竞争指数及其在小红珠绢蝶保护生物学研究中的应用

Competition Index and Application to Conservation Biology of Parnassius nomion

利用多样性指数和种群动态相结合 ,建立竞争指数对小红珠绢蝶东灵山种群的濒危机制进行分析。结果表明 ,小红珠绢蝶的竞争指数在不同年份的下降过程中有不同的变化。以此为依据可以准确地判断出对该种群动态影响的环境因子。这一方法有很高的普适性 。

Study on dangerous species' biology and population ecology is still a very important subject in biodiversity conservation research. However, there are few studies on internal mechanism between the protected species and the components of community, especially the synchronization of dangerous species population dynamics and fluctuation of concomitant species diversity. Caughley presented the common distinguish method and protect procedure of descending population (1994). He reported that the study of a descending population should base on long time observation and general knowledge of the species. However, Caughley's method is difficult to apply when the descending population is a small population. First of all these populations descend so quickly and may extinct before people know them. Secondly, it is difficult to get individual number for small population and information of random disturbing to their mortality. We have studied a local population of Parnassius nomion and the other butterflies on the spot. Loss of habitat and increase of natural enemy are two factors to cause Parnassius nomion population decrease on Dongling Mountain peak from 1998 to 2001. But these two factors play different roles in different years. In this paper the competition index is presented as D j= P 2 j/λ;P j=N j/N;λ=∑(Ni(Ni-1)/ N(N-1)). D j is the competition index of the jth species, N j is the individual number of the jth species on the spot, and N is the total individual number on the spot. λ is relating with the biodiversity and 1-λ is the Simpson index as a measure for biodiversity. The change of competition index can be used to determine what is the major effect to cause Parnassius nomion population fluctuations. From 1998 to 2000, competition index of Parnassius nomion population had a small change with the descending of the population density, so the loss of habitat was the main factor. In 2001, its competition index decreased rapidly with the population density, so the natural enemy is the main factor. The results of this paper show that the competition index is a useful tool to reveal which is the major effcet to cause small and descending population to be dangerous.