梁子湖浮游甲壳动物的生物多样性

基于2006年8月至2008年3月对梁子湖浮游甲壳动物的采样调查,记录了该湖区浮游甲壳动物22种,隶属9科18属,其中枝角类(Cladocera)16种,桡足类(Copepoda)6种,包括9属新记录.物种多样性季节性动态变化明显:枝角类优势种在春、夏和秋冬季依次为透明溞(Daphnia hyalina,优势度Y = 0.80±0.01),小栉溞(Daphnia cristata,Y = 0.50±0.03)和长额象鼻溞(Bosmina longirostris,Y = 0.58±0.04);而桡足类优势种在夏、秋和冬春季依次为长江新镖水蚤(Neodiaptomus yangtsekiangensis,Y = 0.41±0.01)、近邻剑水蚤(Cyclops vicinus,Y = 0.46)和特异荡镖水蚤(Neutrodiaptomus incongruens,Y = 0.65±0.18).浮游甲壳类个体密度以春季最高((292±85) ind/L),夏、秋、冬季渐低(依次为(169±104)、(140±53)、(120±0) ind/L).物种多样性冬春季较低(物种数S≤12,丰富度指数D = 0.77和0.71,香农-威纳指数H = 1.79和1.45),夏秋季较高(S≥17,D = 0.98和0.88,H = 1.78和1.83).梁子湖浮游甲壳类动物多样性年际差异不显著,表明湖区环境条件较为优越、稳定.

The biodiversity of crustacean zooplankton in Lake Liangzi

Crustacean zooplanktons were seasonally sampled at 11 sites in Lake Liangzi from August, 2006 to March, 2008. Totally 22 crustacean species, which were composed of 16 Cladocera species and six Copepoda species, were identified. These species belong to nine families and 18 genera, nine of which were recorded for the first time in this lake area. Analysis of the species dominance index (Y), Shannon-Wiener diversity index (H), number of species (S), species richness index (D) and individual density (ind./L) revealed significant seasonal variation of the crustacean diversity. Daphnia hyalina (Y = 0.80±0.01), Daphnia cristata (Y = 0.50±0.03) and Bosmina longirostris (Y = 0.58±0.04) were the dominant Cladocera species in spring, summer and autumn-winter respectively. Neodiaptomus yangtsekiangensis (Y = 0.41±0.01), Cyclops vicinus (Y = 0.46) to Neutrodiaptomus incongruens (Y = 0.65±0.18) were the dominant Copepod species in summer, autumn and winter-spring respectively. Population density of Crustacean declined gradually from 292 (±85, S.D.) to 169 (±104), 140 (±53) and 120 (±0) through spring to winter. Similarly, species diversity remained low in winter and spring (S ≤ 12, D = 0.77 and 0.71, H = 1.79 and 1.45, respectively), but increased in summer and autumn (S ≥ 17, D = 0.98 and 0.88, H = 1.78 and 1.83, respectively). Further analysis indicated that species composition and diversity indexes of Crustacean community were relatively stable between 2006 and 2007 summers (August), as well as between 2007 and 2008 springs (March). Our results indicated that Lake Liangzi was in good condition for Crustacean species.