Hot Topic

Ongoing destruction of critical rock habitat threatens biodiversity

Tuesday, 6 August 2019  | 

Author: Damian Michael (Charles Sturt University),

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.

A downloadable pdf on this Hot Topic can be found here.

Supporting Research

Couper, P., & Hoskin, C. (2008) Litho-refugia: the importance of rock landscapes for the long-term persistence of Australian rainforest fauna. Australian Zoologist, 34(4), 554-560.
To outline examples of rainforest fauna that exemplify the importance of rock landscapes in the persistence of rainforest lineages.
Fitzsimons, J. A., & Michael, D. R. (2017) Rocky outcrops: a hard road in the conservation of critical habitats. Biological conservation, 211, 36-44.
A review of the literature on the ecological, cultural and economic values of rocky outcrops, threatening processes and conservation solutions.
McDougall, A., Milner, R. N., Driscoll, D. A., & Smith, A. L. (2016) Restoration rocks: integrating abiotic and biotic habitat restoration to conserve threatened species and reduce fire fuel load. Biodiversity and Conservation, 25(8), 1529-1542.
To examine the influence of rock habitat and native grass restoration and management scenarios (fire and herbicide application) on the use of the threatened Pink-tailed Worm Lizard (Aprasia parapulchella).
Michael, D. & Lindenmayer, D. (2018) Rocky Outcrops in Australia: Ecology, Conservation and Management. CSIRO Publishing, Collingwood, Australia.
To increase awareness of the biological, cultural and social values of rocky outcrops, the flora and fauna that depend on these systems and to provide management recommendations to improve their conservation values.
Michael, D. R., Cunningham, R. B., & Lindenmayer, D. B. (2008) A forgotten habitat? Granite inselbergs conserve reptile diversity in fragmented agricultural landscapes. Journal of Applied Ecology, 45(6), 1742-1752.
To examine the relationships of reptile diversity, rocky outcrop patch size and habitat condition.
Michael, D. R., Lindenmayer, D. B., & Cunningham, R. B. (2010) Managing rock outcrops to improve biodiversity conservation in Australian agricultural landscapes. Ecological Management & Restoration, 11(1), 43-50.
A review of the literature on granite outcrops in agricultural landscapes.
Pike, D. A., Croak, B. M., Webb, J. K., & Shine, R. (2010) Subtle–but easily reversible–anthropogenic disturbance seriously degrades habitat quality for rock‐dwelling reptiles. Animal Conservation, 13(4), 411-418.
To investigated the effects of human-induced rock disturbance on saxicolous reptiles.
Shine, R., Webb, J. K., Fitzgerald, M., & Sumner, J. (1998) The impact of bush-rock removal on an endangered snake species, Hoplocephalus bungaroides (Serpentes: Elapidae). Wildlife Research, 25(3), 285-295.
To examine the impact of rock removal on an endangered snake species (Hoplocephalus bungaroides).
Wong, D. T. (2013). Environmental factors affecting the occurrence and abundance of the Pink-tailed Worm-lizard (Aprasia parapulchella) in the Australian Capital Territory (Doctoral dissertation, University of Canberra).
To investigate the factors driving theoccurrence and abundance of the threatened Pink-tailed Worm Lizard (Aprasia parapulchella) in the ACT at regional and patch scales.