Evaluating Habitat Restoration Efforts for the Bi-State Sage Grouse Rosemary Frederick

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1 Evaluating Habitat Restoration Efforts for the Bi-State Sage Grouse Rosemary Frederick Whitman College, Department of Environmental Studies, Walla Walla, WA DOI: Abstract: Populations of the Bi-State Sage Grouse, a distinct population segment of the Greater Sage Grouse (Centrocercus urophasianus), have been declining steadily since the 1950s, a trend largely attributed to habitat loss and fragmentation due in part to Pinyon-Juniper expansion in the Great Basin region. Due to this decline, the Nevada Department of Wildlife, in partnership with the U.S. Forest Service and the Bureau of Land Management has implemented several habitat restoration projects to remove Singleleaf Pinyon Pine (Pinus monophylla) and Utah Juniper (Juniperus osteosperma) from identified sage grouse habitat. The China Camp field site is one such area that received treatment through tree thinning techniques and intermittent burn piles in 2011 and has been monitored with vegetation survey techniques for four years following treatment. Using this monitoring data, I determined the success of these tree-removal restoration techniques using a number of metrics which include investigating of the changes in sagebrush, graminoid and forb cover as well as the changes in invasive grass abundance and plot-level biodiversity. With reference to remote temperature and precipitation data, I explore how this treatment affected the vegetation structure of this area. I find several potential effects of Pinyon-Juniper treatment techniques, including changes in sage-brush structure, increases in forb and graminoid abundance, and slight increases in cheat-grass (Bromus tectorum) abundance. Long-term monitoring over a broader spectrum of climatic conditions will provide a better understanding of the success of these treatment techniques. Introduction The Greater Sage-grouse (Centrocercus urophasianus), whose range once spanned much of the inter-mountain west, has been facing significant population declines in recent decades (Fig. 1). This trend is largely attributed to habitat loss and fragmentation, as well as nest disturbance and predation (United States Fish and Wildlife Service 2015). These ground-dwelling birds are sagebrush obligates, occupying seasonal habitats; dwelling in large, mesic areas during the summer months and moving to sagebrush habitat in the winter months for cover and winter forage. There is evidence that sage-grouse populations inhabiting higher altitude areas migrate during these seasonal shifts. One crucial aspect of good sage-grouse habitat is the importance of low, open sagebrush in the spring for mating activity, termed lekking. Use of more closed, taller sagebrush stands for nesting is also an important factor in habitat restoration (Connelly et al. 1988). The loss and fragmentation of this bird s habitat is partly attributed to the expansion of Single-Leaf Pinyon Pine (Pinus monophylla) and Utah Juniper (Juniperus osteosperma) woodlands into semiarid sagebrush desert. As defined by Miller et al. (2008), Pinyon-Juniper expansion occurs in three general successional stages, described as: Phase I: The early successional stage, in which young trees are present but shrubs and forbs remain the dominant vegetative structure. Ecological processes remain reminiscent of sagebrush steppe. Phase II: The mid-successional stage, in which trees and shrubs are co-dominant and equally influence the ecological processes of the site. Phase III: The late-successional stage, occurring when Pinyon-Juniper trees become the dominant vegetation structure and the site experiences woodland ecological processes. This woodland expansion results in decreasing sagebrush and forb cover, increasing bare ground (Baruch-Mordo et al. 2013). Encroachment is due in part to favorable climate conditions, large-scale livestock grazing, and fire suppression in the Great Basin region (Forbis et al. unpublished). There is also evidence that these encroachment stands exhibit a threshold dynamic. Threshold dynamics occur when ecosystems reach a VOLUME 3 ISSUE 1 SPRING

