Will Lynx Lose Their Edge? Canada Lynx Occupancy in Washington

Abstract

Populations of species located at southern range edges may be particularly vulnerable to the effects of climate change as warming temperatures and subsequent changes to ecosystems exceed speciesspecific tolerances. One such species is Canada lynx (Lynx canadensis), a cold-adapted mesocarnivore that maintains a large core population in Alaska, USA, and Canada but exists within several peripheral populations in the contiguous United States. Increases in temperature, declines in snow pack, and climateinfluenced increases in fire frequency and intensity, could negatively affect lynx populations, threatening their long-term persistence in the continental United States. Despite these threats, our understanding of broad-scale effects on lynx occupancy and the extent of current lynx distribution in many of these peripheral populations is minimal. We conducted an occupancy survey of lynx in Washington, USA, using a spatially extensive camera-trapping array covering 7,000 km 2 of potential lynx habitat. We used the resulting database of detection data to develop single-season occupancy models to examine the abiotic and biotic effects on current lynx occupancy and predict future lynx distribution based on climate change forecasts. Our results show lynx occupancy across the Washington landscape is restricted and dictated largely by abiotic factors, disturbance regimes, and distance from source populations in Canada. Predictions of future distribution suggest lynx will be increasingly challenged by climatic changes, particularly at the southern and lower elevation portions of their range in Washington. Our results paint an alarming picture for lynx persistence in Washington that is relevant to current deliberations regarding lynx delisting from the Endangered Species Act. Our simple camera design was a highly effective method for surveying lynx across broad spatial scales, and could be a key monitoring tool for lynx that is easy to implement by researchers and government agencies.

Improved prediction of Canada lynx distribution through regional model transferability and data efficiency

“…Our study area had a mean annual temperature ranging from −1°C to 12°C (Table A1), suggesting that snow‐ice feedback might influence warming patterns in lynx habitat, resulting in faster warming and decreased habitat suitability. King et al (2020) found a similar susceptibility to changes in temperature and snow pack for the persistence of Canada lynx at their range periphery in Washington.…”

The influence of spatial and temporal scale on the relative importance of biotic vs. abiotic factors for species distributions

“…ILBT, 2013; Mote, 2003;Stoelinga et al, 2010). These shifts may have serious deleterious effects on ranges of cold-adapted species (King et al, 2020), while increasing temperature and decreases in snow cover may open more habitat up to more warm-adapted TA B L E 5 Results of conditional two-species occupancy models for six carnivore species pairs in northeastern Washington. The influence of spatial grain on interspecific interactions between dominant-subdominant pairs.…”

“…significant reductions in snow depth within Washington; ILBT, 2013; Mote, 2003; Stoelinga et al., 2010). These shifts may have serious deleterious effects on ranges of cold‐adapted species (King et al., 2020), while increasing temperature and decreases in snow cover may open more habitat up to more warm‐adapted species (e.g. cougars, coyotes, bobcats and black bears; Hansen et al., 2001; ILBT, 2013).…”

Linking camera‐trap data to taxonomy: Identifying photographs of morphologically similar chipmunks

“…Uncertainty in camera‐trap datasets is often ignored. Even species with otherwise obvious distinguishing characteristics can be misidentified by experts if photograph quality is poor or odd angles are captured, yet researchers rarely report how mediocre a photograph must be or the confidence of the identification necessary to merit removal from the dataset (King et al., 2020). Meek et al.…”