Short-term Grazing Management Monitoring and Long-term Changes in Riparian Attributes of the Interior Columbia River Basin.

Abstract

AbstractRangeland managers often use herbaceous vegetation stubble height and woody shrub utilization or stream bank alteration to monitor annual effects of grazing on streams and riparian areas. Many riparian grazing management practices or strategies have been suggested yet little quantitative long-term or effectiveness data has been interpreted with regard to short-term or implementation monitoring and management practices over a diversity of watersheds. This study uses long-term broad scale ecological monitoring by the U.S. Forest Service (USFS) Pacfish/Infish Biological Opinions Effectiveness Monitoring Program (PIBO EMP) to analyze monitoring and management practices across the Interior Columbia River Basin U.S. Forest Service and Bureau of Land Management rangelands. Explorations of these quantitative relations can guide land managers in choosing appropriate grazing management practices and annual monitoring indicators for a site's particular geomorphic and vegetative characteristics.Measures of five year change in seven physical and three vegetation variables measured by PIBO EMP were analyzed as responses to short term monitoring and allotment management practices. Multiple linear regression identified unique variables that were most strongly associated with responses which were then used in classification and regression tree (CART) analyses to facilitate interpretation of interactions and threshold effects. The hierarchical tree structure and splitting criteria aid GIS map algebra for management applications. Vegetation community type and/or geologic parent material were important predictors in all CART models for guiding management decisions. Suggestions for specific monitoring parameters and management practices are provided with caution. More years of use information, more specifics about timing and intensity of grazing activities and additional explanatory variables such as riparian fencing or water improvements would have improved this study. The biggest limitation with this study is sample size needed to account for the spatial and temporal variability inherent in the PIBO EM area.