Office of the Regional Executive for Biology - Central Region
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Bureau of Reclamation Research Needs
TITLE:
Effects of Nutrient
Availability on Native Riparian
Plant Growth/Effects of Prolonged Inundation on Native Riparian
Plant Species and Salt Cedar
SUBMITTING BUREAU: Bureau of Reclamation
Originating Office:
DATE SUBMITTED: May 22,1996
FY 98 PRIORITY: Central Region 7
FY 97 PRIORITY: Central Region 9
FY 96 PRIORITY: Combination of Midcontinent Region FY 1996 Needs
7 and 9
BRD REGION: Central
DESCRIPTION OF NEED:
The effects of prolonged inundation on native riparian plant species and saltcedar need to be documented. The length of the period of inundation and the season of inundation need to be studied to determine survivorship and regeneration changes for these species.
An understanding of nutrients and trace elements in post-dam soils is necessary to successful revegetation efforts. Documentation of nutrient types and amounts needed to grow native riparian plant species is needed. Effects of other trace elements are not well understood.
MANAGEMENT PROBLEM WITH NEED:
Native riparian plant species are disappearing along the lower Colorado River. Two of the reasons for this are prolonged inundation behind dams and the invasion of the exotic saltcedar. These native riparian plant communities are considered to be the most important wildlife habitat in the Desert Southwest, especially for neotypical migrant birds. One species, the Southwestern Willow Fly Catcher, was added to the endangered species list in January 1995. This information may enable us to better manage this important resource.
One possible explanation for the lack of success of most revegetation efforts along the lower Colorado River is the lack of available nutrients or necessary trace elements. Too much of one of these trace elements may also affect native plant growth. A better understanding of soil nutrients and trace elements is needed to help ensure successful wildlife habitat improvement projects.
BUREAU CONTACT: John Swett (702)-293-8574
BRD PRIMARY CENTER: MESC
BRD CENTER CONTACT: Greg Auble
RESULTS OF BRD INITIATED COMMUNICATION:
Auble updated Bureau contact concerning results and progress of ongoing research activities relating to this continuing research need and solicited further specific directions, ideas, or needs.
MESC research addressing this need includes a field study on the Bill Williams and Agua Fria Rivers in AZ involving concomitant riparian plant, hydrologic, and soil chemistry sampling; a long-term cottonwood-willow seedling demography study with BLM on the Missouri River in MT examining the interaction of streamflow (inundation), grazing, ice, and channel change in controlling riparian regeneration; and a large-scale analysis of 300-350 gage sites aimed at discerning pattern in the balance between native cottonwood-willow and exotic salt cedar and Russian-olive. If successful, this study may help to isolate relative contributions of hydrology and salinity in determining the gross distribution of some of these riparian species.
Several completed, ongoing, or potential studies focus more specifically on nutrient (or at least excessive salt) availability and inundation. A completed, small-scale experimental study examined salinity control of salt cedar seedling establishment. Work by Roelle and Gladwin at a gravel pit restoration site has examined the role of inundation in influencing the mix of salt cedar and cottonwood-willow seedling establishment. This project was initiated as a direct response to the BOR identified BIN. We also have several studies (Gunnison and Little Colorado Rivers) aimed at quantifying the aspects of streamflow (inundation and shear) that limit the streamward extent of woody riparian vegetation. Finally, we have been discussing a larger emphasis on nutrients and nutrient cycling for redirected work to begin in FY99.
DATE SUBMITTED TO REGIONAL OFFICE: October 31, 1997
PREPARED BY: Greg Auble, Stream and Riparian Ecology Section, Fort Collins Science Center (970)226-9448; Email: greg_auble@usgs.gov
U.S. Department of the Interior | U.S. Geological Survey
URL: http://biology.usgs.gov/cro/98bor-7.htm
Page Contact Information:
tlwilliams@usgs.gov
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