Reports of wetland loss in New Zealand are typically related to the historical, pre-European coverage of wetland ecosystems. It is widely accepted that large areas of wetlands were converted to other land uses prior to the 1990s before comprehensive national and regional environmental legislation was established. We sought to investigate recent (post 1990) changes in wetland extent to determine if current rates of wetland loss remain a concern for natural resources management.
We used recent satellite imagery to quantify the extent, type, and rate of conversion of remaining indigenous grasslands in the inland eastern South Island of New Zealand in recent years. We describe the pattern of conversion in relation to national classifications of land use capability and land environments, and ecological and administrative districts and regions. We show that although large areas of indigenous grasslands remain, grassland loss has been ongoing. Indigenous grassland was reduced in the study area by 3% (70 200 ha) between 1990 and 2008.
Loss of indigenous habitat is a key factor in the decline of New Zealand’s biodiversity. A recent contribution by Walker et al. (2006, New Zealand Journal of Ecology 30: 169–177) described losses of indigenous vegetation between 1996/97 and 2001/02 (some 17 000 ha) based on an analysis of changes in the Land Cover Database, LCDB1 and LCDB2, respectively.