Czerniawski Robert, Kowalska-Góralska Monika
Department of General Zoology, Centre of Molecular Biology and Biotechnology, University of Szczecin, Szczecin, Poland.
Institute of Biology, Department of Hydrobiology and Aquaculture, Wrocław University of Environmental and Life Sciences, Wroclaw, Poland.
PeerJ. 2018 Jul 3;6:e5087. doi: 10.7717/peerj.5087. eCollection 2018.
River damming causes a decrease in water current velocity which leads to an increase in richness and abundance of organisms atypical for running waters. Zooplankton is a representative example of such organisms. The influx of zooplankton from carp ponds is an additional factor that increases richness and abundance of zooplankton in rivers. We hypothesized that zooplankton dispersing from the carp ponds colonize the impoundments in river and the richness of zooplankton increase in impoundments by development of new species, not observed in the upstream. The zooplankton was collected monthly from April to September of 2013 and 2014. Sampling sites were located in the Barycz river (in the lotic sections and in the dam impoundments), as well as in its tributaries, which are the outlets of carp ponds. The most changes in zooplankton richness and abundance were observed at sites located within the dam impoundments, especially in relation to the lower values of the current velocity. Since the abundance of pelagic rotifers, cladocerans and copepods in the carp pond outlets was similar to that at lower sites in the Barycz, the influence of the carp pond outlets on the abundance in the dam and lotic sections was significant. The river itself in its impounded sections provides advantageous conditions for retention and colonization by a high abundance of zooplankton dispersing from the carp ponds, and for the development of species not occurred in the upstream, which, in turn, increases richness.
筑坝拦河会导致水流速度降低，进而使适合流水环境的生物种类和数量增加。浮游动物就是这类生物的一个典型例子。来自鲤鱼池塘的浮游动物涌入是另一个增加河流中浮游动物种类和数量的因素。我们假设，从鲤鱼池塘扩散而来的浮游动物会在河中的水库中定殖，并且水库中浮游动物的种类会通过新物种的出现而增加，这些新物种在上游并未出现。在2013年和2014年的4月至9月期间每月采集浮游动物样本。采样点位于巴雷奇河（在急流段和大坝水库中）及其支流，这些支流是鲤鱼池塘的出水口。浮游动物种类和数量的最大变化出现在大坝水库内的采样点，特别是与较低的水流速度相关。由于鲤鱼池塘出水口的浮游轮虫、枝角类和桡足类的数量与巴雷奇河下游采样点的数量相似，所以鲤鱼池塘出水口对大坝段和急流段浮游动物数量的影响显著。河流在其筑坝段为从鲤鱼池塘扩散而来的大量浮游动物的滞留和定殖，以及在上游未出现的物种的发展提供了有利条件，进而增加了物种丰富度。
