Recent increase of North Sea houting and prospects for recolonization in the Netherlands

Two monitoring programmes in estuarine and freshwater systems in the Netherlands both show a recent increase in anadromous North Sea houting Coregonus oxyrhynchus after it disappeared there in the 1940s. Most houting were immature and caught during the feeding season indicating that at present the riverine and estuarine waters in the Netherlands mainly function as a feeding habitat.     

The Postglacial History of Lake Flarken,Southern Sweden,Interpreted from Subfossil Insect Remains

A correlation of changes in the composition of chironomid and chaoborid remains and changes in sediment chemical composition, floristic, and other faunistic information indicate that a decreasing productivity and an increasing humic level characterized the development of the small Lake Flarken, Southern Sweden, during the postglacial period. Pronounced changes in the fauna were correlated with fluctuations of the water level in the lake, which was caused by changes in the humidity of the climate. Significant human influence on the lake has only occurred in recent years, during which a rapid acidification has caused the most dramatic change in the fauna, by far, in the whole history of the lake.