The Influence Of Conifers And Abiotic Factors On Big Sagebrush Cover

Scientific Disciplines
Biological Sciences - Terrestrial
Biological Sciences - Botany
Keywords
Montana State University
Montana
sagebrush
artemisia tridentata
Department of Animal and Range Sciences
rocky mountain juniper
Years
Authors
Volumes
Volume 17, No. 1-4

The influence of conifers and abiotic factors on big 
Sagebrush cover
Karen Kitchen, Department of Animal and Range Sciences, Montana State University, PO Box 
172900, Bozeman, Montana 59717-2900
Brittany Mendelsohn, Department of Animal and Range Sciences, Montana State University, P.O. 
Box 172900, Bozeman, Montana 59717-2900
Mike Frisina, Department of Animal and Range Sciences, Montana State University, P.O. Box 
172900, Bozeman, Montana 59717-2900
Jim Robison-Cox, Department of Mathematical Sciences, Montana State University, P.O. Box 
172400 Bozeman, MT 59715-2400
Bok Sowell,  Department of Animal and Range Sciences, Montana State University, P.O. Box 
172900, Bozeman, Montana 59717-2900
Expansion of conifers into sagebrush is a concern since it reduces sagebrush cover 
for wildlife. The objective of this study was to model the relationship between the 
cover of Douglas-fir (Pseudosuga menziesii) and Rocky Mountain juniper (Juniperus 
scopulorum
), and the cover of Wyoming big sagebrush (Artemisia tridentate spp. 
Wyomingensis) and mountain big sagebrush (Artemisia tridentate
 spp. Vaseyana). Two 


hundred forty 30x30 m plots were established at three locations in southwest Montana 
in 2009 to establish this relationship. The best-fit model using AIC criteria found  
sagebrush
  cover Intercept 
. )a negative relationship between 

.
0 401 conifer
  cover
i
 ;; R2 =
(
0 61
conifer cover and sagebrush cover. No abiotic factors (elevation, slope, aspect, soil depth, 
soil texture and percent rock) significantly influenced sagebrush cover. Douglas-fir trees 
were found to have three-times the canopy area of similar aged Rocky Mountain juniper 
trees. Conifer removal to increase sagebrush cover is not recommended, since the increase 
in sagebrush cover is small. If conifer control is deemed necessary, Douglas-fir should be 
removed before Rocky Mountain juniper, and begin at low levels of conifer cover.