Should ranchers value sagebrush? Why we need sagebrush

USDA-ARS?s Scientific Manuscript database

Sagebrush is an important native species that has potential benefits to ranchers who desire multiple services from their lands. Here, we outline how sagebrush benefits other range plants, improves forage and habitat for wildlife, and can be valuable for winter livestock grazing and revegetation....

Western land managers will need all available tools for adapting to climate change, including grazing: a critique of Beschta et al.

PubMed

Svejcar, Tony; Boyd, Chad; Davies, Kirk; Madsen, Matthew; Bates, Jon; Sheley, Roger; Marlow, Clayton; Bohnert, David; Borman, Mike; Mata-Gonzàlez, Ricardo; Buckhouse, John; Stringham, Tamzen; Perryman, Barry; Swanson, Sherman; Tate, Kenneth; George, Mel; Ruyle, George; Roundy, Bruce; Call, Chris; Jensen, Kevin; Launchbaugh, Karen; Gearhart, Amanda; Vermeire, Lance; Tanaka, John; Derner, Justin; Frasier, Gary; Havstad, Kris

2014-06-01

In a previous article, Beschta et al. (Environ Manag 51(2):474-491, 2013) argue that grazing by large ungulates (both native and domestic) should be eliminated or greatly reduced on western public lands to reduce potential climate change impacts. The authors did not present a balanced synthesis of the scientific literature, and their publication is more of an opinion article. Their conclusions do not reflect the complexities associated with herbivore grazing. Because grazing is a complex ecological process, synthesis of the scientific literature can be a challenge. Legacy effects of uncontrolled grazing during the homestead era further complicate analysis of current grazing impacts. Interactions of climate change and grazing will depend on the specific situation. For example, increasing atmospheric CO₂ and temperatures may increase accumulation of fine fuels (primarily grasses) and thus increase wildfire risk. Prescribed grazing by livestock is one of the few management tools available for reducing fine fuel accumulation. While there are certainly points on the landscape where herbivore impacts can be identified, there are also vast grazed areas where impacts are minimal. Broad scale reduction of domestic and wild herbivores to help native plant communities cope with climate change will be unnecessary because over the past 20-50 years land managers have actively sought to bring populations of native and domestic herbivores in balance with the potential of vegetation and soils. To cope with a changing climate, land managers will need access to all available vegetation management tools, including grazing.

Greater bud outgrowth of Bromus inermis than Pascopyrum smithii under multiple environmental conditions

Treesearch

Jacqueline P. Ott; Jack L. Butler; Yuping Rong; Lan. Xu

2017-01-01

Tiller recruitment of perennial grasses in mixed-grass prairie primarily occurs from belowground buds. Environmental conditions, such as temperature, soil moisture and grazing can affect bud outgrowth of both invasive and native perennial grasses. Differential bud outgrowth responses of native and invasive species to climate change and grazing could alter...

Influence of grazing management on the seasonal change in testicular morphology in Corriedale rams.

PubMed

Bielli, A; Pedrana, G; Gastel, M T; Castrillejo, A; Moraña, A; Lundeheim, N; Forsberg, M; Rodriguez-Martinez, H

1999-06-28

The present study was conducted: (a) to determine the degree of seasonal variation in testis stereology in Corriedale rams between autumn and winter; (b) to test the hypothesis that testis stereology of Corriedale rams grazing native pastures during autumn and winter would differ from those of Corriedale rams grazing sown pastures and supplemented with grain during the same period; and (c) to determine whether Sertoli cell numbers differ in adult rams between the breeding season (autumn) and the following non-breeding season (winter). Twenty experimental animals were studied. Six rams (autumn control group, C-A) that had been grazing on native pasture (stocking rate = 2-3 animals ha(-1)) were castrated at the beginning of the experiment (March, early autumn). Seven rams (winter control group, C-W) continued to graze on native pasture at the same stocking rate until the end of the experiment (August, late winter). Another seven rams (treated group, T) grazed on improved pasture (stocking rate = 1-2 animals ha(-1)) and were supplemented with 1 kg grain ram(-1) day(-1) until the end of the experiment. Live weight, scrotal circumference, serum testosterone concentration and selected testicular stereological parameters were measured. The treatment did not impede the winter reduction in testicular activity and reduced its magnitude slightly (group T) compared with controls (group C-W). Sertoli cell numbers were higher in autumn (group C-A) than in winter, both on native (group C-W) and sown pastures (group T). Diminishing Sertoli cell numbers between autumn and the following winter suggest the occurrence of that Sertoli cell death during this period. The results indicate that, although the reproductive activity of Corriedale rams is moderately seasonal, a restricted change in grazing and grain supplementation can only modify it to a limited extent.

Water-Borne Cues of a Non-Indigenous Seaweed Mediate Grazer-Deterrent Responses in Native Seaweeds, but Not Vice Versa

PubMed Central

Yun, Hee Young; Engelen, Aschwin H.; Santos, Rui O.; Molis, Markus

2012-01-01

Plants optimise their resistance to herbivores by regulating deterrent responses on demand. Induction of anti-herbivory defences can occur directly in grazed plants or from emission of risk cues to the environment, which modifies interactions of adjacent plants with, for instance, their consumers. This study confirmed the induction of anti-herbivory responses by water-borne risk cues between adjoining con-specific seaweeds and firstly examined whether plant-plant signalling also exists among adjacent hetero-specific seaweeds. Furthermore, differential abilities and geographic variation in plant-plant signalling by a non-indigenous seaweed as well as native seaweeds were assessed. Twelve-day induction experiments using the non-indigenous seaweed Sargassum muticum were conducted in the laboratory in Portugal and Germany with one local con-familiar (Portugal: Cystoseira humilis, Germany: Halidrys siliquosa) and hetero-familiar native species (Portugal: Fucus spiralis, Germany: F. vesiculosus). All seaweeds were grazed by a local isopod species (Portugal: Stenosoma nadejda, Germany: Idotea baltica) and were positioned upstream of con- and hetero-specific seaweeds. Grazing-induced modification in seaweed traits were tested in three-day feeding assays between cue-exposed and cue-free ( = control) pieces of both fresh and reconstituted seaweeds. Both Fucus species reduced their palatability when positioned downstream of isopod-grazed con-specifics. Yet, the palatability of non-indigenous S. muticum remained constant in the presence of upstream grazed con-specifics and native hetero-specifics. In contrast, both con-familiar (but neither hetero-familiar) native species reduced palatability when located downstream of grazed S. muticum. Similar patterns of grazer-deterrent responses to water-borne cues were observed on both European shores, and were almost identical between assays using fresh and reconstituted seaweeds. Hence, seaweeds may use plant-plant signalling to optimise chemical resistance to consumers, though this ability appeared to be species-specific. Furthermore, this study suggests that native species may benefit more than a non-indigenous species from water-borne cue mediated reduction in consumption as only natives responded to signals emitted by hetero-specifics. PMID:22701715

Water-borne cues of a non-indigenous seaweed mediate grazer-deterrent responses in native seaweeds, but not vice versa.

