Cumulative environmental assessment in Tasmania : a catchment case study

The cumulative impact of multiple stressors on the environment over time and space has been acknowledged as a key process in the ongoing loss of habitat and biodiversity and as a driver of landscape change. Regulatory approaches that address environmental impacts only at the level of the individual project footprint may facilitate significant environmental impacts through the cumulative effects of those projects. Such approaches are unlikely to ensure that current and future development of natural resources is sustainable. The catchment spatial scale and the regulatory processes that govern three key activities within it - farm dams, forest practices and water abstraction - form the basis for an examination of cumulative effects in Tasmania. International and Commonwealth regulatory approaches to cumulative effects, key concepts and methodologies are examined through a literature review. The potential cumulative impact of farm dams, forest practices and water abstraction on the natural flow regime, freshwater ecological processes and biota is established through the relevant literature. A case study of the Great Forester ‚ÄövÑvÆ Brid catchment in north east Tasmania is used to determine the potential for these impacts to occur in Tasmanian catchments. The results of this study show that there are measurable cumulative impacts on the natural flow regime, connectivity and special natural values within the catchment. Relevant legislation, policies and processes are examined to establish an understanding of how cumulative effects are addressed in Tasmania for these activities. Cumulative impacts of these activities are not adequately addressed in the current legislative and policy environment in Tasmania. An explicit legislative requirement for cumulative effects needs to be considered. In addition a pro-active, regional framework to manage and assess cumulative effects, incorporating integrated catchment management, is a fundamental requirement for the sustainable use of natural resources in Tasmania.