Friday, August 6, 2010

PS 97-72: Measuring the performance, and identifying gaps in an existing reserve system. A case study from Victoria, Australia

Seyedeh Mahdieh Sharafi, Australian Centre of Excellence for Risk Analysis (ACERA Lab)


A key focus in conservation planning is the design of reserve systems that “optimise” for the protection of multiple biodiversity surrogates for least cost .However across much of the world, reserve systems are already in place. These reserve systems are rarely the consequence of reserve selection strategies or strictly rational criteria. Typically reserve systems emerge from a protracted sequence decisions strongly influenced by political, social and economic motivations.The state of Victoria Australia – covering an area of some 22.7 million hectares - has an established and legally defined conservation reserve system within which, most resource exploitation has been excluded. The total area dedicated to nature conservation is approximately 17% of total area of the state (some 3.86 million hectares). 

What we intend to do is to measure how one such haphazardly developed reserve system has performed in capturing the State’s environmental space as defined by a selected suite of both continuous and discrete biophysical variables – intended to perform as biodiversity and/or ecosystem level surrogates (Faith and Walker 1996).

We frame our reserve system metrics within the context of concepts that have been developed as part of Australia’s conservation reserve system aspirations (Commonwealth of Australia 1999; Natural Resource Management Ministerial Council 2004). In short a conservation reserve system should be ‘comprehensive’, ‘adequate’ and ‘representative’.  These concepts have emerged from negotiations between State and Federal Governments in Australia with respect to the reservation of land for biodiversity conservation. 


The computational intensity of this task necessitated significant data reduction. we have reduced complexity of the environmental space to a series of categorical landscape properties embodied in a suite of spatially explicit environmental variables that were assumed a-priori to be useful in describing the terrestrial environmental space.  The assumption being that the interplay of climatic, edaphic and physiographic variables broadly captures the terrestrial ecosystem variation across the state.

Using our comprehensiveness metric we discovered 94,000 hectares across Victoria that coincides with regions of our environmental space that are not sampled by the reserve system. Of this area some 79,450 is on freehold land the remainder is publically owned land.

The Comprehensiveness analysis highlights regions of real absolute deficiency in the reserve system.The adequacy results draw attention to the competition between intensive human land use and the reserve system. It also highlights that these absolute deficiencies are largely on freehold land tenures (report on percentages).