Research PapersHydrologic Vulnerability of Sagebrush Steppe Following Pinyon and Juniper Encroachment
Section snippets
INTRODUCTION
The 10-fold expansion in the density and distribution of pinyon (Pinus spp.) and juniper (Juniperus spp.) woodlands during the past 130 yr has altered the ecological structure and function of shrub steppe ecosystems in the western United States (Burkhardt and Tisdale 1969; Tausch et al. 1981; Tausch and Tueller 1990; Tausch and West 1995; Bunting et al. 1999; Bates et al. 2000; Miller et al. 2000; Roberts and Jones 2000; Miller and Tausch 2001; Miller et al. 2005; Tausch and Hood 2007; Miller et
METHODS
This study is part of the larger Sagebrush Steppe Treatment Evaluation Project (SageSTEP) aimed at investigating the ecological impacts of invasive species and woodland encroachment into sagebrush steppe ecosystems in the Great Basin and the effects of various sagebrush steppe restoration methods, including tree removal (McIver et al. 2010).
Vegetation, Water Repellency, and Soils
The observed preponderance of shrub skeletons in shrub-interspace zones at Marking Corral and Onaqui indicate coarsening of the vegetative structure with increasing tree dominance, and the lack of observed large tree stumps and woody debris imply the emergence of tree co-dominance was through tree encroachment into historic sagebrush steppe (Miller et al. 2005; Tausch and Hood 2007; Miller et al. 2008). Shrub-interspace zones represented approximately 75% of both study areas and were
DISCUSSION
The discretely different hydrologic behavior of intercanopy (shrub-interspace zones) and tree coppice areas in this study and others from pinyon and juniper woodlands (Roundy et al. 1978; Reid et al. 1999; Pierson et al. 2007a; Petersen and Stringham 2008) suggest the hydrologic impact of woodland encroachment on sagebrush steppe likely depends on its effect on the expanse of interspace and bare ground within the intercanopy. Tree coppices across spatial scales in this study represented
MANAGEMENT IMPLICATIONS
This study documents the high spatial variability in hydrologic function of tree and shrub-interspace zones after woodland encroachment into sagebrush steppe, and provides a basis for predicting amplified runoff and erosion as a function of intercanopy area. Sediment yield from the two woodland sites (25% tree cover) in this study was highly affected by runoff rates and surface protection afforded by litter. Relative runoff rates for a given rainfall intensity and initial soil moisture were
ACKNOWLEDGMENTS
The authors wish to thank Jaime Calderon and Matthew Frisby for assistance with data collection. We also thank the Desert Research Institute, Reno, Nevada, for assistance with processing the numerous soil samples.
References (0)
Cited by (88)
A multi-sensor, multi-scale approach to mapping tree mortality in woodland ecosystems
2020, Remote Sensing of EnvironmentQuantifying Pinyon-Juniper Reduction within North America's Sagebrush Ecosystem
2020, Rangeland Ecology and ManagementEffectiveness of prescribed fire to re-establish sagebrush steppe vegetation and ecohydrologic function on woodland-encroached sagebrush rangelands, Great Basin, USA: Part I: Vegetation, hydrology, and erosion responses
2020, CatenaCitation Excerpt :Overland flow velocity and flowpath widths and depths were measured on each plot to characterize overland flow. Overland flow velocity was measured for each flow release rate on each plot by releasing a concentrated salt solution (CaCl2, ~50 mL) into the flow and using electrical conductivity probes to track the mean transit time of the salt over a 2-m flowpath length (Pierson et al., 2008a, 2010, 2015). The flow velocity (m s−1) was calculated by dividing the flowpath length (2 m) by the mean of multiple sampled salt travel times (n = 2 to 3 per rate per plot) in seconds.
Long-term vegetation responses to pinyon-juniper woodland reduction treatments in Nevada, USA
2019, Journal of Environmental Management
This is Contribution Number 15 of the Sagebrush Steppe Treatment Evaluation Project (SageSTEP), funded by the US Joint Fire Science Program.
Mention of a proprietary product does not constitute endorsement by USDA and does not imply its approval to the exclusion of the other products that may also be suitable.