Novel outbreaks of emerging pathogens require rapid responses to enable successful mitigation. We simulated a 1-day emergency meeting where experts were engaged to recommend mitigation strategies for a new outbreak of the amphibian fungal pathogen Batrachochytrium salamandrivorans. Despite the inevitable uncertainty, experts suggested and discussed several possible strategies. However, their recommendations were undermined by imperfect initial definitions of the objectives and scope of management. This problem is likely to arise in most real-world emergency situations. The exercise thus highlighted the importance of clearly defining the context, objectives, and spatial–temporal scale of mitigation decisions. Managers are commonly under pressure to act immediately. However, an iterative process in which experts and managers cooperate to clarify objectives and uncertainties, while collecting more information and devising mitigation strategies, may be slightly more time consuming but ultimately lead to better outcomes.
In southeast Alaska, United States, multiple-use forest management objectives include both timber production and wildlife habitat. Following stand-replacing disturbances such as clear-cutting, Sitka spruce (Picea sitchensis (Bong.) Carrière) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) naturally regenerate and competitively dominate resources, excluding understory biomass and biodiversity. Thinning may mitigate the effects of canopy closure and permit understory development, but evidence of the effect on understories 8–10 years after thinning is lacking. We report results 4–5 and 8–10 years after thinning experiments on the Tongass National Forest to demonstrate the effects of precommercial thinning (thinned versus control), stand age (15–25, 25–35, and 35–50 years), and weather on understory dynamics and Sitka black-tailed deer (Odocoileus hemionus sitkensis Merriam, 1898) forage availability. Stand density negatively affected understory biomass, whereas temperature and precipitation positively interacted to increase biomass. Thinning had an enduring effect on understories, with biomass at least twice as great in thinned versus unthinned stands through year 10. We identified compositional differences from thinning as stand age class increased. Deer forage responded similarly to biomass, but thinning-induced differences faded with increased winter snowfall scenarios, especially in older stands. This study aids the understanding of stand overstory and understory development following silvicultural treatments in the coastal temperate rain forest of Alaska and suggests management implications and applications for balancing objectives throughout the forest type.
Monitoring vegetation phenology is important for managers at several scales. Across decades, changes in the timing, pattern, and duration of significant life cycle events for plant groups can foreshadow shifts in species assemblages that can affect ecosystem services. In the shorter term, managers need phenological information to time activities such as grazing, ecological restoration plantings, biocontrol of pests, seed collection, and wildlife monitoring. However, tools to deliver timely seasonal development have been limited either spatially (data from a single tower or weather station, or on a single species, or both) or temporally (annually, quarterly, or monthly summaries). We developed another option called PhenoMap. This is a weekly assessment of land surface “greenness” across the continental United States that employs the Normalized Differential Vegetation Index (NDVI) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data. Here we present the PhenoMap Web map and its validation by using 54 in situ PhenoCam camera sites representing six vegetation structure types and 31 different ecoregions. We found that PhenoMap effectively tracks phenology on grasslands, shrublands, deciduous broadleaf and mixed forests. Results for evergreen needleleaf sites were poor owing to the low green-up signal relative to the total amount of foliage detected by NDVI. Issues of extent and field of view were critical when assessing remotely sensed data with in situ oblique camera imagery.
