Effects of clear-fell harvest on bat home range.

Kerry M Borkin,Stuart Parsons

doi:10.1371/journal.pone.0086163

Abstract

We investigated effects of roost loss due to clear-fell harvest on bat home range. The study took place in plantation forest, inhabited by the New Zealand long-tailed bat (Chalinolobus tuberculatus), in which trees are harvested between the ages 26–32 years. We determined home ranges by radiotracking different bats in areas that had and had not been recently clear-fell harvested. Home ranges were smaller in areas that had been harvested. Adult male bats selected 20–25 year old stands within home ranges before and after harvest. Males selected edges with open unplanted areas when harvest had not occurred but no longer selected these at proportions greater than their availability post harvest, probably because they were then readily available. This is the first radiotracking study to demonstrate a change in home range size and selection concomitant with felling of large areas of plantation forest, and thus quantify negative effects of forestry operations on this speciose group. The use of smaller home ranges post-harvest may reflect smaller colony sizes and lower roost availability, both of which may increase isolation of colonies and vulnerability to local extinction.

Highlights

Clear-fell harvest – the logging of usually large areas of evenaged trees at regular intervals – has been heavily criticised for its potential impacts on vegetation structure and forest-dependent fauna [1]
We report 100% Minimum Convex Polygon (MCP) because these are the most commonly used metric used in reporting of other studies of C. tuberculatus’ home range [28,29] and so allow other researchers to compare those home ranges found in this study with those elsewhere
There were no statistical differences in home range sizes or spans between bats in different reproductive states (100% MCP: H (3) = 4.83, P = 0.188; 95% MCP: H (3) = 3.00, P = 0.418; 85% MCP: H (3) = 1.78, P = 0.653; Range span: H (3) = 3.34, P = 0.365)

Summary

Introduction

Clear-fell harvest – the logging of usually large areas of evenaged trees at regular intervals – has been heavily criticised for its potential impacts on vegetation structure and forest-dependent fauna [1]. When bats choose home ranges that include plantation forests they are likely to come into contact with harvest operations [2,3]. Effects on foraging activities have not been investigated for many species and most studies have taken place in areas where harvest had not recently taken place [4]. Well-designed radiotracking studies are required in actively managed plantation forests to investigate individual bat species’ home range characteristics and habitat selection to resolve effects of harvest operations [4,8]. A search of the literature suggests that there have been no studies comparing bats’ home ranges in areas where clearfell harvest operations had and had not occurred recently

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Conclusion