The Ecological Distribution of Soil Beetle in Jiuhua Mountains

From April,1988 to December,1992,8 investigations on soil beetles are conducted under the vegetations of Pinus massoniana,laurilignosa and aestilignosa,Pinus taiwanensis and shrub-meadow of Jiuhua Mountains respectivcly.417 specimens were collectd,which belong to 33 families.Among them,220 individuals are larvas,which belong to 15 families;197 individuals are adults,which belong to 28 families,64 species (genera).The average density is 705 individuals/m3.Melolonthidae (L) and Elateridae (L) are dominant genera.18 kinds are common genera,which belong to Curculionidae (L),Staphylinidae (L),Platystethus operosus (A) and Longitasus succinens (A),etc.With increase of elevation,the habitat condition emerges vertical changes obviously,which results in the difference on the community structure of soil beetles.The richness,evenness and domiance indexes of community composition are all higher under the vegetations of mixed forest and shrub-meadow,than those under the vegetations of Pinus taiwanensis and Pinus massoniana;the difference is considerable among each community composition,Jaccard similarity index is small.Species (genera) which appears in only one habitat are more,but the common species (genus) are fewer.Changes of individual number are not totally identical with genera number.The density of soil beetles under the vegetation of Pinus taiwanensis is higest,which is 1083.2 individuals/m3 averagely,however,the density under Pinus massoniana is lowest,which is 652.8/m3,But the seasonal changes of number in each habitat are different,the number under Pinus taiwanensis is more only in winter,and fewer in other seasons;numbers under shrub-meadow and mixed forest are steadier.As regards seasonal changes of species (genera) number and individual number of soil beetles,the general trend is winter>artumn>spring>summer.The individual number of larva is 2 times more than adults,but the individual number of adults is 2.5 times more than larvats in mixed forest.The law of vertical distribution of soil beetles in soil bed is obvious,that is,many genera and individuals centralize in A layer,and obviously decreasing downwards.Individual numbers in A layer constitute 56.8% averagely.This is not same in four seasons,the individual number of A layer is the most in summer,constitutes 67.5%;in spring is lowest,constitutes 38.3%.Families which mainly distribute in A layer are Staphylinidae(A),Curculionidae (A),Chrysomelidae (A),Leiodidae (A),Tenebrionidae (A),Monommatidae (A),Scaphidiidae,Silphidae (L) etc.Genera which only distribute in D layer are very few,only Dermestidae (A) and Hydrophilidae (L).