Range-Wide Latitudinal and Elevational Temperature Gradients for the World's Terrestrial Birds: Implications under Global Climate Change

Abstract

Species' geographical distributions are tracking latitudinal and elevational surface temperature gradients under global climate change. To evaluate the opportunities to track these gradients across space, we provide a first baseline assessment of the steepness of these gradients for the world's terrestrial birds. Within the breeding ranges of 9,014 bird species, we characterized the spatial gradients in temperature along latitude and elevation for all and a subset of bird species, respectively. We summarized these temperature gradients globally for threatened and non-threatened species and determined how their steepness varied based on species' geography (range size, shape, and orientation) and projected changes in temperature under climate change. Elevational temperature gradients were steepest for species in Africa, western North and South America, and central Asia and shallowest in Australasia, insular IndoMalaya, and the Neotropical lowlands. Latitudinal temperature gradients were steepest for extratropical species, especially in the Northern Hemisphere. Threatened species had shallower elevational gradients whereas latitudinal gradients differed little between threatened and non-threatened species. The strength of elevational gradients was positively correlated with projected changes in temperature. For latitudinal gradients, this relationship only held for extratropical species. The strength of latitudinal gradients was better predicted by species' geography, but primarily for extratropical species. Our findings suggest threatened species are associated with shallower elevational temperature gradients, whereas steep latitudinal gradients are most prevalent outside the tropics where fewer bird species occur year-round. Future modeling and mitigation efforts would benefit from the development of finer grain distributional data to ascertain how these gradients are structured within species' ranges, how and why these gradients vary among species, and the capacity of species to utilize these gradients under climate change.

Canadian butterfly climate debt is significant and correlated with range size

“…A common challenge for all species in our study is the large number of dispersal barriers presented by the complex landscapes of Canada. High levels of topographic variation can result in steep elevational gradients in temperature and precipitation (La Sorte et al 2014), making it difficult for a species to traverse topographic barriers and may restrict movement between habitats. Fragmented landscapes have also been shown to reduce a species' ability to track climate change, regardless of their dispersal ability (Meier et al 2012).…”

Spatial patterns of co‐occurrence of the European wildcat Felis silvestris silvestris and domestic cats Felis silvestris catus in the Bavarian Forest National Park

“…is considered the limit for an all-season wildcat habitat (Klar 2009). However, global warming could potentially lead to range expansions towards higher altitudes, as has been found for several other taxa (La Sorte et al 2014, Sauer et al 2011.…”

Insect elevational specialization in a tropical biodiversity hotspot

“…Tropical species are generally regarded to have low thermal tolerance due to the low seasonal temperature variability experienced, making them potentially vulnerable to extinction from climate change (Addo-Bediako et al, 2000;Deutsch et al, 2008, Bonebrake & Deutsch, 2012. The elevational ranges displayed by species may, at least partially, indicate their thermal tolerances (McCain, 2009;Laurance et al, 2011;Garc ıa-Robledo et al, 2016), and have been used to infer extinction risk from climate change across taxa and geographic locations (Colwell et al, 2008;Sekercioglu et al, 2008;Feeley & Silman, 2010;La Sorte & Jetz, 2010;Mekasha et al, 2013;La Sorte et al, 2014), but little is known about how elevational ranges vary in tropical insects. Here, we assess the variation in elevational specialisation across several insect taxa along an elevational transect in Brazilian Atlantic Forest, and the likely implications for conservation under climate change.…”