| Microsatellite analysis of female mating behaviour in lek-breeding sage grouse (vol 10, pg 2043, 2001) | Semple, KE | 2002 |
Microsatellite analysis of female mating behaviour in lek-breeding sage grouse (vol 10, pg 2043, 2001)KeywordsNo keywords available AbstractNo abstract available AuthorsSemple, KE; Wayne, RK; Gibson, RM Year Published2002 PublicationMolecular Ecology Locations |
| The effect of vegetation structure on predation of artificial Greater Sage-Grouse nests | Watters, ME | 2002 |
The effect of vegetation structure on predation of artificial Greater Sage-Grouse nestsKeywordsNo keywords available AbstractIn Canada, Greater Sage-Grouse (Centrocercus urophasianus) are considered an endangered species by the Committee On the Status of Endangered Wildlife In Canada (COSEWIC), due to declining population numbers and distribution. Encroachment of agriculture and subsequent destruction of suitable sagebrush (Artemisia spp.) habitat is thought to be responsible for historical population declines However, subtle changes in habitat quality may also result in reduced escape and nesting cover, which may lead to increased levels of predation. We examined the influence of vegetation cover and height on the fate of artificial Greater Sage-Grouse nests Because most natural sage-grouse nests are associated with sagebrush, we predicted that sagebrush height and cover would be crucial to the success of nests. Lateral cover is important in protecting nests from detection by predators, and thus we predicted that nests surrounded by shorter grass would suffer greater predation rates than nests with taller grass. To experimentally test this hypothesis, we trimmed grass surrounding some artificial nests Richardson's ground squirrels (Spermophilus richardsonii) were the primary predators of artificial nests, with some predation by corvids and badgers (Taxidea taxus). Successful nests tended to be surrounded by shorter sagebrush, taller grasses, and taller, denser forbs than predated nests. Trimming grass around nests did not affect nest fate However, ground squirrels typically attacked nests with less forb cover and fewer sagebrush, and avian predators tended to destroy nests at inactive leks with greater lateral cover. Thus, lateral cover provided by forbs and sagebrush appeared to be important for protecting nests from mammalian predators. These results suggest implementing management strategies that improve sagebrush habitat by providing tall, dense forbs and sagebrush, which could increase Greater Sage-Grouse nest success and recruitment. AuthorsWatters, ME; McLash, TL; Aldridge, CL; Brigham, RM Year Published2002 PublicationEcoscience Locations |
| Restoring Forbs for Sage Grouse Habitat: Fire, Microsites, and Establishment Methods. | Wirth, Troy A. | 2003 |
KeywordsAstragalus purshii;Centrocercus urophasianus;Crepis modocensis;Crepis occidentalis;fire;forbs;prescribed burning;revegetation;sagebrush steppe;sage grouse AbstractThe decline and range reduction of sage grouse populations are primarily due to permanent loss and degradation of sagebrush-grassland habitat. Several studies have shown that sage grouse productivity may be limited by the availability of certain preferred highly nutritious forb species that have also declined within sagebrush ecosystems of the Intermountain West, U.S.A. The purpose of this study was to determine the suitability of three species of forbs for revegetation projects where improving sage grouse habitat is a goal. Species suitability was determined by evaluating the emergence, survival, and reproduction of Crepis modocensis, C. occidentalis, and Astragalus purshii in response to method of establishment (seeding or transplanting), site preparation treatment (burned or unburned), and microsite (mound or interspace) in an Artemisia tridentata ssp. wyomingensis vegetation association in south central Oregon. For seeded plants A. purshii had the lowest emergence (8%) of all three species. Both seeded Crepis species had similar overall emergence (38%). Significantly more Crepis seedlings emerged from shrub mounds in unburned areas (50%) than in any other fire-by-microsite treatment (33 to 36%). Approximately 10% more Crepis seedlings survived in mounds compared with interspaces. Nearly twice as many emerging Crepis seedlings survived in the burned areas as opposed to unburned areas (p < 0.01). This resulted in more plant establishment in burned mounds despite higher emergence in unburned mounds. Astragalus purshii seedlings also survived better in burned areas (p = 0.06) but had no differential response to microsite. Fire enhanced survival of both Crepis and A. purshii transplants (p = 0.08 and p = 0.001). We believe additional research is needed to improve A. purshii emergence before it will become an effective plant for restoring sage grouse habitat. Conversely, we conclude that these Crepis species provide a viable revegetation option for improving sage grouse habitat in south central Oregon. AuthorsWirth, Troy A. and David A. Pyke. Year Published2003 PublicationRestoration Ecology LocationsDOI10.1046/j.1526-100X.2003.00159.x |
