SCERP Project Number: W-8
Principal Investigator: Juliet Stromberg
Arizona State University
OBJECTIVES OF PROJECT
To determine relationships between surface and subsurface water quantities and quality of riparian communities. Two in press journal articles are enclosed as a final report.
In Press: REGULATED RIVERS
INSTREAM FLOW MODELS FOR MIXED DECIDUOUS RIPARIAN VEGETATION WITHIN A SEMIARID REGION ABSTRACT:
Empirical Evidence froma semiarid watershed of the southwestern United States (Verde River Basin, Arizona) indicated that abundance and species richness of mixed deciduous riparian forests varied in a curvilinear and quantifiable fashion as a function of stream flow parameters. Three indicators of riparian abundance foliage area, stem basal area, and stand width increased most significantly with growing season flow volume, a surrogate indicator of riparian water availability. Tree species richness varied in bell curve fashion with flood size, with greatest richness occurring at streams with intermediate flood magnitudes. These instream flow models have management iplications for riparian habitat. They suggest that flow volume (and related attributes of water table recharge and floodplain soil wetting) is the primary factor regulating riparian vegetation abundance in the Verde River watershed, and provide a first approximation of the extent of riparian loss expected from flow diversion or other types of flow reduction.
In Press: ECOLOGICAL APPLICATIONS VEGETATION-HYDROLOGY MODELS: IMPLICATIONS
FOR MANAGEMENT OF PROSOPIS VELUTINA (VELVET MESQUITE) RIPARIAN ECOSYSTEMS
ABSTRACT:
Prosopis velutina (velvet mesquite) forests are one of many types of aridland riparian ecosystems that are threatened by groundwater pumping and other types of water development. Empirical models developed between hydrological and vegetational data sets have potential implications for management of these threatened ecosytems. To this end, models were developed for Prosopis velutina stands across a xeric to mesic moisture gradient. The models expressed canopy height, basal area, leaf area index, vegetation volume, and leaflet area as functions of plant water potential; and expressed plant water potential and riparian stand structure as functions of water table depth. These data indicated that water availability was strongly related to stand structure. Management applciations of the models include the ability to identify minimum water table depths for riparian stand maintenance and to detect stressful hydrological conditions via water potential measurements, before the onset of structural degradation.
Last updated 7/1/99