GREATER SAGE-GROUSE BROOD-REARING HABITAT MANIPULATION IN MOUNTAIN BIG SAGEBRUSH, USE OF TREATMENTS, AND REPRODUCTIVE ECOLOGY ON PARKER MOUNTAIN, UTAH

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1 GREATER SAGE-GROUSE BROOD-REARING HABITAT MANIPULATION IN MOUNTAIN BIG SAGEBRUSH, USE OF TREATMENTS, AND REPRODUCTIVE ECOLOGY ON PARKER MOUNTAIN, UTAH Abstract We used an experimental design to treat greater sage-grouse (Centrocercus urophasianus) brood-rearing habitat in a high elevation (2700 to 2900m) pastures containing even-aged dense (>38% canopy cover) stands of mountain big sagebrush (Artemesia tridentata vaseyana). We used two mechanical treatments: Dixie harrow and Lawson aerator, and one chemical treatment, Tebuthiuron (in 2000). We monitored vegetation response for both shrub and herbaceous components. Both mechanical treatments effectively reduced shrub canopy to sage-grouse habitat guidelines for brood-rearing habitat (between 10 and 25%). Only the Dixie harrow increased herbaceous cover overall in the first two years post treatment. The Lawson aerator had some time period effects within the summers of 2002 and 2003 on herbaceous cover, but was ineffective overall. We also monitored sage-grouse use within the mechanically-treated plots, chemically-treated plots, and control plots using pellet counts and bird dog surveys. Sage-grouse, in general, and broods, specifically, preferred Tebuthiuron-treated areas compared to the other treatments and control. All treatments had more use than control. We monitored sage-grouse hens during their reproductive efforts in the summers of 2003 and In 2003 and 2004 nest initiation rates were 95% and 56%, nest success was 50% and 80%, and mortality was 36% and 22%, respectively. Preferred nest and brood sites exhibited vegetation characteristics similar to those reported in previous studies, though forb cover was consistently lower. Nest sites exhibited on average 9.3% herbaceous and 13.2% shrub cover, although nest bush diameter and height averaged 97.5 cm and 64.4 cm, respectively. Brood sites on average exhibited 20.1% shrub and 16.5% herbaceous cover. Additionally, these sites exhibited 2.6% forb cover. This work was a continuation of research that began in Introduction Sage-grouse (Centrocercus spp.) populations have been declining, along with sagebrush habitat degradation, in recent years. To address these concerns, the Western Association of Fish and Wildlife Agencies (WAFWA) sage-grouse framework team published their habitat assessment in In this assessment, managers called for more experiments concerning habitat manipulation, and its effect on sage-grouse. To address some of these concerns, we used an experimental design to treat greater sagegrouse (C. urophasianus) brood-rearing habitat in a high elevation (2700 to 2900m) pasture containing even-aged dense (> 38% canopy cover) stands of mountain big sagebrush (Artemesia tridentata vaseyana). We used two mechanical treatments; Dixie harrow and

2 Lawson aerator. The Dixie harrow (Figure 1) has connected pipes with alternating harrows (Figure 2), and is dragged behind a large tractor. The Dixie harrow rips sagebrush from and scarifies the bare soil. The Lawson aerator (Figure 3) is a large drum aerator (Figure 4), pulled behind a large tractor. The aerator has a more crushing effect (Figure 5) on the sagebrush and does not impact the soil. Figure 1. Dixie harrow set-up. Figure 2. Dixie harrow pipes ripping up sagebrush. Figure 3. Lawson aerator set-up. Figure 4. The drum aerator of the Lawson aerator. Figure 5. The Lawson aerator is designed to crush sagebrush, not kill it. Description of the Area Parker Mountain is located in south-central Utah (Figure 6) in Garfield, Piute, and Wayne counties (Figure 7). Parker Mountain is approximately 265,584 acres in size and is managed by

3 private, state, and federal land management entities. It is home to pronghorn, mule deer, elk, sage-grouse, pygmy rabbits, Utah prairie dogs, and many other wildlife species. The landscape is composed of multiple sagebrush species, including big sagebrush, silver sagebrush, and black sagebrush (Figures 8-10) as well as a variety of grasses and forbs. Figure 6. Location of Sevier, Piute, Wayne, and Garfield counties within Utah. Figure 7. Location of Parker Mountain study area. Figure 8. Big sagebrush (A. tridentata). Figure 9. Silver sagebrush (A. cana). Figure 10. Black sagebrush (A. nova).

