Thursday, May 29, 2008 - 9:45 AM
524

Shifting paradigms in stream ecology

Robert Gresswell, U. S. Geological Survery-BRD; Montana State University, Billings, MT

Recognition that lotic systems function as stream networks has grown over the past decade, and it appears that for many organisms, network structure is directly related to persistence.  Conceptually, this represents a significant evolution from a linear perception of streams associated with the River Continuum Concept, to a hierarchical view of stream systems that is focused on the complexity of stream systems in the context of the watershed.  This integrated, multiscale approach incorporates spatial variation from microhabitats to watersheds and persistence from minutes to millennia.  Ideas concerning patch dynamics were a natural outgrowth of this view, and an integrated program of landscape-scale sampling, focused on relationships among upslope landscape characteristics, stream habitat, and spatial patterns of cutthroat trout abundance, has provided new insights into the importance of network connectivity among patches.  Population structure varied within, and among watersheds in concordance with a shifting mosaic of factors, such as geomorphology, climate, and land-management.  Results suggest that lotic habitats can be perceived as matrices of physical sites that are strongly linked by movement.  This view explicitly acknowledges that goods and services do not flow unidirectionally and that network structure represents the physical template that determines the capacity for movement in a system.


Web Page: networks, movement, habitat

See more of Landscapes I
See more of Contributed Sessions

See more of The Nabs 56th Annual Meeting (25-28 May, 2008)