Diversity of the Plant Community of Giant Pandas' Habitat in Wolong Nature Reserve. IV.The Effects of Human Disturbance on the Species Diversity of the Plant Community

In this paper,researches were made on the impacts of human disturbance(mostly forest logging) on the giant pandas'(Ailuropoda melanoleuca) habitat in Wolong Nature Reserve.The 64 plots of the plant community were investigated and analyzed by use of the sampling method,and species diversity index and SPSS 13.0 software.The results have shown that human disturbance affects the species diversity of the plant communities in giant pandas' habitat,especially on the plant components of each layer in plant community.The clear-cutting reduced badly the species diversity indices of arbor layer,and it was propitious to increase the species diversity indices of shrub and grass layers.The species diversity indices of arbor layer of the selective logging forest were more than those of the clearcutting forest,and little than those of the primary forest.The plant components of forest underlayers were abundant in the later-day cutting forest.Along with the prolonging of forest succession,the species diversity indices of arbor layer were mounting up,but those of shrub and grass layers would reduce.The species diversity index of the clear-cutting forest was higher than that of the selective logging forest and primary forest.The number of species was 27.69±7.75 in primary forest,20.78±9.07 in clear-cutting forest,and 26.62±8.81 in selective logging forest,respectively.The number of species and Margelef's indices displayed marked differences,and the other indices were not notable in different logging types.The species diversity indices of different logging times were were more fluctuant,the indices of the initial stages of the 1990's exceeded obviously those of the other years and the primary forest.And this was closely relative to the logging types and the growth pattern of bamboos as the giant pandas' staple diets.The results of the statistical hypothesis testing of the different logging times were similar to those of the different logging types.