Western Juniper Management: Assessing Strategies for Improving Greater Sage-grouse Habitat and Rangeland Productivity.

Shahla Farzan,Derek J N Young,Peter S Coates,Allison G Dedrick,Erik C Porse,Matthew Hamilton,Gabriel Sampson

doi:10.1007/s00267-015-0521-1

Abstract

Western juniper (Juniperus occidentalis subsp. occidentalis) range expansion into sagebrush steppe ecosystems has affected both native wildlife and economic livelihoods across western North America. The potential listing of the greater sage-grouse (Centrocercus urophasianus) under the U.S. Endangered Species Act has spurred a decade of juniper removal efforts, yet limited research has evaluated program effectiveness. We used a multi-objective spatially explicit model to identify optimal juniper removal sites in Northeastern California across weighted goals for ecological (sage-grouse habitat) and economic (cattle forage production) benefits. We also extended the analysis through alternative case scenarios that tested the effects of coordination among federal agencies, budgetary constraints, and the use of fire as a juniper treatment method. We found that sage-grouse conservation and forage production goals are somewhat complementary, but the extent of complementary benefits strongly depends on spatial factors and management approaches. Certain management actions substantially increase achievable benefits, including agency coordination and the use of prescribed burns to remove juniper. Critically, our results indicate that juniper management strategies designed to increase cattle forage do not necessarily achieve measurable sage-grouse benefits, underscoring the need for program evaluation and monitoring.Electronic supplementary materialThe online version of this article (doi:10.1007/s00267-015-0521-1) contains supplementary material, which is available to authorized users.

Highlights

Over the last 130 years, western juniper (Juniperus occidentalis subsp. occidentalis) populations have expanded into large areas of sagebrush steppe habitat across western North America (Miller et al 2000; Davies et al 2011)
Our results suggest that sage-grouse habitat and forage production benefits: (1) are sometimes complementary, (2) exhibit decreasing-returns-to-scale, and (3) depend on landscape characteristics
Each curve shows the maximum production for a given budget, while the concavity of the model results curve indicates tradeoffs in the two goals with decreasing-returns-to-scale (Fig. 4)

Summary

Introduction

Over the last 130 years, western juniper (Juniperus occidentalis subsp. occidentalis) populations have expanded into large areas of sagebrush steppe habitat across western North America (Miller et al 2000; Davies et al 2011). Over the last 130 years, western juniper Occidentalis) populations have expanded into large areas of sagebrush steppe habitat across western North America (Miller et al 2000; Davies et al 2011). Juniper range expansion (Fig. 1a) threatens both native wildlife and agricultural productivity (Miller et al 2000; Bates 2005; Noson et al 2006). The conversion of sagebrush steppe to juniper woodland negatively affects greater sage-grouse (Centrocercus urophasianus, Fig. 1b) by reducing sagebrush cover and the associated plants and insects that comprise the birds’ diet (Crawford et al 2004; Doherty et al 2008; Baruch-Mordo et al 2013). In the Great Plains region, livestock production has dropped by 75 % in areas where the closely related eastern red-cedar (Juniperus virginiana) has encroached into grasslands (Twidwell et al 2013)

Methods

Results

Conclusion