Dispersal among breeding sites in territorial animals (i.e. breeding dispersal) is driven by numerous selection pressures, including competition and spatiotemporal variation in habitat quality. The scale and trend of dispersal movements over time may signal changing conditions within the population or on the landscape. We examined 2,158 breeding dispersal events from 694 male and 608 female individually marked Northern Spotted Owls (Strix occidentalis caurina) monitored over 28 yr on 7 study areas to assess the relative importance of individual (sex, experience), reproductive (annual productivity, mate availability), and environmental (forest alteration, presence of competitor) sources of variation in breeding dispersal distance. Median breeding dispersal distance was 3.17 km, with 99% of all breeding dispersal events <37 km. Mean annual dispersal distances increased by 2.43 km in Oregon and 9.40 km in Washington between 1990 and 2017, which coincided with increases in annual detections of nonnative Barred Owl (S. varia). Frequency of breeding dispersal events, both among and within individuals, also increased over time. Female owls moved farther than males (median of 3.26 and 3.10 km, respectively), and birds with less experience (territory tenure) moved farther than those with more experience. Owls that were single in the year prior to dispersal moved 13–31% farther than those paired prior to dispersal. The greatest environmental change occurring over the course of our study was the expansion of Barred Owl populations. Breeding dispersal distance was positively related to Barred Owls in the study area and disturbance within the originating territory. While it appears that social factors continue to be important drivers of breeding dispersal distance in Spotted Owls, increased competition from Barred Owls and habitat alteration have a contributing effect. Increased breeding dispersal distances should be of concern for conservation efforts and considered in population monitoring because changing dispersal behavior may lead to higher rates of mortality and/or emigration from historical study areas.
Resource managers are under increasing pressure to prioritize conservation efforts by assessing climate risk for numerous species. Amphibians, fish, and reptiles are particularly vulnerable to habitat alteration and climate change, yet many species fly under the conservation radar due to lack of basic information.
Dede Olson, a research ecologist with the Pacific Northwest Research Station, has forged science partnerships among researchers from diverse disciplines that are yielding rapid advances in species threat assessments.
Olson and three U.S. Geological Survey scientists developed an index to rapidly assess the vulnerability of freshwater fish, reptiles, and amphibians native to Oregon based on rarity and sensitivity to climate change. The index can be used to assess inherent climate sensitivity across entire taxonomic groups using existing data.
Olson also worked with geneticists from Washington State University and the University of Michigan to evaluate how landscape variables affect population connectivity for two salamanders found in Northwest forests. The partnership created a new avenue to address dispersal habitat associations for torrent salamanders, highlighting conservation needs that span the salamanders’ life cycle.
Together, these studies illustrate how combining basic- and applied-science perspectives in partnered research is providing new insights for management of at-risk species.
Environmental DNA (eDNA) assays for single‐ and multi‐species detection show promise for providing standardized assessment methods for diverse taxa, but techniques for evaluating multiple taxonomically divergent assemblages are in their infancy. We evaluated whether microfluidic multiplex metabarcoding on the Fluidigm Access Array™ platform and high‐throughput sequencing could identify diverse stream and riparian assemblages from 48 taxon‐general and taxon‐specific metabarcode primers. eDNA screening was paired with electrofishing along a stream continuum to evaluate congruence between methods. A fish hatchery located midway along the stream continuum provided a dispersal barrier, and a point source for non‐native White Sturgeon (Acipencer transmontanus). Microfluidic metabarcoding had 87% accuracy with respect to electrofishing and detected all 13 species electrofishing observed. Taxon‐specific barcoding primers were more successful than taxon‐general universal metabarcoding primers at classifying sequences to species. Both types of markers detected a transition from downstream sites dominated by multiple fish species, to upstream sites dominated by a single species; however, we failed to detect a complementary transition in amphibian occupancy. White Sturgeon was only detected at the hatchery outflow, indicating eDNA transport was not detectable ~2.4 km from its source. Overall, we identified 878 predicted taxa. Most sequences (50.1%) derived from fish (Actinopteri, Petromyzontidae), oomycetes (21.3%), arthropoda (classes Insecta, Decapoda; 16.5%), and apicomplexan parasites (3.8%). Taxa accounting for ~1% or less of sequences included freshwater red algae, diatoms, amphibians, and beaver. Our work shows that microfluidic metabarcoding can survey multiple phyla per assay, providing fine discrimination required to resolve closely related species, and enable data‐driven prioritization for multiple forest health objectives.
