72 research outputs found
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Anaho Island, Nevada: A Relict Area Dominated by Annual Invader Species
This material was digitized as part of a cooperative project between the Society for Range Management, the National Agricultural Library, and the University of Arizona Libraries.The Rangelands archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform March 202
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Seasonal forage production and quality on four native and improved plant communities in Eastern Oregon
Seasonal trends in forage quality and production were studied on improved
and unimproved portions of four plant communities in eastern Oregon. The range
improvements consisted of seeding and/or thinning. Improvement doubled forage
production on the lodgepole pine site (thinned but not seeded), tripled production
on the grassland and moist meadow sites (both seeded), and caused a sixfold rise in
forage production on the mixed conifer site (thinned and seeded). However, only in
the case of the grassland did range improvement lengthen the period when forage
provided adequate nutrition for growth of yearling cattle; the improved nutrition
can be attributed primarily to inclusion of a legume (alfalfa) in the seeding mixture.
On the forested sites, thinning tended to cause forage to mature earlier and thus
decline in forage quality faster than on unthinned controls.Published September 1985. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo
The Sage-Grouse Habitat Mortgage: Effective Conifer Management in Space and Time
AbstractManagement of conservation-reliant species can be complicated by the need to manage ecosystem processes that operate at extended temporal horizons. One such process is the role of fire in regulating abundance of expanding conifers that disrupt sage-grouse habitat in the northern Great Basin of the United States. Removing conifers by cutting has a beneficial effect on sage-grouse habitat. However, effects may last only a few decades because conifer seedlings are not controlled and the seed bank is fully stocked. Fire treatment may be preferred because conifer control lasts longer than for mechanical treatments. The amount of conservation needed to control conifers at large temporal and spatial scales can be quantified by multiplying land area by the time needed for conifer abundance to progress to critical thresholds (i.e., “conservation volume”). The contribution of different treatments in arresting conifer succession can be calculated by dividing conservation volume by the duration of treatment effect. We estimate that fire has approximately twice the treatment life of cutting at time horizons approaching 100 yr, but, has high up-front conservation costs due to temporary loss of sagebrush. Cutting has less up-front conservation costs because sagebrush is unaffected, but it is more expensive over longer management time horizons because of decreased durability. Managing conifers within sage-grouse habitat is difficult because of the necessity to maintain the majority of the landscape in sagebrush habitat and because the threshold for negative conifer effects occurs fairly early in the successional process. The time needed for recovery of sagebrush creates limits to fire use in managing sage-grouse habitat. Utilizing a combination of fire and cutting treatments is most financially and ecologically sustainable over long time horizons involved in managing conifer-prone sage-grouse habitat
Restoring North America’s Sagebrush Steppe Ecosystem Using Seed Enhancement Technologies
Rangelands occupy over a third of global land area, and in many cases are in less than optimum condition as a result of past land use, catastrophic wildfire and other disturbance, invasive species, or climate change. Often the only means of restoring these lands involves seeding desirable species, yet there are few cost effective seeding technologies, especially for the more arid rangeland types. The inability to consistently establish desired plants from seed may indicate that the seeding technologies being used are not successful in addressing the primary sources of mortality in the progression from seed to established plant. Seed enhancement technologies allow for the physical manipulation and application of materials to the seed that can enhance germination, emergence, and/or early seedling growth. In this article we examine some of the major limiting factors impairing seedling establishment in North America’s native sagebrush steppe ecosystem, and demonstrate how seed enhancement technologies can be employed to overcome these restoration barriers. We discuss specific technologies for: (1) increasing soil water availability; (2) enhancing seedling emergence in crusting soil; (3) controlling the timing of seed germination; (4) improving plantability and emergence of small seeded species; (5) enhancing seed coverage of broadcasted seeds; and (6) improving selectivity of pre-emergent herbicide. Concepts and technologies in this paper for restoring the sagebrush steppe ecosystem may apply generally to semi-arid and arid rangelands around the globe
Saving the sagebrush sea: An ecosystem conservation plan for big sagebrush plant communities
Vegetation change and anthropogenic development are altering ecosystems and decreasing biodiversity. Successful management of ecosystems threatened by multiple stressors requires development of ecosystem conservation plans rather than single species plans. We selected the big sagebrush (Artemisia tridentata Nutt.) ecosystem to demonstrate this approach. The area occupied by the sagebrush ecosystem is declining and becoming increasingly fragmented at an alarming rate because of conifer encroachment, exotic annual grass invasion, and anthropogenic development. This is causing rangewide declines and localized extirpations of sagebrush associated fauna and flora. To develop an ecosystem conservation plan, a synthesis of existing knowledge is needed to prioritize and direct management and research. Based on the synthesis, we concluded that efforts to restore higher elevation conifer-encroached, sagebrush communities were frequently successful, while restoration of exotic annual grass-invaded, lower elevation, sagebrush communities often failed. Overcoming exotic annual grass invasion is challenging and needs additional research to improve the probability of restoration and identify areas where success would be more probable. Management of fire regimes will be paramount to conserving sagebrush communities, as infrequent fires facilitate conifer encroachment and too frequent fires promote exotic annual grasses. Anthropogenic development needs to be mitigated and reduced to protect sagebrush communities and this probably includes more conservation easements and other incentives to landowners to not develop their properties. Threats to the sustainability of sagebrush ecosystem are daunting, but a coordinated ecosystem conservation plan that focuses on applying successful practices and research to overcome limitations to conservation is most likely to yield success
Upland Bare Ground and Riparian Vegetative Cover Under Strategic Grazing Management, Continuous Stocking, and Multiyear Rest in New Mexico Mid-grass Prairie
On the Ground
• We compared land cover attributes on rangeland pastures with strategically managed ranches (SGM), continuously stocked (CS), and rested pastures.
