Vertebrate responses to human land use are influenced by their proximity to climatic tolerance limits

Jessica J Williams,Tim Newbold,Cesar Capinha

doi:10.1111/ddi.13282

Abstract

AbstractAimLand‐use change leads to local climatic changes, which can induce shifts in community composition. Indeed, human‐altered land uses favour species able to tolerate greater temperature and precipitation extremes. However, environmental changes do not impact species uniformly across their distributions, and most research exploring the impacts of climatic changes driven by land use has not considered potential within‐range variation. We explored whether a population's climatic position (the difference between species' thermal and precipitation tolerance limits and the environmental conditions a population experiences) influences their relative abundance across land‐use types.LocationGlobal.MethodsUsing a global dataset of terrestrial vertebrate species and estimating their realized climatic tolerance limits, we analysed how the abundance of species within human‐altered habitats relative to that in natural habitats varied across different climatic positions (controlling for proximity to geographic range edge).ResultsA population's thermal position strongly influenced abundance within human‐altered land uses (e.g. agriculture). Where temperature extremes were closer to species' thermal limits, population abundances were lower in human‐altered land uses (relative to natural habitat) compared to areas further from these limits. These effects were generally stronger at tropical compared to temperate latitudes. In contrast, the influences of precipitation position were more complex and often differed between land uses and geographic zones. Mapping the outcome of models revealed strong spatial variation in the potential severity of decline for vertebrate populations following conversion from natural habitat to cropland or pasture, due to their climatic position.Main conclusionsWe highlight within‐range variation in species' responses to land use, driven (at least partly), by differences in climatic position. Accounting for spatial variation in responses to environmental changes is critical when predicting population vulnerability, producing successful conservation plans, and exploring how biodiversity may be impacted by future land‐use and climate change interactions.

Highlights

Human impacts on the environment do not affect species uniformly across their distribution (Orme et al, 2019)
To ensure we did not extrapolate beyond the limits of our data, we found the predicted relative abundance within cropland and pasture for each population from the PREDICTS database included in our models
The relative abundance of a species across land uses differed depending on the populations' thermal position and Ppmin position, with these effects differing between geographic zones (p- values from the backwards stepwise selection process for the interaction between land-use type, geographic zone and (a) Tmax position, pP(Occ) = 0.012, pLogAbund = 0.001 (b) Tmin position, pP(Occ) = 0.008, pLogAbund = 0.186, (c) Ppmin position, pP(Occ) < 0.001, pLogAbund < 0.001; Figures 2 and 3, Table 2; for comprehensive plots for each climatic position, see Appendix S4, Figure S4.8–11; for coefficients and their 95% confidence intervals, see Appendix S9, Figure S9.20–21)

Summary

Introduction

Human impacts on the environment do not affect species uniformly across their distribution (Orme et al, 2019). Physiological tolerances to temperature and precipitation, and the proximity of individuals to these tolerance limits (i.e. how close environmental climatic conditions are to an individual's climatic tolerance limits), lead to important differences across species' ranges in responses to environmental change (Deutsch et al, 2008; Gerick et al, 2014; Kingsolver et al, 2013; Soroye et al, 2020). By predicting where populations will be pushed beyond their climatic tolerances ( unlikely able to persist), species bioclimatic envelopes have frequently been used to project how species' ranges may shift under global climate change (Calosi et al, 2010; Pearson & Dawson, 2003). Climatic changes are occurring at the global level. Land-use changes lead to local-scale climatic changes (Williams & Newbold, 2020)

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Discussion

Conclusion