Relating habitat and climatic niches in birds.

Jean-Yves Barnagaud,Frédéric Jiguet,Frédéric Archaux,Vincent Devictor,Isabelle Le Viol,Morgane Barbet-Massin,Nicolas Salamin

doi:10.1371/journal.pone.0032819

Abstract

Predicting species' responses to the combined effects of habitat and climate changes has become a major challenge in ecology and conservation biology. However, the effects of climatic and habitat gradients on species distributions have generally been considered separately. Here, we explore the relationships between the habitat and thermal dimensions of the ecological niche in European common birds. Using data from the French Breeding Bird Survey, a large-scale bird monitoring program, we correlated the habitat and thermal positions and breadths of 74 bird species, controlling for life history traits and phylogeny. We found that cold climate species tend to have niche positions in closed habitats, as expected by the conjunction of the biogeographic history of birds' habitats, and their current continent-scale gradients. We also report a positive correlation between thermal and habitat niche breadths, a pattern consistent with macroecological predictions concerning the processes shaping species' distributions. Our results suggest that the relationships between the climatic and habitat components of the niche have to be taken into account to understand and predict changes in species' distributions.

Highlights

Biogeography and community ecology are being increasingly integrated into a common framework in which the interaction between local and large-scale processes are recognized as influencing community dynamics [1]
The habitat niche position can tell us which vegetation structure is most usually associated with the presence of a given bird species, while its habitat niche breadth indicates the extent to which the species is able to dwell within other structures
Distribution models often show that climatic variables predict species distributions better than habitat or land use variables, but the underlying causes remain unclear [50] and are scaledependent [16]

Summary

Introduction

Biogeography and community ecology are being increasingly integrated into a common framework in which the interaction between local and large-scale processes are recognized as influencing community dynamics [1]. A species’ niche can be described straightforwardly through its position and breadth along well-defined gradients of resources or environmental conditions A species’ niche position usually reflects the average level of a resource that it exploits (or the average climatic condition it copes with). It can be regarded as a coarse-grained measure of resource use, determined by species’ evolutionary history and long-term adaptive pressures [7,8]. Niche position and breadth have generally been considered as independent drivers of species’ distributions and responses to environmental changes. While climatic niches (or envelopes) are defined by both their average climatic position and their climatic breadth, these two variables have seldom been considered together in models of birds’ response to climatic changes, except as concurrent predictors (e.g. [13,14], but see [15])

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