Climate change and anthropogenic food manipulation interact in shifting the distribution of a large herbivore at its altitudinal range limit

Abstract

Ungulates in alpine ecosystems are constrained by winter harshness through resource limitation and direct mortality from weather extremes. However, little empirical evidence has definitively established how current climate change and other anthropogenic modifications of resource availability affect ungulate winter distribution, especially at their range limits. Here, we used a combination of historical (1997–2002) and contemporary (2012–2015) Eurasian roe deer (Capreolus capreolus) relocation datasets that span changes in snowpack characteristics and two levels of supplemental feeding to compare and forecast probability of space use at the species’ altitudinal range limit. Scarcer snow cover in the contemporary period interacted with the augmented feeding site distribution to increase the elevation of winter range limits, and we predict this trend will continue under climate change. Moreover, roe deer have shifted from historically using feeding sites primarily under deep snow conditions to contemporarily using them under a wider range of snow conditions as their availability has increased. Combined with scarcer snow cover during December, January, and April, this trend has reduced inter-annual variability in space use patterns in these months. These spatial responses to climate- and artificial resource-provisioning shifts evidence the importance of these changing factors in shaping large herbivore spatial distribution and, consequently, ecosystem dynamics.

West Indian Manatees Use Partial Migration to Expand Their Geographic Range Into the Northern Gulf of Mexico

“…Among North American terrestrial birds, those with partial and intra-continental migrations had greater latitudinal range shifts compared to residents and neotropical migrants, likely because the former can more easily track conditions in migratory regions (Hovick et al, 2016). Similar to poleward range shifts, altitudinal migration has enabled roe deer in central Europe to exploit decreased winter snowpack and shift the altitudinal limit of their winter range (Bright Ross et al, 2021). Partial migration may, therefore, be a general mechanism for climate driven range shifts among a diverse range of species as it is the most common type of migration and occurs in most animal phyla (Dingle and Drake, 2007;Chapman et al, 2011Chapman et al, , 2012Shaw and Couzin, 2013).…”

“…Partial migration may benefit populations under climate change scenarios because these migrations allow species to flexibly track favorable conditions through space and time (Naidoo et al, 2012;Hovick et al, 2016;Acker et al, 2021;Bright Ross et al, 2021). Through partial migration, species may be able to exploit new areas as they become available, residing in new areas while conditions are favorable, and retreating, often seasonally, when conditions become unfavorable (Naidoo et al, 2012;Bright Ross et al, 2021). If conditions in the areas of expansion remain favorable for longer periods throughout the year, individuals may be able to stay longer and eventually transition from migrants to residents (Bright Ross et al, 2021).…”

“…Through partial migration, species may be able to exploit new areas as they become available, residing in new areas while conditions are favorable, and retreating, often seasonally, when conditions become unfavorable (Naidoo et al, 2012;Bright Ross et al, 2021). If conditions in the areas of expansion remain favorable for longer periods throughout the year, individuals may be able to stay longer and eventually transition from migrants to residents (Bright Ross et al, 2021). Populations that are living at or near their geographic range limit will likely be the first to experience conditions that allow them to move into new areas (Perry et al, 2005;Parmesan, 2006), and it is likely easier to detect these movements in these areas.…”

“…Populations that are living at or near their geographic range limit will likely be the first to experience conditions that allow them to move into new areas (Perry et al, 2005;Parmesan, 2006), and it is likely easier to detect these movements in these areas. Populations that already exhibit migratory plasticity may be better able to respond to changing environmental conditions (Martin et al, 2018;Bright Ross et al, 2021), making them ideal study populations to examine the role of partial migration in facilitating climate driven range expansions.…”

“…Manatees are also likely harbingers of climate driven, ecological changes in places like the nGoM, as other tropical associated species are becoming increasingly common (Fodrie et al, 2010;Heck et al, 2015;Scheffel et al, 2018). Understanding the ecologically meaningful components of manatee migrations will support ongoing range-wide management, conservation, and species recovery actions, as well as provide evidence for how other species that exhibit partial migration may be affected under future climate scenarios (Martin et al, 2018;Bright Ross et al, 2021).…”