19 research outputs found
Improving Landsat predictions of rangeland fractional cover with multi-task learning and uncertainty
Precipitation and Soil Productivity Explain Effects of Grazing on Grassland Songbirds
Temperate grassland ecosystems are imperiled globally, and habitat loss in North America has resulted in steep declines of endemic songbirds. Commercial livestock grazing is the primary land use in rangelands that support remaining bird populations. Some conservationists suggest using livestock as "ecosystem engineers" to increase habitat heterogeneity in rangelands because birds require a spectrum of sparse to dense vegetation cover. However, grazing effects remain poorly understood because local studies have not incorporated broad-scale environmental constraints on herbaceous growth. We surveyed grassland birds across a region spanning 26 500 km2 in northeast Montana, United States to assess how distribution and abundance were affected by weather, soils, and grazing. We modeled bird abundance to characterize regional response to herbaceous cover, experimentally manipulated grazing to isolate its effect, and then scaled back up to evaluate how the regional environment constrains bird response to grazing. Regional models predict that a quarter of our study region was productive grassland where managed grazing could benefit specialist species; the remainder was nongrassland or low-productivity soils where it had low potential to affect habitat. Grassland species distributed themselves along a gradient of herbaceous cover with predictable shifts in community composition. We demonstrated experimentally that grazing influences bird communities within productive grasslands, with higher utilization promoting more Chestnut-collared Longspur (Calcarius ornatus) and fewer Baird's Sparrow (Ammodramus bairdii). Results inform a new conceptual framework for grazing that explicitly incorporates the role of broad-scale environmental constraints. © Published by Elsevier Inc. on behalf of The Society for Range Management.The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information
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Bird responses to removal of western juniper in sagebrush-steppe
We investigated bird abundance in response to western juniper (Juniperus occidentalis) removal using a short-term chronosequence approach and generated estimates of density and responses to management for the most abundant species. Stands targeted for tree removal were primarily in the middle stages of juniper encroachment (Phase II, 7 851 ha). Trees were removed using hand felling combined with either lop and scatter, single tree burning, or jackpot burning, which were carried out to minimize loss of shrub cover. Brewer's sparrow (Spizella breweri) density was greater at treated versus untreated portions of the study area. At sites in the third year following tree removal, Brewer's sparrow density was 23.6 (95% confidence interval [CI]: 19.4-27.8) territories per km2 higher than locations that had not yet been treated. This equates to a net increase of 1 212-1 737 nesting pairs within the project area. Green-tailed towhee increased by 4.6 (95% CI: 3.1-6.1) territories per km2 for an estimated project wide increase of 194-381 nesting pairs, and vesper sparrow (Poocetes gramineus) increased by 6.5 (95% CI: 4.6-8.4) territories per km2 corresponding to an estimated increase of 460-559 nesting pairs within the project area. Density of gray flycatcher (Empidonax wrighti) was lower in cut areas, and over the entire project area we estimate a net loss of 183-486 nesting pairs as a result of juniper tree removal. This study demonstrates that conifer removal projects designed to retain shrub cover and structure can have benefits to multiple species of ground and shrub nesting birds, including several species of conservation concern.The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information
Special issue: Targeted woodland removal to recover at-risk grouse and their sagebrush-steppe and prairie ecosystems
The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information
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Special issue: Targeted woodland removal to recover at-risk grouse and their sagebrush-steppe and prairie ecosystems
The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information
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Extending conifer removal and landscape protection strategies from sage-grouse to songbirds, a range-wide assessment
Recent and unprecedented scale of greater sage-grouse (Centrocercus urophasianus) conservation in the American West enables assessment of community-level benefits afforded to other sagebrush-obligate species. We use North American Breeding Bird Survey (BBS) count data and machine-learning to assess predictors influencing spatial distribution and abundance of three sagebrush-obligate songbirds (Brewer's sparrow [Spizella breweri], sagebrush sparrow [Artemisiospiza nevadensis], and sage thrasher [Oreoscoptes montanus]). We quantified co-occurrence of songbird abundance with sage-grouse lek distributions using point pattern analyses and evaluated the concurrence of songbird abundance within sage-grouse habitat restoration and landscape protection. Sagebrush land-cover predictors were positively associated with the abundance of each songbird species in models that explained 16-37% of variation in BBS route level counts. Individual songbird models identified an apparent 40% threshold in sagebrush land-cover, over which songbird abundances nearly doubled. Songbird abundances were positively associated with sage-grouse distributions (P b 0.01); range-wide, landscapes supporting N 50% of males on leks also harbored 13-19% higher densities of songbirds compared with range-wide mean densities. Eighty-five percent of the conifer removal conducted through the Sage Grouse Initiative coincided with high to moderate Brewer's sparrow abundance. Wyoming's landscape protection (i.e., "core area") strategy for sage-grouse encompasses half the high to moderate abundance sagebrush sparrow and sage thrasher populations. In the Great Basin half the high to moderate abundance sagebrush sparrow and sage thrasher populations coincide with sage-grouse Fire and Invasive Assessment Tool priorities, where conservation actions are being focused in an attempt to reduce the threat of wildfire and invasive plants. Our work illustrates spatially targeted actions being implemented ostensibly for sage-grouse largely overlap high abundance centers for three sagebrush obligate passerines and are likely providing significant conservation benefits for less well-known sagebrush songbirds and other sagebrush-associated wildlife.The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information
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Short-term response of sage-grouse nesting to conifer removal in the northern great basin
Coniferwoodlands expanding into sage-steppe (Artemisia spp.) are a threat to sagebrush obligate species including the imperiled greater sage-grouse (Centrocercus urophasianus). Conifer removal is accelerating rapidly despite a lack of empirical evidence to assess outcomes to grouse. Using a before-after-control-impact design, we evaluated short-term effects of conifer removal on nesting habitat use by monitoring 262 sage-grouse nests in the northern Great Basin during 2010-2014. Tree removal made available for nesting an additional 28% of the treatment landscape by expanding habitat an estimated 9603 ha (3201 ha [±480 SE] annually). Relative probability of nesting in newly restored sites increased by 22% annually, and femaleswere 43%more likely to nestwithin 1000 m of treatments. From 2011 (pretreatment) to 2014 (3 yr after treatments began), 29% of the marked population (9.5% [±1.2 SE] annually) had shifted its nesting activities into mountain big sagebrush habitats that were cleared of encroaching conifer. Grouping treatments likely contributed to beneficial outcomes for grouse as individual removal projects averaged just 87 ha in size but cumulatively covered a fifth of the study area. Collaboratively identifying future priority watersheds and implementing treatments across public and private ownerships is vital to effectively restore the sage-steppe ecosystem for nesting sage-grouse.The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information
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CEAP Quantifies Conservation Outcomes for Wildlife and People on Western Grazing Lands
Maximizing efficiency and effectiveness of limited resources to conserve America's vast western grazing lands requires a science-based approach. Working Lands for Wildlife, USDA's approach for conserving America's working lands, co-produces scientific tools and quantifies outcomes that help guide future implementation and improve delivery. Quantifying outcomes in conservation provides accountability for investments, and illustrates to readers the role of science in working lands conservation. Together, diverse partners continue expanding into new technologies to further enhance the productivity, profitability, and sustainability of valuable grazing lands.The Rangelands archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information