High-elevation endemic plants predicted to lose habitat from changing climate in Washington State.

Abstract

Premise: High-elevation plants face unique challenges from potential climate change impacts that will likely require upslope migration into increasingly smaller suitable habitat. This situation is particularly acute for endemic species that by definition occupy small geographic ranges. Here we assessed climate risk for eight endemic species occurring in the Cascade Range of Washington State and modeled their ability to persist through the end of the century.

Methods: For current species distributions, we utilized online georeferenced herbarium specimen and observation data from Pacific Northwest herbaria and iNaturalist. We visualized future climate impacts on current habitat space for each species using principal component analysis under two future CO₂ emission levels: SSP245 and SSP585. We then applied an ensemble modeling approach using spatial data for climate, canopy cover, topography, and geology to predict future suitable habitat for each species.

Results: Our models predicted substantial habitat area losses for seven of eight species examined, with four expected to lose 99-100% of suitable habitat if CO₂ emissions continue at current levels (SSP585). Under reduced CO₂ emissions levels (SSP245), an average of 26.8% of the habitat area loss for each species can be abated.

Conclusions: While our models show habitat range shifts for these species, it remains uncertain whether any species will successfully migrate into future potential suitable habitat. Habitat loss predicted in this study informs potential conservation needs. We present a repeatable modeling framework for studying climate change impacts on habitat for targeted species using publicly available distribution and environmental data.