| Effect of sheep grazing and fire on sage grouse populations in southeastern Idaho | Pedersen, EK | 2003 |
KeywordsFire; Grazing; Idaho; Sage grouse; Sagebrush; Sheep; Simulation modeling AbstractThis paper describes the development, evaluation, and use of a model that simulates the effect of grazing and fire on temporal and spatial aspects of sagebrush community vegetation and sage grouse population dynamics. The model is represented mathematically as a discrete-time, stochastic compartment model based on difference equations with a time interval of I week. In the model, sheep graze through sage grouse breeding habitat during spring and fall, and different portions of the area can burn at different frequencies, creating a habitat mosaic of burned and unburned areas.The model was evaluated by examining predictions of (1) growth of sagebrush canopy cover after fire, (2) seasonal dynamics of grass and forb biomass under historical environmental conditions, and (3) sage grouse population dynamics associated with selected sagebrush canopy covers. Simulated changes in sagebrush canopy cover following fire correspond well with qualitative reports of long-term trends, simulated seasonal dynamics of herbaceous biomass correspond well with field data, and simulated responses of sage grouse population size and age structure to changing sagebrush canopy cover correspond well to qualitative field observations.Simulation results suggest that large fires occurring at high frequencies may lead to the extinction of sage grouse populations, whereas fires occurring at low frequencies may benefit sage grouse if burned areas are small and sheep grazing is absent. Sheep grazing may contribute to sage grouse population decline, but is unlikely to cause extinction under fire regimes that are favorable to sage grouse. (C) 2002 Elsevier Science B.V. All rights reserved. AuthorsPedersen, EK; Connelly, JW; Hendrickson, JR; Grant, WE Year Published2003 PublicationEcological Modelling LocationsDOI10.1016/S0304-3800(02)00382-4 |
| Initial effects of prescribed fire on morphology, abundance, and phenology of forbs in big sagebrush communities in southeastern Oregon | Wrobleski, DW | 2003 |
KeywordsAntennaria dimorpha; Astragalus malachus; Astragalus purshii; Centrocercus urophasianus; Crepis modocensis; fire-enhanced flowering; Hart Mountain National Antelope Refuge; Lomatium canbyi; Lomatium nevadense; Lomatium watsonii; morphology; phenology; Phlox gracilis; Phlox longifolia; prescribed fire; restoration; Sage Grouse; sagebrush AbstractHistoric fire return intervals in Artemesia tridentata (big sagebrush) ecosystems have been altered by livestock grazing, fire suppression, and other land management techniques resulting in ecological changes in these areas. Increases in abundance of woody vegetation may be causing declines in native herbaceous understory species. We examined the effects of prescribed fire on the morphology, abundance, and phenology of nine abundant forb (herbaceous dicot) species used selectively by Centrocercus urophasianus (Sage Grouse). In September 1997 prescribed fire was applied to four of eight randomly assigned 400-ha A.t. wyomingensis (Wyoming big sagebrush) study plots at Hart Mountain National Antelope Refuge, Oregon. Livestock had not grazed experimental plots since 1991. Burning caused morphological changes such as significantly greater numbers of racemes and flowers per raceme in Astragalus malachus (shaggy milkvetch-Legumoideae) (9 in burn vs. 6 in control; 23 in burn vs. 21 in control, respectively). Also, prescribed burning caused greater numbers of flowers in Phlox gracilis (microsteris-Polemoniaceae) (57 vs. 13), greater numbers of umbels and umbelletts in Lomatium nevadense (Nevada desert parsley-Umbellifereae) (4 vs. 2 and 59 vs. 31, respectively), greater numbers of flower heads in Crepis modocensis (Modoc hawksbeard-Compositae) (32 vs. 21), and greater number of flowers/cm(3) in Phlox longifolia (longleaf phlox-Polemoniaceae) (0.11 vs. 0.06). Crown volume of Crepis modocensis (7,085 vs. 4,179 cm(3) ) and Astragalus malachus (2,854 vs. 1,761 cm(3) ) plants was greater in burned plots than control plots. However, burning