PubMed

Yun, Hee Young; Engelen, Aschwin H; Santos, Rui O; Molis, Markus

2012-01-01

Plants optimise their resistance to herbivores by regulating deterrent responses on demand. Induction of anti-herbivory defences can occur directly in grazed plants or from emission of risk cues to the environment, which modifies interactions of adjacent plants with, for instance, their consumers. This study confirmed the induction of anti-herbivory responses by water-borne risk cues between adjoining con-specific seaweeds and firstly examined whether plant-plant signalling also exists among adjacent hetero-specific seaweeds. Furthermore, differential abilities and geographic variation in plant-plant signalling by a non-indigenous seaweed as well as native seaweeds were assessed. Twelve-day induction experiments using the non-indigenous seaweed Sargassum muticum were conducted in the laboratory in Portugal and Germany with one local con-familiar (Portugal: Cystoseira humilis, Germany: Halidrys siliquosa) and hetero-familiar native species (Portugal: Fucus spiralis, Germany: F. vesiculosus). All seaweeds were grazed by a local isopod species (Portugal: Stenosoma nadejda, Germany: Idotea baltica) and were positioned upstream of con- and hetero-specific seaweeds. Grazing-induced modification in seaweed traits were tested in three-day feeding assays between cue-exposed and cue-free ( = control) pieces of both fresh and reconstituted seaweeds. Both Fucus species reduced their palatability when positioned downstream of isopod-grazed con-specifics. Yet, the palatability of non-indigenous S. muticum remained constant in the presence of upstream grazed con-specifics and native hetero-specifics. In contrast, both con-familiar (but neither hetero-familiar) native species reduced palatability when located downstream of grazed S. muticum. Similar patterns of grazer-deterrent responses to water-borne cues were observed on both European shores, and were almost identical between assays using fresh and reconstituted seaweeds. Hence, seaweeds may use plant-plant signalling to optimise chemical resistance to consumers, though this ability appeared to be species-specific. Furthermore, this study suggests that native species may benefit more than a non-indigenous species from water-borne cue mediated reduction in consumption as only natives responded to signals emitted by hetero-specifics.

Modeling predicts that redd trampling by cattle may contribute to population declines of native trout

Treesearch

Douglas P. Peterson; Bruce E. Rieman; Michael K. Young; James A. Brammer

2010-01-01

Unrestricted livestock grazing can degrade aquatic ecosystems, and its effects on native vertebrate species are generally mediated by changes to physical habitat. Recently, high estimated rates of cattle trampling on artificial redds within federal grazing allotments in southwestern Montana, USA, has raised concern that direct mortality from trampling may contribute to...

Relationship between body condition score at calving and reproductive performance in young postpartum cows grazing native range

USDA-ARS?s Scientific Manuscript database

Body condition score is used as a management tool to predict competency of reproduction in beef cows. Therefore, a retrospective study was performed to evaluate association of BCS at calving with subsequent pregnancy rate, days to first estrus, nutrient status (assessed by blood metabolites), and c...

Invertebrate community response to a shifting mosaic of habitat

USGS Publications Warehouse

Engle, David M.; Fuhlendorf, S.D.; Roper, A.; Leslie, David M.

2008-01-01

Grazing management has focused largely on promoting vegetation homogeneity through uniform distribution of grazing to minimize area in a pasture that is either heavily disturbed or undisturbed. An alternative management model that couples grazing and fire (i.e., patch burning) to promote heterogeneity argues that grazing and fire interact through a series of positive and negative feedbacks to cause a shifting mosaic of vegetation composition and structure across the landscape. We compared patch burning with traditional homogeneity-based management in tallgrass prairie to determine the influence of the two treatments on the aboveground invertebrate community. Patch burning resulted in a temporal flush of invertebrate biomass in patches transitional between unburned and patches burned in the current year. Total invertebrate mass was about 50% greater in these transitional patches within patch-burned pastures as compared to pastures under traditional, homogeneity-based management. Moreover, the mosaic of patches in patch-burned pastures contained a wider range of invertebrate biomass and greater abundance of some invertebrate orders than did the traditionally managed pastures. Patch burning provides habitat that meets requirements for a broad range of invertebrate species, suggesting the potential for patch burning to benefit other native animal assemblages in the food chain.

The utilization of historical data and geospatial technology advances at the Jornada Experimental Range to support western America ranching culture

USDA-ARS?s Scientific Manuscript database

In the early 1900s, concerns were expressed by ranchers, academicians, and federal scientists that widespread overgrazing and invasion of native grassland by woody shrubs were having severe negative impacts upon normal grazing practices in Western America. Ranchers wanted to reverse these trends an...

Biogeographic, cultural, and historical setting of the Northern Rocky Mountains [Chapter 2

Treesearch

S. Karen Dante-Wood

2018-01-01

The Northern Rockies Adaptation Partnership (NRAP) includes diverse landscapes, ranging from high mountains to grasslands, from alpine glaciers to broad rivers (fig. 1.1). This region, once inhabited solely by Native Americans, has been altered by two centuries of settlement by Euro- Americans through extractive practices such as timber harvest, grazing, and mining,...

Eighty years of grazing by cattle modifies sagebrush and bunchgrass structure

USDA-ARS?s Scientific Manuscript database

Grazing by cattle is ubiquitous across the sagebrush steppe, however, little is known about its effects on sagebrush and native bunchgrass structure. Understanding the effects of long-term grazing on sagebrush and bunchgrass structure is important because sagebrush is a keystone species and bunchgra...

Wild Herbivore Grazing Enhances Insect Diversity over Livestock Grazing in an African Grassland System

PubMed Central

Roets, Francois; Samways, Michael J.

2016-01-01

Southern Africa’s grassland biodiversity is threatened by habitat transformation such as commercial forestry. Ecological networks (ENs) have been instigated to alleviate the pressure of habitat transformation on local biodiversity. ENs are large scale webs of corridors and patches of natural vegetation criss-crossing production landscapes that can simulate conditions in protected areas (PAs). Many ENs have lost many native large mammal species, which have been replaced by domestic livestock to retain natural grazing dynamics, which could have an impact on the long-term value of ENs for insects. Here we compared dung beetle, butterfly and grasshopper diversity in ENs across a landscape mosaic of timber plantations, where 1) wild megaherbivores were maintained, 2) in ENs where these herbivores were replaced by livestock and, 3) in a nearby World Heritage PA which retained its natural complement of megaherbivores. Sites in the PA far from any plantation were similar in composition to those in the wild grazed EN. Presence of the wild grazers improved the alpha- and beta-diversity of all focal insect taxa when compared to domestic grazing. Furthermore, species composition shows significant differences between the two grazing systems indicating that an assemblage of native large mammals facilitates insect diversity conservation. We support the maintenance or introduction of large native mammals in ENs or similar conservation areas in production landscapes to simulate the ecological conditions and natural heterogeneity in nearby PAs. PMID:27783685

Wild Herbivore Grazing Enhances Insect Diversity over Livestock Grazing in an African Grassland System.

PubMed

Pryke, James S; Roets, Francois; Samways, Michael J

2016-01-01

Southern Africa's grassland biodiversity is threatened by habitat transformation such as commercial forestry. Ecological networks (ENs) have been instigated to alleviate the pressure of habitat transformation on local biodiversity. ENs are large scale webs of corridors and patches of natural vegetation criss-crossing production landscapes that can simulate conditions in protected areas (PAs). Many ENs have lost many native large mammal species, which have been replaced by domestic livestock to retain natural grazing dynamics, which could have an impact on the long-term value of ENs for insects. Here we compared dung beetle, butterfly and grasshopper diversity in ENs across a landscape mosaic of timber plantations, where 1) wild megaherbivores were maintained, 2) in ENs where these herbivores were replaced by livestock and, 3) in a nearby World Heritage PA which retained its natural complement of megaherbivores. Sites in the PA far from any plantation were similar in composition to those in the wild grazed EN. Presence of the wild grazers improved the alpha- and beta-diversity of all focal insect taxa when compared to domestic grazing. Furthermore, species composition shows significant differences between the two grazing systems indicating that an assemblage of native large mammals facilitates insect diversity conservation. We support the maintenance or introduction of large native mammals in ENs or similar conservation areas in production landscapes to simulate the ecological conditions and natural heterogeneity in nearby PAs.

Grazing management for healthy watersheds

Treesearch

Karl Wood

2008-01-01

(Please note, this is an abstract only) New Mexico was historically grazed by many native and introduced ungulates, often called wildlife. Their distribution was limited especially in deserts until domestic animals were introduced and drinking water was provided. Plants respond to grazing with little resistance (black grama), to great resistance (blue grama), and to...

