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At least 109 records · Page 6Linked to original sources
USGS2011

A simple graphical approach to quantitative monitoring of rangelands

The article reviews graphical interpretation of the four monitoring methods that can be used to generate a variety of indicators of rangeland ecosystem function. Data for all four of the monitoring methods can be recorded on a single data sheet that is designed to be usable by somebody with minimal literacy. Indicators of plant and ground cover are central to most long-term monitoring systems. Plant and ground-cover data inform managers about forage availability, plant community composition and structure, and risk of runoff and erosion. The spatial arrangement of plants at a site in addition to the percent of the ground that is covered by plants is an important determinant of erosion potential. Vertical vegetation structure can be monitored by capturing data on maximum plant height at each stick location. Plant density method can provide an early indicator of future changes in plant cover, forage, quality, and habitat structure.

Rangelands↗
USGS2014

Human infrastructure and invasive plant occurrence across rangelands of southwestern Wyoming, U.S.A.

Although human influence across rural landscapes is often discussed, interactions between the native, natural systems and human activities are challenging to measure explicitly. We assessed the distribution of introduced, invasive species as related to anthropogenic infrastructure and environmental conditions across southwestern Wyoming. to discern direct correlations as well as covariate influences between land use, land cover, and abundance of invasive plants, and assess the supposition that these features affect surrounding rangeland conditions. Our sample units were 1 000 m long and extended outward from target features, which included roads, oil and gas well pads, pipelines, power lines, and featureless background sites. Sample sites were distributed across the region using a stratified, random design with a frame that represented features and land-use intensity. In addition to land-use gradients, we captured a representative, but limited, range of variability in climate, soils, geology, topography, and dominant vegetation. Several of these variables proved significant, in conjunction with distance from anthropogenic features, in regression models of invasive plant abundance. We used general linear models to demonstrate and compare associations between invasive plant frequency and Euclidian distance from features, natural logarithm transformed distances (log-linear), and environmental variables which were presented as potential covariates. We expected a steep curvilinear (log or exponential) decline trending towards an asymptote along the axis representing high abundance near features with rapid decrease beyond approximately 50–100 m. Some of the associations we document exhibit this pattern, but we also found some invasive plant distributions that extended beyond our expectations, suggesting a broader distribution than anticipated. Our results provide details that can inform local efforts for management and control of invasive species, and they provide evidence of the different associations between natural patterns and human land use exhibited by nonnative species in this rural setting, such as the indirect effects of humans beyond impact areas.

Wyoming↗
USGS2022

Intra-site sources of restoration variability in severely invaded rangeland: Strong temporal effects of herbicide-weather interactions; weak spatial effects of plant-community patch type and litter

Invasions by exotic annual grasses (EAGs) are replacing native perennials in semiarid areas globally, including the vast sagebrush-steppe rangelands of western North America. Efforts to eradicate EAGs and restore perennials have had mixed success, especially in relatively warm and dry areas where EAGs had high dominance prior to intervention. Greater consideration of the ecological sources of variability in EAG treatment outcomes may improve success. We hypothesized that herbicide and restoration outcomes would be influenced by restoration strategy (type of herbicide, seeding or planting, timing of treatment) and underlying spatial variability associated with plant community patch type and litter, all applied in a landscape-scale experiment in a severely invaded area in Southern Idaho, USA. EAGs, specifically medusahead ( Taeniatherum caput-medusae [L.] Nevski), were strongly reduced for up to 3 years (maximum observation period) by the pre-emergent herbicide indaziflam, whereas the pre/post-emergent imazapic reduced EAGs only when applied twice. Indaziflam effects were greater when post-spray moisture was greater, and also when co-applied with imazapic, but reapplying indaziflam did not lead to additional reduction of EAGs. Imazapic and indaziflam each stimulated species-specific, secondary invasion by exotic and/or invasive tall forbs. Application of the broadleaf herbicide aminopyralid provided only a fleeting 1 year of control of a dominant, highly noxious forb skeletonweed ( Chondrilla juncea L.). Underlying heterogeneity in plant community patch type (dominant herb species) explained only ∼5% of variation in the herbicide effects, and manipulation of litter prior to spraying had no effect. Several years of seedings and planting resulted in no establishment of native perennials. Herbicides, especially indaziflam, appear to be an effective tool for reducing EAGs for multiple years in the challenging restoration conditions we evaluated, particularly if their application coincides with suitable moisture. However, restoring the perennials required for longer term resistance to reinvasion is a serious challenge that could be avoided with preservation of perennials.

