPS collars estimating locations at a 5-minute interval (n = 40 deployments, 19 individuals). For most martens, 80% of maximum VHF home range size was reached after 72 hours of GPS monitoring, and we could accurately estimate annual home range in <1 week. Size or location of annual or seasonal home ranges did not differ depending on data type. The ability to estimate annual home ranges within days could greatly improve the efficiency of addressing other research questions such as how home ranges vary with density, resource availability, and demography.
Wood decay elements include snags, down wood, root wads, tree stumps, litter, duff, broomed or diseased branches, and partially dead trees, all of which contribute to ecological processes and biodiversity of the forest ecosystem. Down wood can serve as reservoirs for moisture and mycorrhizal fungi beneficial to the health and growth of commercial tree species. Decaying wood, leaf litter, small twigs, and roots contribute nutrients and structure to humus and soil organic matter, and host microbes that play beneficial roles in nitrogen cycles and other processes. Snags and down wood provide nurse functions for tree and shrub species, and can aid in restoration of degraded forest environments. Various elements of wood decay provide habitat for many species of wildlife including invertebrates, amphibians, reptiles, birds, and mammals. Fire can influence the amounts and distributions of wood decay elements and enhance or detract desired ecosystem processes, depending on severity, charring, soil temperature, and other factors. Managing wood decay elements for ecosystem processes entails better understanding decay dynamics, the role of coarse wood in soil, the role of wood decay in carbon cycling and sequestration, and other considerations.
Forest policymakers and managers have long sought ways to evaluate the capability of forest landscapes to jointly produce timber, habitat, and other ecosystem services in response to forest management. Currently, carbon is of particular interest as policies for increasing carbon storage on federal lands are being proposed. However, a challenge in joint production analysis of forest management is adequately representing ecological conditions and processes that influence joint production relationships. We used simulation models of vegetation structure, forest sector carbon, and potential wildlife habitat to characterize landscape-level joint production possibilities for carbon storage, timber harvest, and habitat for seven wildlife species across a range of forest management regimes. We sought to (1) characterize the general relationships of production possibilities for combinations of carbon storage, timber, and habitat, and (2) identify management variables that most influence joint production relationships. Our 160 000-ha study landscape featured environmental conditions typical of forests in the Western Cascade Mountains of Oregon (USA). Our results indicate that managing forests for carbon storage involves trade-offs among timber harvest and habitat for focal wildlife species, depending on the disturbance interval and utilization intensity followed. Joint production possibilities for wildlife species varied in shape, ranging from competitive to complementary to compound, reflecting niche breadth and habitat component needs of species examined. Managing Pacific Northwest forests to store forest sector carbon can be roughly complementary with habitat for Northern Spotted Owl, Olive-sided Flycatcher, and red tree vole. However, managing forests to increase carbon storage potentially can be competitive with timber production and habitat for Pacific marten, Pileated Woodpecker, and Western Bluebird, depending on the disturbance interval and harvest intensity chosen. Our analysis suggests that joint production possibilities under forest management regimes currently typical on industrial forest lands (e.g., 40-to 80-yr rotations with some tree retention for wildlife) represent but a small fraction of joint production outcomes possible in the region. Although the theoretical boundaries of the production possibilities sets we developed are probably unachievable in the current management environment, they arguably define the long-term potential of managing forests to produce multiple ecosystem services within and across multiple forest ownerships.
Information on the distribution of rare and little known species is critical for managers and biologists challenged with species conservation in an uncertain future. Pacific Martens (Martes caurina) historically resided throughout Oregon and northern California’s coastal forests, but were considered extinct until 1996 when a population in northern California was rediscovered. Only 26 verified contemporary (1989–2012) records were known within Oregon prior to this survey. The coastal subspecies (M. c. humboldtensis) was petitioned for listing under the federal Endangered Species Act in 2010. We surveyed for martens during 2014–2015 with 3 separate, non-invasive surveys. We conducted exploratory surveys in 2014, and surveyed at 2 scales during 2015 to confirm the persistence of historical populations (<5 km prior detections) and to determine the limits of current distributions in the region (5–50 km). We surveyed 348 sample units using a total of 72 track plate and 908 remote camera stations for >14 d within a 25,330 km2 area, yielding 355,018 photographs. Martens were detected (photographs, tracks, or genetically verified hair samples) at 72 sample units.We detected 28 individual martens in coastal Oregon using a combination of genetic confirmation and captured individuals. Marten observations were clustered in the Central and South Coast regions, suggesting existing populations have persisted since published observations prior to 1998.We did not locate new populations despite an extensive effort to survey new areas, but did learn a unique population exists in the coastal dunes of Central Oregon. Future research could include surveys at a finer-scale to refine population boundaries and estimate minimum population sizes, better define habitat conditions, and evaluate potential threats to population stability (such as disease, genetic bottlenecks). Until population estimates and trends are known, conservation effortsmay benefit from localmanagement actions, such as restricting or eliminating kill-trapping in the Coast Ranges, as well as broad efforts to increase connectivity, especially where existing populations face significant barriers to movement, such as a major roadway (Highway 101). Based on our observations, efforts to increase the size, number, and extent of populations could be valuable for long-term conservation of the species.
Context Conservation planning for at-risk species requires understanding of where species are likely to occur, how many individuals are likely to be supported on a given landscape, and the ability to monitor those changes through time. Objectives We developed a distribution model for northern spotted owls that incorporates both habitat suitability and probability of territory occupancy while accounting for interspecies competition. Methods We developed range-wide habitat suitability maps for two time periods (1993 and 2012) for northern spotted owls that accounted for regional differences in habitat use and home range size. We used these maps for a long-term demographic monitoring study area to assess habitat change and estimate the number of potential territories based on available habitat for both time periods. We adjusted the number of potential territories using known occupancy rates to estimate owl densities for both time periods. We evaluated our range-wide habitat suitability model using independent survey data. Results Our range-wide habitat maps predicted areas suitable for territorial spotted owl presence well. On the demographic study area, the amount of habitat declined 19.7% between 1993 and 2012, while our estimate of the habitat-based carrying capacity declined from 150 to 146 territories. Estimated number of occupied territories declined from 94 to 57. Conclusions Conservation and recovery of at-risk species depends on understanding how habitat changes over time in response to factors such as wildfire, climate change, biological invasions, and interspecies competition, and how these changes influence species distribution. We demonstrate a model-based approach that provides an effective planning tool.