Revegetation on farming sites brings birds back
Field work conducted by Earthwatch volunteers has helped scientists discover promising results for woodland bird species.
In New South Wales, 33 woodland bird species (24%) have declined due to habitat loss, grazing pressure and fertiliser usage. Planting native trees and shrubs has been proposed as a measure for capturing regional diversity, becoming a cornerstone strategy in natural resource management across south-eastern Australia.
Before now, studies have shown that the benefits of revegetation work are limited. Earthwatch volunteers, together with the CSIRO staff and Holbrook Landcare members, have helped determine how the planting of native trees and shrubs on farms has affected woodland bird species.
During 2004-2006, Earthwatch volunteers joined Drs David Freudenberger and Geoff Barrett on Earthwatch’s Return of the Dawn Chorus expedition to help carry out studies in environmental plantings near Holbrook, situated in Australia’s agricultural heartland, where the tension between farm production and conservation is greatest.
The research helped determine which bird species were present, while captured and banded birds helped provide data on number, diversity, survival, breeding and movement between and within study sites.
Seventy percent of the woodland bird species were recorded in revegetated sites, challenging the view that planted habitat in temperate woodland agricultural landscapes is usually of poor quality.
Some of the key biodiversity benefits included the rapid colonisation of revegetated sites by birds, an improvement in the health of old trees within the new plantings and a likely improvement in the bio-control of insect pests as birds forage from the revegetated sites into the nearby crops and pastures.
Early results of this woodland rehabilitation project are, at least for birds, encouraging. Long-term monitoring will be necessary to establish whether bird assemblages in the Holbrook planted sites eventually become indistinguishable from those in remnant woodland.
And through further banding and recapture of individuals, and observations of breeding success, estimates of survival and persistence for birds in planted sites will also be possible.
• Barrett et al (2008), “Colonisation of native tree and shrub plantings by woodland birds in an agricultural landscape”, CSIRO PUBLISHING, Wildlife Research, 2008, 35, pp19–32.
• Barrett, G. & Filmer, M, (2007) "Native plants bringing birds back onto farms", Farming Ahead October 2007 No. 189, CSIRO Sustainable Ecosystems