| Post-fire seeding on Wyoming big sagebrush ecological sites: Regression analyses of seeded nonnative and native species densities | Eiswerth, Mark E. | 2009 |
KeywordsRangeland; Great Basin; Emergency fire rehabilitation; Sagebrush; Seeding AbstractSince the mid-1980s, sagebrush rangelands in the Great Basin of the United States have experienced more frequent and larger wildfires. These fires affect livestock forage, the sagebrush/grasses/forbs mosaic that is important for many wildlife species (e.g., the greater sage grouse (Centrocercus urophosianus)), post-fire flammability and fire frequency. When a sagebrush, especially a Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis (Beetle & A. Young)), dominated area largely devoid of herbaceous perennials burns, it often transitions to an annual dominated and highly flammable plant community that thereafter excludes sagebrush and native perennials. Considerable effort is devoted to revegetating rangeland following fire, but to date there has been very little analysis of the factors that lead to the success of this revegetation. This paper utilizes a revegetation monitoring dataset to examine the densities of three key types of vegetation, specifically normative seeded grasses, normative seeded forbs, and native Wyoming big sagebrush, at several points in time following seeding. We find that unlike forbs, increasing the seeding rates for grasses does not appear to increase their density (at least for the sites and seeding rates we examined). Also, seeding Wyoming big sagebrush increases its density with time since fire. Seeding of grasses and forbs is less successful at locations that were dominated primarily by annual grasses (cheatgrass (Bromus tectorum L.)), and devoid of shrubs, prior to wildfire. This supports the hypothesis of a "closing window of opportunity" for seeding at locations that burned sagebrush for the first time in recent history. (c) 2008 Elsevier Ltd. All rights reserved. AuthorsEiswerth, Mark E.; Krauter, Karl; Swanson, Sherman R.; Zielinski, Mike Year Published2009 PublicationJournal of Environmental Management LocationsDOI10.1016/j.jenvman.2008.07.009 |
| 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 |
| Greater sage-grouse Centrocercus urophasianus migration links the USA and Canada: a biological basis for international prairie conservation | Tack, Jason D. | 2012 |
KeywordsKeywords Canada, Centrocercus urophasianus, greatersage-grouse, migration, Near Threatened species, prairie,transboundary conservation, USA AbstractMigratory pathways in North American prairies are critical for sustaining endemic biodiversity. Fragmentation and loss of habitat by an encroaching human footprint has extirpated and severely truncated formerly large movements by prairie wildlife populations. Greater sage-grouse Centrocercus urophasianus, a Near Threatened landscape species requiring vast tracts of intact sagebrush Artemisia spp., exhibit varied migratory strategies across their range in response to the spatial composition of available habitats. We unexpectedly documented the longest migratory event ever observed in sage-grouse (> 120 km one way) in 2007-2009 while studying demography of a population at the north-east edge of their range. Movements that encompassed 6,687 km(2) included individuals using distinct spring and summer ranges and then freely intermixing on the winter range in what is probably an obligate, annual event. The fate of greater sage-grouse in Canada is in part dependent on habitat conservation in the USA because this population spans an international border. Expanding agricultural tillage and development of oil and gas fields threaten to sever connectivity for this imperilled population. Science can help delineate high priority conservation areas but the fate of landscapes ultimately depends on international partnerships implementing conservation at scales relevant to prairie wildlife. AuthorsTack, Jason D.; Naugle, David E.; Carlson, John C.; Fargey, Pat J. Year Published2012 PublicationOryx LocationsDOI10.1017/S003060531000147X |
| Microsatellite analysis of female mating behaviour in lek-breeding sage grouse | Semple, K | 2001 |
Keywordslek mating; microsatellite DNA; paternity; sexual selection; sage grouse AbstractWe used microsatellite DNA markers to genotype chicks in 10 broods of lek-breeding sage grouse, Centrocercus urophasianus, whose mothers' behaviour was studied by radiotracking and observing leks. Previous behavioural studies suggested that almost all matings are performed by territorial males on leks and that multiple mating is rare. Two broods (20%) were sired by more than one male. Genetic analyses of the broods of eight females that visited an intensively studied lek were consistent with behavioural observations. Four females observed mating produced singly sired broods and males other than the individual observed copulating were excluded as sires for most or all of their chicks. Territorial males at the study lek were excluded as sires of broods of four other females that visited the lek but were not observed mating there. Radio-tracking suggested that two of these females mated at other leks. Our results confirm the reliability of mating observations at leks, but do not rule out a possible unseen component of the mating system. AuthorsSemple, K; Wayne, RK; Gibson, RM Year Published2001 PublicationMolecular Ecology LocationsDOI10.1046/j.0962-1083.2001.01348.x |
| Spatial patterns of population regulation in sage grouse (Centrocercus spp.) population viability analysis | La Montagne, JM | 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. AuthorsLa Montagne, JM; Irvine, RL; Crone, EE Year Published2002 PublicationJournal of Animal Ecology LocationsDOI10.1046/j.1365-2656.2002.00629.x |