Idaho↗
USGS2023

Manipulation of rangeland wildlife habitat

Rangeland manipulations have occurred for centuries. Those manipulations may have positive or negative effects on multiple wildlife species and their habitats. Some of these manipulations may result in landscape changes that fragment wildlife habitat and isolate populations. Habitat degradation and subsequent restoration may range from simple problems that are easy to restore to complex problems that require multiple interventions at multiple scales to solve. In all cases, knowledge of the wildlife species’ habitat needs throughout their life history, of their population dynamics and habitat-related sensitivities, and of their temporal and spatial scale for home ranges and genetic exchange will assist in determining appropriate restoration options. Habitat restoration will begin with an understanding of the vegetation’s successional recovery options and their time scales relative to wildlife population declines. We discuss passive and active manipulations and their application options. Passive manipulations focus on changes to current management. Active manipulations may include removal of undesirable vegetation using manual harvesting, mechanical, chemical, or biological methods while desirable vegetation is enhanced through the reintroduction of desirable wildlife habitat structure and function. These techniques will require monitoring of wildlife and their habitat at both the landscape and site level in an adaptive management framework to learn from our past and improve our future management.

Book chapter↗
USGS2017

Survey of beaver-related restoration practices in rangeland streams of the western USA

Poor condition of many streams and concerns about future droughts in the arid and semi-arid western USA have motivated novel restoration strategies aimed at accelerating recovery and increasing water resources. Translocation of beavers into formerly occupied habitats, restoration activities encouraging beaver recolonization, and instream structures mimicking the effects of beaver dams are restoration alternatives that have recently gained popularity because of their potential socioeconomic and ecological benefits. However, beaver dams and dam-like structures also harbor a history of social conflict. Hence, we identified a need to assess the use of beaver-related restoration projects in western rangelands to increase awareness and accountability, and identify gaps in scientific knowledge. We inventoried 97 projects implemented by 32 organizations, most in the last 10 years. We found that beaver-related stream restoration projects undertaken mostly involved the relocation of nuisance beavers. The most common goal was to store water, either with beaver dams or artificial structures. Beavers were often moved without regard to genetics, disease, or potential conflicts with nearby landowners. Few projects included post-implementation monitoring or planned for longer term issues, such as what happens when beavers abandon a site or when beaver dams or structures breach. Human dimensions were rarely considered and water rights and other issues were mostly unresolved or addressed through ad-hoc agreements. We conclude that the practice and implementation of beaver-related restoration has outpaced research on its efficacy and best practices. Further scientific research is necessary, especially research that informs the establishment of clear guidelines for best practices.

Environmental Management↗
USGS1993

Evaluating landsat thematic mapper derived vegetation indices for estimating above-ground biomass on semiarid rangelands

Ground data from the Central Plains Experimental Range in northeast Colorado and Landsat satellite images of that area acquired in August 1989, June 1990, and September 1990 were used to evaluate the level of association that can be expected from a univariate model relating spectrally derived vegetation indices (difference, ratio, and normalized difference vegetation indices) and dried green vegetation biomass. The vegetation indices were related to the ground sample estimates using a sample point, spectral class, and greenness strata approach. No strong relationships were found between the vegetation indices and sample estimates of dried green biomass using the sample point approach. The spectral class approach produced significant results only for the June 1990 sample period ( r =0.96). Significant relationships were found for the August 1989, June 1990, and September 1990 samples periods ( r 2 =0.95, 0.71, and 0.95, respectively) when the data were aggregated by greenness strata. The high degree of association between green biomass and the NDVI, obtained when the data were combined into greenness strata, indicated that it is possible to predict green biomass levels on semiarid rangelands using univariate regression models.

