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A network theory for resource exchange between rivers and their watersheds
Author(s) -
Sabo John L.,
Hagen Elizabeth M.
Publication year - 2012
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2011wr010703
Subject(s) - watershed , meander (mathematics) , environmental science , tributary , hydrology (agriculture) , ecosystem , sinuosity , resource (disambiguation) , terrestrial ecosystem , geology , ecology , geography , geomorphology , computer network , geometry , mathematics , cartography , geotechnical engineering , machine learning , computer science , biology
Watersheds are drained by river networks, which route materials and energy from headwaters to terminal water bodies. River networks likewise perfuse the terrestrial portion of watershed ecosystems and reroute some of these materials upslope via material exchange between rivers and land. Here we develop a model of resource exchange between rivers and watersheds to predict the spatial extent of material and nutrient fluxes from aquatic portions of watershed ecosystems. The model is based on a geomorphic template that includes river network structure, topography, and channel sinuosity as well as important biological attributes (productivity and dispersal ability). Analysis of this model suggests that the geomorphic template strongly influences the spatial extent of resource flows in watershed ecosystems. The geomorphic template also predicts the location of areas of concentrated resource exchange, typically at ridge crests, in meander bends, and tributary junctions. We contend that these areas represent hotspots of foraging activity for terrestrial consumers, especially those at the reach scale (meander bends). More generally, our model suggests that the spatial extent of aquatic resource flow equal in magnitude to 20% or greater of terrestrial production may encompass as much as 20%–50% of terrestrial portions of watersheds. Resource flow from rivers to terrestrial ecosystems is not merely an edge effect. Instead, the river network may reroute a substantial flux of materials into watershed ecosystems.