Climate change in our backyards: the reshuffling of North America's winter bird communities

Abstract

Much of the recent changes in North American climate have occurred during the winter months, and as result, overwintering birds represent important sentinels of anthropogenic climate change. While there is mounting evidence that bird populations are responding to a warming climate (e.g., poleward shifts) questions remain as to whether these species-specific responses are resulting in community-wide changes. Here, we test the hypothesis that a changing winter climate should favor the formation of winter bird communities dominated by warm-adapted species. To do this, we quantified changes in community composition using a functional index--the Community Temperature Index (CTI)--which measures the balance between low- and high-temperature dwelling species in a community. Using data from Project FeederWatch, an international citizen science program, we quantified spatiotemporal changes in winter bird communities (n = 38 bird species) across eastern North America and tested the influence of changes in winter minimum temperature over a 22-year period. We implemented a jackknife analysis to identify those species most influential in driving changes at the community level and the population dynamics (e.g., extinction or colonization) responsible for these community changes. Since 1990, we found that the winter bird community structure has changed with communities increasingly composed of warm-adapted species. This reshuffling of winter bird communities was strongest in southerly latitudes and driven primarily by local increases in abundance and regional patterns of colonization by southerly birds. CTI tracked patterns of changing winter temperature at different temporal scales ranging from 1 to 35 years. We conclude that a shifting winter climate has provided an opportunity for smaller, southerly distributed species to colonize new regions and promote the formation of unique winter bird assemblages throughout eastern North America.

Cold tolerance, and not earlier arrival on breeding grounds, explains why males winter further north in an Arctic‐breeding songbird

“…Climate change models predict less snow and warmer temperatures for the current snow bunting wintering range (Krasting et al , Williams et al ), and winter bird communities are already shifting to favour more warm‐adapted species (Princé and Zuckerberg ). As winter temperatures increase, snow buntings may move further north within their winter range; however, they could be limited in the extent of northwards movement by the boreal forest, which stretches coast‐to‐coast across North America.…”

A bust but no boom: responses of floodplain bird assemblages during and after prolonged drought

“…Increased drought frequency alongside other climate pressures will alter the structure and composition of animal assemblages. More resistant and resilient species will become more dominant, while less resistant and resilient species will decline, potentially to local extirpation or extinction (Princé & Zuckerberg ). Maintaining and, more problematically, restoring the condition of ecosystems may improve the resistance and resilience of species to extreme climate events.…”

Thermal Characterization of European Ant Communities Along Thermal Gradients and Its Implications for Community Resilience to Temperature Variability

“…Our results are supported by recent research. For instance, Princé and Zuckerberg (2015) analyzed the changes that took place over a 22-year period in winter bird communities in North America, and they found that bird communities at southern latitudes were the most affected by climatic variability. Jarzyna et al (2015) found that bird communities in fragmented landscapes are less vulnerable to climate change than communities found in homogenous habitats, probably due to the fact that they are comprised of species with wider thermal niches and are less susceptible to shifts in climatic variability.…”

“…This is because species do not usually live in isolation; instead, they form communities where they interact with each other, and often species respond to environmental changes as a group. More recently, several studies have examined community responses to climate change (Devictor et al, 2008;Kampichler et al, 2012;Lindström et al, 2013;Jarzyna et al, 2015;Nieto-Sánchez et al, 2015;Princé and Zuckerberg, 2015); nonetheless, our understanding of how climate change affects community-level biodiversity remains incomplete. Moreover, previous studies have focused on the alarming expected increase in global mean temperature.…”

“…In contrast to most recent studies exploring community-level thermal responses to climate change (Devictor et al, 2008;Kampichler et al, 2012;Nieto-Sánchez et al, 2015;Princé and Zuckerberg, 2015), our study addresses the full range of species-specific thermal responses present within communities rather than focusing exclusively on each species' thermal optimum. To develop this framework, we used ants (family Formicidae), which are an ideal study system in this context because they are geographically widespread, ecologically diverse, and one of the most abundant invertebrate groups in terrestrial ecosystems (Hölldobler and Wilson, 1990).…”