Plant Community Characteristics At Recovered Field Of Opencast Coal Mine In Semi-arid Areas

In order to gain insights into the community characteristics of different configuration models and carry out species diversity monitoring in reclaimed land, a0.8hm2permanent plot (Robinia pseudoacacia+Pinus tabuliformis) was established in Antaibao opencast coal mine dump in2010, following the standard census procedure of the Centre for Tropical Forest Science (CTFS). The main results were as follows:Through17a vegetation restoration, there were10073survival individuals in the plot, among which Robinia pseudoacacia and Pinus tabuliformis were the species planted in the initial reclamation, while Ulmus pumila was the invasion plant. There were68dead standing trees in the plot, which accounted for0.7%of the total number of species. The statistics of breast-height basal area and the important value showed that Robinia pseudoacacia was obviously dominant species. The size-class distribution of all individuals showed an invert J-shape, which indicated that the community regenerated well. Based on their size-class frequencies, the size-class distribution of the species showed the unimodal shape or L-shape. The analysis of spacial pattern showed that Robinia pseudoacacia and Pinus tabuliformis planted in the initial reclamation showed uniform distribution, while showed random distribution through17a vegetation restoration. The regeneration individuals of Robinia pseudoacacia and Ulmus pumila showed aggregated distribution. The spacial pattern was closely associated with seed nature and the habitat.One point pattern analysis method, O-ring statistics, was used to analysis the spatial patterns of the species in overstory layer and understory layer, and the inter-specific association of species. The results showed that Robinia pseudoacacia and Pinus tabuliformis populations, and the understory layer mainly showed aggregated distributions at relatively smaller scales and random distributions at larger scales. The overstory layer showed even distributions at relatively smaller scales and random distributions at larger scales. All the results above were consistent with the analysis of spatial pattern. The spatial pattern of Ulmus pumila showed significantly difference with Robinia pseudoacacia and Pinus tabuliformis. From the analysis of the inter-specific association of species showed that two layers of Robinia pseudoacacia and Pinus tabuliformis populations showed positive correlation at small scales, while no correlation at large scales. Ulmus pumila showed negative correlation at small scales and positive correlation at large scales. The association of species in two layers showed that there was no correlation between Robinia pseudoacacia and Pinus tabuliformis, the overstory layer of Ulmus pumila had no obvious relevance, while the spcae relevance between the updated layer of Ulmus pumila and the each layer of Robinia pseudoacacia and Pinus tabuliformis showed negative correlation in small scale and positive correlation in large scale.Based on the herb census of320quadrats (lmxlm) in a0.8hm2plot of Locust+pinus mixed forest of opencast coal mine ecological reclamation area in Antaibao, the species composition, the species composition, basic quantitative properties and spatial pattern of herbs in the area after reclaiming for17years were studied. The results showed that: the plot was rich in herb species. And44species, which subordinate to30genera under16families, were investigated. The dominant families were Poaceae and Asteraceae, and the dominant species were Artemisia annua, Elymus dahuricus and Artemisia sieversiana. The initially planted Bromus inermis has deteriorated badly. The important value, species abundance and frequency were different among families or species. The dominant families and species were distributed widely. However, the spatial patterns of herb layer presented obvious spatial heterogeneity.