Conservation of wetlands in the Paroo and Warrego River catchments in arid Australia

Abstract

Irrigation proposals to divert water from the Paroo and Warrego Rivers in arid Australia will affect their aquatic ecosystems. These two are the last of 26 major rivers in the Murray-Darling Basin without large dams and diversions. Knowledge of the extent of their biodiversity value is critical to assessing likely impacts. During the 1990 flood, 1.73 million ha of wetlands, or 12.5% of the land surface of the Paroo and Warrego River catchments, were flooded. Flooded wetland area in the respective catchments was 781 330 ha and 890 534 ha. Most of the wetland area (97%) was floodplain, with 37 freshwater lakes (>50 ha) occupying 2.5% of the wetland area and 177 salt lakes covering 0.8%. A high diversity and abundance of biota depend on these wetlands. Only 7% of the wetland area, all in the Paroo catchment, is in conservation reserves. New South Wales has a high proportion of the wetland area on the Paroo (60%) and a substantial proportion of the wetland area on the Warrego River (23%). Queensland, the upstream state, will influence the ecology of the entire catchment areas of both river systems through its proposed water management plan. Any resulting extraction practices will have detrimental ecological consequences within a decade. Conservation of wetlands is usually site-focused and reflects a paradigm of conservation based on reservation of parcels of land. However, wetlands are dependent on water that is seldom adequately protected. Intergovernment co-operation should protect the entire catchment of the Paroo River from major diversions and stop further development on the Warrego River. This would do more for the conservation of wetlands than the formal reservation of small parts of their catchments.