resulted in a smaller crown area of Antennaria dimorpha (low pussytoes-Compositae) (20 vs. 37 cm(2) ). Phenology and time of flowering were also affected by fire. The period of active growth for each species was extended later into the summer in burned plots (p<0.01). In addition, Crepis modocensis and Lomatium nevadense flowered 12 to 14 days earlier in burned plots. Fire had no effect on frequency, density, and relative abundance of seven of the nine studied species. Fire reduced the frequency and relative abundance of A. dimorpha and Phlox longifolia and reduced the density of A. dimorpha . AuthorsWrobleski, DW; Kauffman, JB Year Published2003 PublicationRestoration Ecology LocationsDOI10.1046/j.1526-100X.2003.00084.x |
| Estimation of greater sage-grouse survival in North Park, Colorado | Zablan, MA | 2003 |
Keywordsband recoveries, Centrocerucuros phasianuCso, loradog, reaters age-grouseh, unting,p rogramM ARKs,u rvival. AbstractWe estimated survival rates of greater sage-grouse (Centrocercus urophasianus) in North Park, Colorado, USA, from band-recovery data of 6,021 birds banded during spring, 1973-1990, with recoveries through 1993. Average annual adult female survival ((S) over bar = 0.59, SE = 0.011) was greater than average adult male survival ((S) over bar = 0.37, SE = 0.007), and average subadult (<1 yr old at time of banding) female survival ((S) over bar = 0.77, SE = 0.030) was greater than average subadult male survival ((S) over bar = 0.63, SE = 0.034). Four weather covariates (spring and winter precipitation and temperature) did not contribute to predicting annual survival. AuthorsZablan, MA; Braun, CE; White, GC Year Published2003 PublicationJournal of Wildlife Management LocationsDOI10.2307/3803070 |
| Response of greater sage-grouse Centrocercus urophasianus populations to different levels of exploitation in Idaho, USA | Connelly, JW | 2003 |
Response of greater sage-grouse Centrocercus urophasianus populations to different levels of exploitation in Idaho, USAKeywordsCentrocercus urophasianus, exploitation, greater sage-grouse, hunting, Idaho, lek counts, population AbstractWe investigated the response of greater sage-grouse Centrocercus urophasianus populations to different levels of exploitation. From 1995 through 2002 we monitored breeding populations in areas closed to hunting, open to limited hunting (1-bird daily bag limit; 7-day season), and open to moderate hunting (2-bird daily bag limit; 23-day season). We used three approaches to assess the effects of hunting on sage-grouse populations. Results were consistent regardless of the method used and indicated that overall, areas closed to hunting had greater rates of increase for breeding populations than areas open to hunting (P = 0.018). Limited or moderate rates of exploitation apparently slowed population recovery for sage-grouse. These effects may have been more pronounced for grouse occupying relatively xeric habitats close to human population centers or highly fragmented habitats. Our results suggest that hunting seasons for sage-grouse should generally be conservative and reflect both sage-grouse population trend and quality of habitat occupied by the population. AuthorsConnelly, JW; Reese, KP; Garton, EO; Commons-Kemner, ML Year Published2003 PublicationWildlife Biology Locations |
| Greater sage-grouse Centrocercus urophasianus nesting success and habitat use in northeastern California | Popham, GP | 2003 |
Greater sage-grouse Centrocercus urophasianus nesting success and habitat use in northeastern CaliforniaKeywordsArtemisia tridentata wyomingensis, California, Centrocercus urophasianus, Galliformes, greater sage-grouse, nest site selection, radio-telemetry AbstractFrom mid-March through mid-August 1998-2000, we studied greater sage-grouse Centrocercus urophasianus nesting habitat in northeastern California, USA. We located nest sites of 45 radio-marked hens, which had an average nest success of 40.2%. The radio-marked grouse used low sagebrush Artemisia arbuscula cover type less than expected; big sagebrush A. tridentata wyomingensis and mixed shrub cover types were used in proportion to their availability. Grouse used sites with habitat characteristics similar to random sites for nesting. However, successful nests differed from unsuccessful nests in several respects. Mean distance between nest and lek was greater for successful nests ((x) over bar = 3,588 m, SE = 811 m, N = 20) than for unsuccessful nests ((x) over bar = 1,964 m, SE = 386 m, N = 20). Rock cover was greater at successful nests ((x) over bar = 27.7%, SE = 4.6%) than at unsuccessful nests ((x) over bar = 14.49%, SE = 3.04%). Total shrub height was greater at successful nests ((x) over bar = 65.5 cm, SE = 4.7) than at unsuccessful nests ((x) over bar = 49.2 cm, SE = 1.7). The height of visual obstruction was greater at successful nests ((x) over bar = 40.2 cm, SE = 2.6) than at unsuccessful nests ((x) over bar = 32.5 cm, SE = 2.0). Our results suggest that sage-grouse use more diverse vegetation than previously reported, and we conclude that either this represents a natural behaviour for sage-grouse in this area, or we observed a selection response to a landscape altered by human activity. AuthorsPopham, GP; Gutierrez, RJ Year Published2003 PublicationWildlife Biology Locations |
