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Towards a national approach to vegetation condition assessment that meets government investors’ needs: A policy perspective. By David Parkes1 and Peter Lyon2 (1Victorian Department of Sustainability and Environment, PO Box 500 East Melbourne, Vic. 3002: E-mail: david.parkes@dse.vic.gov.au; 2Australian Government, Department of the Environment and Heritage, GPO Box 787 Canberra, ACT 2601, Australia).

Key words: assessment and monitoring, benchmarks, national policy, native vegetation condition, natural resource management.

National drivers for condition assessment and reporting.  Landscape-scale assessment of the status and change in vegetation condition is a relatively new field for scientists and governments. While some agencies have experience in assessing native vegetation condition in specific circumstances, in general the methodologies used have not been immediately applicable to comparisons between vegetation types and to reporting on change over time.

Existing or emerging condition assessment methodologies are principally intended to support:

  • • 
    Implementation of clearing control legislation
  • • 
    Implementation of conservation incentive schemes
  • • 
    Vegetation management planning at multiple scales
  • • 
    Reporting of progress towards strategic objectives

The National Natural Resource Management Monitoring and Evaluation (M&E) Framework (Natural Resource Management Ministerial Council 2002) established the requirement for nationally agreed indicators including one on native vegetation condition. The purpose of this indicator is to support and inform target-based approaches to regional planning for native vegetation management, and to provide a basis for ongoing reporting of progress against targets. National-level agreement on this indicator is required to ensure that information generated as part of target setting and reporting will be consistent across regions, and capable of collation in statewide or national assessments.

However, the National M&E Framework is one of a number of drivers for governments in native vegetation condition assessment. Although there is general agreement across the states and territories on the need for a nationally consistent approach, it is critical that this complements relevant processes and methods used in the states to meet their policy and legislative requirements. Ideally, vegetation-condition information will be useful and communicable across the different levels (site assessment to strategic goal setting) and activities (planning, implementation and review) of natural resource management.

The process for developing a national indicator on vegetation condition.  In 2002, a request for development of an indicator on native vegetation condition was put to the Executive Steering Committee for Australian Vegetation Information (ESCAVI), which sits within the committee arrangements under the NRM Ministerial Council. ESCAVI's development of an indicator has sought to make use of progress already made in this area by a number of states. In particular, the methodology used in the Victorian Government's Native Vegetation Management Framework, known as Habitat Hectares (State of Victoria, Department of Natural Resources and Environment 2002) appeared to have potential as a starting point, and was used as a basis for an ‘approach’ paper (Executive Steering Committee for Australian Vegetation Information 2003). This approach is now being progressively trialled and adapted in other states through a series of pilots funded under the Natural Heritage Trust.

Areas under consideration.  In reporting on key elements of ESCAVI discussions, we stress that this does not represent an agreed ESCAVI viewpoint at this stage and the views presented here are not binding on governments. It is also recognized that the purpose for condition assessment discussed in this paper is for use in regional target setting and in evaluating progress. As discussed above, there are other objectives in condition assessment that may require different approaches.

The following sections discuss elements of a native vegetation condition indicator that are under consideration.

Condition for what?  The term ‘condition’ has differing meanings depending on management objectives. For example, good condition for biodiversity habitat might be less than optimal for grazing potential. For reasons relating to the objectives of the national NRM M&E Framework, ESCAVI has agreed that this indicator should relate to biodiversity habitat provision only, although the information collected will also be directly relevant to broader ecosystem functions like water flow, soil protection and carbon sequestration.

Reference points (benchmarks) for all vegetation types.  Condition is inherently a comparative concept and any assessment of condition therefore requires an agreed frame of reference. The conceptual basis for developing a reference point will be the condition that would support the full range of native species that might be expected to use a stand of vegetation of a particular type under natural circumstances and given the dynamics of the ecosystem through time. The reference point will be expressed as a ‘benchmark’ that represents the characteristics of mature and apparently long-undisturbed stands of the same vegetation type. ‘Mature and apparently long-undisturbed’ will mean different time periods for different vegetation types, depending on the dominant growth forms and their reproductive strategies (Parkes et al. 2004). For example, 5 years may be an appropriate period for a temperate lowland grassland. Use of a ‘mature’ reference point does not imply that this is necessarily an optimal or inevitable condition state – condition scores lower than the reference point may be most suitable for particular species and may be the preferred management outcome. Benchmarks can be expressed as single values or ranges for each attribute depending on how the scoring methodology is designed to accommodate natural variation.

Benchmarks need to be specifically developed for individual vegetation types. Known areas of long-undisturbed vegetation of a particular type will often provide a ready basis for benchmark identification. Where a vegetation type has been extensively cleared and/or degraded by disturbances following European settlement, expert extrapolation using a combination of direct observations, historical records and retrospective predictions of impact will be required. The framework for the National Vegetation Information System (NLWRA 2001) defines a hierarchy of six levels of detail in structural/floristic information that can be used to describe vegetation types. Level V information (vegetation associations) is the preferred goal for application of an indicator for native vegetation condition. For consistency, benchmark documentation should be coordinated at the state level.