Remote Sensing of Environment↗
USGS2013

Phenology-based, remote sensing of post-burn disturbance windows in rangelands

Wildland fire activity has increased in many parts of the world in recent decades. Ecological disturbance by fire can accelerate ecosystem degradation processes such as erosion due to combustion of vegetation that otherwise provides protective cover to the soil surface. This study employed a novel ecological indicator based on remote sensing of vegetation greenness dynamics (phenology) to estimate variability in the window of time between fire and the reemergence of green vegetation. The indicator was applied as a proxy for short-term, post-fire disturbance windows in rangelands; where a disturbance window is defined as the time required for an ecological or geomorphic process that is altered to return to pre-disturbance levels. We examined variability in the indicator determined for time series of MODIS and AVHRR NDVI remote sensing data for a database of ∼100 historical wildland fires, with associated post-fire reseeding treatments, that burned 1990–2003 in cold desert shrub steppe of the Great Basin and Columbia Plateau of the western USA. The indicator-based estimates of disturbance window length were examined relative to the day of the year that fires burned and seeding treatments to consider effects of contemporary variability in fire regime and management activities in this environment. A key finding was that contemporary changes of increased length of the annual fire season could have indirect effects on ecosystem degradation, as early season fires appeared to result in longer time that soils remained relatively bare of the protective cover of vegetation after fires. Also important was that reemergence of vegetation did not occur more quickly after fire in sites treated with post-fire seeding, which is a strategy commonly employed to accelerate post-fire vegetation recovery and stabilize soil. Future work with the indicator could examine other ecological factors that are dynamic in space and time following disturbance – such as nutrient cycling, carbon storage, microbial community composition, or soil hydrology – as a function of disturbance windows, possibly using simulation modeling and historical wildfire information.

California;Idaho;Nevada;Oregon;Utah;Washington↗
USGS2023

Adapting to climate change on desert rangelands: A multi-site comparison of grazing behavior plasticity of heritage and improved beef cattle

Climate change is amplifying the spatiotemporal heterogeneity of desert rangeland forages through its impact on precipitation variability. Foraging behavior plasticity (an animal's ability to alter its behavior to cope with environmental variation) could be a key trait for climate adaptation of beef cattle in arid environments. We analyzed GPS-derived movement and activity data of Criollo and commercial beef cattle from eight studies conducted at sites in North and South America to determine whether seasonal and year-to-year behavior plasticity varied significantly between breeds. We calculated dormant/brown season or driest year percent change in foraging behavior relative to growing/green season or wettest year. Compared to commercial beef breeds, Criollo cattle exhibited significantly greater seasonal adjustment in daily distance traveled (20% increase vs. 2% decrease, P ≤ 0.02) and daily grazing effort (25% vs. 1.5% increase, P = 0.01) during the dormant/brown vs. growing/green season. Increase in daily area explored during the dormant/brown season was almost three times greater in Criollo vs. commercial beef cattle (P = 0.09). Seasonal adjustment in daily time spent grazing was similar for Criollo and commercial beef breeds. Increase in daily area explored during the dormant/brown season of dry vs. wet years was three times greater for Criollo vs. commercial beef breeds (P = 0.03). Criollo cattle tended (P = 0.09) to exhibit greater behavior adjustment than commercial beef counterparts in daily distance traveled during the dormant/brown season of dry vs. wet years (22% vs. 4% increase, respectively). No breed differences in adjustment of time spent grazing (P = 0.36) or grazing effort (P = 0.20) during dormant/brown season of dry vs. wet years were observed. Dry vs. wet year grazing behavior adjustments during the growing/green season were similar for both breeds. Grazing behavior plasticity observed in Criollo cows could be a critical trait for desert beef herds in the face of increasingly variable rainfall patterns occurring as a result of climate change.