| Fidelity of greater sage-grouse Centrocercus urophasianus to breeding areas in a fragmented landscape | Schroeder, MA | 2003 |
Fidelity of greater sage-grouse Centrocercus urophasianus to breeding areas in a fragmented landscapeKeywordsCentrocercus urophasianus, fidelity, greater sage-grouse, landscape fragmentation, lek visitation, nesting success, Washington AbstractIn this paper, we report on breeding site fidelity for a small, localized population of greater sage-grouse Centrocercus urophasianus inhabiting a highly altered and fragmented landscape in north-central Washington, USA. One hundred sixteen greater sage-grouse were captured, fitted with radio transmitters and monitored during 1992-1998. Of 19 males captured as adults and nine captured as yearlings, one and four, respectively, were observed visiting two different leks. Of 78 females, 24 were observed visiting at least two leks, and eight visited at least three leks. Although the incidence of multiple lek visitation was similar to what has been reported for other regions, the average of 10.2 km distance between neighbouring leks was substantially further in north-central Washington. Average distance between a female's first nest and her renest was higher for yearlings (6.3 km) than for adults (2.0 km). Successful females moved an average of 1.6 km and unsuccessful females moved 5.2 km to nest in subsequent years. Most distances between consecutive nests were < 3.0 km, but some females, including adults, moved > 20 km. These data suggest that fidelity of greater sage-grouse to nesting areas in north-central Washington is substantially lower than has been found for other populations. Although the relationship between behaviour of greater sage-grouse and regional habitat fragmentation is a possible explanation for these observations, we were not able to detect a correlation between fidelity and local habitat availability. AuthorsSchroeder, MA; Robb, LA Year Published2003 PublicationWildlife Biology Locations |
| Spatial patterns of population regulation in sage grouse Centrocercus spp.) population viability analysis (vol 71, pg 672, 2002) | LaMontagne, JM | 2003 |
Spatial patterns of population regulation in sage grouse Centrocercus spp.) population viability analysis (vol 71, pg 672, 2002)KeywordsAICc;
population dynamics;
spatial correlation Abstract1
Population viability analyses (PVAs) are commonly used to identify species of concern. Many PVA techniques assume that all populations are regulated by a single mechanism.
2
We compared population viability predictions for three subspecies of sage grouse ( Centrocercus spp.) based on the assumptions that: (i) population regulation was density-independent vs. dependent on more complex feedback mechanisms; (ii) the mechanism of population regulation was homogeneous within a region vs. heterogeneous among leks; (iii) environmental variation was spatially correlated within regions vs. uncorrelated among leks.
3
We used sage grouse as a model species for this analysis because counts of lekking male grouse are available in some areas since the 1950s, these counts are known to fluctuate widely, and sage grouse appear to be declining throughout their range.
4
We fit population regulation models to data including density-independence, density-dependence, delayed density-dependence and a simplified version of Turchin & Taylor's (1992) response surface model.
5
We show that the best-fit models typically include spatial heterogeneity in mechanisms of population regulation. Inclusion of spatial heterogeneity increased expected time for population persistence, and changed the rank order of risk of extinction for different regions.
6
We suggest that it is important to consider multiple models of population regulation when applying population viability analysis techniques because viability projections are influenced strongly by model structure. AuthorsLaMontagne, JM; Irvine, RL; Crone, EE Year Published2003 PublicationJournal of Animal Ecology Locations |
