River Ecosystem Concepts and Hydrogeomorphology

Landscape ecologists study physical, chemical, and biological interactions among multiple ecosystems. In the case of the highly interdisciplinary riverine landscape ecology, the focus is on studies of the four-dimensions of rivers (longitudinal, lateral, vertical, and temporal), with a particular emphasis on interactions between the wetted riverscape and the occasionally wetted floodscpae. Riverine landscape ecologists view rivers not as a smooth gradient of physical conditions from headwaters to mouth, but as a discontinuous series of hierarchically nested patches that range in scale from entire watersheds to individual boulders that provide habitat for aquatic life. Patches of particular interest are functional process zones (FPZs) which are large hydrogeomorphically distinct patches that exist between the river valley and reach scale. Understanding how ecosystem function varies among FPZs is crucial to our understanding of riverine landscapes and the development of more effective watershed management and restoration plans.

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Current research in Riverine Landscape Ecology

River typing

We are presently implementing a GIS / remote sensing based river classification technique that identifies FPZs within river networks. We are currently in the process of identifying the functional process zones of several major U.S. Rivers including the Kansas, Delaware, and Willamette. You can download the RESonate Software from our lab’s webpage here.

Ecological Significance of FPZs

We are testing a number of RES model tenants relating to species diversity and distributions. A variety of techniques are being used to mine data from large species databases in order to examine patterns of diversity and community structure among the FPZs of entire river networks.

FPZ

Each FPZ features different hydrological cycles, connectivity (longitudinal, lateral, vertical), and ecological processes, such as food chain length, nutrient spiraling rates, and biodiversity traits. Figure from Thorp et al. (2008).

Developing an ecosystem services framework

We are collaborating with the U.S. EPA, U.S. Army Corps of Engineers, our colleagues at other universities, and non-govermental organizations to develop an ecosystem services based framework for managing and rehabilitating riverine ecosystems. Identifying the ecosystem services provided by different FPZs will enable policy makers to make more informed decisions regarding watershed management.