Journal of Arid Environments↗
USGS2025

Soil-microbial communities respond less than plant communities to synthetic- or bio-herbicides applied to address the exotic grass-fire cycle in rangelands

The exotic grass-fire cycle is degrading semiarid rangelands, such as the vast areas of shrub-steppe in North America now invaded by fire-promoting cheatgrass. Chemical- or bio-herbicides are sprayed onto soils to inhibit the invaders, but information on chemical- or bio-herbicide impacts to soil microbial communities is limited. We asked how the soil-microbiome responded to the bioherbicide Pseudomonas fluorescens strain ACK55 in comparison to the separate and combined effects of a conventional pre-emergent chemical herbicide, imazapic, in two cheatgrass-invaded sagebrush-steppe sites. First-year microbial responses were evaluated using targeted sequencing of the 16S and LSU rRNA genes for bacteria+archaea and fungi, respectively, and were related to plant-community responses. A strong cheatgrass reduction with imazapic at one site was accompanied by a small shift in bacteria+archaea (16S) community composition with no effect on microbial alpha diversity, and this shift was small in comparison to natural microbiome variation between sites. ACK55 was not detected in soil a year after application, and it caused only transient and marginally significant reductions in annual grass cover accompanied by small reductions in soil fungi species richness. Full-length sequencing of the ACK55 16S rRNA gene and phylogenetic analyses revealed that ACK55 is more likely P. salmonii than P. fluorescens . Knowledge gaps remain on the duration and consequences of microbial-community shifts with imazapic and why molecular analyses showed ACK55 did not persist in soils. Confusion regarding microbial biopesticides can result where isolation, effectiveness testing, commercial release, and regulation are not guided by molecular taxonomic analyses.

Idaho↗
USGS2001

Field soil aggregate stability kit for soil quality and rangeland health evaluations

Soil aggregate stability is widely recognized as a key indicator of soil quality and rangeland health. However, few standard methods exist for quantifying soil stability in the field. A stability kit is described which can be inexpensively and easily assembled with minimal tools. It permits up to 18 samples to be evaluated in less than 10 min and eliminates the need for transportation, minimizing damage to soil structure. The kit consists of two 21×10.5×3.5 cm plastic boxes divided into eighteen 3.5×3.5 cm sections, eighteen 2.5-cm diameter sieves with 1.5-mm distance openings and a small spatula used for soil sampling. Soil samples are rated on a scale from one to six based on a combination of ocular observations of slaking during the first 5 min following immersion in distilled water, and the percent remaining on a 1.5-mm sieve after five dipping cycles at the end of the 5-min period. A laboratory comparison yielded a correlation between the stability class and percent aggregate stability based on oven dry weight remaining after treatment using a mechanical sieve. We have applied the method in a wide variety of agricultural and natural ecosystems throughout western North America, including northern Mexico, and have found that it is highly sensitive to differences in management and plant community composition. Although the field kit cannot replace the careful laboratory-based measurements of soil aggregate stability, it can clearly provide valuable information when these more intensive procedures are not possible.

Catena↗
USGS2007

Natural restoration of degraded rangeland ecosystem in Heshan hilly land

This study examined the 20-yr trend of natural restoration of a degraded rangeland ecosystem after disturbance in Heshan hilly land. The results showed that herbs and shrubs were the dominant plants in the community and only a small number of the shade-intolerant tree species had invaded, showing the characteristics of assembly of pioneer communities. The organic matter content, soluble nitrogen, available phosphorus and available potassium had recovered to the level of the local climax community. Part of the ecological functions such as water and soil conservation had also recovered. While the functions of water and soil conservation recovered first, more time was needed for productivity and other functions to completely recover, suggesting the idiosyncratic nature of different ecosystem variables in response to time and microclimate change. Particularly, nutrient cycling recovered very slowly by natural restoration and artificial plantation may be necessary to accelerate the restoration process. ?? 2007 Ecological Society of China.

Acta Ecologica Sinica↗
USGS2010

Comparison of Penman-Monteith, Shuttleworth-Wallace, and modified Priestley-Taylor evapotranspiration models for wildland vegetation in semiarid rangeland

