草原区煤电基地景观格局演变及对群落α多样性的影响

Landscape pattern evolution of coal-electricity base in grassland area and its impact on theα-diversity of plant communities

为探明我国北方草原区在矿业开采背景下景观格局演变规律以及对群落α多样性的影响,选择锡林浩特市大型煤电基地为研究对象,分析了该区土地利用/覆盖变化和景观格局动态变化,以及景观格局变化对草原群落α多样性指标(Shannon-Wiener指数与Pielou均匀度指数)的影响。主要结论如下:1)在1991-2016年间,作为主要土地利用类型的草原面积持续减少,斑块数量持续增加,斑块破碎化显著。主要的人工斑块工矿仓储用地、交通运输用地及住宅用地数量持续增加,人工斑块类型的增加是导致草原斑块破碎化的主要原因。2)在1991-2016年间,研究区景观格局发生了巨大变化。工矿业活动使研究区景观结构复杂化程度加深,大面积连通性强的生境斑块被以小斑块为主导的破碎化生境所替代,引入了很多人为非生境。3)在小尺度景观中(半径1km缓冲区),草原群落当前物种多样性分布格局与景观格局的相关性较弱,而较大尺度的景观中(半径2km和3km缓冲区),两者的相关关系显著。景观格局的破碎化和复杂程度的提高不利于物种多样性的保持,而景观连通性提高有利于物种多样性的增加。4)与小尺度(半径1km缓冲区)相比,物种均匀度在较大尺度(半径2km和3km缓冲区)上对景观历史的响应更为敏感,且景观异质性越高越不利于物种均匀度的提高,景观连通性越好物种在生境中的空间配置越均匀。

In order to explore the evolution of landscape pattern and its influence on communityα-diversity in the steppe region of northern China under the background of mining,the large coal-electricity base of Xilinhot city was selected as the research object,the land use/cover change and landscape pattern dynamic change in this area were analyzed,and the effect of landscape pattern change on theα-diversity index of grassland community(Shannon-Wiener index and Pielou evenness index).The main conclusions are as follows:1)From 1991 to 2016,the grassland area as the main land use type continued to decrease,the number of patches continued to increase,and the patch fragmentation was significant.The number of major artificial patches of industrial and mining storage land,transportation land and residential land continued to increase.The increase of artificial patches was the main cause of grassland patch fragmentation.2)From 1991 to 2016,the landscape pattern of the study area had undergone great changes.The industrial and mining activities made the landscape structure of the study area more complicated,and the large area of habitat patches with strong connectivity were replaced by the small patches dominated by the fragmented metaecological environment,which introduced a lot of anthropogenic non-habitats.3)In the small landscape scale(buffer with radius of 1 km),the current species diversity distribution pattern showed on relation to the landscape pattern.For larger landscapes(buffers with radius of 2 km and 3 km),the correlation between the two was significant.The fragmentation and complexity of landscape pattern were not conducive to the maintenance of species diversity,while the improvement of landscape connectivity was conducive to the increase of species diversity.4)Compared with small scales(buffer with radius of 1 km),species evenness was more sensitive to landscape history at large scales(buffers with radius of 2 km and 3 km).Moreover,the higher the landscape heterogeneity was,the worse the species evenness was,and the better the landscape connectivity was,the more uniform the species spatial distribution in the habitat was.