| A population genetic comparison of large- and small-bodied sage grouse in Colorado using microsatellite and mitochondrial DNA markers | Oyler-McCance, SJ | 1999 |
KeywordsColorado;gene flow;microsatellites;mtDNA;sage grouse;speciation AbstractSage grouse (Centrocercus urophasianus) from southwestern Colorado and southeastern Utah (United States) are 33% smaller than all other sage grouse and have obvious plumage and behavioural differences. Because of these differences, they have been tentatively recognized as a separate 'small-bodied' species. We collected genetic evidence to further test this proposal, using mitochondrial sequence data and microsatellite markers to determine whether there was gene flow between the two proposed species. Significant differences in the distribution of alleles between the large- and small-bodied birds were found in both data sets. Analysis of molecular variance (AMOVA) revealed that 65% of the variation in mitochondrial DNA (mtDNA) haplotypes could be explained by the large- vs, small-bodied distinction. Genetic distances and neighbour-joining trees based on allelic frequency data showed a distinct separation between the proposed species, although cladistic analysis of the phylogenetic history of the mitochondrial sequence haplotypes has shown a lack of reciprocal monophyly. These results further support the recognition of the small-bodied sage grouse as a distinct species based on the biological species concept, providing additional genetic evidence to augment the morphological and behavioural data. Furthermore, small-bodied sage grouse had much less genetic variation than large-bodied sage grouse, which may have implications for conservation issues. AuthorsOyler-McCance, SJ; Kahn, NW; Burnham, KP; Braun, CE; Quinn, TW Year Published1999 PublicationMolecular Ecology Locations- Cold Springs, Colorado (40.8672, -108.827)
- North Park, Colorado (40.7835, -106.176)
- Blue Mountain Colorado (40.2483, -108.861)
- Middle Park, Colorado (40.0867, -106.217)
- Eagle Colorado (39.6553, -106.828)
- Crawford, Colorado (38.7039, -107.608)
- Gunnison Basin, Colorado (38.5458, -106.925)
- Dry Creek, Colorado (38.0459, -108.554)
- Dove Creek, Colorado (37.6331, -108.915)
DOI10.1046/j.1365-294x.1999.00716.x |
| Viability and Conservation of an Exploited Sage Grouse Population | Johnson, KH | 1999 |
KeywordsNo keywords available AbstractWe analyzed the viability of the Sage Grouse (Centrocercus urophasianus) population of North Park, Colorado, to evaluate its supposed decline due to hunting pressure and habitat degradation. Demographic data from 23 years of surveys were used to parameterize a post-breeding, female-based projection matrix with three life stages:juveniles, yearlings, and adults The population was found to be approximately stable or in decline only if immigration and apparent surveying errors were factored from the data set. Adult and juvenile survival and adult and juvenile reproduction, respectively, were identified as the most limiting demographic factors. Empirical evidence from designed experiments with Sage Grouse has shown that these demographic factors respond markedly to habitat manipulations, especially brush manipulation. Several plausible management scenarios were evaluated with 100-year population projections generated through Monte Carlo simulation (1000 iterations), sampling from a normal probability distribution entraining the observed variability in each demographic parameter (95% confidence limits). Habitat manipulations to achieve moderate levels (similar to 15% canopy cover) of sagebrush (Artemisia tridentata) are recommended Regression analyses with power tests showed correspondence between hunting mortality and total mortality for juveniles and adults. Provided that habitat manipulations improve the survival of juveniles and adults, population viability may be conserved without reducing harvest by hunters. AuthorsJohnson, KH; Braun, CE Year Published1999 PublicationConservation Biology LocationsDOI10.1046/j.1523-1739.1999.97284.x |
| Modeled Effects of Sagebrush-Steppe Restoration on Greater Sage-Grouse in the Interior Columbia Basin, U.S.A. | Wisdom, MJ | 2002 |
KeywordsNo keywords available AbstractHabitats of Greater Sage-Grouse (Centrocercus urophasianus) have declined across western North America, and most remaining habitats occur on lands administered by the U.S. Forest Service (FS) and U.S. Bureau of Land Management (BLM). Consequently, managers of FS-BLM lands need effective strategies to recover sagebrush (Artemisia spp.) habitats on which this species depends. In response to this need, we evaluated the potential benefits of two restoration scenarios on Greater Sage-Grouse in the interior Columbia Basin and adjacent portions of the Great Basin of the western United States. Scenario 1 assumed a 50% reduction in detrimental grazing effects (through changes in stocking rates and grazing systems) and a six-fold increase in areas treated with active restoration (e.g., prescribed burning, native seedings, wildfire suppression) compared with future management proposed by the FS-BLM. Scenario 2 assumed a 100% reduction in detrimental grazing effects and the same increase in active restoration as scenario 1. To evaluate benefits, we estimated the risk of population extirpation for sage grouse 100 years in the future under the two scenarios and compared this risk with that estimated for proposed (100-year) FS-BLM management. We used estimates of extirpation risk for historical (circa 1850-1890) and current time periods as