4 The sagebrush habitat on the Parker Mountain is one of the largest contiguous tracts in Utah, and has escaped development pressures. Annual precipitation on Parker Mountain varies in elevation, ranging from inches per year. Precipitation comes mostly in the winter in the form of snow and late summer monsoonal rains. In addition to a few springs at higher elevations (>7400 ft), many water developments are scattered throughout the area. The predominant land use in the area is grazing by domestic livestock; in fact it has a fairly intensive grazing management system. The Parker Mountain allotment is divided into a series of 10 pastures totaling 72,143 acres: 5,120 acres of BLM lands and 67,023 acres of state trust lands. The pastures are grazed seasonally on an elevation gradient. Beginning in early May through June 1, approximately 1,348 cow-calf pairs are placed into the two lower elevation pastures (<7400 ft) and grazed for three to four weeks. The timing of this rotation depends on forage utilization. The allotment is managed to achieve 50-60% forage utilization prior to rotations. During May, sage-grouse nest (Figure 11) in the mountain big sagebrush and Wyoming big sagebrush found in the upper end of these spring pastures. Figure 11. Sage-grouse nest in mountain big sagebrush. After 3-4 weeks, the livestock are moved to four midelevation pastures ( ft) and graze there through July. Again, the timing of the rotation depends on achieving 50-60% forage utilization. Although sage-grouse also nest in these pastures, this area provides important brood-rearing habitat (Figure 12). Figure 12. Sage-grouse brood. After July, most of the cattle have roamed to the four higher elevation pastures (>8000 ft). These pastures contain aspen stands, conifers, and mountain big sagebrush. Likewise, these fall pastures provide late-season sage-grouse brood-rearing habitat as the hens move their chicks to higher elevations when the vegetation in lower pastures begins to dry out. After completing this seasonal rotation, the cattle are gradually moved back through the pastures in late September and are taken out on the winter range or housed in feed lots by October 15. In interviews with retired ranchers, we learned that in the 1930s and 40s when sage-grouse populations on Parker Mountain were at an estimated all-time high, the livestock stocking density was considerably higher than it is currently and there were more sheep moving in small bands around the mountain. To enhance the forage potentials for their livestock, the herders and ranchers burned and treated small patches in big sagebrush. Thus, they created a landscape that

5 exhibited different age classes of vegetation types. It is also interesting to note that sheep bedding areas were and are used as lek sites by sage-grouse. History of the Area Although, Parker Mountain exhibits one of the largest contiguous tracts of sagebrush in Utah sage-grouse populations in the area were experiencing declines similar to other areas in the West. Sage-grouse population estimates were 5,200-9,200 in , but by 1969 the population estimate was only 3,000. The Utah Division of Wildlife Resources (UDWR) has counted the number of strutting cocks on leks nearly every year since 1967 (Figure 13). The lek is the area where cocks gather to strut and attract females for the chance to breed (Figure 14). Lek counts are used to estimate population numbers. The sage-grouse population estimates have fluctuated over the last two decades. Although increasing trends in sage-grouse numbers are being reported rangewide, the Parker Mountain population has increased nearly 6 fold over the last 8 years # of males Figure 13. Parker Mountain male sage-grouse lek counts Year Figure 14. Two sage-grouse cocks strutting on a lek.

6 To address sage-grouse declines and assist in recovery, researchers initiated a study to determine the status of sage-grouse populations, their habitat use patterns, and factors that potentially limited sage-grouse production. This began with identifying all active and historic sage-grouse leks, and counting strutting males following UDWR protocols. This was followed up by research conducted to evaluate sage-grouse response to management projects. Study Methods Treatments Because vegetation sampling indicated that the increased sagebrush canopy cover was outcompeting grasses and forbs for water, we set up an experiment to test this hypothesis. We set up several 100-acre experimental plots to be treated with the Dixie harrow (Figure 15), Lawson aerator (Figure 16), and a chemical treatment, Spike (Figure 17) to reduce sagebrush canopy coverage from 40% down to 20%. This work was done in 2000 and The cost of treating the plots was cost-shared through the NRCS WHIP. Figure 15. An experimental plot treated with the Dixie harrow. Figure 16. An experimental plot treated with the Lawson aerator. Figure 17. An experimental plot treated with Tebuthiuron. Use of Treatments Following the treatments, we went back to the plots and measured the vegetation and use of the area by sage-grouse and sage-grouse broods. This was done by using trained bird dogs to locate and flush grouse and their broods in early August (Figure 18). This way they could count the birds flushed from each plot to compare grouse numbers between experiment plots. In addition, they also counted sage-grouse pellet piles in each plot to see if some plots had more pellets than others (Figure 19). Figure 18. Trained bird dogs are used to find sage-grouse in study plots. Figure 19. Sage-grouse pellet piles were counted as an index of sage-grouse use of an area.

