长江三峡库区蝶类群落的物种获得率、小生境占有率及相对多度

研究于 1998～ 2 0 0 3年在库区 10个区县 ,35个调查点进行。研究时 ,库区蝴蝶的生活环境被划分为 80个小生境 ,设置样带6 6 1条 ;调查期间获得 (Sampled)蝴蝶 331种 ,10 780只个体。报道三峡库区蝴蝶群落的部分参数 :2 5 3种蝴蝶的小生境占有率低于 10 % ,占有 4 0 %以上小生境的蝴蝶只有 7种 ;在 6 0条以上样带都获得的蝴蝶有 16种 ,而在 10条以下样带内获得的蝴蝶 2 19种 ,占总数的 6 6 .2 % ;优势种 2 1个 (6 .3% ) ,常见种 12 5个 (37.8% ) ,少见种 10 3个 (31.1% ) ,罕见种 82个 (2 4 .8% ) ;相对多度高于 1%的种类 2 2个 ,仅占总数的 6 .6 % ;个体数分布的规律接近对数级数法则。三峡库区蝶类现在的分布反映了库区生境破碎化的结果 ,意味着适宜的生境斑块周围分布不适宜生境 ,种群受到面积、隔离、边缘等多种效应的影响 ,形成了现有的物种多样性及其空间格局

The occupied rate of microhabitats,sampled percentage of species and relative abundance of butterfly community in the Three Gorge Reservoir Area of Yangtze River

Butterflies are considered one of the most useful groups of organisms for monitoring environmental changes because they are easy observe, highly diverse in microhabitat choices, and with survival of many species strongly subject to environmental factors. The building of the Three Gorge Dam in the Yangtze River has raised concern about possible negative impacts on the ecosystem resulting from construction work. Thus, a program of monitoring species in the area prior to dam construction is important for assessing the post-construction effects. To achieve this goal, a survey of the butterfly community structure was carried out at 35 sites in 10 counties within the Three Gorge Reservoir Area of Yangtze River from 1998 to 2003, before the dam started to store water. This study investigated:(1) the structure and dynamic of butterfly communities, (2) intraspecific and interspecific relationship,(3)growth and decline of populations and (4) interactions between the species and their environments. The monitoring protocol included 661 sampling lines, grouped into 80 microhabitatsbased on the characteristics in vegetation type and landscape.The present article is the first in a series of reports to show results of the monitoring protocol. Characteristics of a few parameters of butterfly communities in the Three Gorge Reservoir Area are given, including: (1) sampled percentage of a species, (2)occupied rate of microhabitats of a given species and (3) relative abundance of a species. A total of 331 species occurred among the 10780 individuals of butterflies recorded during the survey. Overall, 253 species were found in less than 10% of defined microhabitat types, whereas only 7 species were obtained from over 40% of the microhabitat types. Only 16 species of butterflies were found from over 60 sampling lines, whereas 219 species were observed in less than 10 sampling lines. Also, 21 species (6.3%) were considered as dominant, 125 (37.8%) as common, 103 (31.1%) as unusual, and 82 (24.8%) as rare. Only 22 species of butterflies, consisting of just 6.6% of total species found, exhibited a value of relative abundance index exceeding 0.01. The patterns of butterfly species abundance and distribution in the Three Gorge Reservoir Area approached a logarithmic progression distribution, favoring a niche pre-emption hypothesis. The environments of the Three Gorge Reservoir Area were found to be generally harsh to the survival of butterflies, with few dominant common species.The nest article of the series will report other parameters of butterfly Communities in the Three Gorge Reservoir Area, including diversity indexes and evenness.