Study Of The Relation Between Grasshopper And Vegetation Community In The Upper Reaches Of Hei River

Grasshopper disaster is a global biological disaster, the economic losses caused by locust disaster and the huge influence will affect the natural ecosystem and socio-economic system. In recent years, with global climate change and the increase of extreme weather events and the inappropriate human activities, grasshopper disaster become increasingly rampant, therefore the study of relation between the occurrence and distribution of locusts and environmental factors was receiving more and more attention of people. At present the characteristics and spatial distribution of grasshopper communities gradually received an in-depth research and investigation from the basic grasshopper species investigation and fauna gradually penetrated into their diversity and the relationship of environmental factors, spatial distribution pattern and factors of influence and so on. Grasshopper community composition, community structure characteristic and spatial distribution of grasshopper are important ecological response process to the environmental factors, especially to vegetation community. The study of coupled relation between grasshopper and vegetation could help revealing the habitat selection and adaptability of the grasshopper and collaborative relationship within populations. There is a close relationship between plant communities and grasshoppers,and it has been the research focus of ecologists over the years. On the one hand vegetation provide food, the appropriate micro-climate and habitat for the locusts, on the other hand, grasshoppers'diet election to different plants can change competitive landscape of plant communities and affect plant community structure and diversity.This article choose the arid grassland in upper reaches of the Hei River as study area, the area has dry climate, scarce precipitation, in addition to, in recent years, climate become warming and human overgrazing, resulting in the increase of grasshoppers disaster occurrence frequency and scale, which bring serious harm to livestock production. Herbivorous insects, as locusts, vegetation characteristics and spatial distribution of their community has an important influence, and relationship analysis between plant and grasshopper has important reference for forecasting, monitoring and biological disasters prevent. This article on the basis of orientation observation and large-scale survey, GIS technology was used for precise positioning of sampling points and spatial data management and analysis. In this study, Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA) were used to quantify the grasshopper population and analyze ecology relationship between grasshopper community spatial distribution pattern and vegetation community characteristic and dominant plant coverage; besides we analyzed the relation between plants coverage and grasshopper abundance. The above analysis will be help to explore the spatial distribution of grasshoppers and plant communities'relationship, and provide the basis for reference for grasshopper forecasting and monitoring, so as to improve the efficiency of grasshopper control.Draws following conclusion through the research paper:(1) A total of 1149 grasshoppers were collected in seven plants community on the altitude of 2400-2800m,belonging to 3 families, 10 genera,13 species, Oedaleus decoratus, Gomphocerus licenti and Chorthippus albonemus are the dominant species in the research area, and their abundance are the highest in the plant community dominant by Artemisia dalailamae and Stellera chamaejasme respectively.(2) The grasshopper community composition and dominant species are obviously different in seven plant community; Grasshopper community diversity and dominance index existed significant difference (P<0.05) in different plant community, evenness index existed no significant difference (P>0.05).(3) Grasshopper community diversity and the number of species have significantly positive correlation with the numbern of plant species (P<0.01); Grasshopper species richness has significant correlation with plant coverage (P<0.05). There is negative relation between grasshopper abundance with plant dominance index,and positive relation with other plant indexes, and very significantly correlated with plant height (r=0.872,P<0.01), which indicated that the vegetation community with high plant coverage and high species richness will lead to a great number of grasshopper distribution.(4) 13 species of grasshoppers were divided into six groups through DCA analysis. The number of grasshopper species, dominance, predatory behaviors and habitat choice of grasshopper are significantly different in those six groups. Meanwhile, no overlap was found within the same group in the hatch time, life form and tropic niche of grasshopper.(5) There are three complex co-relationships between dominant plant coverage and grasshopper abundance, including extremely significant correlation, significant correlation and no correlation. The effect of plant coverage on grasshopper abundance is very different; Euchorthippus unicolor has very significantly positive relation with Artemisia dalailamae, Gomphocerus licenti and C.brunneus huabeiensis both have significant positive relation with Stipa Krylovii and Aneurolepidium dasystanchys.(6) Gramineae and Compositae plant have higher impact on the grasshopper distribution than other plants. Plant community affected grasshopper distribution pattern by providing food resource and proper habitat environment.(7) The six grasshopper groups corresponded to different plant communities, and presented three kinds of correspondence relations, such as one-to-one correspondence relation between Chorthippus fallax and Stellera chamaejasme community; multiple-to-one correspondence of Oedaleus decorus, Myrmeleotettix palpalis and Filchnerella sunanensis with Artemisia dalailamae community; the rest of grasshopper community corresponded to multiple plant community types.