Home range size scales to habitat amount and increasing fragmentation in a mobile woodland specialist.

Kirstin Proft,Riana Gardiner,Chris N Johnson,Sebastien Comte,Menna Jones

doi:10.1002/ece3.5837

Abstract

Studies of impacts of fragmentation have focused heavily on measures of species presence or absence in fragments, or species richness in relation to fragmentation, but have often not considered the effects of fragmentation on ranging behavior of individual species. Effective management will benefit from knowledge of the effects of fragmentation on space use by species.We investigated how a woodland specialist, the eastern bettong (Bettongia gaimardi), responded to fragmentation in an agricultural landscape, the Midlands region of Tasmania, Australia. We tested whether individual bettongs could adjust home range size to maintain access to essential habitat across three sites differing in degree of fragmentation.We used GPS tracking to measure the home ranges of individual bettongs. Our models tested the effects of habitat aggregation and habitat amount measured at two radii comparable to a typical core range (250 m) and a typical home range (750 m), and habitat quality and sex on individual home range. We also tested the relationship between fragmentation on woodland used to determine whether individuals could compensate for fragmentation.Depending on the spatial scale of fragmentation measured, bettongs altered their movement to meet their habitat requirements. Our top model suggested that at the core range scale, individuals had smaller ranges when habitat is more aggregated. The second model showed support for habitat amount at the core range, suggesting individuals can occupy larger areas when there is a higher amount of habitat, regardless of configuration.Species that are relatively mobile may be able to compensate for the effects of habitat fragmentation by altering their movement. We highlight that any patch size is of value within a home range and management efforts should focus on maintaining sufficient habitat especially at the core range scale.

Highlights

Habitat loss is a global threat to biodiversity and a challenge for conservation managers (Haddad et al, 2015; Hanski, 2015)
We tested whether individual bettongs could adjust home range size to maintain access to essential habitat across three sites differing in degree of fragmentation
We highlight that any patch size is of value within a home range and management efforts should focus on maintaining sufficient habitat especially at the core range scale

Summary

| INTRODUCTION

Habitat loss is a global threat to biodiversity and a challenge for conservation managers (Haddad et al, 2015; Hanski, 2015). Effects of fragmentation on these variables are often interpreted in relation to classic metapopulation and island biogeography theories, or more recent ideas such as the habitat continuum and habitat amount hypotheses (Fahrig, 2013; Fischer, Lindenmayer, & Kaitala, 2006; Hanski, 2015; Lindgren & Cousins, 2017) Each of these hypotheses places importance on the amount and configuration of habitat patches and how these determine species persistence. Occupancy of eastern bettongs in this region is predicted by the quality and amount of habitat within a home range radius (Gardiner, Bain, Hamer, Jones, & Johnson, 2018); little is known regarding their movement and response to fragmentation. If the amount of habitat used does not change and or increases with increasing fragmentation individuals are able to use movement to access the required habitat regardless of fragmentation

| MATERIALS AND METHOD

Findings

| DISCUSSION