Research On The Species Diversity Of Herbs Communities Along The Different Elevation Gradient Of Yiluo River Watershed

Diversity of community species, an important part of biodiversity, constitute a key part in synecology as well as the whole ecological studies. It not only reflects the abundance of species in a habitat or community, diversified temporal and spatial variation, and manifests the characteristics and the evolution regularity of a community and eco-system, but also reflects the interrelationship between geological conditions, human factors and the community.This study researches on the herb communities in different habitats formed by different disturbance types and intensity in the drainage area of Yiluo River. A field investigation was conducted in August and September of 2009, investigating the distribution patterns and the abundance features of the species in different habitats, summarizing from two aspects,α-diversity andβ-diversity, the altitudinal gradient distribution pattern of the herb biodiversity and its environmental explanation. This study explored the influence of human and natural disturbance on the distribution patterns of species within the drainage area, with purposes of offering a scientific guidance over the restoration of the biodiversity in the herbs communities, the management of the watershed and the evaluation of its ecological environment, so as to promote the sustainable use and harmonious development of the watershed eco-system.In the middle watershed, with the influence of community types replacement and natural, human disturbance,α-diversity along the altitudinal gradient fluctuates, but still sticks to some rules. Through the exploration of variation regularity of the biodiversity in different habitats, we find: either in the riparian land with less human disturbance or in the farmland of corn field with intense disturbance, the abundance and diversity index are higher in the border area of upper and middle stream, and are the lowest in the downstream area;while in the habitets of the old-field and woodland, the change ofα-diversity along the altitudinal gradient is not obvious, with little influence from the altitude, while has something to do with the stage of succession the community belongs to.In the habitats of farmland of corn field and riparian land,β-diversity reaches the highest in the mountain area in the upper steam, the lowest in the downstream plain with severe human disturbance; in the habitats of old-field land and woodland, according to the fitted trend line co-efficient of the Cody index along the altitude, anf its variation regularity,β-diversity in the two types of habitats doesn't vary obviously with the change of altitude, but has something to do with the stage of succession the community belongs to.