浙江海岛鸟兽地理生态学的初步研究

对浙江洞头岛及舟山五岛的鸟兽调查表明,海岛动物的种数较相邻大陆为低,但种群密度却高于大陆,岛上的某些种类出现生态位扩展的现象。舟山五岛兽类的种数和岛屿面积呈正相关,其关系式为S=2.12A~(0.29),但种群密度随着岛屿面积的增大而下降。文中据此提出了保护和发展岛屿动物资源的某些措施。

PRELIMINARY STUDIES ON GEOGRAPHICAL ECOLOGY OF BIRDS AND MAMMALS ON SOME ISLANDS OF ZHEJIANG PROVINCE

This paper reports on a survey (conducted during 1979, 1981-1982) of the birds and mammals on Dongtou Island and its adjacent mainland area, as well as on five islands of the Zhoushan Archipelago, Zhejiang Province.The survey shows that there are fewer species of animals on the islands than those on the mainland because of the separating effect of strait. For instance, a total of 16 species of birds and mammals were found on Dongtou Island during May-June 1979, while 51 species on the adjacent mainland area. However the population density on the former is higher than that on the latter The reason is that there are fewer competitors and fewer carnivores on the islands so that the population densities of some species of birds and mammals are quite high and the phenomena of 'niche expansion' occur. The survey also reveals that Passer montanus and Rattus rattoides are the dominant species on all the islands.Preston (1962) pointed out that the number of species on islands increases with island area, and suggested a formula for the relation as S=cAz. In our investigation of mammals on the five islands of the Zhoushan Archipelago a similar conclusion has been reached: S=2.12 A0.29. The density of mammals on these islands, however, tends to decrease with the extension of island area. In addition, the species number and population density of both birds and mammals are found to be closely related to the different types of vegetation on the islands.Over-hunting and destruction of habitats have led to the decrease or even to the extinction of some species of mammals on the islands. Therefore, some measures of protecting and developing the animal resources on the islands are suggested in the paper.