Indicator: LD-41 Research/examples relating to declines in terrestrial genetic diversity and/or role of genetic diversity in ecosystem resilience
CSIRO Plant Industry scientists are comparing the levels of genetic variation within rare species to those of closely related common species, in order to identify any consistent differences in the amount and distribution of genetic diversity. They are also studying plants that were once widespread and common, but which are now rare due to clearing woodlands and grasslands for agriculture.
One such study, of remaining populations of a threatened grassland daisy Rutidosis leptorrhynchoide, has shown that as population size decreases genetic diversity is lost and inbreeding increases due to increased self-pollination.
In the long-term, a loss of genetic variation (sometimes referred to as "genetic erosion") will leave species with few evolutionary options in the face of changing environmental pressures. In the short-term, increased inbreeding can result in offspring that are not as fit as their parents, producing plants that do not grow as quickly, set as many flowers, or have as many seeds.
The CSIRO work provides further evidence of the importance of genetic diversity in maintaining the health and resilience of species.
The data gives no indication of the condition of genetic diversity across the full range of Australian ecosystems.
Genetic diversity of species is essential to the health and resilience of ecosystems and to maintaining the health of terrestrial biodiversity and the contribution of biodiversity to the land. It is not clear whether there is any way of measuring ‘genetic diversity’, either marine or terrestrial, across an entire continental ecosystem other than in terms of the diversity among and within species.
Population size is crucial to genetic diversity so many of the species listed as threatened due to low population size will be facing a loss of genetic diversity. It may at some stage be possible to extrapolate a surrogate indicator of rate of loss of genetic diversity from the rate of increase in species whose populations are decreasing. However, this rate of increase currently reflects the rate at which knowledge of the populations of species is increasing rather than the rate at which populations of species are declining.
In the meantime, examples and research into loss of biodiversity in particular species, or into the role of genetic diversity in ecosystem resilience, may provide the best insight into this issue.
Examples and research into loss of biodiversity in particular species, or into the role of genetic diversity in ecosystem resilience, may provide insight into this issue.
Other indicators for this issue:
- CO-69 Research/examples relating to declines in marine biodiversity and/or the role of genetic diversity in ecosystem resilience