Estimating climate-induced 'Nowhere to go' range shifts of the Himalayan Incarvillea Juss. using multi-model median ensemble species distribution models

Global climate change threatens the range and resilience of species in the major biodiversity, particularly those in mountain regions. As the climatic conditions at high altitudes becomes suitable for colonization, many alpine plants experiences novel competitive pressures along as well as range-shift limitations along alpine peaks. To estimate climate-induced 'Nowhere to go' scenarios, we modelled habitat suitability for the Himalayan Incarvillea Juss. and its subgenera using a multi-model median (MMM) ensemble species distribution modelling (eSDM). This model incorporated 13 climatic and other 15 environmental variables with n = 542 spatially rarefied occurrence records of the Incarvillea species. Meanwhile, contributions of environmental factors to ecological divergence were statistically verified using principal component analysis (PCA) and discriminant function analysis (DFA). Finally, the geographic range was projected under n = 4 different climatic scenarios and analysed for plausible range shifts. The niche divergence test suggested larger ecological differentiation within the genus and subgenera by climatic rather than environmental variables. In response to climatic factors, the consensus projection resulted in a wide range of suitability for Incarvillea across the three foremost Biodiversity hotspots of Asia. The spatio-temporal projection of the Incarvillea species in the Hengduan Mountains expand their range north-westward in future without diminishing their range size under climate warming, but not promisingly occupied niche range as anticipated by the Nowhere to go hypothesis. Therefore, a better understanding of the potential range of the genus Incarvillea and its subgenera envisioned through solely climate-induced variables might provide better insights to biogeographers in understanding geographic range amalgamating climate change adaptation and biodiversity conservation in the biodiversity hotspots.

Automated summary

This study used a species distribution model under climate change to explore the adaptability range changes of Incarvillea species in the Himalayas, showing larger ecological differentiation within the genus and subgenera by climatic rather than environmental variables. The model predicted an expansion of the species range in the Hengduan Mountains under future climate warming, but did not fully support the "Nowhere to go" hypothesis.