Changes to the hydrology of Australian landscapes are discussed in detail in Chapter 4: Inland water and Chapter 5: Land. The many alterations to Australian landscapes since European settlement (especially clearing of land for agricultural and urban development) have affected the processes by which rainwater enters the soil and flows into underground channels or creeks and rivers. Throughout large parts of Australia, vegetation removal has caused watertables to rise to the surface, bringing salt with them. Changed hydrology has directly affected biodiversity associated with inland waters through, for example, salinisation, impacts on flow rates in rivers, and drying of wetlands as overland and below ground water provision is reduced.15
Despite substantial literature on the processes by which salinisation affects native and introduced vegetation, there is little information on the spatial extent to which changed hydrology has affected terrestrial ecosystems. Concern has been expressed for several years about the lack of information on the combined effects of water extraction for irrigation and changed hydrology on groundwater (underground water) systems, and the biota that rely on them.138-139 However, there is still very limited information on the extent or distribution of pressures on groundwater-dependent biota.