Assessment of serum IGF-I and ß-hydroxybutyrate concentrations on reproductive performance prior to calving and breeding in young beef cows grazing native range

USDA-ARS?s Scientific Manuscript database

Metabolites involved in the metabolic adaptation to negative energy balance may have the potential to regulate timing of reproductive success. Therefore, the objective of this 4-yr study was to determine the association of serum metabolites, cow BW, BCS, and calf performance on conception date in 2...

Assessment of serum IGF-1 and ¿-hydroxybutyrate concentrations on reproductive performance prior to calving and breeding in young beef cows grazing native range

USDA-ARS?s Scientific Manuscript database

Metabolites involved in the metabolic adaptation to negative energy balance may potentially contribute to regulation of reproductive success. Therefore, the objective of this 4-yr study was to determine the association of serum metabolites, cow BW, BCS, and calf performance on conception date in sp...

Grazing management contributions to net global warming potential: a long-term evaluation in the Northern Great Plains.

PubMed

Liebig, M A; Gross, J R; Kronberg, S L; Phillips, R L; Hanson, J D

2010-01-01

The role of grassland ecosystems as net sinks or sources of greenhouse gases (GHGs) is limited by a paucity of information regarding management impacts on the flux of nitrous oxide (N(2)O) and methane (CH(4)). Furthermore, no long-term evaluation of net global warming potential (GWP) for grassland ecosystems in the northern Great Plains (NGP) of North America has been reported. Given this need, we sought to determine net GWP for three grazing management systems located within the NGP. Grazing management systems included two native vegetation pastures (moderately grazed pasture [MGP], heavily grazed pasture [HGP]) and a heavily grazed crested wheatgrass [Agropyron desertorum (Fisch. ex. Link) Schult.] pasture (CWP) near Mandan, ND. Factors evaluated for their contribution to GWP included (i) CO(2) emissions associated with N fertilizer production and application, (ii) literature-derived estimates of CH(4) production for enteric fermentation, (iii) change in soil organic carbon (SOC) over 44 yr using archived soil samples, and (iv) soil-atmosphere N(2)O and CH(4) fluxes over 3 yr using static chamber methodology. Analysis of SOC indicated all pastures to be significant sinks for SOC, with sequestration rates ranging from 0.39 to 0.46 Mg C ha(-1) yr(-1). All pastures were minor sinks for CH(4) (<2.0 kg CH(4)-C ha(-1) yr(-1)). Greater N inputs within CWP contributed to annual N(2)O emission nearly threefold greater than HGP and MGP. Due to differences in stocking rate, CH(4) production from enteric fermentation was nearly threefold less in MGP than CWP and HGP. When factors contributing to net GWP were summed, HGP and MGP were found to serve as net CO(2equiv.) sinks, while CWP was a net CO(2equiv.) source. Values for GWP and GHG intensity, however, indicated net reductions in GHG emissions can be most effectively achieved through moderate stocking rates on native vegetation in the NGP.

Herbivory enhances the resistance of mangrove forest to cordgrass invasion.

PubMed

Zhang, Yihui; Meng, Hanyu; Wang, Yi; He, Qiang

2018-06-01

The biotic resistance hypothesis proposes that biotic interactions, such as competition and herbivory, resist the establishment and spread of non-native species. The relative and interactive role of competition and herbivory in resisting plant invasions, however, remains poorly understood. We investigated the interactive role of competition and herbivory (by the native rodent Rattus losea) in resisting Spartina alterniflora (cordgrass) invasions into mangrove forests. In southern China, although exotic cordgrass numerically dominates intertidal mudflats and open gaps in mangrove forests, intact forests appear to be highly resistant to cordgrass invasion. A field transplant and rodent exclusion experiment showed that while the impact of rodent grazing on cordgrass was weak on mangrove forest edges and open mudflats, rodent grazing strongly suppressed cordgrass in mangrove understory habitats. A greenhouse experiment confirmed a synergistic interaction between grazing and light availability (a proxy for mangrove shading and light competition) in suppressing cordgrass establishment, with the strongest impacts of grazing in low light conditions that likely weakened cordgrass to survive and resprout. When both were present, as in mangrove understory habitats, grazing and low light acted in concert to eliminate cordgrass establishment, resulting in resistance of mangrove forests to cordgrass invasion. Our results reveal that grazing by native herbivores can enhance the resistance of mangrove forests to cordgrass invasion in southern China, and suggest that investigating multifactor interactions may be critical to understanding community resistance to exotic invasions. © 2018 by the Ecological Society of America.

Nongame bird communities on managed grasslands in North Dakota

USGS Publications Warehouse

Renken, Rochelle B.; Dinsmore, James J.

1987-01-01

Grazed native prairie, unmanipulated native prairie, and planted alfalfa-wheatgrass habitats each supported prairie bird species unique to that habitat type. Comparisons of the three habitats, using community coefficients and overlap indices, showed that grazed and alfalfa-wheatgrass habitats supported the most dissimilar or unique bird communities. All three habitat types, or habitats with similar vegetation structure, must be incorporated in grassland management plans to support all members of the mixed-grass prairie bird community.

Effect of frame size and season on enteric methane (CH4) and carbon dioxide (CO2)emissions in Angus brood cows grazing native tall-grass prairie in central Oklahoma USA

USDA-ARS?s Scientific Manuscript database

Effect of frame size and season on enteric methane (CH4) and carbon dioxide (CO2) emissions in Angus brood cows grazing native tall-grass prairie in central Oklahoma, USA J.P.S. Neel USDA ARS, El Reno, OK A reduction in enteric CH4 production in ruminants is associated with improved production effic...

Interaction of historical and nonhistorical disturbances maintains native plant communities.

PubMed

Davies, K W; Svejcar, T J; Bates, J D

2009-09-01

Historical disturbance regimes are often considered a critical element in maintaining native plant communities. However, the response of plant communities to disturbance may be fundamentally altered as a consequence of invasive plants, climate change, or prior disturbances. The appropriateness of historical disturbance patterns under modern conditions and the interactions among disturbances are issues that ecologists must address to protect and restore native plant communities. We evaluated the response of Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh plant communities to their historical disturbance regime compared to other disturbance regimes. The historical disturbance regime of these plant communities was periodic fires with minimal grazing by large herbivores. We also investigated the influence of prior disturbance (grazing) on the response of these communities to subsequent disturbance (burning). Treatments were: (1) ungrazed (livestock grazing excluded since 1936) and unburned, (2) grazed and unburned, (3) ungrazed and burned (burned in 1993), and (4) grazed and burned. The ungrazed-burned treatment emulated the historical disturbance regime. Vegetation cover, density, and biomass production were measured the 12th, 13th, and 14th year post-burning. Prior to burning the presence of Bromus tectorum L., an exotic annual grass, was minimal (<0.5% cover), and vegetation characteristics were similar between grazed and ungrazed treatments. However, litter accumulation was almost twofold greater in ungrazed than in grazed treatments. Long-term grazing exclusion followed by burning resulted in a substantial B. tectorum invasion, but burning the grazed areas did not produce an invasion. The ungrazed-burned treatment also had less perennial vegetation than other treatments. The accumulation of litter (fuel) in ungrazed treatments may have resulted in greater fire-induced mortality of perennial vegetation in ungrazed compared to grazed treatments. Our results demonstrate that prior disturbances exert a strong influence on the response of plant communities to subsequent disturbances and suggest that low-severity disturbances may be needed in some plant communities to increase their resilience to more severe disturbances. Modern deviations from historical conditions can alter ecosystem response to disturbances, thus restoring the historical disturbance regime may not be an appropriate strategy for all ecosystems.

Eaten Out of House and Home: Impacts of Grazing on Ground-Dwelling Reptiles in Australian Grasslands and Grassy Woodlands

PubMed Central

Howland, Brett; Stojanovic, Dejan; Gordon, Iain J.; Manning, Adrian D.; Fletcher, Don; Lindenmayer, David B.