Eddy correlation measurements of sensible and latent heat flux are used with measurements of net radiation, soil heat flux, and other micrometeorological variables to develop the Penman-Monteith, Shuttleworth-Wallace, and modified Priestley-Taylor evapotranspiration models for use in a sparsely vegetated, semiarid rangeland. The Penman-Monteith model, a one-component model designed for use with dense crops, is not sufficiently accurate ( r 2 = 0.56 for hourly data and r 2 = 0.60 for daily data). The Shuttleworth-Wallace model, a two-component logical extension of the Penman-Monteith model for use with sparse crops, performs significantly better ( r 2 = 0.78 for hourly data and r 2 = 0.85 for daily data). The modified Priestley-Taylor model, a one-component simplified form of the Penman potential evapotranspiration model, surprisingly performs as well as the Shuttle worth-Wallace model. The rigorous Shuttleworth-Wallace model predicts that about one quarter of the vapor flux to the atmosphere is from bare-soil evaporation. Further, during daylight hours, the small leaves are sinks for sensible heat produced at the hot soil surface.

Water Resources Research↗
USGS2010

Use of ground-based remotely sensed data for surface energy balance evaluation of a semiarid rangeland

An interdisciplinary field experiment was conducted to study the water and energy balance of a semiarid rangeland watershed in southeast Arizona during the summer of 1990. Two subwatersheds, one grass dominated and the other shrub dominated, were selected for intensive study with ground-based remote sensing systems and hydrometeorological instrumentation. Surface energy balance was evaluated at both sites using direct and indirect measurements of the turbulent fluxes (eddy correlation, variance, and Bowen ratio methods) and using an aerodynamic approach based on remote measurements of surface reflectance and temperature and conventional meteorological information. Estimates of net radiant flux density ( R n ), derived from measurements of air temperature, incoming solar radiation, and surface temperature and radiance compared well with values measured using a net radiometer (mean absolute difference (MAD) ≃ 50 W/m 2 over a range from 115 to 670 W/m 2 ). Soil heat flux density ( G ) was estimated using a relation between G / R n and a spectral vegetation index computed from the red and near-infrared surface reflectance. These G estimates compared well with conventional measurements of G using buried soil heat flux plates (MAD ≃ 20 W/m 2 over a range from −13 to 213 W/m 2 ). In order to account for the effects of sparse vegetation, semiempirical adjustments to the single-layer bulk aerodynamic resistance approach were required for evaluation of sensible heat flux density ( H ). This yielded differences between measurements and remote estimates of H of approximately 33 W/m 2 over a range from 13 to 303 W/m 2 . The resulting estimates of latent heat flux density, LE , were of the same magnitude and trend as measured values; however, a significant scatter was still observed: MAD ≃ 40 W/m 2 over a range from 0 to 340 W/m 2 . Because LE was solved as a residual, there was a cumulative effect of errors associated with remote estimates of R n , G , and H .

Water Resources Research↗
USGS2023

Supplying ecosystem services on US rangelands

Rangelands comprise 40% of the conterminous United States and they supply essential ecosystem services to society. A scenario assessment was conducted to determine how accelerating biophysical and societal drivers may modify their future availability. Four scenarios emerged: two may maintain rural communities by sustaining the prevailing ecosystem service of beef cattle production, and two may transform rural communities through expansion of renewable energy technologies and infusion of external capital from amenity land sales. Collaborative organizations representing diverse societal sectors may most effectively identify and manage trade-offs among ecosystem service availability, and equitably prioritize food and energy security, environmental quality and cultural identity.

Nature Sustainability↗
USGS2010

Capability of AVHRR data in discriminating rangeland cover mixtures

A combination of high temporal resolution Advanced Very High Resolution Radiometer (AVHRR) data and high spatial information Map Information Analysis and Display System (MIADS) landuse/landcover data from the United States Department of Agriculture-Natural Resources Conservation Service (USDA-NRCS) were used to investigate the feasibility of using the combined dataset for regional evapotranspiration (ET) studies. It was shown that the biweekly maximum Normalized Difference Vegetation Index (NDVI) composite AVHRR data were capable of discriminating rangelands with different types of trees and shrubs species. AVHRR data also showed a potential to distinguish canopy cover differences within a mix of similar species. The combination of MIADS data and AVHRR data can be used to study temporal dynamics of various cover types for use in regional ET estimates.

