Bird's Response to Revegetation of Different Structure and Floristics - Are "Restoration Plantings" Restoring Bird Communities?

Abstract

Revegetation plantings have been established throughout the world to mitigate the effects of clearing, including loss of faunal habitat. Revegetation plantings can differ substantially in structural complexity and plant diversity, with potentially differing habitat qualities for fauna. We studied bird occurrence in revegetation of different complexity and floristics in southern Australia. We assessed bird species richness and composition in remnant forest and cleared agricultural land as reference points, and in two types of plantings differing in structure and floristics-(1) "woodlot plantings" composed of native trees only and (2) "ecological plantings" composed of many species of local trees, shrubs and understorey. By approximately 20 years of age, both types of plantings had a similar bird species richness to that in remnants. Bird species richness was greater in ecological plantings than woodlot plantings. Species composition also differed. Ecological plantings contained a shrub-associated bird assemblage, whereas woodlot plantings were dominated by generalist bird species. Remnants contained a unique bird assemblage, which were not found in either of the two types of plantings, suggesting that plantings are not a viable replacement of remnant vegetation over this time period. Bird species richness responded positively to structural complexity, but not to floristic richness. Bird species richness was greater in plantings that were older, in riparian locations, and where weed cover was lower. We conclude that plantings in general can provide habitat for many species of birds, and that structurally complex ecological plantings in particular will provide unique and valuable additional habitat for birds.