Study On Vegetation Quantitative Ecology Of Abandoned Minelands In Ningwu County, Shanxi

For a long time, excessive development of coal mineral resources has caused many abandoned minelands in Ningwu County of Shanxi province. To understand its current situation of natural resource and the relationships between the natural plant communities and environment in the regions, the composition, interspecific relationships, ecological species groups and biodiversity of the natural plant communities were measured by the use of TWINSPAN classification, DCA ordination, Spearman rank correlation analysis, respectively on the basis of field investigation of the natural plant communities in the study area. It was aimed to provide support and basis for the protection and artificial vegetation restoration of abandoned minelands in Shanxi. The main research contents and conclusions were as follows:(1)The 52 species belonged to 22 family and 42 genus, including 47 herbs (perennial herbs 69.2%, annual herbs 17.3%, biennial herbs 3.85%) 2 shrubs (3.85%),3 trees (5.77%) on the basis of the field investigation for the natural plant communities in the abandoned minelands of Ningwu County.(2)The 51 natural plant communities of the abandoned minelands based on TWINSPAN classification were classified into 7 associations:Ⅰ. Ass. Melilotuso fficinalis+Artemisia lavandulaefolia, Ⅱ. Ass. Elymus dahuricus +Artemisia sacrorum+Eragrostis pilosa, Ⅲ. Ass. Cleistogenes squarrosa+ Artemisia sacrorum, Ⅳ. Ass. Artemisia sacrorum+Poa pratensis, Ⅴ. Ass. Poa pratensis+Dendranthema chanetii+Cleistogenes squarrosa, Ⅵ. Ass. Commelina diffusa+Geranium wilfordii+Plantago minuta, Ⅶ. Ass. Geranium wilfordii+Ixeris polycephala. The results well reflected the ecological relationships among different plant communities. Meanwhile, the results of DCA ordination also well reflected the relationships between the natural plant communities and environment in its abandoned minelands. The first DCA ordination axis of plots and species indicated the stacking time of the abandoned minelands and variation of slope aspect of communities. Along the first DCA ordination axis from left to right, the stacking time of the abandoned minelands reduced, and the slope aspect transformed the sunny slope into the shady one. The second DCA ordination axis showed the change of plant community types. The determined factors which influenced the natural plant communities’ composition and structure of the abandoned minelands were the stacking time of the abandoned minelands, soil moisture and slope aspect of communities.(3) The interspecific relationships among 31 dominant species in total 465 species-pairs of the natural plant communities in the abandoned minelands of Ningwu County were analyzed by the use of Fisher’s exact test and Spearman’s rank correlation. Based on the results of Fisher’s exact test, 139 species-pairs had a positive association coefficience, accounting for 29.89%, of which 12 species-pairs had a significant positive association coefficience (P<0.01). The results from Spearman’s rank correlation showed that 130 species-pairs had a positive association coefficience, accounting for 27.96%, of which 22 species-pairs had a significant positive association coefficience (P<0.01), and 335 species-pairs had a negative association coefficience. However, there were no species-pairs that had a significant negative association coefficience (P<0.01). The species-pairs with negative association coefficience accounted for a high proportion, while the species-pairs with significant association coefficience were few. The results indicated that the natural plant communities were primary community succession, with weak and simple composition and structure. On the basis of the analysis of TWINSPAN clustering,31 dominant species of the natural plant communities were divided into 6 ecological species groups in the study area. The interspecific relationships among Elymus dahuricus, Melilotusofficinalis, Hippophae rhamnoides, Spiraea pubescens, Ulmus macrocarpa had a significant positive coefficience or positive coefficience. These species were applied as pioneer species by the mixed planting for the artificial vegetation restoration of the abandoned minelands of Ningwu County due to their ecological adaptability.(4)The species diversity were analyzed by the use of the diversity indices of the natural plant communities in the abandoned minelands of Ningwu County. The rank of species richness among seven associations were represented as association Ⅱ> association Ⅵ> association Ⅴ> association Ⅳ> association Ⅲ> association Ⅰ> association Ⅶ; the rank of species evenness among seven associations were similar to species richness, representing as association Ⅱ> association VI> association Ⅴ> association Ⅳ> association Ⅶ> association Ⅰ> association Ⅲ. In the whole, the diversity of association Ⅱ was the highest, while association Ⅲ was the lowest. With the stacking time of the abandoned minelands going by, the ecological habitat of communities would be well improved, and the species composition of communities would be gradually increased.