2014-01-01

Large mammalian grazers can alter the biotic and abiotic features of their environment through their impacts on vegetation. Grazing at moderate intensity has been recommended for biodiversity conservation. Few studies, however, have empirically tested the benefits of moderate grazing intensity in systems dominated by native grazers. Here we investigated the relationship between (1) density of native eastern grey kangaroos, Macropus giganteus, and grass structure, and (2) grass structure and reptiles (i.e. abundance, richness, diversity and occurrence) across 18 grassland and grassy Eucalyptus woodland properties in south-eastern Australia. There was a strong negative relationship between kangaroo density and grass structure after controlling for tree canopy cover. We therefore used grass structure as a surrogate for grazing intensity. Changes in grazing intensity (i.e. grass structure) significantly affected reptile abundance, reptile species richness, reptile species diversity, and the occurrence of several ground-dwelling reptiles. Reptile abundance, species richness and diversity were highest where grazing intensity was low. Importantly, no species of reptile was more likely to occur at high grazing intensities. Legless lizards (Delma impar, D. inornata) were more likely to be detected in areas subject to moderate grazing intensity, whereas one species (Hemiergis talbingoensis) was less likely to be detected in areas subject to intense grazing and three species (Menetia greyii, Morethia boulengeri, and Lampropholis delicata) did not appear to be affected by grazing intensity. Our data indicate that to maximize reptile abundance, species richness, species diversity, and occurrence of several individual species of reptile, managers will need to subject different areas of the landscape to moderate and low grazing intensities and limit the occurrence and extent of high grazing. PMID:25501680

Eaten out of house and home: impacts of grazing on ground-dwelling reptiles in Australian grasslands and grassy woodlands.

PubMed

Howland, Brett; Stojanovic, Dejan; Gordon, Iain J; Manning, Adrian D; Fletcher, Don; Lindenmayer, David B

2014-01-01

Large mammalian grazers can alter the biotic and abiotic features of their environment through their impacts on vegetation. Grazing at moderate intensity has been recommended for biodiversity conservation. Few studies, however, have empirically tested the benefits of moderate grazing intensity in systems dominated by native grazers. Here we investigated the relationship between (1) density of native eastern grey kangaroos, Macropus giganteus, and grass structure, and (2) grass structure and reptiles (i.e. abundance, richness, diversity and occurrence) across 18 grassland and grassy Eucalyptus woodland properties in south-eastern Australia. There was a strong negative relationship between kangaroo density and grass structure after controlling for tree canopy cover. We therefore used grass structure as a surrogate for grazing intensity. Changes in grazing intensity (i.e. grass structure) significantly affected reptile abundance, reptile species richness, reptile species diversity, and the occurrence of several ground-dwelling reptiles. Reptile abundance, species richness and diversity were highest where grazing intensity was low. Importantly, no species of reptile was more likely to occur at high grazing intensities. Legless lizards (Delma impar, D. inornata) were more likely to be detected in areas subject to moderate grazing intensity, whereas one species (Hemiergis talbingoensis) was less likely to be detected in areas subject to intense grazing and three species (Menetia greyii, Morethia boulengeri, and Lampropholis delicata) did not appear to be affected by grazing intensity. Our data indicate that to maximize reptile abundance, species richness, species diversity, and occurrence of several individual species of reptile, managers will need to subject different areas of the landscape to moderate and low grazing intensities and limit the occurrence and extent of high grazing.

Increasing Native Forb Seed Supplies for the Great Basin

Treesearch

Nancy L. Shaw; Scott M. Lambert; Ann M. DeBolt; Mike Pellant

2005-01-01

Over the last 150 years, excessive grazing, annual weed invasions, increased wildfire frequency, and other human disturbances have negatively impacted native plant communities of the Great Basin. Native plant materials and appropriate planting strategies are needed to recreate diverse communities in areas requiring active restoration. Although native forbs are critical...

Assessing the potential to restore historic grazing ecosystems with tortoise ecological replacements.

PubMed

Griffiths, Christine J; Zuël, Nicolas; Jones, Carl G; Ahamud, Zairabee; Harris, Stephen

2013-08-01

The extinction of large herbivores, often keystone species, can dramatically modify plant communities and impose key biotic thresholds that may prevent an ecosystem returning to its previous state and threaten native biodiversity. A potentially innovative, yet controversial, landscape-based long-term restoration approach is to replace missing plant-herbivore interactions with non-native herbivores. Aldabran giant (Aldabrachelys gigantea) and Madagascan radiated (Astrochelys radiata) tortoises, taxonomically and functionally similar to the extinct Mauritian giant tortoises (Cylindraspis spp.), were introduced to Round Island, Mauritius, in 2007 to control the non-native plants that were threatening persistence of native species. We monitored the response of the plant community to tortoise grazing for 11 months in enclosures before the tortoises were released and, compared the cost of using tortoises as weeders with the cost of using manual labor. At the end of this period, plant biomass; vegetation height and cover; and adult, seedling, flower, and seed abundance were 3-136 times greater in adjacent control plots than in the tortoise enclosures. After their release, the free-roaming tortoises grazed on most non-native plants and significantly reduced vegetation cover, height, and seed production, reflecting findings from the enclosure study. The tortoises generally did not eat native species, although they consumed those native species that increased in abundance following the eradication of mammalian herbivores. Our results suggest that introduced non-native tortoises are a more cost-effective approach to control non-native vegetation than manual weeding. Numerous long-term outcomes (e.g., change in species composition and soil seed bank) are possible following tortoise releases. Monitoring and adaptive management are needed to ensure that the replacement herbivores promote the recovery of native plants. © 2013 Society for Conservation Biology.

Long-term deer exclusion has complex effects on a suburban forest understory

USGS Publications Warehouse

Faison, Edward K.; Foster, David R.; DeStefano, Stephen

2016-01-01

Herbivory by deer is one of the leading biotic disturbances on forest understories (i.e., herbs, small shrubs, and small tree seedlings). A large body of research has reported declines in height, abundance, and reproductive capacity of forbs and woody plants coupled with increases in abundance of graminoids, ferns, and exotic species due to deer herbivory. Less clear is the extent to which (and the direction in which) deer alter herbaceous layer diversity, where much of the plant diversity in a forest occurs. We examined the effect of 15 y of deer exclusion on the understory of a suburban hardwood forest in Connecticut exposed to decades of intensive herbivory by white-tailed deer (Odocoileus virginianus). We compared species richness (at subplot and plot scale), individual species and life form group abundance (% cover), and community composition between grazed and exclosure plots, as well as between mesic and wet soil blocks. Forb cover was more than twice as abundant in exclosure as in grazed plots, whereas sedge (Carex spp.) cover was 28 times more abundant, and exotic species cover generally higher in grazed than in exclosure plots. Native and exotic species richness were both higher in grazed than exclosure plots at the subplot scale, and native herbaceous richness was higher in grazed plots at both spatial scales. In contrast, native shrub richness increased with deer exclusion at the plot scale. Our results suggest that deer exclusion had contrasting effects on species richness, depending on plant life form, but that overall richness of both exotic and native plants declined with deer exclusion. In addition, site heterogeneity remained an important driver of vegetation dynamics even in the midst of high deer densities.

