The effects of a moratorium on land-clearing in the Douglas-Daly region, Northern Territory, Australia

摘要

Land-clearing represents the first step in agricultural development and signals a shift in landscape function towards provisioning ecosystem services, in particular food production. In the process, other types of ecosystem services are often unintentionally lost as illustrated by the associated decline in biodiversity, increased soil erosion and emission of greenhouse gases. In 2003, the Northern Territory state government in Australia promulgated a moratorium on the clearing of native vegetation on freehold land in the Douglas-Daly river catchment, an area experiencing increasing pressure from agricultural development. The moratorium was intended to limit the rate and extent of land-clearing for a period of time so that informed policy could be concurrently developed to guide future land-clearing and minimise negative impacts. Under the moratorium, land-clearing required a permit and had to conform to broad guidelines; clearing was confined to freehold land, was prohibited in close proximity to wetlands, rivers and rainforest to safeguard water quality, and there were prescribed limits on percentages cleared by property, vegetation type, sub-catchment, and the whole catchment. Remotely sensed data (1977-2011) were used to explore the effectiveness of the moratorium. The analysis shows that, during moratorium years (2002-2009), clearing rates accelerated rather than slowed in the moratorium area and was mostly (81%) conducted without the required permits. The extent of land cleared after the moratorium was declared, and the fallow nature of some of this land a decade later, suggests that much of the land-clearing may have been completed in anticipation of stricter future controls. The moratorium failed because it was not formally legislated and was too broadly defined. Consequently, the non-binding nature of the land-clearing guidelines, and the absence of systematic monitoring of land cover change or penalties for clearing land without a permit, led to uninformed and uncontrolled clearing. This paper demonstrates that effective policy is only as good as its level of implementation.