Climate velocities and species tracking in global mountain regions

Abstract

Mountain ranges contain high concentrations of endemic species and are indispensable refugia for lowland species that are facing anthropogenic climate change1,2. Forecasting biodiversity redistribution hinges on assessing whether species can track shifting isotherms as the climate warms3,4. However, a global analysis of the velocities of isotherm shifts along elevation gradients is hindered by the scarcity of weather stations in mountainous regions5. Here we address this issue by mapping the lapse rate of temperature (LRT) across mountain regions globally, both by using satellite data (SLRT) and by using the laws of thermodynamics to account for water vapour6 (that is, the moist adiabatic lapse rate (MALRT)). By dividing the rate of surface warming from 1971 to 2020 by either the SLRT or the MALRT, we provide maps of vertical isotherm shift velocities. We identify 17 mountain regions with exceptionally high vertical isotherm shift velocities (greater than 11.67 m per year for the SLRT; greater than 8.25 m per year for the MALRT), predominantly in dry areas but also in wet regions with shallow lapse rates; for example, northern Sumatra, the Brazilian highlands and southern Africa. By linking these velocities to the velocities of species range shifts, we report instances of close tracking in mountains with lower climate velocities. However, many species lag behind, suggesting that range shift dynamics would persist even if we managed to curb climate-change trajectories. Our findings are key for devising global conservation strategies, particularly in the 17 high-velocity mountain regions that we have identified.

Global hotspots of butterfly diversity in a warming world

“…Over 40% of terrestrial vertebrate species are mountain endemics 28 , but despite the strong implication for conservation whether and how this extends to insects remains unknown. At the same time, temperature-induced up-slope shifts and losses in habitat combined with strong geographic isolation put mountain biodiversity in great peril [29][30][31][32] . Impacts from warming might be particularly severe for insects due to their known strong temperature sensitivity [33][34][35][36] , but to date a global assessment of the geographic coincidence of diversity, rarity, and climate change threats for an insect system does not exist.…”

“…Through their role as buffers for past climatic change, their diversity of microclimatic conditions, and their isolation, mountains have repeatedly served as fundamental refugium for terrestrial global biodiversity [26][27][28]31,33,42 . During the projected upcoming period of rapid global warming, the same attributes have been hypothesized to convert mountain habitats from safe havens 26 to graves, especially in combination with growing land-use pressures [52][53][54] .…”