2 This area received treatment through tree thinning and intermittent burn piles in 2011 and has been monitored with vegetation survey techniques since the initial treatment. These surveys were carried out once before treatment and three subsequent times over a 5-year span following treatment (Nevada Department of Wildlife 2016). Fig. 1. Current and historic range of the Greater Sage-Grouse. Both ranges occupy a majority of the great basin region of the western United States. However, the dark-shaded current range indicates a significant reduction from the grey-shaded historic range. (United States Fish and Wildlife Service 2015). tipping point in compositional change, after which they do not naturally return to their previous ecological state. These later successional stages of Pinyon-Juniper encroachment could therefore reach an ecological threshold, resisting restoration efforts after this point. (Forbis et al. unpublished). Due to this Pinyon-Juniper encroachment into important habitat, populations of the Greater Sage Grouse have been in decline for several decades (United States Fish and Wildlife Service 2015). As a result, the Greater Sage- Grouse, as well as the Bi-State Sage Grouse, a distinct population segment distinguished genetically and existing in the South-western region of Nevada, have both been warranted for listing, due in part to the abundance and success of private, state, and federal conservation efforts. However, in September 2015, the U.S. Fish and Wildlife Service found the Greater Sage-grouse not warranted for listing. The Bi-State Sage Grouse was also found to be not warranted for listing in the U.S. Fish and Wildlife Service s 2013 decision (United States Fish and Wildlife Service 2015). One of the programs undertaken to protect the Bi-State Sage Grouse was initiated by the Nevada Department of Wildlife in This program has implemented over fifty habitat restoration projects to remove Single-Leaf Pinyon Pine and Utah Juniper from sage-grouse habitat. The China Camp field site located in the Bodie Hills Population Management Unit, approximately 25 miles South-west of Walker Lake is one such project (Fig. 2). Fig. 2. Bi-State Sage Grouse population management units in the California/Nevada Bi-State region. The China Camp field site is located in the Mount Grant Population Management Unit, located below in Mineral County, between Mono Lake and the White Mountains. The China Camp site is indicated in yellow within this PMU (Nevada Department of Wildlife 2016). Methods Using aerial imaging software, plots are identified and placed randomly in treatment and non-treatment areas (Fig. 3). During yearly monitoring, which occurs from early June to mid-august, these plots are located using GPS points and physical marking stakes. Transect measurements are then taken along three 50-meter transects at 0, 120, and 240 degrees from the central GPS point, located using a compass and tape measure (Fig. 4). Photo points are taken of each transect azimuth with scale poles and standardized framing to inform changes in habitat structure over successive years. VOLUME 3 ISSUE 1 SPRING

3 To determine the richness of species present, a 15-minute search and identification of all species found within the plot is done, covering all areas of the plot evenly. To determine the cover of the most common vegetation and plant structure, a line-point intercept method is used by dropping a pin flag along a fifty meter transect and recording ground cover layers including plant species hit, soil type, and dead woody cover. The tallest herbaceous and woody species within a 15-centimeter radius of the pin drop point are measured every 5 meters to determine vegetation structure in relation. Fig meter transect monitoring method. Plots are measured 50 meters from the GPS-identified center point, creating a 50 m 2 total circular plot. Transects are conducted at 0, 120 and 240 from the center point. This provides a standardized, representative measure of vegetation over the plot area. To investigate the canopy structure of the vegetation within the plot, a canopy-gap method is used. Walking along each fifty-meter transect, gaps greater than 20 centimeters of bare earth between perennial plant species are recorded in succession. To determine the density of woody species, the species and size class of all trees and woody shrubs along each of the transects are recorded. Fig. 3. Detailed vegetation sampling plots (yellow) in the Mount Grant sampling unit. Plots are located using a combination of random and purposive sampling to achieve a set of vegetation plots representative of local vegetative cover and ecosystem type. Fifteen of the pictured plots are located in areas of restoration treatment, and seven are located in control areas which did not receive treatment (Nevada Department of Wildlife 2016). Results I find that the vegetation structure of this study area underwent several changes. Pinyon-Juniper mastication efforts resulted in increased sage-brush abundance, including Artemisia arbuscula, Artemisia tridentata ssp. tridentata and Artemisia tridentata ssp. wyomingensis indicating that there was a positive restoration effect on sagebrush abundance (Fig. 5). Furthermore, decreased sagebrush abundance and density in control plots suggest that as Pinyon-Juniper stands mature and close, sagebrush abundance decreases. This supports the theory of threshold dynamics in Pinyon-Juniper encroachment and sagebrush restoration efforts. Forb and graminoid abundance also increased slightly after restoration treatments (Fig. 5). VOLUME 3 ISSUE 1 SPRING

