Rangeland Ecology & Management

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ANALYSIS OF INFLUENCES ON VEGETATIVE COVER: A MONITORING CASE STUDY
Author
Owings, Glenn
Racich, Loren
Many, Daren
Sommers, Albert
Publisher
Society for Range Management
Publication Year
2014
Body

Measures of ground cover on rangelands are used by managing agencies to assess the ability of the landscape to provide necessary ecological functions.  The purpose of this analysis is to quantify the influence of precipitation metrics, livestock numbers, and utilization on first intercept cover in a federal grazing allotment.  The study area is located in a USFS cattle grazing allotment in Northeast Sublette County, WY.  Locations for line-point intercept transects were selected by an interdisciplinary team.  Cover and utilization data were collected each year from 1996 to 2012.  Cover data for each year were averaged across the allotment to combat effects of potentially misplaced transect lines.  Regression analysis was used to detect relationships between response (total and foliar cover) and annual predictor variables (precipitation, stocking, and utilization metrics).  The experimental unit is one year's data (n=17).  No predictor was significantly correlated with total cover. Foliar cover was an important surrogate to test factor influences.  Foliar cover was significantly correlated with three independent variables: annual precipitation (p=0.30, r²=27.7%), June precipitation (p=0.43, r²=24.7%), and date of snow disappearance (p=0.001, r²=52.7%).  Changes in annual use and stocking rate could not be expected to alter cover at a detectable level within the constraints of this grazing system, monitoring protocol, and period of observation.  While annual indicators such as utilization may be predictive under some circumstances, their effects were masked by the larger ecological processes addressed in this study.  Assumptions about common monitoring techniques may not apply where systems are in high ecological condition, under light stocking rates, and exhibit a strong precipitation influence. If a relationship between changes in annual indicators and landscape function is inferred, it is imperative that managing agencies employ indicative monitoring methods.

Language
English
Resource Type
Text
Document Type
Conference Proceedings
Conference Name
SRM Orlando, FL