Thick-billed Grasswren (Eastern Subspecies) (Amytornis textilis modestus) (North, 1902) Recovery Plan
NSW National Parks and Wildlife Service, July 2002
ISBN 0 7313 65143
6 Management Issues
Major contractions of range have been recorded for A. textilis, and these are thought mostly to have been associated with degradation of habitat through overstocking of sheep (and possibly cattle), and by further damage caused by Rabbits and Goats (Schodde 1982a; Ford 1987; McAllan 1987; Garnett 1993). The species is adversely affected by damage to soil and the loss of understorey vegetation caused by overstocking, and thought to be especially vulnerable during times of drought (Davies & Chapman 1975; Schodde 1982a; Blakers et al. 1984; Storr 1986, 1987; Ford 1987; McAllan 1987; Brooker 1988; Garnett 1993; Coate 1994; Saunders & Ingram 1995; Chapman 1996).
In Western Australia, A .t. textilis occupies successional habitats at least a few years after fire, and possibly benefits from infrequent, widespread wildfires following heavy initial grazing (Curry 1983, 1986). However, A. t. textilis may be threatened by repeated burning, and the subspecies A. t. modestus is also thought to have been adversely affected in the past by wildfires (Storr 1985a; McAllan 1987; Brooker 1988).
Introduced predators are considered a threat to the species, and to have caused its disappearance from many areas (Schodde 1982a; McAllan 1987; Garnett 1993). Feral Cats are thought to have been responsible for the local extinction of the population of A. t. textilis on Dirk Hartog Island, WA (Garnett 1993).
The Thick-billed Grasswren in NSW has undergone a dramatic reduction of its former distribution because of past land management practices and the impacts of feral animals. For almost half a century there has been no authenticated record of the species in NSW and it may well be extinct in this state. The primary aim of this Recovery Plan is to determine its status within NSW through targeted surveys and by increasing community and interest groups' awareness in a hope that future records may be forthcoming. The Recovery Plan does not propose any regulation of current land use. However, should future populations of the species be discovered and changes to current land use practices are thought necessary for the conservation of the species then a cooperative approach to management is advocated. Accordingly, no significant social or economic impacts are likely to arise from actions in this Recovery Plan.
The maintenance of biodiversity is increasingly becoming a significant social issue as today's society places a greater value on species, ecological communities and ecosystem function. Because of this change in priorities, environmental considerations now have equal standing to social and economic issues in the decision-making process of Government. From these changes society aims to reach certain goals from which they obtain benefits. Social benefits associated with the recovery of the threatened Thick-billed Grasswren include the sense of well being derived from the knowledge that the species is conserved for both current and future generations.
The plight of the Thick-billed Grasswren highlights the fate of many western New South Wales species whose populations have severely declined or become extinct since European settlement. The role the species plays in the ecology of the arid zone is unknown. A greater understanding of the pressures that resulted in the Thick-billed Grasswren's decline in New South Wales may be of considerable value in the future management of populations and of other species in the west that occupied a similar habitat or niche.
A greater understanding of the exact mechanisms that caused the decline of the species would be of great assistance in the management of biodiversity and threatened species in western New South Wales in general. The halting of this trend through the recovery of threatened species will have significant biodiversity benefits that reach further than individual species in western NSW. The impacts associated with the decline of the Thick-billed Grasswren may be similar to those influencing the decline of other species. Through an understanding of these impacts, actions can be taken that may be of benefit to many species suffering a similar fate. Active management undertaken through the recovery process will have indirect benefits for species such as the Redthroat (Pyrrholaemus brunneus) and the Rufous Fieldwren (Calamanthus campestris) that occupy the same habitat.