荒漠啮齿动物群落对开垦干扰的响应及其种群生态对策

Abstract

开垦对功能相对脆弱的荒漠生态系统是重要的干扰,这种干扰往往导致栖息地破碎化,并对动植物群落产生强烈影响。作为荒漠生态系统的重要成分,啮齿动物群落受到开垦干扰后对环境的响应及其群落中种群的生态对策,是荒漠生态系统生物多样性及其功能维持稳定的重要基础。2006-2011年,采用标志重捕法对内蒙古阿拉善荒漠区未开垦和开垦草地啮齿动物群落格局及其不同生态对策种群的数量组成进行了专门研究。目的(1)明确开垦干扰下啮齿动物群落格局时间尺度变化;(2)验证假设:人为干扰区(开垦区)啮齿动物群落中<em>r</em>-对策者占据优势,未干扰区(未开垦区)以<em>K</em>-对策者为主;(3)依据啮齿动物群落中不同生态对策种群的数量组成来判断群落所受干扰的程度。结果表明,开垦干扰降低了啮齿动物群落多样性,改变了群落中不同生态对策种群的数量组成,种群以<em>r</em>-对策者为优势;未开垦区啮齿动物群落中以<em>K</em>-对策种群为主。开垦区啮齿动物群落受到严重干扰。;Cultivation on grassland ecosystem, as one of the greatest disturbance, is well studied. Grassland cultivation, especially in desert region, often results in habitat fragmentation, and subsequently affects plant and animal communities. Under intensive disturbance, the responses of rodent species with different bionomic strategies to environmental change could play a key role in determining structure of their communities. Few literatures on Chinese western desert have focused on the impacts of cultivation on rodents. A study was conducted from 2006 to 2011at cultivated and non-cultivated sites to investigate effect of cultivation on rodent community diversity, community structure with different bionomic strategies, and their population abundance in Alashan, Inner Mongolia, China. We expected that rodents with <em>r </em>strategy will dominate in cultivated site, while <em>K</em> strategists will dominate in non-cultivated site. Rodent communities monitoring using live trapping method showed that cultivation significantly decreased Shannon-Wiener index and Simpson index, but did not affect Pielou evenness index. In the cultivated site, species richness and population abundance of rodents with <em>r</em> strategy were higher than those of<em> K</em> strategy. In non-cultivated site, rodent population abundance was lower for <em>r</em> strategists than <em>K</em> strategists. ABC curve analysis showed that cumulative dominance of species abundance was higher cumulative dominance of species biomass in cultivated site. The results suggested that cultivation had a negative impact on the rodent community diversity, and severely disturbed rodent community, therefore, excluded or decreased rodents with <em>K</em> strategy. Our results supported our hypothesis that rodents with <em>r</em> strategy will be dominant in communities in cultivated site.