The owls are coming: positive effects of climate change in Northern ecosystems depend on grassland protection

Abstract

Climate-driven migrations towards Northern latitudes are expected to reorganize biotic communities as result of range shift dynamics. However, the establishment of healthy populations of migrating species depends on habitat provision by receptor landscapes. Here, we ask if the rising temperatures and changes in precipitation regimes in western North America are likely to lead to an expansion of warm and dry-affiliated species, using the burrowing owl (Athene cunicularia) as a study case. This migratory species depends on grassland habitats for nesting and breeding, so we test for the effect of the lack of grasslands on the occupancy of future suitable environments. To estimate the burrowing owl's potential distribution, we used ecological niche models (ENMs) calibrated with climate and soil information and projected onto future scenarios of climate change (low versus high greenhouse gas emission). Then, we simulated environmental sorting using habitat filter masks derived from information on habitat use and forecasts of future land use change, focusing on grasslands as nesting and breeding habitat. We found that the burrowing owl could expand its geographic distribution by 3 to 10-fold towards Northern latitudes, especially under high-emission scenarios of climate change. However, nearly half of the suitable environments (up to 53,593 km² of locations with suitable climate and soil) might not be covered by grasslands, due to conversion to agriculture and other human land uses which may prevent the establishment of breeding populations. Our results shed light on the pervasive effects of neglecting the preservation of grasslands across western North America, which could provide critically needed habitat for migrating species from lower latitudes. Enhancing and facilitating the colonization of novel species is a shift in the static paradigm of biodiversity conservation and a proactive measure for climate change adaptation.

Keywords: Climate change; Ecosystem services; Fire management; Grassland protection; Land use change; Paris agreement; Range expansion; Species distribution models; UN decade of ecosystem restoration.