Shifts in the climate space of temperate cyprinid fishes due to climate change are coupled with altered body sizes and growth rates

Ana Ruiz‐Navarro,J Robert Britton,Phillipa K Gillingham

doi:10.1111/gcb.13230

Abstract

Predictions of species responses to climate change often focus on distribution shifts, although responses can also include shifts in body sizes and population demographics. Here, shifts in the distributional ranges (‘climate space’), body sizes (as maximum theoretical body sizes, L∞) and growth rates (as rate at which L∞ is reached, K) were predicted for five fishes of the Cyprinidae family in a temperate region over eight climate change projections. Great Britain was the model area, and the model species were Rutilus rutilus, Leuciscus leuciscus, Squalius cephalus, Gobio gobio and Abramis brama. Ensemble models predicted that the species' climate spaces would shift in all modelled projections, with the most drastic changes occurring under high emissions; all range centroids shifted in a north‐westerly direction. Predicted climate space expanded for R. rutilus and A. brama, contracted for S. cephalus, and for L. leuciscus and G. gobio, expanded under low‐emission scenarios but contracted under high emissions, suggesting the presence of some climate‐distribution thresholds. For R. rutilus, A. brama, S. cephalus and G. gobio, shifts in their climate space were coupled with predicted shifts to significantly smaller maximum body sizes and/or faster growth rates, aligning strongly to aspects of temperature‐body size theory. These predicted shifts in L∞ and K had considerable consequences for size‐at‐age per species, suggesting substantial alterations in population age structures and abundances. Thus, when predicting climate change outcomes for species, outputs that couple shifts in climate space with altered body sizes and growth rates provide considerable insights into the population and community consequences, especially for species that cannot easily track their thermal niches.

Highlights

Climate change will be a major driver of biodiversity changes throughout this century (Sala et al, 2000), with evidence that species across a range of taxonomic groups are already responding to recent climatic change by shifting their ranges (Root et al, 2003; Hickling et al, 2006; Comte et al, 2013)
The ensemble model for R. rutilus had an area under the ROC curve (AUC) 0.95 and predicted that their climate space in Great Britain would expand in each climate change projection, with increased space with higher emissions (44 to 84%; Table 1; Fig. S2)
It was predicted that for three of the model species, R. rutilus, A. brama and S. cephalus, shifts in their climate space under the climate change projections were coupled with shifts to populations comprising of individuals of significantly smaller maximum theoretical body sizes that would grow faster, resulting in predictions of reduced lengths at age under high-emission climate change projections

Summary

Introduction

Climate change will be a major driver of biodiversity changes throughout this century (Sala et al, 2000), with evidence that species across a range of taxonomic groups are already responding to recent climatic change by shifting their ranges (Root et al, 2003; Hickling et al, 2006; Comte et al, 2013). Common responses are distribution shifts polewards and/or to increased altitudes (Chen et al, 2011; Bebber et al, 2013; Comte & Grenouillet, 2013), as these facilitate species tracking their climate niches (Crimmins et al, 2011). For this to be successful requires the rate of distribution change to match the pace of isotherm shifts, that is the climate change velocity (Isaak & Rieman, 2013). Movements in many plant species will need to be in excess of 1 km per year to track climate change

Methods

Results

Conclusion