太湖霍甫水丝蚓(Limnodrilus hoffmeisteri Claparède)的时空格局

2005年1-12月对太湖霍甫水丝蚓进行了逐月调查.太湖霍甫水丝蚓年均密度和生物量分别为3273.75 ind./m2和4.697 g/m2,均在2月份达到最大值.根据体长频数分布的周年变化,推测太湖霍甫水丝蚓一年有三代.太湖霍甫水丝蚓密度和生物量在空间上表现出明显的差异性,且随季节变化较小,其高值区域均出现在太湖北部梅梁湾和竺山湾及西部河口湖区,而在其它区域的现存量均较低.分析表明太湖霍甫水丝蚓空间差异可能与营养水平、底质类型、可摄食的食物及生境的稳定性等因素有关.

Temporal and spatial patterns of Limnodrilus hoffmeisteri Claparède in Lake Taihu

The population of Limnodrilus hoffmeisteri Claparède in Lake Taihu(Eastern China) was investigated in 2005by monthly sampling.The annual average density and biomass of this worm were 3273.75ind./m2 and 4.697g/m2,respectively.Both population density and biomass peaked in February.According to the annual dynamics of the frequency distributions of body length,the species had three generations and reproduced in considerable time throughout the year.The results showed a strong clumped distribution pattern of L.hoffmeisteri but it changed little among seasons.The highest population density and biomass of L.hoffmeisteri were found in Meiliang Bay,Zhushan Bay and the river-mouths areas in the west,while other places of the lake had very low worm density.The key factors regulating this spatial distribution pattern may be nutrient state,types of substrate,food availability and habitat stability.