• SGM pastures had less upland bare ground and more riparian vegetative cover than adjoining CS pastures, and SGM pastures had bare ground cover comparable to pastures rested from grazing for three or more years.
• Differences in riparian cover between management types were greatest in years of near-average precipitation and lower in years of high precipitation or drought.
• Remote sensing technologyprovided a means of quantifying range condition and comparing management effectiveness on large landscapes in a constantly changing environment
Upland Bare Ground and Riparian Vegetative Cover Under Strategic Grazing Management, Continuous Stocking, and Multiyear Rest in New Mexico Mid-grass Prairie
On the Ground
• We compared land cover attributes on rangeland pastures with strategically managed ranches (SGM), continuously stocked (CS), and rested pastures.
• SGM pastures had less upland bare ground and more riparian vegetative cover than adjoining CS pastures, and SGM pastures had bare ground cover comparable to pastures rested from grazing for three or more years.
• Differences in riparian cover between management types were greatest in years of near-average precipitation and lower in years of high precipitation or drought.
• Remote sensing technologyprovided a means of quantifying range condition and comparing management effectiveness on large landscapes in a constantly changing environment
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Abundances of Coplanted Native Bunchgrasses and Crested Wheatgrass after 13 Years
Crested wheatgrass (Agropyron cristatum [L] Gaertm) has been seeded on more than 5 million hectares in western North America because it establishes more readily than native bunchgrasses. Currently, there is substantial interest in reestablishing native species in sagebrush steppe, but efforts to reintroduce native grasses into crested wheatgrass stands have been largely unsuccessful, and little is known about the long-term dynamics of crested wheatgrass/native species mixes. We examined the abundance of crested wheatgrass and seven native sagebrush steppe bunchgrasses planted concurrently at equal low densities in nongrazed and unburned plots. Thirteen years post establishment, crested wheatgrass was the dominant bunchgrass, with a 10-fold increase in density. Idaho fescue (Festuca idahoensis Elmer), Thurber’s needlegrass (Achnatherum thurberianum (Piper) Barkworth), basin wildrye (Leymus cinereus [Scribn. & Merr.] A. Löve), and Sandberg bluegrass (Poa secunda J. Presl) maintained their low planting density, whereas bluebunch wheatgrass (Pseudoroegneria spicata [Pursh] A. Löve), needle-and-thread (Hesperostipa comata [Trin. & Rupr.] Barkworth), and squirreltail (Elymus elymoides [Raf.] Swezey) densities declined. Our results suggest that densities of native bunchgrasses planted with crested wheatgrass are unlikely to increase and that some species may only persist at low levels. The high recruitment of crested wheatgrass suggests that coplanting of some native bunchgrasses may be a viable way of avoiding crested wheatgrass monocultures when this species is necessary for rehabilitation or restoration.Keywords: Agropyron cristatum, Revegetation, Sagebrush steppe, Restoratio
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Of Grouse and Golden Eggs: Can Ecosystems Be Managed Within a Species-Based Regulatory Framework?
Declining greater sage-grouse populations are causing concern for the future of this species across the western United States. Major
ecosystem issues, including exotic annual grass invasion and conifer encroachment, threaten vast acreages of sagebrush rangeland
and are primary threats to sage-grouse. We discuss types of problems facing sage-grouse habitat and argue that complex ecosystem
problems may be difficult to address under the Endangered Species Act as currently applied. Some problems, such as
anthropogenic development, can be effectively regulated to produce a desired outcome. Other problems that are complex and
involve disruption of ecosystem processes cannot be effectively regulated and require ongoing commitment to adaptive
management. We believe that historical inertia of the regulatory paradigm is sufficient to skew management toward regulatory
mechanisms, even though complex ecosystem problems impact large portions of the sage-grouse range. To overcome this situation,
we suggest that the regulatory approach embodied in the Endangered Species Act be expanded to include promoting management
trajectories needed to address complex ecosystem problems. This process should begin with state-and-transition models as the
basis for a conceptual framework that outlines potential plant communities, their value as sage-grouse habitat, and their ecological
status. Desired management trajectories are defined by maintenance of an ecologically resilient state that is of value as sage-grouse
habitat, or movement from a less desired to a more desired state. Addressing complex ecosystem problems will involve shifting
conservation roles. Under the regulatory approach, programmatic scales define regulatory policies, and local scales focus on
implementing those policies. With complex ecosystem problems, programmatic scales empower local conservationists to make
decisions necessary to adaptively manage problems. Putting ecosystem management on par with traditional regulatory actions
honors obligations to provide regulatory protections while maintaining the capacity of the ecosystem to produce habitat and
greatly expands the diversity of stakeholders willing to participate in sage-grouse conservation.Keywords: Sage-grouse, Endangered Species Act, State-and-transition, Sagebrus
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