Selection of plant species as indicators of desertification in Mu Us sandy land, China

摘要

Desertification has long been a worldwide environmental problem, but a simple, yet scientifically sound indicator of its extent in a specific area is lacking. Here, we explored the relationships between vegetation and soil factors in Mu Us sandy landwith the aim of developing a simple plant index for the extent of desertification in this area. This study was also aimed to offer a method for the selection of plant indicators of severity of desertification. The density, height and aboveground biomassof plant species as well as soil data, including moisture, hardness, bulk density, electrical conductivity, organic matter, totalN, P， K, and exchangeable Ca2', Na卞，Mg2' in different soil depths were measured in fixed, semi-fixed, semi-shifting and shifting sand dunes. Two-way cluster analysis based on importance value (IV) of plant species were used to classify vegetation types. Canonical correspondence analysis was used to identify soil factors linked to the distribution of plant species. The plantspecies with higher IV in each group were selected as plant indicators of their habitats. The methods used in this study successfully separated plants' types and correlated plant types with soil conditions. We classified desertification degree in Mu Ussandy land into 3 extents and selected Stipa bungeana, Artemisia ordosica and Agriophyllum squarrosum as indicator plants for slight, medium and extreme desertification extents, respectively. Based on our results, it is entirely feasible to use plant species as simple indicators of desertification extents.