Farmland bird responses to intersecting replanted

Authors: David B Lindenmayer Ross Cunningham Mason Crane Damian Michael Rebecca MontagueDrake

Publish Date: 2007/09/12

Volume: 22, Issue: 10, Pages: 1555-1562

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Abstract

Despite increasing revegetation of cleared landscapes around the world there is limited research on the implications of different types of plantings for birdlife We examined the “intersection effect” whereby species richness is higher at the intersection of “corridors” or vegetation strips for birds inhabiting replanted areas We also examined individual species responses Replicated sites at the intersections of plantings were compared with “internal controls” located in the same plantings ∼100 m from intersections “external controls”sites in isolated linear plantings and block plantings We surveyed the 39 sites in our experimental design repeatedly – on different days by different observers and in different seasons We found no significant difference in species richness between intersections and block plantings but intersections had higher species richness than isolated linear strips and the internal controls Similar results were found for bird assemblage scores derived by correspondence analysis We found evidence of extravariation at the farmlevel for species richness and derived assemblage scores suggesting a farmscale response This suggests the importance of other often unmeasured factors at the farm level eg baiting for feral animals Our results suggest that replanting programs aimed at maximizing bird species richness may benefit from consideration of planting geometry In particular linking strip plantings to create intersections and/or establishing block plantings appear to be superior to isolated strips for aggregate species richnessThis work was supported by Natural Heritage Trust Land and Water Australia and Australian Research Council grants to The Australian National University Dr J Fischer and Dr A Manning kindly assisted with several aspects of the study and made useful critical comments on earlier versions of the manuscript We most gratefully acknowledge the private landholders who allowed access to their properties

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