Multiple benchmarks for a site.  Some vegetation types (e.g. wetlands) are characterized by more than one readily identifiable stable state depending on the natural progression of environmental changes (e.g. wetting/drying cycles). These types require multiple benchmarks; however, potential difficulties with this approach lie in the need for the assessor to identify the relevant benchmark to use, as well as how to report progress when monitoring shows a change from one benchmark to another.

There are also cases where the environmental drivers at a site have been irreversibly altered (e.g. a floodplain downstream of a permanent dam) and there is no potential to return to the original benchmark state. In such cases, it will be sensible to describe loss of condition with respect to the original benchmark, but use a different benchmark for setting the recovery direction.

Attribute sets for all benchmarks.  Documentation of benchmarks will include identification of a set of attributes to be considered in assessment. The attributes required are likely to vary considerably across vegetation types. At the site level, attributes which reflect the following four areas should be included:

  • 1
    diversity and cover of species life forms of dominant vascular plants;
  • 2
    growth stages of dominant vascular plants including mature individuals (e.g. large old trees) and regeneration;
  • 3
    litter, bare ground and, where feasible, gross soil integrity; and
  • 4
    weed intrusions.

In addition, attributes which describe the landscape context of an area of vegetation are also critical to interpreting condition for habitat provision. These could include:

  • 1
    for intensively managed landscapes, ‘patch size’ and ‘amount of vegetation in neighbourhood’; and
  • 2
    for extensively managed landscapes, determinants of disturbance such as ‘distance from watering points’.

Landscape context may also include consideration of threatening processes that are not easily included in rapid site level assessments, for example, pressure from introduced predators and grazers, or risk associated with potential dry land salinity.

Indices incorporating defined weightings of attributes.  Although scoring across a range of attributes gives a detailed comparison against a benchmark, there is a need for an overall score that allows simple comparison between different areas of vegetation or the same area at different times. This requires the development of indices in the documentation of benchmarks, which define how the attributes scores should be weighted. Additive or multiplicative weightings could be used, provided a consistent approach is used statewide and that source data are retained to allow later re-assessment if required. Because of potential contradictions, biotic and landscape attributes are best analysed separately and should only be combined with due consideration.

Assessment using benchmarks requires interpretation.  There is recognition that assessment and reporting information generated by comparison to mature benchmarks will not be sufficient alone to guide management decisions or to describe overall trends. Site scores present a view of the vegetation at the time of assessment, but say nothing about the reasons for current condition, which may include natural or unnatural disturbance factors. In this regard, a ‘lower’ condition score does not necessarily reflect ‘degradation’, although even in natural circumstances major fluctuations in condition may have important broader consequences. For example, a wildfire event will alter condition in a way that is appropriate for an ecosystem (even necessary for particular species) but will also reduce water quality and increase the risk of soil erosion. Three pieces of information are required to enable interpretation of condition information:

  • 1
    current condition score relative to the benchmark;
  • 2
    estimated trajectory of change, i.e. whether the net result of regenerative (e.g. recruitment and growth) and degenerative (e.g. threats) processes is positive, negative or neutral; and
  • 3
    a view on the predominant driver of any change and whether active intervention is desired.

Building indicators.  Once scoring approaches based on a common conceptual basis are being applied, it is possible to extrapolate the information generated to allow reporting of two indicators that address the following questions:

  • 1
    What is the relative condition of native vegetation in a region?
  • 2
    What is the area of each vegetation type in a region where management practices are improving, maintaining or degrading the condition of native vegetation?

The availability of maps of estimated condition will increase our ability to address these questions, and this is the next phase of development that ESCAVI will encourage.

Allow for future revision and improvement of this indicator.  There is agreement that, given the relatively new nature of condition assessment and reporting, there will need to be flexibility built into the indicator to allow for its ongoing review, development and improvement. Source information from site assessments of condition should be stored in a reliable data management system for possible subsequent re-analysis. It will be insufficient to store index scores only. All states and territories should develop databases with appropriate structures to serve this purpose.

Conclusions.  In comparison to vegetation extent, condition assessment and reporting is in its infancy. However, there are strong drivers for establishing an information base on vegetation condition to support decision-making, and this is likely to see increasing quantities of condition information of variable quality being put forward by a range of organizations.

ESCAVI's response has informed discussion and provided an opportunity for engagement by relevant government agencies. However, the need for an agreed indicator to assist regional NRM target setting remains and ESCAVI is revising the current ‘approach’ indicator. A key goal will be ensuring sufficient consistency and utility so that condition data collected under the indicator will be useable for multiple purposes.

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