Modeling the impact of climate change and wildfire on the Dusky Grouse (Dendragapus obscurus) in the American Southwest: implications for conservation

Climate change is recognized as a threat to the Dusky Grouse (Dendragapus obscurus), in part because of changes in weather that might lead to more frequent and severe wildfire that can cause loss of habitat. Our goal was to better understand the geographic range and habitat suitability for the Dusky Grouse in the American Southwest, and to predict impacts of future climate change and recent wildfire on the Dusky Grouse in this region. We developed a species distribution model (SDM) to describe the species' geographic range in Arizona and New Mexico using climate, topographic, and landcover variables. We modeled the impact of future climate on Dusky Grouse habitat for the years 2041-2060 and 2081-2100 according to two carbon emission scenarios and modeled the loss of habitat due to recent moderate and severe wildfires. Our SDM indicated that the distribution of the Dusky Grouse was best predicted solely by climate variables and consequently is fragmented, particularly in the southern region of the study area. Under future climate scenarios, high quality habitat was predicted to be almost entirely lost regardless of time frame or climate scenario, with the most rapid loss of habitat in the southern region. However, contemporary (2000-2017) wildfires have already caused substantial loss of habitat in the southern region, particularly in the Mogollon Mountains and adjacent areas of southwestern New Mexico. Our finding that loss of habitat due to wildfires may precede and outpace loss of habitat via climate change, suggests that populations may become imperiled or extirpated more quickly than anticipated according to conventional climate models, and that these impacts are likely to first affect trailing-edge populations at the southern extent of the species geographic range, but will spread to more northern regions.