The volcanic plains of south west Victoria contain a mosaic of endorheic temporary wetlands. These occupy up to 10% of the landscape in some areas, and contain high biodiversity values in an otherwise highly modified agricultural environment. The decline of the wool industry in the late 1990s prompted a transition from grazing to broadacre cropping. This intensification of agricultural production coincided with the introduction of autosteering on cropping machinery which favours block sowing patterns.
An investigation was undertaken to determine the current and previous incidence of cropping in wetlands. There has been a substantial increase in the number of wetlands that are cropped. Cropping has been found to have a range of detrimental effects on temporary wetland ecosystems, from altered hydrology, reduced germination and plant establishment, through to being less able to support dependant vertebrate populations.
GIS techniques were used to categorise the types of cropping encroachment. Small freshwater wetlands face the greatest risk from cropping, and wetlands that are adjacent to a crop are also at a higher risk. The spatial arrangement of cropped wetlands has implications at the landscape scale. Fragmentation patterns are likely to influence the connectivity between wetlands, which is important for repopulating degraded wetlands and for biodiversity resilience.
A multi-disciplinary approach was then used to evaluate the drivers and repercussions of the land use decisions made by farmers. The perceived values associated with different elements of the landscape is dependent on the subjective evaluations of individuals. The success of future projects that aim to preserve privately owned wetlands will depend on understanding the social and economic imperatives of the land owners, as well as the biological complexity of these unique ecosystems.