Persistence at distributional edges: Columbia spotted frog habitat in the arid Great Basin, USA

PubMed Central

Arkle, Robert S; Pilliod, David S

2015-01-01

A common challenge in the conservation of broadly distributed, yet imperiled species is understanding which factors facilitate persistence at distributional edges, locations where populations are often vulnerable to extirpation due to changes in climate, land use, or distributions of other species. For Columbia spotted frogs (Rana luteiventris) in the Great Basin (USA), a genetically distinct population segment of conservation concern, we approached this problem by examining (1) landscape-scale habitat availability and distribution, (2) water body-scale habitat associations, and (3) resource management-identified threats to persistence. We found that areas with perennial aquatic habitat and suitable climate are extremely limited in the southern portion of the species’ range. Within these suitable areas, native and non-native predators (trout and American bullfrogs [Lithobates catesbeianus]) are widespread and may further limit habitat availability in upper- and lower-elevation areas, respectively. At the water body scale, spotted frog occupancy was associated with deeper sites containing abundant emergent vegetation and nontrout fish species. Streams with American beaver (Castor canadensis) frequently had these structural characteristics and were significantly more likely to be occupied than ponds, lakes, streams without beaver, or streams with inactive beaver ponds, highlighting the importance of active manipulation of stream environments by beaver. Native and non-native trout reduced the likelihood of spotted frog occupancy, especially where emergent vegetation cover was sparse. Intensive livestock grazing, low aquatic connectivity, and ephemeral hydroperiods were also negatively associated with spotted frog occupancy. We conclude that persistence of this species at the arid end of its range has been largely facilitated by habitat stability (i.e., permanent hydroperiod), connectivity, predator-free refugia, and a commensalistic interaction with an ecosystem engineer. Beaver-induced changes to habitat quality, stability, and connectivity may increase spotted frog population resistance and resilience to seasonal drought, grazing, non-native predators, and climate change, factors which threaten local or regional persistence. PMID:26380699

Persistence at distributional edges: Columbia spotted frog habitat in the arid Great Basin, USA.

PubMed

Arkle, Robert S; Pilliod, David S

2015-09-01

A common challenge in the conservation of broadly distributed, yet imperiled species is understanding which factors facilitate persistence at distributional edges, locations where populations are often vulnerable to extirpation due to changes in climate, land use, or distributions of other species. For Columbia spotted frogs (Rana luteiventris) in the Great Basin (USA), a genetically distinct population segment of conservation concern, we approached this problem by examining (1) landscape-scale habitat availability and distribution, (2) water body-scale habitat associations, and (3) resource management-identified threats to persistence. We found that areas with perennial aquatic habitat and suitable climate are extremely limited in the southern portion of the species' range. Within these suitable areas, native and non-native predators (trout and American bullfrogs [Lithobates catesbeianus]) are widespread and may further limit habitat availability in upper- and lower-elevation areas, respectively. At the water body scale, spotted frog occupancy was associated with deeper sites containing abundant emergent vegetation and nontrout fish species. Streams with American beaver (Castor canadensis) frequently had these structural characteristics and were significantly more likely to be occupied than ponds, lakes, streams without beaver, or streams with inactive beaver ponds, highlighting the importance of active manipulation of stream environments by beaver. Native and non-native trout reduced the likelihood of spotted frog occupancy, especially where emergent vegetation cover was sparse. Intensive livestock grazing, low aquatic connectivity, and ephemeral hydroperiods were also negatively associated with spotted frog occupancy. We conclude that persistence of this species at the arid end of its range has been largely facilitated by habitat stability (i.e., permanent hydroperiod), connectivity, predator-free refugia, and a commensalistic interaction with an ecosystem engineer. Beaver-induced changes to habitat quality, stability, and connectivity may increase spotted frog population resistance and resilience to seasonal drought, grazing, non-native predators, and climate change, factors which threaten local or regional persistence.

Persistence at distributional edges: Columbia spotted frog habitat in the arid Great Basin, USA

USGS Publications Warehouse

Arkle, Robert S.; Pilliod, David S.

2015-01-01

A common challenge in the conservation of broadly distributed, yet imperiled species is understanding which factors facilitate persistence at distributional edges, locations where populations are often vulnerable to extirpation due to changes in climate, land use, or distributions of other species. For Columbia spotted frogs (Rana luteiventris) in the Great Basin (USA), a genetically distinct population segment of conservation concern, we approached this problem by examining (1) landscape-scale habitat availability and distribution, (2) water body-scale habitat associations, and (3) resource management-identified threats to persistence. We found that areas with perennial aquatic habitat and suitable climate are extremely limited in the southern portion of the species’ range. Within these suitable areas, native and non-native predators (trout and American bullfrogs [Lithobates catesbeianus]) are widespread and may further limit habitat availability in upper- and lower-elevation areas, respectively. At the water body scale, spotted frog occupancy was associated with deeper sites containing abundant emergent vegetation and nontrout fish species. Streams with American beaver (Castor canadensis) frequently had these structural characteristics and were significantly more likely to be occupied than ponds, lakes, streams without beaver, or streams with inactive beaver ponds, highlighting the importance of active manipulation of stream environments by beaver. Native and non-native trout reduced the likelihood of spotted frog occupancy, especially where emergent vegetation cover was sparse. Intensive livestock grazing, low aquatic connectivity, and ephemeral hydroperiods were also negatively associated with spotted frog occupancy. We conclude that persistence of this species at the arid end of its range has been largely facilitated by habitat stability (i.e., permanent hydroperiod), connectivity, predator-free refugia, and a commensalistic interaction with an ecosystem engineer. Beaver-induced changes to habitat quality, stability, and connectivity may increase spotted frog population resistance and resilience to seasonal drought, grazing, non-native predators, and climate change, factors which threaten local or regional persistence.

Interactions of Grazing History, Cattle Removal and Time since Rain Drive Divergent Short-Term Responses by Desert Biota

PubMed Central

Frank, Anke S. K.; Dickman, Chris R.; Wardle, Glenda M.; Greenville, Aaron C.

2013-01-01

Arid grasslands are used worldwide for grazing by domestic livestock, generating debate about how this pastoral enterprise may influence native desert biota. One approach to resolving this question is to experimentally reduce livestock numbers and measure the effects. However, a key challenge in doing this is that historical grazing impacts are likely to be cumulative and may therefore confound comparisons of the short-term responses of desert biota to changes in stocking levels. Arid areas are also subject to infrequent flooding rainfalls that drive productivity and dramatically alter abundances of flora and fauna. We took advantage of an opportunity to study the recent effects of a property-scale cattle removal on two properties with similarly varied grazing histories in central Australia. Following the removal of cattle in 2006 and before and after a significant rainfall event at the beginning of 2007, we sampled vegetation and small vertebrates on eight occasions until October 2008. Our results revealed significant interactions of time of survey with both grazing history and grazing removal for vascular plants, small mammals and reptiles. The mammals exhibited a three-way interaction of time, grazing history and grazing removal, thus highlighting the importance of careful sampling designs and timing for future monitoring. The strongest response to the cessation of grazing after two years was depressed reproductive output of plants in areas where cattle continued to graze. Our results confirm that neither vegetation nor small vertebrates necessarily respond immediately to the removal of livestock, but that rainfall events and cumulative grazing history are key determinants of floral and faunal performance in grassland landscapes with low and variable rainfall. We suggest that improved assessments could be made of the health of arid grazing environments if long-term monitoring were implemented to track the complex interactions that influence how native biota respond to grazing. PMID:23874635

A comparison of native tallgrass prairie and plains bluestem forage systems for cow-calf production in the southern great plains.

