Author: Damian Michael (Charles Sturt University), dmichael@csu.edu.au
With over 220 vertebrate species, Australia has a rich diversity of wildlife associated with, and in many cases, dependent on rocky environments and component microhabitat features such as surface rock. In all their complexity and form, rocky outcrops support a rich diversity of endemic species, are collectively referred to as biological hotspots, and represent refugia for specialised plants and animals, including more than 55 species listed as nationally threatened.
Despite their well-recognised ecological, cultural and economic values, rock formations are fragile ecosystems, easily degraded by human activities and lack adequate levels of protection on private land. The impacts of rock removal on the population viability of the threatened rock-dwelling broad-headed snake (Hoplocephalus bungaroides) is well-established. However, limited assessment of rock-dwelling vertebrate communities, especially in agricultural landscapes, makes it difficult to determine the spatial extent of threatened faunal groups and the impacts associated with landscape transformation and farmland intensification.
Recent developments in broad-acre cropping technology has triggered a rapid increase in the removal of surface rock habitat from across Australia’s prime agricultural landscapes. Whilst not illegal, the removal of bush rock is listed as a key threatening process under the Threatened Species Conservation Act 1995 (TSC Act). The new wave of habitat loss associated with rock-crushing machinery has massive implications for nationally threatened reptile species such as the pink-tailed worm-lizard, striped legless lizard and grassland earless dragon species, which are on the brink of extinction. This practice is at odds with the current philosophy of sustainable farming, whereby agricultural activities and wildlife conservation can co-occur on the same land with mutual conservation and economic benefits. Pressure to maximise productivity by increasing crop yields and intensifying land use could spell disaster for threatened species that primarily occur on farmland.
There is urgent need to develop high resolution maps of critical rock refugia, spatially explicit species distribution models, and improve our understanding of the attributes of rock microhabitat that are important for threatened species, to reduce ongoing biodiversity declines in commodity production landscapes.
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