Genetic and species diversity

2011

Genetic diversity within species is at the heart of biodiversity, but it has been very difficult to assess directly or for more than a sample of species. New genomic technologies are beginning to change this situation, but information from them remains limited.21 Instead, we use surrogates, such as assessments of the current range of species compared with their previous range.

Two surrogate measures currently used in assessments of threats to species are the extent of occupation (EOO), which is the overall area within which a species or community is found, and the area of occupation (AOO), which is the amount of area within the EOO that is actually used by the species or community.22-23 These measures are two means of incorporating threats to genetic diversity in conservation assessments, although there is some debate about how consistently these methods are applied in listing processes22,24 and about how well they are taken into account in planning for future reserve networks.25 Criterion 2 for listing ecological communities under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act; i.e. small geographic distribution coupled with demonstrable threats) is intended to capture naturally restricted communities that are under threat.26 It uses EOO and AOO, as well as consideration of patch size distribution.

In theory, representation of past distributions and existing genetic diversity should be considered in assessing the representativeness of the National Reserve System, which is discussed in Section 4.4.1. Use of more direct measures of genetic diversity in biodiversity conservation planning and management will become more feasible as genomic information becomes more readily and more routinely available.27

With respect to species diversity, there has been considerable progress made since the last national SoE report on collecting data on levels of endemism (how many species are native and unique to a region) nationally (Figure 8.3).

The data presented in Figure 8.3 are not corrected for sampling error (i.e. there is a greater intensity of sampling in some places than others), but they still give an indication of where priorities for conservation need to be explored in more detail. For example, some regions, such as the south-west, wet tropics and New South Wales – Queensland border ranges, are areas of high endemism and/or richness for many species. Figure 8.3 also illustrates the wide distribution and diversity of locations important for biodiversity. There is a strong overlap between many of these areas with those that have historically suffered the greatest pressures on biodiversity and contain the highest numbers of threatened species, creating a major conservation challenge.

It is worth noting that few invertebrates—a highly diverse group that comprises the majority of animal species in Australia—have been mapped in this way, illustrating the extent to which our current knowledge is incomplete.

Cork S (2011). Biodiversity: Genetic and species diversity. In: Australia state of the environment 2011, Australian Government Department of the Environment and Energy, Canberra, https://soe.environment.gov.au/science/soe/2011-report/8-biodiversity/2-state-and-trends/2-2-diversity, DOI 10.4226/94/58b65ac828812