PubMed

Coleman, S W; Phillips, W A; Volesky, J D; Buchanan, D

2001-07-01

The objective of this study was to compare an introduced warm-season perennial grass (plains bluestem, Bothriochloa ischaemum) to native tallgrass prairie for cow-calf production. Three systems were used, two based on tallgrass prairie with two different forms of protein supplementation and one based on plains bluestem as the primary forage. The systems were as follows: 1) native tallgrass prairie with pelleted oilseed meal as the winter protein supplement (native-control); 2) native tallgrass prairie with limited access to wheat pasture as the winter protein supplement (native-wheat); and 3) plains bluestem with limited access to wheat pasture as the protein supplement (bluestem-wheat). Oilseed meal protein supplements were fed twice weekly. Cows grazing wheat pasture were allowed 6 h of grazing twice weekly. Ninety-nine cows per year were used over the 3-yr study. Cows were sired by either Charolais, Gelbvieh, Angus, or Hereford bulls out of commercial Angus-Hereford dams. Calves were sired by Simmental bulls. Calving and weaning rate increased over time but did not differ among systems or breed types. System did not influence the size or body condition score of cows or the performance of calves, but changes in the weight and condition scores of cows were greater on either native system than on the bluestem-wheat system. Cows from Charolais and Gelbvieh bulls were taller (P < 0.05), and heavier (P < 0.05), and weaned heavier (P < 0.05) calves than cows from Angus or Hereford bulls. The weight of cows on the bluestem-wheat system tended to decrease over time, whereas cows grazing on the native systems tended to gain weight over time. The native-control system was the most profitable system based on cow production. If excess hay produced from the bluestem-wheat system was sold as a cash crop, then this system was the most profitable. In general, we conclude that limit-grazing wheat pasture is a viable alternative to oilseed meal as protein supplement for wintering dry cows. Although the bluestem system had 2.5 times the carrying capacity of the native prairie systems, increased productivity was offset by increased production costs. All systems were equal on a cow basis for providing nutrients for the cow-calf production system.

Effects of Introduced Grasses, Grazing and Fire on Regional Biogeochemistry in Hawaii

NASA Astrophysics Data System (ADS)

Elmore, A. J.; Asner, G. P.

2003-12-01

African grasses introduced for grazing have expanded in geographic extent in mesic tropical systems of Hawaii and other regions of the world. Grassland expansion leads to increases in fire frequency, speeding woodland and forest destruction at greater geographic scales than occurs with grazing alone. At Pu'uwa'awa'a Ranch, Hawaii, restoration of the native woodland habitat has become a critical objective following the introduction and dominance of the African grass species Pennisetum clandestinum and P. setaceum. Grazing and grass-fueled fires have destroyed over 60% of the original forest. To stabilize these communities, managers must balance the combined effects of grazing and fire. Grazing reduces the recruitment success of native tropical trees, but grazing also reduces fire risk by moderating grass fuel conditions and restricting the extent and density of the most flammable grass species. Our study focuses on two questions: (1) What grazing intensity is necessary to change the fire conditions of a region given in situ soil and precipitation conditions? (2) Have long-term grazing conditions altered soil carbon and nitrogen stocks? We used high resolution imaging spectrometer data to measure photosynthetic and non-photosynthetic vegetation cover, analysis of soil carbon and nitrogen stocks, and measurements of plant community composition along gradients in grazing intensity. P. setaceum, the more flammable alien grass, was dominant where grazing intensity was low and at lower elevations where precipitation is low. The less flammable grass, P. clandestinum, occurred in regions of high grazing intensity and higher precipitation. Grazing influenced the dominance of P. setaceum and P. clandestinum only where precipitation and soil characteristics were suitable for both grasses to occur. At suitable sites, grazing reduced fire conditions through a species sift towards P. clandestinum. Soil carbon and nitrogen stocks decreased with grazing intensity, which was correlated with the fractional cover of P. setaceum. Soil carbon also increased with precipitation. These results show how grazing impacts fire conditions and soil chemistry through changes in species composition, and not through removal of carbon inputs (direct removal of biomass).

Irrigation to enhance native seed production for Great Basin restoration

Treesearch

Clinton C. Shock; Erik B. G. Feibert; Nancy L. Shaw; Myrtle P. Shock; Lamont D. Saunders

2015-01-01

Native shrublands and their associated grasses and forbs have been disappearing from the Great Basin as a result of grazing practices, exotic weed invasions, altered fire regimes, climate change and other human impacts. Native forb seed is needed to restore these areas. The irrigation requirements for maximum seed production of four key native forb species (Eriogonum...

Vegetation responses to natural regulation of elk in Rocky Mountain National Park

USGS Publications Warehouse

Zeigenfuss, Linda C.; Singer, Francis J.; Bowden, David

1999-01-01

Some grazing-induced responses were detected. Grazing-resistant species such as sedges (native), timothy (exotic), and club mosses increased and the amount of bare ground increased on some grazed sites. However, the changes within this sampling program alone were not alarming. The amount of bare ground increase was minor (4%), and grass and shrub cover increased in the shrub plots. The inferential power ofthis sample design was limited to the study plots only. Other factors (climate change, succession) were not controlled for using fenced plots and the sensitivity ofthe methods and plots to detect change were limited. For example, the low number oftransects in willow was not adequate to monitor conditions on the entire winter range. Lacking controls, observed changes may have been due to other factors (climate trends, beaver dam abandonment, stream channel changes), not elk herbivory alone. We recommend using a new sampling design that would include controls, pretreatment data, random site selection, and much more replication.

Thunder on the Yellowstone revisited: An assessment of management of native ungulates by natural regulation, 1968-1993

USGS Publications Warehouse

Singer, F.J.; Swift, D.M.; Coughenour, M.B.; Varley, J.D.

1998-01-01

Natural regulation of native ungulates was initiated in 1968 in Yellowstone National Park (YNP) based on the premise that ungulates would reach an equilibrium with their plant resources. The natural-regulation management model stated: density dependence will regulate ungulates (i.e., a dynamic equilibrium will result between ungulates and their food supply, within some bounds of vegetation and soil effects); and no retrogression of soil and vegetation will occur from elk (Cervus elaphus) grazing during this process. The historical record indicated that elk were abundant in the system and elk were primarily food limited before settlement by European man (i.e., wolves [Canis lupus] and Native Americans were only an adjunct to the density dependent population regulation of ungulates). Density dependence was demonstrated in elk, but not in bison (Bison bison). No widespread evidence of overgrazing was observed through 1993 in study sites within vegetation communities that comprised about 97% of the winter range. No evidence of increased exotics, increased sediment yield, warming or drying of the soil, changes in soil nutrients, or differences in aboveground standing-crop biomass of plants was found between grazed and ungrazed plots. Ungulate herbivory apparently stimulated aboveground production of grasses, enhanced nitrogen and macronutrients in grasses, increased nutrient cycling, and enhanced measures of fitness in 6 common plants. However, exposed soil surface (bare ground and pebbles combined) was 11-18% greater on grazed than ungrazed plots, apparently due to a 71% decline in dead and standing litter on grazed plots. Percent live-plant basal cover, however, did not differ on grazed versus ungrazed plots, and there was no difference in soil microclimate or sediment yield. Differences in the abundance of 12% of the herbaceous species were found in grazed versus ungrazed sites (16 of 128 species); 10 were declines and 6 were increases. Willow (Salix spp.) and aspen (Populus tremuloides) declines predated the new management policy, but their slow declines also continued after 1968. Three uncommon plant species (aspen, willow, and Wyoming big sagebrush [Artemisia tridentata tridentata]) and 1 herbivore (moose [Alces alces]) declined under natural-regulation management. Two uncommon species of woody browse (aspen, Wyoming big sagebrush) were overutilized by ungulates (consumption of >2/3 current annual growth occurred). We conclude the natural-regulation model for YNP was flawed in its assumptions of a single, steady state for the park, based on conditions presumed to exist in 1870 prior to establishment of the national park. The period selected as a standard (1870) was an unusual period characterized by frequent large fires and floods, common wolves, few elk, and a cooler, wetter climate. We also conclude there is a high level of uncertainty surrounding what elk densities were in pre-Columbian times (element 3 of the management model) and what effects wolves and Native Americans had in regulating the elk population.

Long-term lesser prairie-chicken nest ecology in response to grassland management

USGS Publications Warehouse

Fritts, Sarah R.; Grisham, Blake A.; Haukos, David A.; Boal, Clint W.; Patten, Michael; Wolfe, Don H.; Dixon, Charles; Cox, Robert D.; Heck, Willard R.

