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Significance Definitions

• Definition of significance
• Flora
• Fauna

Definition of significance

Significance in the biological context has a similar meaning as in general use, significant being defined as noteworthy or of considerable importance (Oxford Dictionary). Sites of biological significance are areas where features of the flora and fauna meet defined biological criteria. These assessments are independent of land-use classifications (e.g. biological reserves) or land ownership (e.g. public or private), instead being an assessment of the qualities of the indigenous vegetation and habitat in the context of its current distribution, conservation status and integrity.

In the context of the present study the significance of vegetation communities, plant species, fauna species and fauna habitat is assessed at the following levels:

• Local - City of Monash
• Regional - Greater Melbourne as described by Beardsell (1997)
• State - Victoria
• National - Australia

Flora

Criteria for determining significant indigenous plant species

The assessment of significance of plant species recorded from the sites during this study is based on the application of one or more of the following criteria:

• Naturally uncommon or rare in Australia, Victoria, the region or the municipality;
• Formerly widespread in Australia, Victoria, the region or the municipality but now depleted through habitat destruction or degradation;
• Remnant population(s) with important information content on floristics of the regional or local vegetation;
• Species which are taxonomically or biogeographically interesting, e.g. alpine forms of more widespread species, disjunct populations;
• Species which may play a keystone role in particular environments or display unusual characteristics e.g. Podocarpus lawrencei.

Species are of National Significance if they are either rare, threatened or endangered on an Australia-wide basis. Many of these taxa are listed as Rare or Threatened Australian Plant Species (ROTAPS) by Briggs and Leigh (1995), ANZECC (1993) or listed under the Endangered Species Protection Act 1992; listings are updated on the basis of new data.

Regionally significant species are assessed on the basis of regional studies and our knowledge of the regional flora. Relevant studies for the present study are Bedggood et al. (1997), Robinson et al. (1986), Bedggood et al. (1992), Yugovic et al. (1990).

Criteria for determining significant vegetation communities

The significance of a particular vegetation community is primarily a function of rarity. This is represented by the following criteria:

• Distribution and abundance of the community in the study area, the region and the site;
• Level of depletion since European settlement;
• Number and ranking of significant species (of which rarity is an important criterion) occurring in the community;
• Landscape context: the position in the landscape occupied by the vegetation e.g. patch size, the degree of continuity of indigenous vegetation, potential linkage role.

This aspect of the vegetation community is primarily a function of disturbance and is represented by the following ratings:

Quality 1

Vegetation structurally and floristically intact or almost so; weed invasions minimal or weeds absent; disturbance minimal or absent.

Quality 2

Vegetation structurally and floristically substantially intact; low levels of weed invasion; low levels of disturbance.

Quality 3

Vegetation partially intact structurally and/or floristically; moderate levels of weed invasion: woody vegetation intact and herbaceous vegetation greater than 50% cover; moderate levels of disturbance.

Quality 4

Vegetation comprised of less than 50% cover of indigenous species and/or with much reduced species richness; in the case of woody vegetation the upper strata may provide moderate to high cover but field layer substantially exotic or only scattered overstorey remnants but moderately dense understorey and/or field layer; high levels of disturbance.

Quality 5

Vegetation grossly modified with scattered to rare dominants of upper strata only persisting; very high cover of weeds; current or former levels of disturbance high or very high.

The extent to which a particular vegetation community is present in biological reserves is termed 'reservation status'. Terminology appropriate for a continuum of increasing reservation status is adapted from the JANIS criteria; a widely used set of criteria for forested ecosystems.

• very poor to nil
• poorly represented: clearly below the JANIS criteria of 15% of pre-1750 distribution, or 60% of remaining extent of threatened communities
• moderate representation: satisfies or considered marginally above JANIS criteria
• substantial areas reserved: clearly above JANIS criteria.

Fauna

Criteria for determining significant fauna species

The following criteria have been applied in the present study to determine the significance of fauna species:

Local

All indigenous fauna is considered significant at a Local level, because of the overall decline in the fauna since European settlement, and the continued incremental loss of habitat and reduction in abundance due to development.

Regional

A taxon is considered significant at a Regional level if:
- it has a disjunct distribution in the region, or
- it is represented in high concentrations in terms of colonial nesting, roosting or feeding sites, or
- it is substantially depleted or restricted in the region, or
- it has an unusual ecological or biogeographical occurrence.

State

A taxon is considered significant at a State level if it is:
- listed under Threatened Vertebrate Fauna in Victoria - 2000 (NRE 2000).
- listed under Schedule 2 of the Victorian Flora and Fauna Guarantee Act 1988.

