The Reservation Status of Plant Species and Vegetation Types in the Northern Territory

Abstract

The terrestrial conservation reserve system of the Northern Territory comprises 83 reserves covering 3.79% of the land area. This system includes representation of only 63 of the 112 vegetation types recognised in the Northern Territory at 1:1000000 scale. Of these, only 31 are represented to at least 5% of their extent. The reserve system has a strong geographic bias, with very poor representation of vegetation types occurring across a broad band in the mid-latitudes of the Northern Territory. Broad vegetation categories which are particularly poorly reserved include tussock grasslands, chenopod shrublands, Acacia woodland and hummock grasslands: by contrast, closed forests and floodplains have > 20% of their extent reserved. In some contrast to the poor reservation extent of vegetation types, 80% of the 3632 named native vascular plant species known from the Northern Territory have been recorded from reserves. The distribution of the 743 unreserved plants is mapped, and coincides reasonably well with the pattern of unreserved vegetation types. The high proportion of the flora which is reserved is due in part to judicious (or fortuitous) reserve placement-for example, one reserve, Kakadu, contains almost half of the plant species known from the Northern Territory. There are substantial taxonomic and ecological biases in the reported reservation rates for NT plants. Rainforest plants tend to be reasonably well reserved (80% of 585 species), but designated threatened plants are poorly reserved(44% of 553 species). Due to its largely intact environment, the Northern Territory offers an unusually good opportunity for the establishment of a comprehensive reserve network. However, most of the unreserved plants and vegetation types occur on either freehold Aboriginal lands or pastoral leaseholds, suggesting that substantial enhancement of the existing reserve network may not be simple.