Muskrats as a bellwether of a drying delta

Abstract

Wetlands worldwide are under threat from anthropogenic impacts. In large protected North American areas such as Yellowstone and Wood Buffalo National Parks, aquatic habitats are disappearing and wetland-dependent fauna are in decline1–3. Here we investigate population dynamics of an indicator species in Canada’s Peace-Athabasca Delta (“the delta”), a World Heritage Site. Based on population surveys, habitat mapping and genetic data from 288 muskrats, we use agent-based modeling and genetic analyses to explain population expansion and decline of the semi-aquatic muskrat (Ondatra zibethicus). Simulations quantify a large population (~500,000 individuals) following flood-induced habitat gains, with decreased size (~10,000 individuals) during drying. Genetic analyses show extremely low long-term effective population size (Ne: 60–127), supporting a legacy of population bottlenecks. Our simulations indicate that the muskrat population in the delta is a metapopulation with individuals migrating preferentially along riparian pathways. Related individuals found over 40 km apart imply dispersal distances far greater than their typical home range (130 m). Rapid metapopulation recovery is achieved via riparian corridor migration and passive flood-transport of individuals. Source-sink dynamics show wetland loss impacts on the muskrat metapopulation’s spatial extent. Dramatic landscape change is underway, devastating local fauna, including this generalist species even in a protected ecosystem.

HexFire: A Flexible and Accessible Wildfire Simulator

“…HexSim [24] is a well-established software application that has been used in >60 peer-reviewed publications. Although HexSim models have traditionally been designed to conduct population viability analysis for species of conservation concern [25][26][27][28][29][30][31][32][33][34], use of the platform has expanded to a wider range of topics (e.g., disease models [35]). HexSim and HexFire are spatially explicit and can easily incorporate multiple static or dynamic maps quantifying the amounts and patterns of fuels, moisture levels, wind, ignition sites, management interventions, and other drivers relevant to wildfire.…”

Celerity of Ice Breakup Front in the Regulated Peace River, Canada, and Implications for the Recharge of the Peace–Athabasca Delta

“…Moreover, the delta is a homeland for the Indigenous Peoples of the region. During the past five decades or so, this complex and dynamic delta has, in-between rare overland flooding events, experienced prolonged dry periods and considerable reduction in the area covered by the myriad of lakes, ponds, and wetlands (basins) that provide habitat for aquatic life [2][3][4][5][6][7][8][9][10]. Regulation of Peace River began with construction (1968), reservoir-filling (1968)(1969)(1970)(1971), and operation (1972 onwards) of the W.A.C.…”

The Drying Peace–Athabasca Delta, Canada: Review and Synthesis of Cryo-Hydrologic Controls and Projections to Future Climatic Conditions

“…During the past five decades or so, this complex and dynamic region has, in-between rare overland flooding events, experienced prolonged dry periods and considerable reduction in the area covered by lakes and ponds that provide habitat for aquatic life [4][5][6][7][8][9][10][11][12]. The drying trend coincides with the regulation of Peace River, which began with construction (1968), reservoir-filling (1968)(1969)(1970)(1971) and operation (1972 onwards) of the W.A.C.…”