a context for our comparison. Under historical conditions, risk of extirpation was very low on FS-BLM lands, but increased to a moderate probability under current conditions. Under proposed FS-BLM management, risk of extirpation on FS-BLM lands increased to a high probability 100 years in the future. Benefits of the two restoration scenarios, however, constrained the future risk of extirpation to a moderate probability. Our results suggest that expansive and sustained habitat restoration can maintain desired conditions and reduce future extirpation risk for sage grouse on FS-BLM lands in western North America. The continued spread of exotic plants, however, presents a formidable challenge to successful restoration and warrants substantial research and management attention. AuthorsWisdom, MJ; Rowland, MM; Wales, BC; Hemstrom, MA; Hann, WJ; Raphael, MG; Holthausen, RS; Gravenmier, RA; Rich, TD Year Published2002 PublicationConservation Biology LocationsDOI10.1046/j.1523-1739.2002.01073.x |
| Performance of Greater Sage-Grouse Models for Conservation Assessment in the Interior Columbia Basin, U.S.A. | Wisdom, MJ | 2002 |
KeywordsNo keywords available AbstractValid modeling of habitats and populations of Greater Sage-Grouse (Centrocercus urophasianus ) is a critical management need because of increasing concern about population viability. Consequently, we evaluated the performance of two models designed to assess landscape conditions for Greater Sage-Grouse across 13.6 million ha of sagebrush steppe in the interior Columbia Basin and adjacent portions of the Great Basin of the western United States (referred to as the basin). The first model, the environmental index model, predicted conditions at the scale of the subwatershed (mean size of approximately 7800 ha) based on inputs of habitat density, habitat quality, and effects of human disturbance. Predictions ranged on a continuous scale from 0 for lowest environmental index to 2 for optimal environmental index. The second model, the population outcome model, predicted the composite, range-wide conditions for sage grouse based on the contribution of environmental index values from all subwatersheds and measures of range extent and connectivity. Population outcomes were expressed as five classes (A through E) that represented a gradient from continuous, well-distributed populations (outcome A) to sparse, highly isolated populations with a high likelihood of extirpation (outcome E). To evaluate performance, we predicted environmental index values and population outcome classes in areas currently occupied by sage grouse versus areas where extirpation has occurred. Our a priori expectations were that models should predict substantially worse environmental conditions (lower environmental index) and a substantially higher probability of extirpation (lower population outcome class) in extirpated areas. Results for both models met these expectations. For example, a population outcome of class E was predicted for extirpated areas, as opposed to class C for occupied areas. These results suggest that our models provided reliable landscape predictions for the conditions tested. This finding is important for conservation planning in the basin, where the models were used to evaluate management of federal lands for sage grouse. AuthorsWisdom, MJ; Wales, BC; Rowland, MM; Raphael, MG; Holthausen, RS; Rich, TD; Saab, VA Year Published2002 PublicationConservation Biology LocationsDOI10.1046/j.1523-1739.2002.01074.x |
| Sagebrush-Steppe Vegetation Dynamics and Restoration Potential in the Interior Columbia Basin, U.S.A. | Hemstrom, MA | 2002 |
KeywordsNo keywords available AbstractWe modeled the dynamics and restoration of sagebrush (Artemisia spp.) habitats for Greater Sage-Grouse (Centrocercus urophasianus) in the interior Columbia Basin and adjacent portions of the Great Basin (referred to as the basin). Greater Sage-Grouse have undergone widespread decline and are the focus of conservation on over 13 million ha of sagebrush steppe in the basin, much of which is managed by the U.S. Forest Service (FS) and U.S. Bureau of Land Management (BLM ). Consequently, we evaluated changes in the amount and quality of sage-grouse habitat on 8.1 million ha of FS-BLM lands in the basin. Changes were estimated from historical to current conditions and from current conditions to those projected 100 years in the future under proposed management and under two restoration scenarios. These two scenarios were designed to improve long-term (100-year) projections of sage-grouse habitat on FS-BLM lands in relation to current conditions and proposed management. Scenario 1 assumed a 50% reduction in detrimental grazing effects by livestock (through changes in stocking rates and grazing systems) and a six-fold increase in areas treated with active restoration relative to proposed management. Scenario 2 assumed a 100% reduction in detrimental grazing effects and the same level of active restoration as scenario 1. Under the two scenarios, the amount of FS-BLM habitat for sage grouse within treated areas declined by 17-19% 100 years in the future compared with the current period, but was 10-14% higher than the 100-year projection under proposed management. Habitat quality under both scenarios was substantially improved compared with the current period and proposed management. Our results suggest that aggressive restoration could slow the rate of sagebrush loss and improve the quality of remaining habitat. AuthorsHemstrom, MA; Wisdom, MJ; Hann, WJ; Rowland, MM; Wales, BC; Gravenmier, RA Year Published2002 PublicationConservation Biology LocationsDOI10.1046/j.1523-1739.2002.01075.x |
