Document: JES-3-75-17

Primary productivity and nutrient dynamics in the Upper Colorado River Basin: Implications for floodplain restoration.

GOURLEY, J.L.*, T.A.CROWL and M.J.TOWNSEND

Utah State University, Logan, UT 84341, USA ¹

Abstract:
Several hypotheses currently exist to describe how river ecosystems function. The river continuum concept, flood pulse concept, and riverine productivity model all provide competing theories on sources and dynamics of energy in river systems. We investigated these theories in association with a large-scale floodplain restoration project recently initiated on the Green River in the Upper Colorado River Basin (Utah). Specifically, we explored primary production and nutrient resource pools in this large floodplain-river ecosystem. During 1998 and 1999, primary productivity and nutrient levels were measured in floodplain, backwater, and main channel habitats to determine the overall quantity and distribution of these resources. Much of the primary production appeared to originate in the floodplain but backwater and main channel habitats were of increased importance during base flow conditions in the late summer. The importance of exchange and flow of these potentially limiting resources between riverine and lateral habitats was also evaluated. Specifically, the vector from the main channel to the floodplain appeared to be a significant flow pathway for nutrients in the system. In this paper, we discuss the significance of river-floodplain connectivity in the Green River and evaluate the applicability of existing riverine hypotheses to describe the energy dynamics of this system.

Keywords: primary productivity, nutrients, river-floodplain ecology

This abstract is being presented at: 10:30 AM in session:
RESTORATION ECOLOGY AND INVASIONS