Of Grasshopper Community Diversity And Edge Effect Of The Guanzhong Plain Of Shaanxi Province

GuanZhong region lied in the middle of Shaanxi Province, The plague oflocusts is one of the most serious factors that hinder the development of agriculture.Thepaper mainly studied the composition, distributed structure, biodiversity, seasonal changeand the edge effect of grasshoppers communities in GuanZhong region. The results are asfollow:According to character of geography and vegetation, seven types of habitats are stud-ied, (a). the field nearby the Qin - Mountain; (b) arid plain to the North Wei - River;(c) river marshland; (d) bottomland meadow; (e)the desertland on the Li - Mountain;(f) the gritty field; (g) the salty and alkaline region. All thirty - three species of grasshopper (OrthOPtera: Acridoidea) collected in studied areas were classified as twentygenus and six families, which composes three fourths of the total number of species ofgrasshoppers in this region. Among them, the quantity of Oedipodidae is the most whilethat of Arcypteridae is the fewest. By compairing the resemblance of grasshoppers' com-munities in different environment with clustering and PCA analysis, seven studied regionscan be divided into two types, the vegetation abundance type and the arid or worse vege-tation type. the result suggested that the resemblance of condintions resulted in the resem-blance of different grasshoppers' communities. Based on the sampling investigation, thepatterns of species - abundance relationship model was established;N(R) = 7exp[-0.1860(R-3)²] (x² = l4.602_7,0.01 = 18.475).According to the data obtained from the investigation in different habitat region, thediversity index of Shannon - Wiener (H') from high to low was: a>d>b>e>c>f>g.Eveness index (E) is approximately corresponded with H' while the simpson index (D) isconverse to H', by the related analysis on the diversity indexes, this tendeney has statisti-cally significant. the seasonal change of diversity about grasshoppers were also studied,The results showed that the plague of locusts is once every year, the value of biomass and quanlty Is biggest In seotember,the value of H［ndex Is biggest injuly,the value of C In－ dex Is maximum In June and minimum In september,but the E Index s seasollal challge。 converse to C Index． The edge effect of grasshoppers communities were studied amony five types of edge ZOfl6S ill this Y6g1Oll．1:CYOp fi6ld—HU8llg flV6r ShO81 6dg6 ZOfl6；11．rlV6r ffisrshlsnd一 wei river shoal edge zon引 皿．grltty land—wasteland edge zone；w．grlttyland—Luo river shoal edge zone ； V．crop field—salty and alk field e�'�e zone．On the whole,the grasshoppers diversity In edge。ne are higher than those In the Interior of adjacent corn－ munltles at the similar edges except edge V．Two famous measuring the Intensity of edge effect(E。,and Ec)were used In analysis．Results show that EH。about edge．11．m． w．areblgger than,·It show the edge effect Is positive．EH,abut edge V Is smaller than,so the edge effect Is negatively．The different edge resPOnses ofvarlouS grasshop－ pers were discussed．Analysis reveal that different spedes respond to the identical edge differently．Acrila c。nerea Thunberg and Atractomo�'�a slnensts．hl．are habitat gen－ erallst edge exploiter；Oedleus。＂f6rnalls Saussure Is habitat specialist edge avoider； Shi。kiacris shi。kit(I．Bol．)and Trilophidia annulata(Thunberg)can be regarded as habitat specialist；Locusta mlg。torla man。lensls(Meyen)can be considered as habitat generallst． Inbrief,we should consider all respects aboubout grassbppers communities when we take prevention and control of grasshoppers...