7 Reproductive ecology Using radio telemetry, we followed sage-grouse hens from breeding habitats to brood-rearing habitats. Nests were monitored for fate, and nest site characteristics were measured. Following hatch, we followed sage-grouse broods by attaching radio-transmitters to some chicks from the broods of marked hens through the summer to determine brood fate and gather vegetation characteristics of brood sites. Results Use of treatments Through pellet counts, we concluded that sage-grouse preferred the treated areas to non-treated areas, and the Spike-treated plots most of all (Figure 20). This preference was echoed by the bird dog surveys (Figure 21). This may be because Spike treatments provide smaller open patches with nearby sagebrush skeletons for cover. Within treatment plots, we found most sage- foraging areas and sagebrush cover. Thus, to benefit grouse the strategy should be to open small linear plots in the middle of sagebrush seas as opposed to treating large stands. Once small areas grouse pellet piles within 30 meters of the edge. This suggests that any future treatment to reduce sagebrush canopy cover should be done to increase the amount of edge between open recovered from treatment, other plots can be treated. Clusters/Acre Figure 20. Sage-grouse pellet cluster density by treatment in 2003 and # of grouse Control (n=135) Dixie (n=225) Lawson (n=207) Spike (n=433) Treatment Type Control (n=6) Dixie (n=79) Lawson (n=109) Spike (n=252) Treatment Type Figure 21. Total sage-grouse flushed with bird dogs by treatment in 2003 and 2004.

8 Reproductive ecology We monitored sage-grouse hens during their reproductive efforts in the summers of 2003 and In 2003 and 2004 nest initiation rates were 95% and 56%, nest success was 50% and 80%, and mortality was 36% and 22%, respectively. Preferred nest and brood sites exhibited vegetation characteristics similar to those reported in previous studies, though forb cover was consistently lower. Nest sites exhibited on average 9.3% herbaceous and 13.2% shrub cover, although nest bush diameter and height averaged 97.5 cm and 64.4 cm, respectively. Brood sites on average exhibited 20.1% shrub and 16.5% herbaceous cover. Additionally, these sites exhibited 2.6% forb cover. This work was a continuation of research that began in Sage-grouse brood-hopping In 2005 a 1.5 gram radio was attached to >50 random chicks to document mortality of marked chicks, overall brood mortality, and brood-hopping (chick leaving its mother to join another hen). We documented high brood survival for the Parker Mountain population. In 2005 and and 21 broods had radioed chicks, respectively; of these 13 (54%) and 17 (81%) in 2005 and 2006, respectively, had at least one chick survive 42 days. We documented brood-hopping from the first week through the sixth week in 10 (46%) and 9 (43%) broods in 2005 and 2006, respectively. Prior to this study, it was thought that chicks would not brood-hop during their first 3 weeks and any chicks missing from the brood were thought dead. Thus brood survival and recruitment may have been underestimated. It may be useful to think of brood-rearing as a community effort rather than mothers and their chicks as a separate unit. We believe that management within brood-rearing areas is increasing recruitment, along with timely precipitation, conservative grazing practices, and predator control. One of the most interesting phenomena documented during this study was individual chicks leaving their mother brood to join other broods, or brood-hopping. Future Research Based on the findings of these experiments, more treatments were implemented. In 2001, the Parker Mountain Adaptive Resource Management (PARM) local working group received a $35,000 grant from the Intermountain West Joint Venture. These funds were used to manipulate an additional 1000 acres and fence upland areas adjacent to water sources to enhance vegetation cover and reduce sediment loading in ponds. Given the increasing cost of using fossil fuels to conduct mechanical treatments, the PARM group is now looking at using biological methods like prescribed livestock grazing to maintain treated areas, treat new areas, and create a landscape that offers a mosaic of vegetation types and structure. To date, about 3000 acres have been treated in the form of small plots scattered throughout the mid-elevation pastures.