洞庭湖洲滩及滨湖区鼠类分布格局及其多样性

为全面了解洞庭湖洲滩及滨湖区鼠类分布格局,统计自2003—2013年该湖区15个调查点5种不同生境的鼠类群落调查数据,并对鼠类群落的物种多样性进行分析。结果表明:2003—2013年洞庭湖区捕获鼠类有10种,主要优势种为黑线姬鼠(Apodemus agrarius)和东方田鼠(Microtus fortis);不同生境下的优势种不同,东方田鼠为湖滩生境优势种,黑线姬鼠是滨湖农田和退田还湖洲滩生境优势种,针毛鼠(Niviventer fulvescens)和社鼠(Niviventer confucianus)为滨湖丘岗林地优势种,小家鼠(Mus musculus)及黄胸鼠(Rattus tanzumi)则多出现在农房生境;不同生境的鼠类群落物种多样性不同,滨湖丘岗林地生境受人类活动或洪水干扰程度最低,因此,优势集中性指数最低,而物种多样性Shannon-Wiener指数在干扰较少的滨湖丘岗林地生境物种多样性指数最高。尽管湖滩生境受三峡工程的影响,物种数大量增加,但由于仍受汛期洪涝的干扰,依然具有优势种突出的特征。研究表明,人类社会活动或洪涝等干扰因素降低了鼠类群落物种多样性,致使优势种突出,形成只利于少数几个种群栖息的环境,最终导致种群大暴发。

Distribution pattern and diversity of rodent communities at beach and lakeside areas in the Dongting Lake region

To understand rodent distribution patterns at beach and lakeside areas of Dongting Lake and effectively prevent and control a rodent outbreak, a rodent survey was conducted at 15 survey sites from 2003 to 2013. Survey sites included the East, West, and South Dongting Lake. Snap traps were used throughout the census. The survey was conducted in each season, in addition to a survey in the mature bottomland. Surveys were usually carried out in January (winter), April (spring), July (summer), and October (autumn).All habitats were divided into five different types-beach, beach reconverted from farmland, lakeside farmland, hilly woodland, and residential premises surrounding the lake. We set 80,111 traps and caught 3,769 animals consisting of 10 species:Microtus fortis, Apodemus agrarius, Rattus norvegicus, R.tanezumi, R.losea, R. nitidus, Mus musculus, Niviventer fulvescens, N.confucianus, and Micromys minutus. The total trap succession of all species of rodents was 4.75%, the capture rate in the field was 4.77%, and the capture rate in farmhouses was 2.34%. The highest capture rate of the five habitats occurred at the beach, followed by the beach reconverted from farmland, hilly woodland, residential premises, and lakeside farmland. Since species abundance on the beaches increased after the Three-Gorges Project commenced, eight rodent species were captured at the beach, which was the habitat where the most species were captured. However, the diversity index of Shannon-Weiner was not highest among habitats, duo to the outstanding dominant species in the beach. The two dominant species were A.agrarius and M.fortis, because they were caught in all habitats, except residential premises. Dominant species differed in different habitats. M. fortis was the dominant species at beach wetlands of the Dongting Lake, where as A.agrarius was the dominant species at lakeside farmland and beach reconverted from farmland. N.fulvescens and N.confucianus mainly dominated the hilly woodland habitats surrounding the lake. R.tanezumi and M. musculus usually appeared in the farmhouse habitat. The species diversity indexes of the rodent community indifferent habitats differed. The concentration index of the beach reconverted from farmland was highest, whereas the Shannon-Wiener index was the lowest. The Shannon-Wiener index of hilly woodland was higher than that of other habitats, whereas the concentration index was lower, owing to the least disturbance by human activities or water. Although the species abundance on lakeside farmland and beach (7 and 8 species, respectively)were as high as in hilly woodland(7 species), their dominant species concentration indexes (0.4434 and 0.5365, respectively)were not as low as that in hilly woodland (0.2386), and their Shannon-Wiener indices (0.9380 and 0.8149, respectively) were not as high as in hilly woodland (1.5685), as a result of more disturbance in farmland and beach habitat sowing to human social activities or water submergence. The similarity index between residential premises and beach reconverted from farmland or hilly woodland was the lowest. The highest value appeared among beach and lakeside farmland habitats. This study showed that some human social activities or water disasters could lead to reduced rodent species diversity, and increase the dominant rodent species populations, which is a major reason for outbreak of rodent.