Ribi Georg
Zoological Museum, University of Zürich, CH-8057, Zürich, Switzerland.
Oecologia. 1986 Apr;69(1):60-63. doi: 10.1007/BF00399038.
The gastropod species Viviparus ater and Potamopyrgus jenkinsi have both colonized Lake Zürich relatively recently. If it is assumed that they have dispersed in the Lake starting from one location, a model of random diffusion is insufficient to explain their present distribution in Lake Zürich. It is suggested that both species were dispersed by humans. In P. jenkinsi, passive dispersal by birds, fish or on floating algae may also have occurred. To estimate the rate of within-lake dispersal, life tables were constructed and the diffusivity estimated for the two species. Per capita population growth rates were calculated to be 0.00337/d for V. ater and 0.0159/d for P. jenkinsi. Diffusivity was close to 1 m/d in both species.
腹足纲物种暗黑田螺和詹氏扁蜷均于相对较近的时期在苏黎世湖定殖。如果假设它们是从一个地点开始在湖中扩散，那么随机扩散模型不足以解释它们目前在苏黎世湖中的分布情况。有人提出这两个物种都是由人类扩散的。对于詹氏扁蜷，鸟类、鱼类或附着在漂浮藻类上的被动扩散也可能发生过。为了估计湖内扩散速率，构建了生命表并估算了这两个物种的扩散系数。计算得出暗黑田螺的人均种群增长率为0.00337/天，詹氏扁蜷为0.0159/天。两个物种的扩散系数均接近1米/天。
