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Relationships Between Western Juniper (Juniperus occidentalis) and Understory Vegetation

Published online by Cambridge University Press:  20 January 2017

D. E. Coultrap ,
K. O. Fulgham ,
D. L. Lancaster ,
J. Gustafson ,
D. F. Lile  and
M. R. George
D. E. Coultrap
Affiliation:
Department of Plant Sciences, University of California, Davis, CA 95616
K. O. Fulgham
Affiliation:
Department of Forestry and Wildland Resources, Humboldt State University, Arcata, CA 95521
D. L. Lancaster
Affiliation:
Department of Plant Sciences, University of California, Davis, CA 95616
J. Gustafson
Affiliation:
USDA Natural Resources Conservation Service, Davis, CA 95616
D. F. Lile
Affiliation:
Department of Plant Sciences, University of California, Davis, CA 95616
M. R. George*
Affiliation:
Department of Plant Sciences, University of California, Davis, CA 95616
*
Corresponding author's E-mail: [email protected]
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Abstract

Western juniper has been actively invading sagebrush plant communities for about 130 yr. Western juniper canopy cover generally increases as western juniper invades sagebrush steppe communities and succession progresses toward a western juniper woodland. Our goal was to estimate the impact of juniper invasion and canopy increase on understory vegetation structure and productivity on 101 sites in northeastern California. The primary objectives of this study were to: (1) examine the influence of increasing western juniper canopy cover on the composition and productivity of understory vegetation; and (2) assess the effects of western juniper removal on understory vegetation. Sites in early, mid-, and late successional stages and sites on the same soils that had not been invaded were selected. Sites where western juniper had been removed by prescribed fire, mechanical, or chemical methods were compared to adjacent untreated sites. Western juniper canopy cover, understory cover and species composition, productivity, and bare ground were determined at each site during May through July 2005 and 2006. Regression analysis was used to evaluate the relationship between western juniper canopy cover and understory vegetation parameters. Logistic regression was used to detect understory differences between treated (juniper removed) and untreated (juniper not removed) sites. A significant relationship was found between western juniper canopy cover and understory species richness, shrub cover, forb cover, total grass cover, cheatgrass cover, herbaceous productivity, and bare ground. Removal of western juniper increased total grass cover, cheatgrass cover, and productivity, and reduced bare ground. The results of this study support findings by researchers in other states that western juniper influences plant community structure and productivity, and removal of western juniper might reverse these changes in structure, but also might increase opportunities for invasion of cheatgrass.

Keywords

Western juniper, Juniperus occidentalis var. occidentalis Hook.sagebrush, Artemisia tridentata Nutt.cheatgrass (Bromus tectorum L.)Successionspecies richnesscoverproductivitybare ground
Type
Research Articles
Information
Invasive Plant Science and Management , Volume 1 , Issue 1 , January 2008 , pp. 3 - 11
Copyright
Copyright © Weed Science Society of America 

