Ecosystems Threatened Status Evaluation Of Horqin Sandy Land In Inner Mongolia

With the rapid development of economic society, since environmental resources are used excessively and destroyed seriously by human, ecological degradation has become the main environmental problem facing mankind today. As a whole, ecosystem represents biodiversity more convincing than a single species for it can reflect status of biodiversity more accurately. Evaluating the threat status of ecosystems is a vital measure to protect biodiversity. In2008, the International Union for Conservation of Nature (IUCN) initiated to formulate and implement criteria for evaluating ecosystem threat status at the fourth World Conservation Congress. A working group established by IUCN started to develop a series of standards that were similar to the criteria for evaluating ecosystem threat status; the threat status of ecosystems can be assessed by applying the criteria at local, regional, and global scales. Furthermore, the group established ecosystem red lists which were complementary to species red lists in biodiversity conservation.In this study, BEPS, based on a carbon-water coupled, was used to simulate9indexes that can reflect ecosystems functioning of Horqin Sandy Land in Inner Mongolia, including vegetation fractional coverage, net primary productivity, aboveground net primary productivity, belowground net primary production, gross primary productivity, net ecosystem productivity, vegetation evaporation, soil organic carbon and soil water deficit. Four ecosystems’ distribution indexes in the year of2000and2010were obtained from remote sensing data, area, extent of occurrence, area of occupancy and the number of occurrences. For4distribution indexes, the variability degree of every ecosystem in the10years time was calculated; for the9functioning indexes, degeneration in the degree and range of every ecosystem in the10years was quantitatively analyzed. Based on threshold computing formula, the shrinkage of each ecosystem area and the responding scope of nine functional indexes at three different shrink degrees(≥80%,≥50%and≥30%) were calculated in the past50years, respectively, the evaluation framework of IUCN’s ecosystem red lists was adopted to evaluate the12ecosystems’threatened status of Horqin Sandy Land in Inner Mongolia.The results showed that12ecosystems of Horqin Sandy Land were threatened in different degree, among of them, the threat levels of birch forest ecosystem and poplar forests ecosystem were critically endangered, were the highest; the Stipa capillata meadow steppe ecosystem, Achnatherum splendens grassland ecosystem and filifolium meadow steppe ecosystem were endangered; the other kinds of ecosystems were vulnerable. Simultaneously, the dangerous factors to various ecosystems were analyzed. Other ecosystems all had more than one risk factor except Stipa steppe and Ostryopsis Decne shrubs. Standard B (limited distribution) and standard D (environmental degradation) were considered as the major factors threatening ecosystems.