Salinisation, eutrophication and land-clearing have been identified as some of the most serious environmental issues degrading rivers in agricultural landscapes in Australia.

One of the major challenges is to preserve genetic biodiversity in river fauna against this context of increasing environmental degradation. Despite the importance of conserving genetic diversity, few studies (none in WA) have investigated the effect of environmental degradation on genetic diversity of aquatic fauna.

Many rivers in south-western Australia have been substantially degraded due to secondary salinisation. However, there are still tributaries arising from less-cleared sub-catchments that may function as “refuges” for aquatic fauna.

This partitioning and fragmentation of a once widespread fauna is likely to lead to a reduction in gene flow. Furthermore, by reducing the size and increasing the isolation of subpopulations, genetic variation within these populations may be severely eroded, making these fauna more prone to extinction.

Project aims

This project aims to further understanding of the effects of environmental degradation on genetic diversity in lotic organisms by:

• Characterising genetic variation in selected fish and invertebrate fauna whose distribution has been affected by elevated salinities, nutrient enrichment and land-clearing
• Exploring the relationship between gene flow and environmental degradation to identify critical levels at which gene flow is drastically reduced
• Assessing how fragmentation can limit river restoration for biodiversity
• Making recommendations regarding critical “target” levels of environmental degradation that result in significant changes to faunal distribution.