Ecohydrology in The Netherlands: principles of an application-driven interdiscipline

Ecohydrology was introduced in The Netherlands as ‘the science of the hydrological aspects of ecology; the overlap between hydrology and ecology, studied in view of ecological problems’. The pith of it is the hypothesis that hydrology controls the composition of vegetation of a site through the water and solute budgets and through the conditions imposed upon the local nutrient cycling. Social impulses in the early 1970s shaped a niche for ecohydrology in studies for integrated water resources management, because agro-hydrological models fell short for nature conservation. Mires and river valleys were favourite objects of landscape-scale ecohydrological pattern analyses. Other substantial work was done on the occurrence of species with environmental factors, in search of suitable botanical indicators of complex hydrological conditions. In this contribution, we discuss how non-aquatic ecohydrology developed into a landscape-ecological discipline, with firm roots in various branches of vegetation science in particular. Approaches and concepts were developed in order to understand the influence of water management on the observed decline of endangered plant species, even in seemingly undisturbed nature reserves. The more recent ecohydrological investigations for the restoration of damaged ecosystems benefited considerably from a further integration with geohydrological and soil-chemical studies.