Macroclimate data overestimate range shifts of plants in response to climate change

Abstract

Current conservation policy has been shaped by the expectation that, for many species, places with suitable climate will lie outside their current range, thus leading to predictions of numerous extinctions. Here we show that the magnitude of range shifts is often overestimated as climate data used do not reflect the microclimatic conditions that many organisms experience. We model the historic (1977–1995) distributions of 244 heathland and grassland plant taxa using both macro- and microclimate data and project these distributions to present day (2003–2021). Whereas macroclimate models predicted major range shifts (median 14 km shift), microclimate models predicted localized shifts, generally of less than 1 km, into favourable microclimates that more closely match observed patterns of establishment and extirpation. Thus, improving protection of refugial populations within species’ existing geographic range may, for species living in environments exposed to sunlight, be more effective than assisted translocations and overhaul of protected area networks.