1. introduction

1.1 BACKGROUND

The Nationally Agreed Criteria for the Establishment of a CAR Reserve System for Forests in Australia (JANIS 1997) specify a number of criteria relating to the spatial design or configuration of reserves. Section 7 of the JANIS report specifies general design criteria which should influence selection of reserves. In addition to these general criteria the report also specifies a number of specific criteria relating to the required spatial configuration of reservation for individual biodiversity entities. In relation to species, Biodiversity Criterion 6 states that “reserves should be large enough to sustain the viability, quality and integrity of populations”. In relation to forest ecosystems, Biodiversity Criterion 4 states that “reserved areas should be replicated across the geographic range of the forest ecosystem to decrease the likelihood that chance events such as wildfire or disease will cause the forest ecosystem to decline” while Biodiversity Criterion 7 states that “to ensure representativeness, the reserve system should, as far as possible, sample the full range of biological variation within each forest ecosystem, by sampling the range of environmental variation typical of its geographic range”. In relation to old growth, Old Growth Criterion 2 includes two specific spatial configuration objectives, namely “representation of old-growth forest across the geographic range of the forest ecosystem” and “protection of the largest and least fragmented areas of old-growth”.

Application of the JANIS spatial configuration criteria has proved to be problematic in previous NSW forest assessments (Interim Forest Assessment and Eden CRA). The C-Plan decision support software used in these assessments has not allowed spatial configuration criteria to be addressed in an effective manner. Previous approaches to dealing with spatial configuration have resulted in an overly cumbersome and inefficient reserve selection process. For example, criteria relating to geographical and environmental spread have been addressed by splitting entities into sub-regions and assigning separate reservation targets to each of these sub-regions. This has resulted in a proliferation of reservation targets and has severely limited the flexibility with which geographical and environmental spread of reservation can be achieved. Criteria relating to patch size were addressed in the Eden CRA by visually identifying areas containing large patches of particular entities, which required working with entities one at a time. This resulted in a very slow selection process, and probably promoted inefficiencies in reservation because overlap between the needs of multiple entities could not be readily considered.

1.2 PROJECT OBJECTIVES AND GENERAL APPROACH

The primary objective of this project was to develop functionality within the C-Plan software package to automate derivation of measures (indices) to guide achievement of spatial configuration objectives in building a CAR reserve system. Spatial configuration criteria specified in JANIS (1997) were addressed through implementation of two types of measure:

• Patch size and connectivity, to facilitate improved consideration of Biodiversity Criterion 6 “reserves should be large enough to sustain the viability, quality and integrity of populations”, Old Growth Criterion 2 “protection of the largest and least fragmented areas of old-growth” and General Reserve Design Criteria 2 “large reserved areas are preferable to small reserved areas”, 3 “boundary-area ratios should be minimised” and 7 “reserves should be linked through a variety of mechanisms”.
  
  
• Geographical and environmental spread, to facilitate improved consideration of Biodiversity Criteria 4 “reserved areas should be replicated across the geographic range of the forest ecosystem” and 7 “the reserve system should ... sample the full range of biological variation within each forest ecosystem, by sampling the range of environmental variation typical of its geographic range”, Old Growth Criterion 2 “representation of old-growth forest across the geographic range of the forest ecosystem” and General Reserve Design Criterion 4 “reserves should be developed across the major environmental gradients”.

The functionality developed by this project was designed to enable ‘patch size/connectivity’ and ‘geographical/environmental spread’ to be considered at two different points within C-Plan:

• When assessing the ‘potential contribution’ that individual unreserved planning units would make if they were added to the reserve system. With the new software, potential contribution can now be measured not only in terms of the contribution to achieving areal targets (via existing irreplaceability indices) but also in terms of the contribution to achieving spatial configuration objectives relating to patch size/connectivity and geographical/environmental spread.
  
  
• When evaluating the ‘current configuration’ of the reserve system. With the new software, current configuration can now be measured (and reported on) not only in terms of the achievement of areal targets but also in terms of the achievement of spatial configuration objectives relating to patch size/connectivity and geographical/environmental spread.

This project was closely linked to the C-Plan Development Project, funded separately by the NSW CRA process. The scope of the current project was the development of software modules for calculating the above spatial configuration measures, using data held in C-Plan databases. These modules were designed to be called by the C-Plan software package. The C-Plan Development Project was primarily responsible for integrating this new functionality into the existing C-Plan system, including the development of a user-interface to control the operation of the spatial configuration functionality and to present results to users.

1.3 PURPOSE AND STRUCTURE OF THIS REPORT

The main purpose of this report is to describe the analytical techniques underlying each of the new spatial configuration measures employed in C-Plan. Techniques relating to measures of patch size and connectivity are described in Section 2, while techniques relating to measures of geographical and environmental spread are described in Section 3. Each of these sections is further divided into two sub-sections, one dealing with measures relating to the potential contribution of individual planning units and the other dealing with measures relating to the current configuration of the reserve system.

Section 4 provides a brief overview of the software modules developed to calculate the new spatial configuration measures. This report does not provide a detailed description of the C-Plan user-interface for invoking and reporting spatial configuration measures (see the C-Plan software package and accompanying user’s documentation for this detail), nor does it include technical system or programmer’s documentation for the developed software (such documentation has been provided to, and is held by, the C-Plan Development Team within NSW NPWS).

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