2016-01-01

Long-term population and range declines from habitat loss and fragmentation caused the lesser prairie-chicken (Tympanuchus pallidicinctus) to be a species of concern throughout its range. Current lesser prairie-chicken range in New Mexico and Texas is partially restricted to sand shinnery oak (Quercus havardii; hereafter shinnery oak) prairies, on which cattle grazing is the main socioeconomic driver for private landowners. Cattle producers within shinnery oak prairies often focus land management on shrub eradication using the herbicide tebuthiuron to promote grass production for forage; however, herbicide application alone, and in combination with grazing, may affect nest site selection and nest survival of lesser prairie-chickens through the reduction of shinnery oak and native grasses. We used a controlled, paired, completely randomized design study to assess the influence of grazing and tebuthiuron application and their combined use on nest site selection and nest survival from 2001 to 2010 in Roosevelt County, New Mexico, USA at 2 spatial scales (i.e., treatment and microhabitat) in 4 treatments: tebuthiuron with grazing, tebuthiuron without grazing, no tebuthiuron with grazing, and a control of no tebuthiuron and no grazing. Grazing treatment was a short-duration system in which plots were grazed once during the dormant season and once during the growing season. Stocking rate was calculated each season based on measured forage production and applied to remove ≤25% of available herbaceous material per season. At the treatment scale, we compared nest site selection among treatments using 1-way χ2 tests and nest survival among treatments using a priori candidate nest survival models in Program MARK. At the microhabitat scale, we identified important habitat predictors of nest site selection and nest survival using logistic regression and a priori candidate nest survival models in Program MARK, respectively. Females typically used treatments as expected and we did not detect trends in selection. Nest survival did not differ among treatments. At the microhabitat scale, nest sites had less bare ground (P = 0.001) and greater angles of obstruction (P ≤ 0.001) compared to random sites. There was a high degree of model selection uncertainty among our candidate models at the microhabitat scale and survival estimates were similar among habitat covariates. Results suggest a tebuthiuron application rate of 0.60 kg/ha, short-duration grazing, and a combination of these management techniques were not detrimental to lesser prairie-chicken nest site selection or nest survival. However, intensified management that increases bare ground or reduces overhead cover may negatively affect lesser prairie-chicken nesting habitat and nest survival.

Nocturnal and diurnal activity of armored suckermouth catfish (Loricariidae: Pterygoplichthys) associated with wintering Florida manatees (Trichechus manatus latirostris)

USGS Publications Warehouse

Nico, Leo G.

2010-01-01

Several Pterygoplichthys species, members of the Neotropical catfish family Loricariidae, have been widely introduced outside their native ranges. In this paper, I present observations on the diel activity pattern of non-native Pterygoplichthys, tentatively identified as P. disjunctivus, with respect to their attachment and grazing on endangered Florida manatees, Trichechus manatus latirostris. The study was conducted in December 2009 at Volusia Blue Spring, an artesianal spring system in the St. Johns River basin, Florida (USA). Supplemented by information gathered during previous visits to the spring site, this study revealed that adult Pterygoplichthys are active throughout the diel period (day, twilight and night). However, juvenile Pterygoplichthys were largely nocturnal and only at night did they consistently join adults in attaching to manatees. The juveniles generally remain hidden during the day, probably responding to presence of diurnal predators, mainly birds. Differences in diel behaviors among different Pterygoplichthys size classes in Florida are consistent with published observations on loricariids inhabiting clearwater streams within their native ranges.

Bison grazing ecology at the Rocky Mountain Arsenal National Wildlife Refuge, Colorado

USGS Publications Warehouse

Germaine, Stephen S.; Zeigenfuss, Linda C.; Schoenecker, Kathryn A.

2013-01-01

The Rocky Mountain Arsenal (RMA) National Wildlife Refuge reintroduced bison to a small pasture in 2007. Refuge managers needed information on the effects of bison grazing on vegetation communities in the bison pasture as well as information on how bison might affect other management priorities at RMA. In particular, RMA managers were interested in bison grazing effects on vegetation productivity, amount of vegetation utilization by bison, and habitat selection by bison to inform RMA herd managers and for potential expansion of bison range on the refuge. In 2007, U.S. Geological Survey (USGS) designed a study to investigate bison grazing effects through measurement of vegetation in the 600-hectare enclosure where the bison are currently pastured. This research was a collaborative effort between USGS and RMA refuge staff and had active field components in 2007 and 2010. We found that the effects and intensity of bison grazing on vegetation in the RMA bison pasture is linked to prairie dog presence. Where both species were present, they were removing a significant amount of biomass compared to areas where only bison were present. Also, prairie dogs appeared to enhance the greater production of native forbs, but we were not able to identify the mechanism for this increased production. We were not able, however, to generate an accurate vegetation map for the bison pasture, and this limited our ability to achieve the level of statistical precision necessary to identify grazing impacts and habitat selection of bison.

Multi-scale responses of vegetation to removal of horse grazing from Great Basin (USA) mountain ranges

USGS Publications Warehouse

Beever, E.A.; Tausch, R.J.; Thogmartin, W.E.

2008-01-01

Although free-roaming equids occur on all of the world's continents except Antarctica, very few studies (and none in the Great Basin, USA) have either investigated their grazing effects on vegetation at more than one spatial scale or compared characteristics of areas from which grazing has been removed to those of currently grazed areas. We compared characteristics of vegetation at 19 sites in nine mountain ranges of the western Great Basin; sites were either grazed by feral horses (Equus caballus) or had had horses removed for the last 10-14 years. We selected horse-occupied and horse-removed sites with similar aspect, slope, fire history, grazing pressure by cattle (minimal to none), and dominant vegetation (Artemisia tridentata). During 1997 and 1998, line-intercept transects randomly located within sites revealed that horse-removed sites exhibited 1.1-1.9 times greater shrub cover, 1.2-1.5 times greater total plant cover, 2-12 species greater plant species richness, and 1.9-2.9 times greater cover and 1.1-2.4 times greater frequency of native grasses than did horse-occupied sites. In contrast, sites with horses tended to have more grazing-resistant forbs and exotic plants. Direction and magnitude of landscape-scale results were corroborated by smaller-scale comparisons within horse-occupied sites of horse-trail transects and (randomly located) transects that characterized overall site conditions. Information-theoretic analyses that incorporated various subsets of abiotic variables suggested that presence of horses was generally a strong determinant of those vegetation-related variables that differed significantly between treatments, especially frequency and cover of grasses, but also species richness and shrub cover and frequency. In contrast, abiotic variables such as precipitation, site elevation, and soil erodibility best predicted characteristics such as forb cover, shrub frequency, and continuity of the shrub canopy. We found species richness of plants monotonically decreased across sites as grazing disturbance increased, suggesting that either the bell-shaped diversity-disturbance curve of the intermediate-disturbance hypothesis does not apply in this system or that most sites are already all on the greater-disturbance slope of the curve. In our study, numerous vegetation properties of less-grazed areas and sites differed notably from horse-grazed sites at local and landscape scales during a wetter and an average-precipitation year. ?? 2007 Springer Science+Business Media B.V.

Quantifying livestock effects on bunchgrass vegetation with Landsat ETM+ data across a single growing season

USDA-ARS?s Scientific Manuscript database

Working grassland systems provide important habitat for native biodiversity and forage for livestock, with proper livestock grazing playing an important role for sustainable ecosystem function. Traditional in-field techniques to monitor the effects of grazing on vegetation are costly and limited to ...

Early season grazing by cattle of waxy larkspur (Delphinium glaucescens) in Central Idaho

USDA-ARS?s Scientific Manuscript database

Toxic larkspurs (Delphinium spp.) in western North America are abundant native plants on foothill and mountain rangelands. Previous analysis for toxic alkaloids in waxy larkspur indicated that this plant was highly toxic. However, no information on cattle grazing of waxy larkspur was available. We c...

