景观历史对物种多样性的影响: 以内蒙古伊敏露天煤矿为例

矿产开采等人类活动极大地改变着生态环境和景观格局, 景观变化又是导致区域和全球物种多样性丧失的主要原因之一。然而, 物种多样性对周边景观变化响应的时间尺度问题往往被人们忽略。作者以内蒙古草原区伊敏露天煤矿为例, 从物种和功能群两个层次上, 探讨了不同的空间范围(1 km、2 km、3 km、4 km、6 km、8 km、10 km)内在不同时期(1975年、1990年、2000年、2010年)的景观格局(景观优势度指数、生境综合连接度指数和生境连接度概率指数)与生物多样性之间的关系。结果显示: 当前物种多样性与开矿前和开矿初期周边景观格局之间的相关性更高, 而且与4–8 km缓冲区范围内景观格局之间的关系更加密切。不同功能群物种丰富度与景观格局之间的关系不同, 其中, 多年生根茎禾草物种丰富度和当前小尺度(1–3 km)景观格局之间呈显著相关; 多年生杂类草和开矿前和开矿初期大尺度(4–10 km)景观格局之间相关显著; 多年生丛生禾草与景观格局的相关性并未达到显著水平, 但是随着空间尺度的增加出现单峰趋势, 在6 km范围上最高; 灌木、半灌木与景观格局的相关关系随着空间尺度的增加而增加; 一二年生草本与景观格局的相关性始终最低。为此, 本文得出如下结论: (1)物种多样性对周边景观格局变化的响应存在一定时间的滞后, 人类当前不合理的土地利用方式可能引起未来一段时间内该地区一些物种的消失; (2)区域种库决定小尺度物种多样性的大小, 研究区4–8 km范围内具有连通性的生境斑块是主要的种库资源; (3)植物的繁殖策略及种子传播方式是破碎化生境中物种多样性维持的重要机制。

Effect of mining landscape history on local species diversity: a case study of the Yimin open-pit coal mine in Inner Mongolia

The exploration and utilization of mineral resources accelerates local economic and social development and simultaneously exacerbates the effects of climate and landscape changes, resulting in landscape fragmentation. Landscape change is widely considered as a major threat to species loss at a regional and global scale. However, how species diversity responds to landscape changes on a temporal scale has usually been ignored. In this study, we explored relationships between landscape and biodiversity (species level and functional group level) during different years 1975, 1990, 2000 and 2010) at the Yimin open-pit coal mine, a mine that has been exploited for more than 30 years and that has produced obvious fragmentation effects on the landscape in Hulunbuir City. The ongoing patterns of transformation of the landscape were measured using the landscape dominance index, the habitat integral index of connectivity (IIC), and the habitat probability of connectivity (PC) at seven different spatial scales. The main results were as follows: The present species diversity is significantly correlated with the landscape pattern indices of previous and earlier mining at a medium-sized spatial scale (4–8 km buffers). Different plant functional groups responded in various ways to changing landscape patterns. The species richness of perennial rhizome grasses was significantly correlated with the present small-scale landscape pattern (1–3 km), and the species richness of perennial forbs was significantly correlated with the previous and earlier mining large-scale landscape patterns (4–10 km). Perennial bunchgrasses were not significantly correlated with landscape patterns. We concluded that the time lag expressed by changes in plant species diversity occurred in response to changing patterns of construction and configurations of habitats in the landscape. The regional species pool determined the local species diversity. The connected habitat patches within a 4–8 km buffer region represented the principal species pool. The propagation strategies and dispersal traits of various functional groups were important mechanisms maintaining species diversity in a fragmented area.