4 Fig. 6: 5-Year Climatic Trends. A: Average monthly precipitation data reveals low precipitation from 2005 to 2015, with 2016 seeing a rise in precipitation and higher than average spring rains. B: Average monthly temperature trends show generally stable temperatures, with a slightly warmer winter in 2014 and a slightly cooler summer and winter in Data courtesy of PRISM climate group (2016). Fig. 5: Five-Year Vegetation Changes. A: The abundance of graminoid species increased notably in both control and treatment plots, though by a slightly larger margin in treatment plots (P-values: C=0.047, T=0.005). B: The abundance of sagebrush species increased in treatment plots, while decreasing in control plots, without statistical significance (P-values: C=0.085, T=0.196). C: Species-count data reveals an overall increase in Bromus tectorum, with a more significant trend in treatment plots (P-values: C=0.148, T=0.028). D: The abundance of forbs in both control and treatment plots increased significantly (P-values: C=<0.001, T=<0.001). There were significant differences between abundance of Bromus tectorum in treatment plots over the course of five years. However, these differences occur on a scale of only up to 6% average hit percentage, which suggests that these increases are relatively small on a landscape scale. Furthermore, fluctuations in 2014 and 2015 suggest a slight correlation with climatic trends (Fig. 6). Wet springs of 2014 and 2016 may have positively influenced the abundance of Bromus tectorum, as well as the relative droughts of 2011 and Similarly, the wet spring of 2016 may have influenced both forb and graminoid abundance trends (Fig. 6), therefore few definitive conclusions can be drawn from these results. With long-term data over a wider swath of climatic variation, more conclusive results could be drawn from these trends. Slight increase in cheat-grass abundance in treatment plots suggests its immediate colonization of disturbed areas. However, this trend must be examined more closely. The fluctuation of cheat-grass abundance slightly correlates with climatic trends (Fig. 6). This suggests that perhaps heavy spring precipitation as seen in 2016 may result in an increase in cheat-grass, while a dry spring, such as 2011 and 2015 will result in a decrease in abundance. Furthermore, the slower reproduction and colonization rate of native grasses and forbs may result in an eventual re-colonization by native vegetation in these areas. Due to the relatively small amount of time between initial restoration efforts and monitoring, it is not possible to determine a significant trend from this data. For this reason, long-term monitoring is necessary to determine the changes in abundance and density of Bromus tectorum in the future, as well as this site s vulnerability to nonnative invasion. No significant changes in biodiversity were found in treatment plots (Fig. 7). However, the phenology of monitoring season could have an effect on this result. Data is taken during the summer season, typically June through August, which presents methodological difficulties due to the drying of identifying features of vegetation and the heterogeneity of identifiable species. Most graminoid species are very difficult to identify after mid-july or early August, depending on the precipitation this site sees during the summer months. It becomes similarly difficult to positively identify forbs in the late summer months. Therefore, a 4-season data collection method could provide a wider range of results, taking into account species which bloom in wetter and colder months. Furthermore, this result may also be explained by slow native re-colonization times. VOLUME 3 ISSUE 1 SPRING

5 Wildlife Foundation crew members who helped collect this data, Taryn Contento, Hannah Lamb, Lucas Wedge and Alec Latuszek. Similarly, I would like to thank the Nevada State Department of Wildlife for their invaluable help and resources in the collection and analysis of data for this project. I would also like to acknowledge the National Science Foundation Research Experience for Undergraduates program and the University of Nevada, Reno for funding this project. Fig. 7: An analysis of 5-year changes in biodiversity using the Shannon-Wiener Diversity Index reveals an insignificant change in biodiversity for treatment plots, and a slightly significant increase in biodiversity was found in control plots (P-values: C=0.022, T=0.138). Discussion While much of the data gathered during this monitoring season reveals little due to the relatively small amount of past vegetation monitoring data, several trends are beginning to appear which suggest the success of the restoration methods used at the China Camp restoration site. The increase in sagebrush cover, along with the rise in graminoid and forb abundance, suggests that the removal of Utah Juniper and Single-Leaf Pinyon Pines from this area of sagebrush steppe has resulted in positive changes in vegetation structure. Many of these trends will become clearer and the minutiae of the effects of this restoration project will become more evident with more data. This is particularly true with a wide range of climatic differences in monitoring years, as dryland vegetation is heavily influenced by fluctuations in temperature and precipitation year to year. This project shows initial signs of success, with potential for more detailed results after further monitoring. Acknowledgements I would like to thank my mentor, Dr. Lee Turner from the Nevada Department of Wildlife, as well as Cody Ernst-Brock, Maria Jesus and Wade Lieurance from the Great Basin Institute for their invaluable help and advice with this project. I would also like to thank the Great Basin Institute National Fish and References Baruch-Mordo, Sharon, Jeffrey S. Evans, John P. Severson, David E. Naugle, Jeremy D. Maestas, Joseph M. Kiesecker, Michael J. Falkowski, Christian A. Hagen, and Kerry P. Reese. "Saving the Sage-grouse from the Trees: A Proactive Solution to Reducing a Key Threat to a Candidate Species." Biological Conservation 167 (2013): Web. Bi-State Technical Advisory Committee Nevada and California. Bi-State Action Plan: Past, Present, and Future Actions, for conservation of the Greater sage-grouse Bistate distinct population segment Web. Connelly, John W., Howard W. Browers, and Robert J. Gates. "Seasonal Movements of Sage Grouse in Southeastern Idaho." The Journal of Wildlife Management, 52.1 (1988): Web. Forbis, Tara A., Owen Baughman, Louis Provencher, Lee Turner, and Julie Thompson. Identification of threshold dynamics in sagebrush ecosystems. Unpublished. Web. Miller, Richard F., Robin Tausch, Durant McAthur, Dustin Johnson, and Stewart Sanderson. Age Structure and Expansion of Pin on-juniper Woodlands: A Regional Perspective in the Intermountain West. Fort Collins, CO: U.S. Dept. of Agriculture, Forest Service, Rocky Mountain Research Station, Web. PRISM Climate Group, Oregon State University, created 20 July United States Fish and Wildlife Service. Greater Sage Grouse 2015 Not Warranted Finding Under the Endangered Species Act VOLUME 3 ISSUE 1 SPRING