Samenvatting

Crustaceans that are very common in streams were often used as the testing of water quality standards. Therefore, it is effective to select Crustaceans as an indicator to examine the influence of decreasing water flow. Climate change induced the extremely dry summer in the Netherlands. Water flow decrease dramatically and water temperature, water quality and dissolved oxygen concentration are changed due to the decreasing water flow. Thus, the Crustaceans which live in the stream will be affected. The effect of stagnation on the Crustaceans assemblages from two sandy lowland streams in the Netherlands(1 high nutrient stream, 1 low nutrient stream) was measured on summer time of 2011. From above, the effect of stagnation on Crustaceans is worth to study as a Bachelor thesis. In order to explain the influences of stagnation on Crustaceans, field experiment and laboratory experiment were carried out during the summer 2011. In the experiment, Crustaceans samples and water samples were taken once a week or once two weeks. Meanwhile, water level and dissolved oxygen concentration were continuously measured. Thus, the relation between water quality, water temperature and dissolved oxygen concentration and Crustaceans was very clear by comparing the variation of them. According to the result, the response of Crustaceans for Water temperature, pH and EC that was influenced by water flow was not significant due to the narrow variation range of them. However, Crustaceans was correlated with dissolved oxygen. The composition of Crustaceans in high nutrient stream and low nutrient stream is marked different.