Grassfinch decline and local extinction of the Crimson Finch Neochmia phaeton in the Fitzroy River Basin, Queensland

Abstract

Many granivorous birds of northern Australia, including several species of grassfinches (Estrildidae), have suffered substantial range contractions in the last 50–100 years, apparently as a result of changes in cattle grazing and fire-management regimes. The Crimson Finch Neochmia phaeton was once widespread in woodlands and savannas of north-eastern Australia, including the extensive Fitzroy River Basin, where it was recorded in all the major subcatchments until the middle of last century. However, surveys in 2006–2008 show that it is now confined to a relatively small area in the north-east of the Basin. A tall river grass, Chionachne Chionachne cyathopoda, is an important component—for food and cover—of its habitat. Complex braiding of river channels, as at the confluence of rivers, is typical of the area where the Finches have persisted, possibly because it increases the availability of water and food, and reduces pressure from cattle grazing during the wet season. A recent local loss of the species was noted in one area where landholders used riparian fencing to maintain greater grazing intensity throughout the year, leading to suppression of Chionachne seeding. Thus, although generally favourable for conservation management, riparian fencing can also be used detrimentally. The loss of one local subpopulation of Finches following changed management practices demonstrates that cattle grazing alone, in the absence of changed fire management, has the capacity to alter habitat suitability for granivorous species.