Recreating on public land is increasingly popular in the Pacific Northwest. Recreation management requires balancing opportunities for people to enjoy the outdoors with mitigating the effects on wildlife and other natural resources. Recreation and wildlife managers grappling with these issues asked Forest Service scientists to quantify the impacts of motorized and nonmotorized recreation on elk. Elk are highly valued for hunting and viewing by the public, and as large herbivores, they play a critical role in many ecosystems of the Intermountain West.
A large fenced area within the Starkey Experimental Forest and Range in eastern Oregon provided a unique setting for assessing how a wide-ranging species like elk respond to four types of recreation. Real-time data recorded by telemetry units worn by people and elk alike allowed scientists to establish a cause-effect relationship between human movements and activities and elk responses. Scientists found that elk avoided areas where humans were recreating. This avoidance resulted in habitat compression. All-terrain vehicle use was most disruptive to elk, followed by mountain biking, hiking, and horseback riding. When exposed to these activities, elk spent more time moving rather than feeding and resting.
Land managers can use this information to assess tradeoffs between multiple, and often competing, land uses. When combined with planning efforts that include stakeholder engagement, it may offer a clearer path forward.
Comparative landscape genetic studies provide insights into whether relationships between landscape features and patterns of spatial genetic structure differ among populations, species, habitat types, and regions. For species with fragmented distributions, especially when management practices contribute to fragmentation, tests of the factors structuring population connectivity are particularly important for understanding continued risks. We determined levels of genetic diversity and tested the relationships of landscape-scale vegetative, geographic, and climate variables with genetic distance in two congeneric, endemic salamander species with status of concern. Using microsatellite data for 326 Rhyacotriton kezeri and 557 Rhyacotriton variegatus individuals collected from 17 to 29 localities, respectively, we implemented a model of landscape resistance based on circuit theory. The northernmost portions of each species’ range is more fragmented than areas to the south, leading to the prediction that these areas would have relatively lower genetic diversity in response. Due to reliance of both species upon cold-water habitats, we predicted that landscape variables maintaining cool, moist microhabitats would be correlated with gene flow. Genetic structure was high overall and trended toward increasing with the proportion of the forested landscape. Based on maximum likelihood population effects models across genetic clusters and species, land cover and roads were the best predictors of genetic distance, even though the degree of fragmentation differed across each species’ geographic range. Our results suggest that forest cover is essential for dispersal in these salamanders, indicating negative effects of fragmentation resulting from timber harvest and other forest disturbances.
The U.S. Forest Service and other federal land managers are responsible for maintaining the productivity of aquatic–riparian ecosystems, the associated native biota, and the ecosystem services they provide. These public lands are important sources of water, recreation opportunities, and habitat for a suite of animals and plants, including many that are protected under the Endangered Species Act. To meet these challenges and responsibilities, recent science suggests modifying practices to provide a broader array of habitat, biological conditions, and ecosystem functions than are associated with traditional management approaches. We suggest that by linking approaches based on natural disturbance and portfolio concepts, managers can achieve a robust strategy and desired outcomes more reliably and cost effectively. Locally complex habitat conditions created by natural disturbances provide the template for biological diversity to play out provided enough time. Accordingly, natural disturbance regimes play an important role in creating and sustaining habitat and biological complexities on the landscape, and management actions can emulate natural disturbance processes at appropriate spatial and temporal scales where possible. The portfolio effect (i.e., diversity that mitigates risk) provides justification for promoting connected heterogeneous habitats that reduce the risk of synchronous large–scale population and ecosystem collapse. In this paper, we describe how disturbance and portfolio concepts fit into a broader strategy of conserving ecosystem integrity and dynamism, and provide examples of how these concepts can be used to address a wide range of management concerns. Ultimately, the outcome for populations, habitats, and landscapes depends on how well environmental change is understood, the degree to which change is appropriately addressed by natural resource managers, and on solutions that allow populations and ecosystems to persist in the presence of and be resilient to a growing scope of human influences.