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References

Literature Cited

Arnold, J. F. 1964. Zonation of understory vegetation around a juniper tree. J. Range Manag. 17:41–42.Google Scholar
Bates, J., Miller, R. F., and Svejcar, T. 1998. Understory patterns in cut western juniper woodlands. Great Basin Nat. 58:363–374.Google Scholar
Bates, J., Miller, R. F., and Svejcar, T. S. 2000. Understory dynamics in cut and uncut western juniper woodlands. J. Range Manag. 53:119–126.Google Scholar
Bates, J. D., Miller, R. G., and Svejcar, T. S. 2005. Long term successional trends following western juniper cutting. Rangeland Ecol. Manag. 58:533–541.Google Scholar
Belsky, J. A. 1996. Viewpoint: Western juniper expansion: is it a threat to arid northwestern ecosystems? J. Range Manag. 49:53–59.Google Scholar
Braun, C. E. 1998. Sage grouse declines in western North America: what are the problems? Proc. Western Assoc. State Fish and Wildlife Agencies 78:139–156.Google Scholar
Briske, D. D., Fuhlendorf, S. D., and Smeins, F. E. 2006. A unified framework for assessment and application of ecological thresholds. Rangeland Ecol. Manag. 59:225–236.Google Scholar
Buckhouse, J. C. and Gaither, R. E. 1982. Potential sediment production within vegetative communities in Oregon's Blue Mountains. J. Soil and Water Conserv. 37/2:120–122.Google Scholar
Bunting, S. C., Kingery, J. L., and Strand, E. 1999. Effects of succession on species richness of the western juniper woodland/sagebrush steppe mosaic. Pages 76–81. in Monsen, S.B., Stevens, R., compilers, eds. Proceedings: Ecology and Management of Pinyon–Juniper Communities Within the Interior West. Ogden, UT USDA For. Ser. Gen. Tech. Rep. RMRS-P-9.Google Scholar
Burkhardt, J. W. and Tisdale, E. W. 1969. Nature and successional status of western juniper vegetation in Idaho. J. Range Manag. 22:264–270.Google Scholar
Burkhardt, J. W. and Tisdale, E. W. 1976. Causes of juniper invasion in southwestern Idaho. Ecology 57:472–484.Google Scholar
Connelly, J. W. and Braun, C. E. 1997. Long-term changes in sage grouse (Centrocercus urophasianus) populations in western North America. Wildl. Biol. 3:229–234.Google Scholar
Dean, S., Burkhardt, J. S., and Meeuwig, R. O. 1981. Estimating twig and foliage biomass of sagebrush, bitterbrush, and rabbitbrush in the Great Basin. J. Range Manag. 34:224–227.CrossRefGoogle Scholar
Evans, R. A. and Young, J. A. 1985. Plant succession following control of western juniper (Juniperus occidentalis) with picloram. Weed Sci. 33:63–68.CrossRefGoogle Scholar
Gaither, R. E. and Buckhouse, J. C. 1983. Infiltration rates of various vegetative communities within the Blue Mountains of Oregon. J. Range Manag. 36:58–60.Google Scholar
Herrick, J. E., Van Zee, J. W., Havstad, K. M., and Whitford, W. G. 2005. Monitoring manual for grassland, shrubland and savanna ecosystems. Las Cruces, NM USDA–ARS Jornada Experimental Range. 200.Google Scholar
Hickman, J. C. 1993. The Jepson Manual: Higher Plants of California. Berkeley, CA University of California Press. 1400.Google Scholar
Hintze, J. 2004. NCSS and PASS. Kaysville, UT Number Cruncher Statistical Systems.Google Scholar
Horman, C. S. and Anderson, V. J. 2003. Understory species response to Utah juniper litter. J. Range Manag. 56:68–71.Google Scholar
Miller, R. F., Bates, J. D., Svejcar, T. J., Pierson, F. B., and Eddleman, L. E. 2005. Biology, Ecology, and Management of Western Juniper. Oregon State University. Corvallis, OR Agricultural Experiment Station Technical Bulletin 152. 77.Google Scholar
Miller, R. F. and Rose, J. A. 1995. Historic expansion of Juniperus occidentalis (western juniper) in southeastern Oregon. Great Basin Nat. 55:37–45.Google Scholar
Miller, R. F., Svejcar, T. S., and Rose, J. A. 2000. Impacts of western juniper on plant community composition and structure. J. Range Manag. 53:574–585.Google Scholar
Miller, R. F. and Wigand, P. E. 1994. Holocene changes in semiarid piñon–juniper woodlands: response to climate, fire and human activities in the U.S. Great Basin. BioScience 44:465–474.Google Scholar
Pellant, M., Herrick, J. E., Shaver, P., and Pyke, D. A. 2005. Interpreting indicators of rangeland health. Version 4. Technical Reference 1734-6. Denver, CO USDI, BLM, National Science and Technology Center. 122.Google Scholar
Pieper, R. D. 1990. Overstory–understory relations in piñon–juniper woodlands in New Mexico. J. Range Manag. 43:413–415.CrossRefGoogle Scholar
Roberts, C. and Jones, J. A. 2000. Soil patchiness in juniper–sagebrush–grass communities of central Oregon. Plant Soil 223:45–61.Google Scholar
Rose, J. R. and Eddleman, L. E. 1994. Ponderosa pine and understory growth following western juniper removal. Northwest Sci. 68:79–85.Google Scholar
[SRM] Society for Range Management 1999. A glossary of terms used in range management. Denver, CO Society for Range Management. 20.Google Scholar
Tausch, R. J. and West, N. E. 1995. Plant species composition patterns with differences in tree dominance on a southwestern Utah piñon-juniper site. Pages 16–23. in Shaw, D.W., Aldon, E.F., LoSapio, C., tech. coordinators, eds. Proceedings: Desired Future Conditions for Piñon–Juniper Ecosystems. Flagstaff, AZ USDA Forest Service, General Technical Report RM-258.Google Scholar
Tausch, R. J., West, N. E., and Nabi, A. A. 1981. Tree age and dominance patterns in Great Basin piñon–juniper woodlands. J. Range Manag. 34:259–264.Google Scholar
Tiedemann, A. R. and Klemmedson, J. O. 1995. The influence of western juniper development on soil nutrient availability. Northwest Sci. 69:1–8.Google Scholar
Vaitkus, M. and Eddleman, L. E. 1987. Composition and productivity of a western juniper understory and its response to canopy removal. Pages 456–460. in Everett, R.L., ed. Proceedings: Piñon–Juniper Conference. Ogden, UT USDA Forest Service, General Technical Report INT-215.Google Scholar
Vaitkus, M. and Eddleman, L. E. 1991. Tree size and understory phytomass production in a western juniper woodland. Great Basin Nat. 51:236–243.Google Scholar
West, N. E. 1993. Biodiversity of rangelands. J. Range Manag. 46:2–13.Google Scholar
Wilcox, B. P. and Breshears, D. D. 1994. Hydrology and ecology of pinon–juniper woodlands: conceptual framework and filed studies. Pages 1009–1019. in Shaw, D. W., Aldon, E. F., and LoSapio, C., eds. Desired Future Conditions for Pinon–Juniper Ecosystems. Fort Collins, CO Rocky Mountain Forest and Range Experiment Station. USDA Forest Service General Technical Report INT-258.Google Scholar
Young, J. A., Evans, R. A., and Rimbey, C. 1985. Weed control and revegetation following western juniper (Juniperus occidentalis) control. Weed Sci. 33:513–517.Google Scholar