SPRINGS ECOSYSTEM ECOHYDROLOGY AND STEWARDSHIP (Invited Presentation)

Springs ecosystems are places at which groundwater reaches, and often flows from the Earth’s surface, emerging either subaerially or subaqueously. Although long-studied from the hydrogeological context and as the proving ground for the first systematic tests of ecosystem energetics theory, springs ecosystem ecology remains understudied. Springs differ from other groundwater-dependent ecosystems (GDEs): 1) by functioning as relatively highly self-contained systems; 2) in the importance of linkage of the supporting aquifer to surface ecosystem functions and characteristics; 3) by emergence in a diverse array of geomorphic types, of which several are strongly biogenic; 4) by having potentially high and spatially variable productivity; 5) through their often distinctive and/or high ecological individuality, biological diversity, and species packing; 6) in their function as keystone ecosystems in relation to adjacent ecosystems; and 7) by virtue of their unique cultural and socio-economic roles. Although clearly important as landscape features, more than a century of springs hydrogeological debate has focused on springs classification up to the point of emergence, but has largely ignored springs surficial ecosystem functions and ecology. Hydrogeological debate over classification has failed to clarify terminology or recognize differences among springs types. This lack of consensus on typology, ecosystem ecology, biotic diversity, and socio-cultural attributes and function has reduced awareness of the importance of springs as ecosystems to the public as well as to the governance, management, and scientific communities. Here we present a conceptual springs ecosystem model, describe the rationale for geomorphological ecosystem classification, and illustrate springs types using examples from throughout the world. We present a dichotomous key to springs types based on classification of emergence geomorphology. In addition, we describe the common microhabitats associated with individual springs types, and the uses to which different types are subjected. We describe our efforts to improve stewardship through standardized inventory, assessment, stewardship implementation, and monitoring-feedback. Such definition, analyses, and practices are presented to improve basic integration of hydrogeology with ecosystem ecology, and to improve understanding and stewardship of springs as ecosystems.