Wiens, J.A Riverine landscapes: taking landscape into the water. Freshwater Biology 47:
River as element of landscape mosaic
River linked with surroundings by boundary dynamics
River as internally heterogeneous landscapes
Central Themes Relevant to Rivers Patches differ in quality Patch boundaries affect flows
Central Themes Relevant to Rivers Patches differ in quality Patch boundaries affect flows Patch context matters Connectivity is critical Organisms are important Importance of scale –Spatial and temporal
FPZ I FPZ II FPZ III FPZ IV FPZ V (B) unconstrained headwater FPZ mobile FPZ unconstrained lowland FPZ anabranch FPZ floodplain FPZ meandering FPZ constrained headwater FPZ armoured FPZ mobile FPZ constrained lowland FPZ mobile FPZ (A) delta FPZ Upland Forests Low-Relief Grasslands
FPZ I FPZ II FPZ III FPZ IV FPZ V (B) unconstrained headwater FPZ mobile FPZ unconstrained lowland FPZ anabranch FPZ floodplain FPZ meandering FPZ constrained headwater FPZ armoured FPZ mobile FPZ constrained lowland FPZ mobile FPZ (A) delta FPZ Upland Forests Low-Relief Grasslands
Biotic Patches Abiotic Patches Patches Formed by Autotrophs Temporal Scale Spatial Scale Hydrogeomorphic Patch Type B Hydrogeomorphic Patch Type …. N Hydrogeomorphic Patch Type A River Network flow regime, flow history, flood pulse (long to short time scales) hydraulics local geology topography and slope substrate size/composition radiation (PAR, UVR) temperature oxygen inorganic nutrients other water chemistry Patches Formed by Heterotrophs Habitat Forming: dams (e.g., beavers) retreats (e.g., caddisfly cases) species clumps (e.g., zebra mussels) biofilm bioturbation Density Patches: reproduction/production dispersal/migration food/habitat aggregation Negative Interactions: competition predation & herbivory parasitism, disease Types: terrestrial vegetation benthic and pelagic, micro- and filamentous algae vascular macrophytes detrital (leaves, woody debris) Mechanisms: terrestrial abiotic disturbances aquatic abiotic disturbances radiation, nutrients, etc. biotic disturbance autotroph-autotroph interactions individual species requirements
Orinoco River - Venezuela Varzea