Rangeland Ecology & Management

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UNGULATES AND FOREST MANAGEMENT: UNDERSTANDING INTERACTIONS BETWEEN LARGE HERBIVORES AND FUELS REDUCTION TREATMENTS ON SHRUB ASSEMBLAGES IN THE INTERMOUNTAIN WEST
Author
Hall Defrees, Dallas K.
Averett, Josh
Endress, Bryan A.
Publisher
Society for Range Management
Publication Year
2018
Body

Upland deciduous shrubs represent keystone species that are pivotal to the biodiversity and resiliency of conifer forests in the interior Pacific Northwest. As an important forage species, deciduous shrubs are highly targeted by wild (elk, deer) and domestic (cow) ungulates, who in turn, are influential contributors to their prolonged arrestment. Moreover, episodic disturbances such as prescribed fire and stand thinning can often create conditions that facilitate heavy use by large herbivores as well as decrease potential refugia by eliminating coarse woody debris and other structural elements in the forest understory. Despite the growing scale of fuels reduction treatments, little is known about how such treatments influence herbivory by ungulates and subsequent impacts on deciduous woody species. This research aims to delineate theses interactions, focusing our studies to mixed-conifer forests of the interior PNW.� Our objectives were to (1) describe the structure and composition of deciduous woody plant assemblages in fuels treated and untreated stands, (2) document browse pressure by ungulates in fuels treated and untreated stands, and (3) explore the role of coarse woody debris and other forest understory structural elements and how they may affect browse rates and plant structure of deciduous woody species. 300 plots were sampled across untreated and fuels reductions treated mixed conifer stands in northeastern Oregon including 126 plots within ungulate exclosures serving as a reference for conditions in the absence of herbivory. Comparisons in height, richness, and diversity were analyzed using mixed models with both fixed (treatment) and random (site) effects. �Multiple regression was used to analyzed the influence of coarse woody debris on herbivory and growth. These findings can provide land managers with greater knowledge about the consequences of fuels reduction treatments and high levels of herbivory on these ecologically important deciduous woody species.

Language
English
Resource Type
Text
Document Type
Conference Proceedings
Conference Name
SRM Reno, NV