Mesocarnivore ecology in Alaska
As top predator populations decline worldwide, the role of mesocarnivores is becoming increasingly important, yet we have a poor understanding of how these top-down forces ripple through food webs. We are investigating how wolves impact mesopredators through both positive pathways (e.g., food provisioning via ungulate carcasses) and negative pathways (e.g., intraguild killing). We are examining interactions among wolves, coyotes, and other mesopredators (wolverines, foxes, lynx, and marten) in Denali National Park and Preserve using a combination of GPS collars, snow tracking, fecal genotyping, and modeling. We are also monitoring prey abundance (hares and voles) and climatic conditions in both areas. This study will help to reveal the relative importance of predation, food supply, and climate in the dynamics of mesopredators.
Funding: National Park Service (Denali)
Endangered grassland community dynamics in California
Increasingly, we are facing conservation dilemmas in which endangered species eat each other or compete for resources; thus, actions which help one sensitive species could inadvertently harm another. In 2007, I initiated a large-scale field experiment with collaborators at UC Berkeley to address this issue in the Carrizo Plain National Monument, a hotspot of endangerment in California with imperiled species at every trophic level and a plant community dominated by exotics. We are examining the effects of a federally endangered keystone species (the giant kangaroo rat, Dipodomys ingens) and livestock grazing on other species in the community using replicated exclosures. This study is revealing that both the engineering and trophic interactions mediated by this burrowing rodent play an important role in structuring this grassland food web. In 2014, we are initiating new precipitation manipulations to examine how kangaroo rats mediate the impact of climate change on plants. For more information, visit the project website.
Funding: National Science Foundation (DEB)
Postdocs: Nicolas Deguines (UW), Josh Grinath (CU Boulder)
Collaborators: Kathy Sharum (BLM), Bob Stafford (CDFW), Scott Butterfield (TNC), Tim Bean (HSU)
Assessing alpine ecosystem vulnerability to environmental change using Dall sheep as an iconic indicator species
Lack of knowledge about climate change impacts in alpine ecosystems represents a critical gap in our understanding of resilience and vulnerability to environmental change in the Arctic and boreal region of western North America. Declines in Dall sheep populations throughout their range have led to emergency harvest closures and made sheep harvest by far the most contentious wildlife management issue in Alaska. Dall sheep likely function as bellwethers of alpine ecosystem health, and signs are pointing towards increasing ailment. The overarching goal of our study is to address the question: How are vegetation and snow conditions changing in alpine ecosystems throughout the ABoVE domain, and how do these changes impact iconic northern wildlife and critical ecosystem services? I am leading a collaborative study from 2015-2019 that will: (1) produce time series of snow extent, NDVI, and shrub encroachment throughout alpine areas of the ABoVE domain, (2) evaluate how these factors affect Dall sheep movements, habitat selection, and population viability, (3) improve a spatially-explicit snowpack evolution model, and (4) relate our improved understanding of alpine ecosystem dynamics to the societal implications of altered sheep harvest.
Funding: NASA Arctic and Boreal Vulnerability Experiment (ABoVE)
Collaborators: Janet Rachlow (U Idaho), Glen Liston (Colorado State), J. Putera, K. Rattenbury, S. Arthur, J. Lawler, P. Sousanes (NPS), T. Lohuis, B. Wendling (ADFG), T. Hegel (YTG), N. Larter, T. Davidson (GNWT), K. Callahan (Gwich'in RRB), C. Wong (Parks Canada)
Animals on the move: Remotely based determination of key drivers influencing movements and habitat selection of highly mobile fauna
Highly mobile fauna of the Arctic-Boreal region (ABR) must navigate through an increasingly complex and dynamic mosaic of environmental and land surface conditions, but how vulnerable or resistant their long-term persistence is to the increasing spatiotemporal heterogeneity is unknown. I am a co-PI on a new study led by Natalie Boelman (Columbia University) that seeks to understand how highly mobile terrestrial fauna navigate and select habitat in the rapidly changing ABR. Facilitated by many data-sharing collaborations with US and Canadian government agencies, we will use space-based wildlife tracking technology to build an integrated dataset of regional-scale and near-continuous descriptions of passerine (American robins), raptor (Golden Eagles), ungulate (caribou, moose), and predator (wolf and brown bear) locations with both static and dynamic remote sensing products and other regional-scale geospatial datasets. We will use Movebank to organize data and build movement and habitat selection models for multiple groups of animals across the ABoVE Study Domain. The geospatial tools and products will be made accessible to natural resource agencies, wildlife managers, First Nations, Alaskan natives, and other stakeholders to aid them in management and adaptation decisions.
Funding: NASA Arctic and Boreal Vulnerability Experiment (ABoVE)
PI: Natalie Boelman (Columbia University)
Postdoc: Peter Mahoney
Effects of tourism on terrestrial wildlife in Glacier Bay National Park, Alaska
Shore excursions from tour vessels in Glacier Bay National Park and Preserve have increased by an order of mangitude during the last 8 years, leading to an increase in human use at various sites throughout the park. Repeated human use and/or disturbance can invoke a variety of anti-predator responses in wildlife, and in order to ensure that visitors are able to enjoy all that the park has to offer without detriment to natural resources, it is necessary to quantify changes in species occupancy and activity levels due to increasing use of the shore areas in Glacier Bay. To do this, remote cameras will be deployed at various sites around the park to monitor wildlife activity both in areas that are designated “Heavy Use”, and in those where human visitation is much less common. In addition, a baseline of activity given the current levels of use in the park will be determined, which will ultimately help inform management decisions as visitation and use of shore areas increases.
Funding: National Park Service (Glacier Bay)
Student thesis: Mira Sytsma (MSc)
Collaborator: Tania Lewis (NPS)
Trophic relationships of reintroduced fishers in the South Cascades
In 2015, Washington Department of Fish and Wildlife (WDFW) began reintroducing fishers (Pekania pennanti) to the South Cascades. The west coast fisher population has been proposed as threatened under the Endangered Species Act, and fisher recovery is thus a high priority in Washington. Fisher habitat use has been studied with respect to denning and rest site characteristics, but effects of forest management and stand characteristics on establishment success of reintroduced fishers remains unknown. In collaboration with agency partners, we will study how forest structure and management impact prey availability, competitor abundance, and fisher establishment in the South Cascades. For more information on the fisher reintroduction program, see the WDFW website.
Funding: McIntire-Stennis Program (USDA)
Student thesis: Mitch Parsons (MSc)
Collaborators: Jeff Lewis (WDFW), Tara Chestnut (NPS)
Climate-induced changes to shrub and moose distributions in northern Alaska: implications for subsistence communities
Climate change is rapidly transforming the North Slope of Alaska through changes such as the expansion of shrubs in arctic ecosystems. Shrub expansion may increase habitat for some wildlife species and reduce habitat for others, which can change the subsistence food resources for local communities. For example, moose were absent from the North Slope prior to 1940s, the but their northern range limit has expanded into this region along with shrubs. However, the minimum threshold of shrub area needed to support the presence of moose is unknown in arctic ecosystems. For residents from the North Slope community of Nuiqsut, moose have become a valued resource, producing many pounds of wildlife meat that add to household food security. Using a combination of spatially-explicit historical data, remote sensing, field surveys, and interviews, this project aims to quantify patterns of change in shrubs and moose that have occurred during the past 40 years in the Coleville River region of the North Slope, with a focus on the implications for subsistence communities.
Student dissertation: Jiake Zhou (PhD)