National

A taxon is considered significant at a National level if it is:
- listed under Schedule 1 (Endangered, Vulnerable or Presumed Extinct) of the Commonwealth Endangered Species Protection Act 1992, or
- listed under the following Australian Action Plans and similar documents: Cogger et al. (1993), Garnett (1993), Lee (1995), Maxwell et al. (1996), Tyler (1997) or Wager and Jackson (1993).

Criteria for determining significant sites

The criteria used here for determining the zoological significance of sites are generally based on the criteria developed by Schulz et al. (1991) and Beardsell (1997) for their sites of faunal significance studies in the Greater Melbourne region. These criteria have been adapted for the present study to incorporate limiting factors associated with small-scale fauna surveys and environmental impact assessment studies.

In such cases, study areas are frequently small, and fauna surveys are usually brief. Given these constraints there is seldom the opportunity for repeated observations over time or surveying over seasons to enable recording of breeding and seasonal migrants. Consequently, they may fail to record rare, transient or cryptic species.

In the significance criteria presented below, the term 'regularly supports' refers to the presence in a habitat of the subject species for a period in its life cycle critical to its survival (e.g. migration, winter or nomadic nectar feeding) or regularly at times of population dispersal (seasonal or long-term).

Local Significance

A site is designated as being of Local significance if:

• it has moderate to high potential for serving as a habitat link between two sites of Regional significance or as a link to suburban areas to enable native species to disperse into such areas, or
• it has moderate to high potential for rehabilitation and management for the public appreciation of fauna values.

Regional Significance

A site is designated as being of Regional significance if:

• it regularly supports species that are classified as Regionally significant, or
• it regularly supports a disjunct population, unusual ecological or biogeographical occurrence or extraordinary concentration in a regional context of a naturally restricted (e.g. colonial nesting, roosting or feeding) or substantially depleted or restricted taxon in the region, or
• it supports a high level of species richness for the Greater Melbourne region (The number of species required to fulfil this criterion will vary depending on the size, scope and season of the survey. For the Greater Melbourne region Schulz et al. (1991) used 2' latitude by 2' longitude blocks within a six year survey period. Their species richness criteria required 7 to 21 native mammal species, 50 to 100 native bird species, or 8 to 24 species of native frogs and reptiles), or
• it contains a partial habitat link between two sites of state fauna significance, or a regional and state site, or a primary habitat link between two sites of regional significance, or between a site of state significance and large urban areas.

State Significance

A site is designated as being of State significance if:

• it regularly supports a population of a taxon listed under the Flora and Fauna Guarantee Act 1988, or
• it supports species listed as Endangered in Victoria (NRE 2000) that visit the site sporadically, and are not recorded breeding at the site, or
• it regularly supports species listed as Vulnerable in Victoria (NRE 2000). For birds, this only includes records of breeding, a single sighting of a large population or repeated sightings of individuals, or
• it regularly supports a population of a taxon listed as Low Risk - near threatened or Data Deficient in Victoria (NRE 2000), or four or more species of international migratory waders, or a roosting colony of cave-dwelling bats, or more than 1,000 waterfowl, or
• it supports very high species richness in the region. For the greater Melbourne region, Schulz et al. (1991) specified 22 or more native mammal species, 110 to 150 native bird species, or 25 or more species of native frogs and reptiles for 2' latitude by 2' longitude blocks surveyed over six years. The number of species required to fulfil this criterion will vary depending on the size, scope and season of the survey, and a knowledge of the fauna of the region, or
• it regularly supports 5% or more of the Victorian population, or an extraordinary concentration in a state context of a native mammal, reptile or frog taxon, or
• it represents an intact primary habitat link containing comparable habitat attributes to two connecting sites or series of sites of state or higher zoological significance, or
• it has high scientific significance, e.g. forms a long term study or monitoring site, or it has biogeographical significance in the region.

National Significance

A site is designated as being of National significance if:

• it regularly supports a population of a species listed as Endangered under Schedule 1 of the Commonwealth Endangered Species Protection Act 1992, or by Cogger et al. (1993), Garnett (1993), Lee (1995), Maxwell et al. (1996), Tyler (1997) or Wager and Jackson (1993), or
• it regularly supports two or more species listed as Vulnerable under Schedule 1 of the Commonwealth Endangered Species Protection Act 1992, or by Cogger et al. (1993), Garnett (1993), Lee (1995), Maxwell et al. (1996), Tyler (1997) or Wager and Jackson (1993), or
• it regularly supports a large population (exceeding 5% of the total known population) of a taxon listed as Vulnerable under Schedule 1 of the Commonwealth Endangered Species Protection Act 1992, Cogger et al. (1993), Garnett (1993), Lee (1995), Maxwell et al. (1996), Tyler (1997) or Wager and Jackson (1993).

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Updated: 23 September 2003

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