Introduction to the Special Issue

This Special Issue contains 13 papers, at least 7 of which are mainly based on results obtained during the CRENODAT Project. Most papers deal with the biodiversity and community ecology of a variety of autotrophic and heterotrophic, macroscopic and microscopic groups of organisms. Several evaluate the relative importance of morphological (from microhabitat to large scale), physical, and chemical factors in determining community composition and structure. Some discuss the conservation implications of the observed patterns. One even applies palaeolimnological techniques to a crenic habitat, showing the effects of land use and management practices around the spring-head. Spatial and temporal changes (from seasonal to long-term) are also considered.