广西天坑森林物种多样性与土壤酶活性和养分的关系

he distribution characteristics and internal links of soil enzyme activities, nutrient content and woody plant diversity in negative topographic habitats of Tiankeng were studied,which provided a theoretical basis for the protection and reconstruction of plant resources in karstareas. The Tiankeng forests of the Dashiwei Tiankeng group in Guangxi were selected as theobject. Based on the community diversity survey and soil habitat survey from the inner and toparea to the outer area of Tiankeng, the relationship between species diversity and soil factors ofwoody plants was explored by correlation analysis and redundancy analysis methods. The resultswere as follows: (1) There were 21 species, 31 genera and 20 families of woody plants in theinside area of Tiankeng, 91 species, 58 genera and 58 families of woody plants in the top area ofTiankeng, and 47 species, 30 genera and 30 families of woody plants in the outside area ofTiankeng. The Margalef index and Patrick index in the inside area of Tiankeng were significantlylower than those in the top and outside area of Tiankeng, indicating that the individuals of speciesincreased, but the species distribution was steady; (2) The total soil nitrogen content in the outsidearea of Tiankeng was significantly higher than those in the top and outside area of Tiankeng. Thesoil total magnesium content, soil phosphorus content and soil available phosphorus content in theinside area of Tiankeng were significantly higher than those in the top and outside area ofTiankeng. The soil alkaline phosphatase content and soil urease activities in the outside area ofTiankeng were significantly higher than those in the top and inside area of Tiankeng. The soilphosphorus content in the Tiankeng was higher, but the soil enzyme activities were lower; (3) Theresults of Pearson correlation analysis and redundancy analysis showed that species diversity wasstrongly correlated with soil nutrients and soil enzyme activities. In conclusion, it can be seen thatthe habitats of the Tiankeng have a great influence on the species diversity, soil enzyme activityand soil nutrient content distribution characteristics. And the soil available phosphorus content,soil alkaline phosphatase activity, soil moisture content, soil urease activity, soil full magnesiumcontent and soil total phosphorus content are the key factors affecting the species diversity ofwoody plants in the Tiankeng forest.