Study On The Plant Diversity On Remnant Patch In Desert Steppe

The desert steppe is a xerophilous grassland ecosystem which the grassland transition to the desert, and the Desert steppe is the strongest xerophytic grassland. Ningxia desert grassland area is located in one of China’s land area of biological conservation priority Alxa-Mu Us desert region.Due to long-term human grazing and natural disturbance, the desert grassland degradation is quite serious, resulting in phenomenon is quite common in desert steppe ecosystem habitat fragmentation and vegetation patches distribution. The remnant patch is a typical fragmentation ecosystem in the study area, and it has important research value.To date, no systematic studies were developed to elucidate plant species diversity. Nevertheless, from the perspective of basic research and biodiversity conservation, it is urgent and important to explore the influence mechanisms of plant species diversity on desert steppe remnant patch, which will help us to understand plant diversity pattern and to acquire specific measures of biodiversity conservation, restoration and management for local region.Based on those considerations,49 remnant patchs on desert steppe in a typical region in Yanchi county of Ningxia hui autonomous region, were selected to investigate the shape characteristics of remnant patchs and plant species composition and the change, to detect the species-area relationship, the relationship between species richness and species-area curve, plant diversity and similarity index and the relationship between patches properties to identify the determinants of plant species diversity. The main conclusions are as follows:(1) The area of remnant patchs on desert steppe as a whole is lesser, large remnant patchs are rarely plaques; Patch shape is irregular, and the boundary is very complicated.(2) the relationship between plant species in desert steppe between patchs area can use be used in island biogeography species-area model is y=4.984x0.267 (R2= 0.243, p= 0.002)(3) With the decreasing of remnant patch, the number of species, diversity index (R), Shannon Wiener index (H’) showed a decreasing trend, while Simpson index (D) is opposite.(4) The patch edge effect is embodied in small patches. The plant diversity inside the large patches and the peninsula remnant patch is higher, it has a certain ability to save the species, The patch of small scale communities in desert steppe has important significance for the maintenance of plant diversity in the area;(5) The influence factors of the plant diversity of the remnant patches in desert steppe are different. Therefore, in the protection of the remnant patches of desert steppe biodiversity should based on local conditions,At the same time, it should give priority to the protection of the regional diversity in the desert steppe to protect the peninsula patches and the large island remnant patches.