Comparative Population Regulation of Two Planktonic Cladocera (Holopedium Gibberum and Daphnia Catawba)
Comparative Population Regulation of Two Planktonic Cladocera (Holopedium Gibberum and Daphnia Catawba)
复制标题
两种浮游枝角类（Holopedium Gibberum 和 Daphnia Catawba）的种群调节比较
DOI：
10.2307/1938573
复制
发表时间：
1986
期刊：
影响因子：
4.8
通讯作者：
A. J. Tessier
中科院分区：
文献类型：
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作者：
A. J. Tessier
在宾夕法尼亚州拉卡瓦克湖，两种浮游食草动物（赤霉素和水蚤）的丰度呈非平行季节性波动。全紫堇在夏初和仲夏盛产，而卡托巴只在春季和夏末盛产。我试图通过确定调节每种种群的季节性因素来解释这种季节性演替。在三年的时间里，我从4月到10月监测浮游生物样本的种群丰度、个体能量储备（脂质含量）、产卵量和体型分布。食物资源和脊椎动物捕食者丰度也按季节进行了调查。在小型（6.4升）和大型（6000升）围场中进行的季节性食物供应和捕食者实验操作的结果支持了从描述性数据中得出的解释。不同的季节丰度模式可以用影响每个物种的食物压力和捕食强度的差异来解释。在大多数情况下，食物供应限制了赤霉病菌的种群增长。在每年的春天，饥饿是死亡的主要原因；在夏季，H. gibberum的个体能量储备和繁殖力几乎为零。成虫的捕食损失可以忽略不计，但幼虫（最小年龄级）被鱼捕食的死亡率有时很高。水蚤调节因子的强度存在季节性变化；食物供应只在春季和夏末限制了种群的增长，而在夏季，捕食控制了种群的增长。夏末对卡托巴的捕食减少，种群丰度急剧增加。在仲夏期间，试验性去除鱼引起了卡托巴病的相应增加。在夏末动物密度高峰时，两种动物均处于食物紧张状态。此时进行的生命表实验表明，d.c awba和H. gibberum之间发生了食物竞争，导致H. gibberum密度的降低。
The abundance of two planktonic grazers (Holopedium gibberum and Daphnia catawba) fluctuated seasonally in a nonparallel manner in Lake Lacawac, Pennsylvania. Holopedium gibberum was abundant in early and midsummer, while D. catawba was common only in spring and late summer. I sought to explain this seasonal succession by identifying seasonal factors which regulate each pop- ulation. I monitored population abundance, individual energy reserves (lipid content), egg production, and body size distributions in plankton samples from April to October in three years. Food resources and vertebrate predator abundance were also examined seasonally. Results of experimental manip- ulations of food availability and predators, conducted seasonally in both small (6.4-L) and large (6000- L) enclosures, supported interpretations drawn from descriptive data. Contrasting seasonal abundance patterns of the species are explained by differences in the intensity of food stress and predation affecting each species. Food supply restricted population growth of H. gibberum at most times. In the spring of each year, starvation was a major cause of mortality; during summer, individual energy reserves and fecundity were near zero for H. gibberum. Predation losses were negligible for adult H. gibberum, but neonate (smallest age class) mortality by fish was occasionally large. Daphnia catawba experienced a seasonal change in the intensity of regulating factors; food supply restricted population growth only in spring and late summer, but predation controlled growth during summer. During late summer, predation on D. catawba was reduced and its population abundance increased sharply. Experimental removal of fish caused a comparable increase of D. catawba during midsummer. At peak animal densities in late summer, both species were food stressed. Life table experiments conducted at this time suggest that competition for food occurs between D. catawba and H. gibberum, and results in a reduction of H. gibberum density.