COS 16-6
A connectivity modelling approach for land use planners applied to regional conservation planning in the Lower Hunter, Australia

Monday, August 11, 2014: 3:20 PM
315, Sacramento Convention Center
Alex M. Lechner, Centre for Environment, University of Tasmania, Hobart, Australia
Edward C. Lefroy, Centre for Environment, University of Tasmania, Hobart, Australia

Habitat fragmentation from human activity is a key threat to natural systems, resulting in landscapes that support smaller, more isolated populations of native species. A consequence is reduced population viability and increased extinction risk. Mitigation efforts often focus on identifying, conserving and restoring habitat patches and connectivity elements such as wildlife corridors or scattered trees that allow for dispersal.

This study developed a connectivity modelling framework for regional conservation planning for use across Australia and potentially internationally. We trialled this framework in the Lower Hunter region of New South Wales, Australia - an area targeted for future urban, industrial and agricultural development. The framework consists of a connectivity model and a landuse planning scenario model. The approach can be used with commonly available spatial data and is developed for intermediate GIS users within consultancies and non-government and government agencies so that they may dynamically assess connectivity in response to landuse planning decisions. It is based on a nested, multi-scale approach with high spatial resolution landcover data processed to provide a representation of the environments encountered by species that use fine-scale landscape features (e.g. scattered trees and wildlife corridors) to move through the landscape over short distances.


We modelled current connectivity and projected future development scenarios between woody vegetation patches using the graph-theoretic approach in conjunction with least-cost paths identified with dispersal cost surfaces. The ecological parameters included: inter-patch dispersal distance, gap crossing distance and minimum patch size. The baseline model describing current connectivity showed that the majority of woody native vegetation in the region exists in two areas composed of interlinked connected patches isolated from each other, one large area in the west and a smaller area in the east. Next we tested five future development scenarios simulated through the removal of vegetation associated with: i) local environmental plans, ii) proposed future state and local government developments, iii) the completion of the Hunter Expressway, iv) high agricultural productivity and v) all scenarios combined. All development scenarios (i-v) resulted in a decrease in vegetation and increase in fragmentation along a central region in between the two large interconnected patches in the west and east. Based on these development scenarios it is unlikely that these two connected areas in the east and west could be linked using a proposed wildlife corridor identified in state government regional strategic plans if development proceeds without consideration of improved connectivity.