International Journal of Remote Sensing↗
USGS2016

Vegetation of semi-stable rangeland dunes of the Navajo Nation, Southwestern USA

Dune destabilization and increased mobility is a worldwide issue causing ecological, economic, and health problems for the inhabitants of areas with extensive dune fields. Dunes cover nearly a third of the Navajo Nation within the Colorado Plateau of southwestern USA. There, higher temperatures and prolonged drought beginning in 1996 have produced significant increases in dune mobility. Vegetation plays an important role in dune stabilization, but there are few studies of the plants of the aeolian surfaces of this region. We examined plant species and their attributes within a moderately vegetated dune field of the Navajo Nation to understand the types and characteristics of plants that stabilize rangeland dunes. These dunes supported a low cover of mixed grass-scrubland with fifty-two perennial and annual species including extensive occurrence of non-native annual Salsola spp. Perennial grass richness and shrub cover were positively associated with increased soil sand composition. Taprooted shrubs were more common on sandier substrates. Most dominant grasses had C4 photosynthesis, suggestive of higher water-use efficiencies and growth advantage in warm arid environments. Plant cover was commonly below the threshold of dune stabilization. Increasing sand movement with continued aridity will select for plants adapted to burial, deflation, and abrasion. The study indicates plants tolerant of increased sand mobility and burial but more investigation is needed to identify the plants adapted to establish and regenerate under these conditions. In addition, the role of Salsola spp. in promoting decline of perennial grasses and shrubs needs clarification.

Arizona, Colorado, New Mexico, Utah↗
USGS2017

Fusing MODIS with Landsat 8 data to downscale weekly normalized difference vegetation index estimates for central Great Basin rangelands, USA

Data fused from distinct but complementary satellite sensors mitigate tradeoffs that researchers make when selecting between spatial and temporal resolutions of remotely sensed data. We integrated data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor aboard the Terra satellite and the Operational Land Imager sensor aboard the Landsat 8 satellite into four regression-tree models and applied those data to a mapping application. This application produced downscaled maps that utilize the 30-m spatial resolution of Landsat in conjunction with daily acquisitions of MODIS normalized difference vegetation index (NDVI) that are composited and temporally smoothed. We produced four weekly, atmospherically corrected, and nearly cloud-free, downscaled 30-m synthetic MODIS NDVI predictions (maps) built from these models. Model results were strong with R 2 values ranging from 0.74 to 0.85. The correlation coefficients ( r ≥ 0.89) were strong for all predictions when compared to corresponding original MODIS NDVI data. Downscaled products incorporated into independently developed sagebrush ecosystem models yielded mixed results. The visual quality of the downscaled 30-m synthetic MODIS NDVI predictions were remarkable when compared to the original 250-m MODIS NDVI. These 30-m maps improve knowledge of dynamic rangeland seasonal processes in the central Great Basin, United States, and provide land managers improved resource maps.

Great Basin rangelands↗
USGS2013

Does seeding after wildfires in rangelands reduce erosion or invasive species?

Mitigation of ecological damage caused by rangeland wildfires has historically been an issue restricted to the western United States. It has focused on conservation of ecosystem function through reducing soil erosion and spread of invasive plants. Effectiveness of mitigation treatments has been debated recently. We reviewed recent literature to conduct a meta-analysis of seeding after wildfires to determine if seedings may (1) protect ecosystems against soil erosion and (2) reduce invasion or abundance of undesirable nonnative plant species. Effectiveness of postfire seedings was examined in 8 erosion and 19 invasive species cases. Seeding has little effect on erosion during the first year after fire and is highly dependent upon initial establishment and coverage of species in successive years. Among all seeding cases, 28% reduced, 67% were neutral, and 5% increased invasive species abundance. Older seedings were more likely to show reductions in invasives than younger seedings. Seedings with high plant establishment were more likely to reduce invasives than those with low establishment. Studies are needed that examine (1) frequency of adequate establishment of postfire seedings and causal factors of success or failure, (2) long-term impacts of seeding along a range of initial establishment and concomitant plant coverage over time as it relates to erosion and abundance of invasive plant species, and (3) auxiliary treatments designed to increase likelihood of germination and establishment given the inevitable variability of environmental conditions. These studies would aid land managers in deciding when postfire treatments are required and their likely level of success.

Restoration Ecology↗