text: The maturity index: an ecological measure of environmental disturbance based on nematode species composition.
  Nematode assemblages constitute a potential instrument for assessing the quality of submersed, temporarily submersed, and terrestrial soils and for the development of an ecological typology and biomonitoring system. Interpretation of physical or pollution-induced disturbances has hitherto mainly been based on changes in diversity, dominance patterns or percentage of dorylaimids (Adenophorea). The maturity index, based on the nematode fauna, is proposed as a gauge of the condition of the soil ecosystem. Values on a coloniser/persister scale are given for nematodes that occur in The Netherlands. The possibilities of the use of this index are demonstrated by a retrospective interpretation of some literature data. The use of nematodes in environmental studies is discussed.