洞庭湖区退田还湖过程中小型兽类的生态位特征

为了解退田还湖工程实施后的小兽群落状况,2003~2010年对洞庭湖区退田还湖后9种不同类型生境中小型兽类的生态位特征进行了调查.共布放64 432夹日,捕获小型兽3 066只,总的捕获率为4.76%,包括啮齿目10种和食虫目2种.小型兽类各种群的生态位宽度以褐家鼠和黑线姬鼠最高,分别为0.819 8和0.765 6,为广生态位的种类;随后依次是臭鼩、东方田鼠、刺猬、巢鼠、黄胸鼠、小家鼠、黄毛鼠、针毛鼠,分别为0.689 0、0.573 7、0.527 3、0.482 8、0.394 8、0.289 7、0.265 1、0.098 5;社鼠和大足鼠最低,仅在1种生境中有捕获.从生态位宽度指数的季节变化看,黑线姬鼠、褐家鼠、东方田鼠和臭鼩在四季的生态位宽度指数均较高.从空间生态位宽度和生态位重叠指数看,除黑线姬鼠和褐家鼠利用生境较广外,洞庭湖小兽群落可分为3个类群:栖息于环湖丘岗林地生境的社鼠、针毛鼠和黄毛鼠类群,以湖滩生境为主的东方田鼠、巢鼠和臭鼩类群,以及以村庄周围的农田生态系统为主的家鼠类群.从生态位指标和捕获数量看,黑线姬鼠、东方田鼠和褐家鼠是当地需要重点关注的种类.东方田鼠种群数量高峰年份与低谷年份比,其生态位宽度以及与其它种类的生态位重叠指数均较高,高峰年份东方田鼠冬季在双退垸出现,说明退田还湖已扩大了东方田鼠的繁殖基地,对东方田鼠种群发展有利,在种群暴发年份,易形成更加严重的危害.

Niche Characteristics of Small Mammal During Process of Returning Cropland back into Lake in Dongting Lake Region

In order to understand the situation of small mammal community in the Dongting Lake Region,China after returning cropland back into lake since 1998,the niche breadth and niche overlap of small mammal community were studied.64 432 traps were set and 3 066 animals were caught.The trap success was 4.76%.The animals trapped belonged two categories: 10 species of Rodentia and 2 species of Insectivora.According to the data of field survey,the niche breadths of the species were 0.819 8(Rattus norvegicus),0.765 6(Apodemus agrarius),0.689 0(Suncus Murinus),0.573 7(Microtus fortis),0.527 3(Erinaceus europaeus),0.482 8(Micromys minutus),0.394 8(Rattus tanezumi),0.289 7(Mus Musculus),0.265 1(Rattus losea),0.098 5(Niviventer fulvescens),0.000 0(Niviventer confucianus) and 0.000 0(Rattus nitidus),respectively.The niche breadth of R.norvegicus,A.agrarius,M.fortis and S.Murinus were bigger than those of other species in all seasons.Based on the indices of niche breadth and niche overlap,the small mammal communities could be divided into three groups: N.confucianus,N.fulvescens and R.losea mainly in hilly woodland around the lake;M.fortis,S.murinus and M.minutus generally at beach of the lake;and R.tanezumi and M.musculus mostly in farmland beside village.R.norvegicus and A.agrarius were caught almost in each habitat,and they had higher niche overlap indices compared with other species.In consideration of the population density and indices of niche,R.norvegicus,A.agrarius and M.fortis should be paid more attention after returning cropland back into lake in the Dongting Lake Region.The niche breadth of M.fortis and niche overlap between M.fortis and other species always were higher in years of high population density of M.fortis than those in years of low population density.M.fortis was found in double restoration polder in winter,which suggested that more habitats were suitable for them to reproduce after returning cropland back into lake.Thus,once the populations of M.fortis outbreaks in the Dongting Lake Region,they may cause more serious damage to crops than before.