The effects of bird exclusion on the chemical and biological characteristics of a soda lake

Document Type: Primary Research paper

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Abstract

The effects of water birds on water quality in a shallow Turkish soda lake, Lake Aktaş, were investigated by comparing protected areas and those exposed to birds, in order to understand interactions between the birds and the ecosystem in this study. The experiment was carried out over five months between June and October 2009, in four widely distributed bird-proof enclosures in treatment areas and four open-top enclosures (control areas), a total of eight plots,  (with a fish density of about 1000 kg.ha-1, similar to the lake) in the lake. Physico-chemical analyses, phytoplankton, zooplankton, Secchi depth measurements, were determined each month in both treatment and control areas.  The significant differences were found only for chlorophyll a (P<0.001) and Secchi depth (P<0.05) throughout the experiment between the open and bird-proof enclosures. Although some effects of water birds were clear in the present study such as decrease in turbidity and chlorophyll a, it is difficult to determine the effect of waterfowl on water chemistry using enclosure experiments, since they are designed to test the effect of ornithogenic inputs on the water column, not the effects of other factors (e.g. natural chemistry).

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