Species Diversity Of Aquatic Plant And Its Correlation With Environment In Jiuzhaigou

With the development of society, biodiversity causes more and more global attention. As part of biodiversity, species diversity is the basis and core of biodiversity protection and research. Insight into the scientific nature and change law of species diversity as well as the relationship between species diversity and the habitat is of great value for the biodiversity protection. In recent years, much work has been carried out about terrestrial plant species diversity but little about aquatic species diversity. As the development of wetland ecolgoy, the protection, restoration and reasonable utilization of marsh has become the hotspot gradually. Because aquatic plant is an important part of wetland ecosystem, even more the main transfer of the material and energy in ecosystem, the population change of the aquatic plants must affect the lake ecosystem and the water environment. Therefore the study on the interactive relationship between aquatic plant species diversity and the environment will be used for the wetland ecosystem protection and water resource exploration.The experimental plant community is the aquatic plant community in different lake water environments in the Jiuzhaigou nature reserve. Based on the sample and field investigation, the species diversity traits, change law of the aquatic plants and its relationship with the water and soil environment were examined using statistics, quantitative ecology. The main study includes: the species composition and flora characteristics, quantitative classification and ordination,α-diversity andβ-diversity, the relationship between species diversity and water, soil environment and the effect of tourism on species diversity and protection strategy.Via the study on the relationship between the aquatic plant species diversity and the environment in Jiuzhaigou, the main results are as follows:The species diversity is high. The primary investigation showed there were 147 species belonging to 30 families and 56 genera. These plants can be classified into emergent, floating-leaved and submerged anchored hydrophytes. Flora analysis demonstrated that the floristic element of aquatic plant was complicated. The species distribution showed obvious regional characteristics. The special species of china was abundant and the temperate traits of aquatic plant were mainly reflected from the level of genera and species. The aquatic plant communities could classified into 15 associations, and most of them were emergent anchored vegetation. DCA ordination and TWINSPAN classification had the similar result. The spatial distribution traits of the aquatic community was consistent with the ecological environment gradient . The first axis can basically reflect the elevation gradient variation and the second axis was closely relative to the relationship between water environment and the life form of constructive species. The spatial distribution of species was similar to the its community distributionThe studies ofα-diversity index of the community showed that it tended to decrease as the increasing of altitude, and the human disturbance could increase its value. Among these indices ofα-diversity, Shannon-Wiener index was more sensitive in terms of the diversity measure, and the Simpson diversity index was more stable because of the limitation by evenness. It was more appropriate to use Pielou index than Alatalo index in the plots with a few species. The diversity index based on important value had involved the parameters of relative height and the relative coverage, made it more general in the measuring of the community diversity. The DCA analysis of species diversity showed the correlation between community and all kinds of species diversity indices. The first axis mainly reflected the tendency of richness as the second axis mainly reflected the change of evenness.The studies ofβ-diversity between communities showed that the species composition between plots changed significantly as the change of altitude and some other factors. The data based on important value was more general and stable. And the analyses of altitude and space cluster showed that the altitude gradient was a main factor which affected theβ-diversity index of aquatic plant community, as the increase of altitude and height difference, theβ-diversity index changed significantly, and also the change of species composition. Meanwhile,β-diversity index could be divide into 4 types, the effects of non-altitude factor of III type indicated that drainage area feature and community type could affect diversity to some extent.The water quality characteristics of each plots in Jiuzhaigou mainly behaved as the decrease of water temperature with the increase of altitude, and an alkalescent water pH value. The total-N and DO (dissolve oxygen) wer differ significantly between these water plots, and the total-P was relatively low. The correlation analysis showed that the altitude was positively correlated with water temperature, and also with the pH value and DO. And the species diversity was generally correlated with pH value negatively, and positively correlated with total-N, but the correlation with total-P is nonsignificant. The DO was more or less negatively correlated with richness and species diversity indices. The partial analyses suggested the altitude factor had limited the correlation between pH value and species diversity. Stepwise regression analyses indicated that the species diversity indices of community are influenced by the synthetical factors significantly, such as water quanlity. Of all the above, total-N was the key factor which influence species diversity. The first axis of DCCA reflected the change of water temperature, and also total-N and pH value had some correlation with it, while the second axis almost reflected the change of DO in the water environment of different plots.The chemical characteristics of soil in all kinds of sample plots was that the soil pH value was above 7.5, with high content of total-N and total-K having significant difference among them., but with low content of total-P, available-N available-P and available-K. The relative analyses showed that the altitude had positive relationship with the soil environment. The total-N and available-N , total-P and total-K had the same results. The water environment and the soil environment had positive relationship between pH values. Total-N in water was positive with soil pH value and total-N. And total-P in water also was positive with soil total-P. Dissolved oxygen had close relation with available N, P, K, while water temperature had great influence on soil total-N, available-N, total-P and available-K. Species diversity in communities had important relation with soil Ph, soil total-N and available-N. Partial correlation analyses indicated that altitude environmental factor had significant impact on the relativity between species abundance in communities and soil environment. Stepwise regression analysis revealed that diversity indices of most communities were extremely affected by soil composite environment factors, while the key factor was soil pH. The first plot of DCCA ordination mainly reflected the changes of soil pH, total-N and available-K while the second plot reflected the changes of soil pH and total-N.In addition, on the foundation of general investigation and study on tourist resources exploitation, this paper summarized the ecology countermeasure from the faces of tourist behavior, inhabitant behavior, tour infrastructure, tourism management and ecological security to reduce the influence of tourism exploitation and protect the ecological environment.