Climate and landscape changes as driving forces for future range shift in southern populations of the European badger

Luís M Rosalino,Carlos Fonseca,Clara Grilo,Pedro Monterroso,João Carvalho,Ana Serronha,Dário Hipólito,Emílio Virgós,Diana Guedes,Xosé Pardavila,Margarida Santos-Reis,Diogo Cabecinha

doi:10.1038/s41598-019-39713-1

Abstract

Human-Induced Rapid Environmental Change (HIREC), particularly climate change and habitat conversion, affects species distributions worldwide. Here, we aimed to (i) assess the factors that determine range patterns of European badger (Meles meles) at the southwestern edge of their distribution and (ii) forecast the possible impacts of future climate and landcover changes on those patterns. We surveyed 272 cells of 5 × 5 km, to assess badger presence and confirmed its occurrence in 95 cells (35%). Our models estimate that badger’s presence is promoted by the occurrence of herbaceous fields and shrublands (5%–10%), and low proportions of Eucalyptus plantations (<~15%). Regions with >50% of podzols and eruptive rocks, higher sheep/goat density (>4 ind/km2), an absence of cattle, intermediate precipitation regimes (800–1000 mm/year) and mild mean temperatures (15–16 °C) are also more likely to host badgers. We predict a decrease in favourability of southern areas for hosting badgers under forecasted climate and landcover change scenarios, which may lead to a northwards retraction of the species southern distribution limit, but the overall landscape favourability is predicted to slightly increase. The forecasted retraction may affect community functional integrity, as its role in southern ecological networks will be vacant.

Highlights

The conservation of rear-edge populations is crucial for maintaining species evolutionary potential[1], but since such populations face different ecological conditions and potentially distinct population dynamics from populations in core distribution areas, conservation measures should be context-specific[2]
The four residuals autocovariate (RAC)-BRT (Residuals AutoCovariate Boosted Regression Trees models) models produced for the H1–H4 hypotheses showed that the percentage cover of herbaceous vegetation, shrubland and Eucalyptus (H1); the density of goats and sheep and cattle (H2); the percentage of soils dominated by podzols and eruptive rocks (H3); and the annual mean temperature and annual precipitation (H4), were the most influential variables in each hypothesis and the only ones included in the first quarter of relative influence per hypothesis (Table 1)
We found no multicollinearity between the candidate variables for the hybrid hypothesis (H5) RAC-BRT model, so all of them were used in the modelling procedure (Table S5 - Supplementary Material)

Summary

Introduction

The conservation of rear-edge populations (i.e. low latitude populations living on species range limits) is crucial for maintaining species evolutionary potential[1], but since such populations face different ecological conditions and potentially distinct population dynamics from populations in core distribution areas, conservation measures should be context-specific[2]. Western Mediterranean regions are considered poor badger habitats due to spatio-temporal inconstancies in environmental conditions (especially in drier areas) and resource availability[29,32], which will be exacerbated by the forecasted increased aridity for this region[33] This variability in environmental conditions, together with the predicted changes in climate and landcover[18], raise the need to assess how the rear-edge badger population inhabiting the most southwestern corner of its range may be distributed in future decades. This is critical information to understand badger resilience, guide possible management actions to maintain population connectivity, and comprehend how ecological processes may be affected in regions where this predator’s distribution may shift

Objectives

Methods

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Conclusion