Biodiversity And Temporospatial Distribution Characteristics Of Newly Formed Wetlands In Coal Mining Subsidence Area

The long-term development of coal resource in China has strategic position.While bringing tremendous economic benefits and promoting development of economic society,coal mining also brings great pressure to the ecological environment.Researches on coal-mining subsidence home and abroad mainly focus on the mining area at present,mining area is the boundary divided artificially,the influence of coal-mining subsidence on biodiversity has been ignored long but more studies are carried out from economy,land reclamation and restoration,water environment and land use pattern,lacking studies on the influence of underground mining on ecological evolution from the ecosystem.There are sporadic studies on biological conditions including water environment,heavy metal pollution,planktons and zoobenthos but few studies and discussions on the evolution of biodiversity and its maintenance mechanism,the summarization of some studies available now is insufficient and there is no uniform recognition on the biodiversity within the coal mining subsidence area.There lacks systematic and intensive discussion on series of ecological effects such as changes in ecological environment and biodiversity caused by coal mining especially in the high-groundwater coal basins in eastern China.The traditional understanding of coal mining subsidence mainly involves its damage to the environment and human property.Based on the present environment situation and real requirement,this study centers on the theme of the biodiversity of the mining subsidence wetlands to develop field investigations and in situ experiments with the subject of mining subsidence wetlands in Jining.We sampled plants,macrozoobenthos and birds from the typical mining subsidence wetlands,studied the species composition and diversity of plants,macrozoobenthos and birds and its distribution patterns from before and after mining subsidence,different mining subsidence stage and seasonal variation,and identified the key factors influencing biodiversity in mining subsidence wetlands,and compare biodiversity between mining subsidence wetlands and traditional farmland.Finally,we discussed the maintenance mechanism of biodiversity of mining subsidence wetlands.The main conclusions are as follows:There are 151 species of wild vascular plants in total within the mining subsidence wetlands.The composition of plant species at initial stage of mining subsidence has significant difference from that at middle stage of mining subsidence and late stage of mining subsidence.There are no significant differences in the structure of plant community at different stages of subsidence and have consistent tendency of seasonal variation.CCA analysis shows that soil moisture content is the main environmental factor in plant species composition.The stage of plant diversity is the highest at middle stage of mining subsidence,factors such as heterogeneity and soil humidity effect plant diversity of mining subsidence wetlands.There are 68 species of macrozoobenthos of the mining subsidence wetlands,in which Chironomidae is the dominant species.The species composition of macrozoobenthos of mining subsidence wetlands at late stage of mining subsidence has significant difference from that at initial stage of mining subsidence and middle stage of mining subsidence.The community structures of macrozoobenthos of newly formed wetlands at different subsidence stages have significant difference,in which richness,biomass and Shannon-Wiener index are the highest at middle stage of mining subsidence;the community structure of macrozoobenthos of newly formed wetlands at initial stage of mining subsidence and middle stage of mining subsidence is influenced significantly by the seasonal variation and there is no significant change at the late stage of mining subsidence.The diversity of macrozoobenthos is the highest at middle stage of mining subsidence.The ORP,area,DO and TDS of water are main influence factors of species composition of macrozoobenthos.At early stage of subsidence,macroinvertebrate diversity mainly depends on the life history and migration capacity,thereafter,habitat conditions and habitat stability that are effected by subsidence time are main factors of difference in macrozoobenthos diversity of newly formed wetlands.There are 138 species of birds in total of mining subsidence wetlands.The species composition of bird community of newly formed wetlands at middle stage of mining subsidence has significant difference from that at initial stage of mining subsidence and late stage of mining subsidence.There are no significant differences in the species composition of bird community of newly formed wetlands at different subsidence stages and have similar seasonal variation.Bird diversity reaches the highest point at middle stage of mining subsidence and the lowest point at initial stage of mining subsidence;CCA result shows that the proportions of natural vegetation within the wetlands and around the wetlands are the main environmental factors of bird species composition.Bird diversity is the highest at middle stage of mining subsidence,food resources,heterogeneity and vegetation conditions are the main influencing factors of bird diversity of newly formed wetlands.There are 271 species of plants in total and 138 species of birds,76 species of traditional agricultural landscapes and 30 species of birds,which demonstrate that the mining subsidence wetland landscape has higher species diversity compared with traditional agricultural landscape.Species compositions of plants and birds within mining subsidence wetland landscape and traditional agricultural landscape have significant differences,the dominant species of these two groups of both landscapes are different.It obtains a time component through comparing the differences of biodiversity of both landscapes: suppose that the local biodiversity has been improved after coal mining subsidence.This is mainly due to i)a series of environmental changes occurred after coal mining subsidence have improved habitat heterogeneity within the landscape.;ii)Synergies between plants and birds of mining subsidence wetlands;iii)long-term crop rotation in traditional farmland.It discusses the maintenance mechanism of biodiversity within the coal mining subsidence area combining with real conditions,spatial and temporal characteristics of biodiversity and key environmental factors including i)natural dispersal mechanism;ii)uneven subsidence-topographic heterogeneity hypothesis iii)aggregated dispersion and multi-species synergy in small-scale.The research on the biodiversity of newly formed wetlands in coal mining subsidence area is a new topic,so there is no mature theory and method system at home and abroad for reference.Moreover,since the environment of the newly formed wetlands in coal mining subsidence area is complicated which involves a wide range of disciplines,it brings great challenges to the research in this field.In the paper,the temporospatial distribution characteristics,evolution rules and maintenance mechanism of the biodiversity of the newly formed wetlands in the coal mining subsidence area were comprehensively expounded,as well as the positive ecological role of the newly formed wetlands in the coal mining subsidence area playing on the local biological diversity.Although there are still many issues to be improved step by step,it is hoped that this paper can provide a reference and data support for biodiversity conservation,management and sustainable use of newly formed wetlands in coal mining subsidence areas.