Where do they go? The effects of topography and habitat diversity on reducing climatic debt in birds

Abstract

The spatial tracking of climatic shifts is frequently reported as a biodiversity response to climatic change. However, species' range shifts are often idiosyncratic and inconsistent with climatic shift predictions. At the community scale, this discrepancy can be measured by comparing the spatial shift in the relative composition of cold- vs. warm-adapted species in a local assemblage [the community temperature index (CTI)] with the spatial shift in temperature isotherms. While the local distribution of climate change velocity is a promising approach to downscaling climate change pressure and responses, CTI velocity has only been investigated on a continental or national scale. In this study, we coupled French Breeding Bird Survey data, collected from 2133 sites monitored between 2001 and 2012, with climatic data in order to estimate the local magnitude and direction of breeding season temperature shift, CTI shift, and their spatiotemporal divergence - the local climatic debt. We also tested whether landscape characteristics that are known to affect climate velocity and spatial tracking of climate change mediated the climatic debt on the local scale. We found a clear spatial structure, together with heterogeneity in both temperature and CTI spatial shifts. Local climatic debt decreased as the elevation, habitat diversity, and the naturalness of the landscape increased. These results suggest the complementary effects of the local topographic patterns sheltering more diverse microclimates and the increasing permeability of natural and diversified landscape. Our findings suggest that a more nuanced evaluation of spatial variability in climatic and biotic shifts is necessary in order to properly describe biodiversity responses to climate change rather than the oversimplified descriptions of uniform poleward shifts.

Can Topographic Variation in Climate Buffer against Climate Change-Induced Population Declines in Northern Forest Birds?

“…High temperature variation also seems to buffer the negative decline of northern forest birds. Our results are thus in line with earlier studies investigating the impacts of topoclimatic variation on the persistence of species populations that are based, as our study is, on data from repeated surveys [27,30,59].…”

“…Thus, the buffering impacts of local air temperatures may not require very large elevational gradients but can be effective already in moderately varying landscape. A study by Gaüzère, Prince and Devictor [59] investigated the climatic debt in bird communities in France using the species community temperature index (CTI), and showed that an increasing range in elevation can affect bird species populations positively by reducing the rate of their change. However, the study area in France also included mountainous landscapes, where the range of elevational variation was measured in several hundreds of meters compared to our study PAs with the variation commonly measured in tens of meters.…”

Multidirectional abundance shifts among North American birds and the relative influence of multifaceted climate factors

“…Redistribution of abundance could be the result of a population growth or a decline within existing species range and thus be less affected by geographical barriers. Landscape composition and configuration, particularly topographic variability, has the potential to significantly mediate species response to climate change (Gaüzère, Princé, & Devictor, ). Variable topography provides several mechanisms to mediate spatial responses to climate change including reducing the distance between isotherms and creating local climate refugia (Gaüzère et al., ; Lenoir et al., ; Loarie et al., ).…”

Unequal contributions of species’ persistence and migration on plant communities’ response to climate warming throughout forests

“…Recently, it has been shown that factors involved in species' persistence absorb more of climate warming in communities than species' migration is able to mitigate through thermophilization of forest plant assemblages (Bertrand et al 2016). The rare studies investigating the underlying factors that explain the climatic debt assumed this determinism was stable over large and heterogeneous areas (Bertrand et al 2016, Gaüzère et al 2017). However, it is likely to vary locally following the proportion of Brevia warm-adapted species present in the regional species pool as well as the magnitude of the climate change or the habitat connectivity and disturbances for instance (Bertrand et al 2011(Bertrand et al , 2016.…”