Glomalin and soil aggregation under six management systems in the Northern Great Plains, USA

USDA-ARS?s Scientific Manuscript database

The soil environment is linked to aboveground management including plant species composition, grazing intensity, lev-els of soil disturbance, residue management, and the length of time of a living plant is growing. Soil samples were col-lected under rangeland [native grass, rotational grazing (NGRG)...

Effects of fire and nitrogen addition on forage quality of Aristida purpurea

USDA-ARS?s Scientific Manuscript database

Purple threeawn (Aristida purpurea Nutt.) is a native perennial bunchgrass with limited forage value that dominates sites with disturbed soils and persists with continued severe grazing. Fire and nitrogen addition have been used to reduce threeawn and may increase grazing utilization of threeawn by...

Grazing effects on plant community succession of early- and mid-seral seeded grassland compared to shortgrass steppe

USGS Publications Warehouse

Milchunas, Daniel G.; Vandever, Mark W.

2013-01-01

Conclusions: Grazing effects on particular functional groups and species were not the same across seral stages, were mixed in terms of speeding or slowing succession, and were generally not large at the community level. Evolutionary history of grazing may serve as a general guide but decisions on whether to graze successional grasslands may best be made after assessing whether tolerant perennial short grass species are significant components. Monitoring may then be necessary to determine species responses in particular community matrixes and effects on subsequent immigration of non-seeded native perennial species.

77 FR 47660 - Attwater Prairie Chicken National Wildlife Refuge, Austin and Colorado Counties, TX; Final...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-09

...: Combination of planting Same as Alternative A; Same as Alternative B; Prairie Restoration. native grasses... production restoration. produce native grass on the Refuge; grazing seed to increase the bison only. number...

Rangeland mismanagement in South Africa: Failure to apply ecological knowledge

Treesearch

Andrew T. Hudak

1999-01-01

Chronic, heavy livestock grazing and concomitant fire suppression have caused the gradual replacement of palatable grass species by less palatable trees and woody shrubs in a rangeland degradation process termed bush encroachment in South Africa. Grazing policymakers and cattle farmers alike have not appreciated the ecological role fire and native browsers play in...

Shrub-steppe vegetation trend, Middle Fork Salmon River, Idaho

Treesearch

James M. Peek

2000-01-01

The Middle Fork Salmon River drainage of the Frank Church River-Of-No-Return Wilderness has a history of livetock grazing from 1890 to 1950, and changes in grazing pressure from native ungulates. High mule deer (Odocoileus hemionus) populations occurred between 1940 and 1960, and high elk (Cervus elaphus) populations occurred in...

Eddy covariance measurements of methane fluxes over grazed native and improved prairies in Oklahoma

USDA-ARS?s Scientific Manuscript database

Although several studies have reported eddy covariance (EC) measurements at several tallgrass prairie sites to investigate the dynamics of carbon and water vapor fluxes, the EC measurements of methane (CH4) fluxes over grazed tallgrass prairie sites are lacking. CH4 fluxes were measured during the 2...

A century of grazing: The value of long-term research

USDA-ARS?s Scientific Manuscript database

A century ago, a small group of scientists at Mandan, ND set out to answer a very practical question: how many acres of native prairie does it take to sustainably support a steer during the grazing season? Part of that original experiment continues today as one of the longest running experiments in ...

Changing restoration rules: exotic bivalves interact with residence time and depth to control phytoplankton productivity

USGS Publications Warehouse

Lucas, Lisa V.; Thompson, Janet K.

2012-01-01

Non-native species are a prevalent ecosystem stressor that can interact with other stressors to confound resource management and restoration. We examine how interactions between physical habitat attributes and a particular category of non-native species (invasive bivalves) influence primary production in aquatic ecosystems. Using mathematical models, we show how intuitive relationships between phytoplankton productivity and controllable physical factors (water depth, hydraulic transport time) that hold in the absence of bivalves can be complicated—and even reversed—by rapid bivalve grazing. In light-limited environments without bivalves, shallow, hydrodynamically “slow” habitats should generally have greater phytoplankton biomass and productivity than deeper, “faster” habitats. But shallower, slower environments can be less productive than deeper, faster ones if benthic grazing is strong. Moreover, shallower and slower waters exhibit a particularly broad range of possible productivity outcomes that can depend on whether bivalves are present. Since it is difficult to predict the response of non-native bivalves to habitat restoration, outcomes for new shallow, slow environments can be highly uncertain. Habitat depth and transport time should therefore not be used as indicators of phytoplankton biomass and production where bivalve colonization is possible. This study provides for ecosystem management a particular example of a broad lesson: abiotic ecosystem stressors should be managed with explicit consideration of interactions with other major (including biotic) stressors. We discuss the applicability and management implications of our models and results for a range of aquatic system types, with a case study focused on the Sacramento-San Joaquin Delta (California, USA). Simple mathematical models like those used here can illuminate interactions between ecosystem stressors and provide process-based guidance for resource managers as they develop strategies to augment valued populations, restore habitats, and manipulate ecosystem functions.

Exotic-Dominated Grasslands Show Signs of Recovery with Cattle Grazing and Fire.

PubMed

Delaney, John T; Moranz, Raymond A; Debinski, Diane M; Engle, David M; Miller, James R

2016-01-01

In grasslands, overgrazing by domestic livestock, fertilization, and introduction of exotic forage species leads to plant communities consisting of a mixture of native and exotic species. These degraded grasslands present a problem for land managers, farmers, and restoration ecologists concerned with improving biodiversity while continuing to use the land for livestock production. Here we assessed the response of butterfly and plant community composition to the use of fire and moderate grazing by domestic cattle on degraded grasslands dominated by exotic plants. We evaluated change by comparing experimental pastures to two reference sites that were grasslands dominated by native plants. We used two burning and grazing treatments: 1) patch-burn graze, a heterogeneously managed treatment, where one third of the pasture is burned each year and cattle have free access to the entire pasture, and 2) graze-and-burn, a homogenously managed treatment, where the entire pasture is grazed each year and burned in its entirety every three years. We tested for change in the butterfly and plant community composition over seven years using Bray-Curtis dissimilarity measures. Over the course of seven years, degraded pastures in both treatments became more similar to reference sites with respect to the butterfly and plant communities. Only two butterfly species and two plant functional guilds exhibited significant linear trends over time, with varying responses. Compositional changes in both the butterfly and plant communities indicate that the use of moderate grazing and fire may shift butterfly and plant communities of exotic-dominated grasslands to be more similar to reference tallgrass prairies over time.

The cost of feeding bred dairy heifers on native warm-season grasses and harvested feedstuffs.

PubMed

Lowe, J K; Boyer, C N; Griffith, A P; Waller, J C; Bates, G E; Keyser, P D; Larson, J A; Holcomb, E

2016-01-01

Heifer rearing is one of the largest production expenses for dairy cattle operations, which is one reason milking operations outsource heifer rearing to custom developers. The cost of harvested feedstuffs is a major expense in heifer rearing. A possible way to lower feed costs is to graze dairy heifers, but little research exists on this topic in the mid-south United States. The objectives of this research were to determine the cost of feeding bred dairy heifers grazing native warm-season grasses (NWSG), with and without legumes, and compare the cost of grazing with the cost of rearing heifers using 3 traditional rations. The 3 rations were corn silage with soybean meal, corn silage with dry distillers grain, and a wet distillers grain-based ration. Bred Holstein heifers between 15- and 20-mo-old continuously grazed switchgrass (SG), SG with red clover (SG+RC), a big bluestem and Indiangrass mixture (BBIG), and BBIG with red clover (BBIG+RC) in Tennessee during the summer months. Total grazing days were calculated for each NWSG to determine the average cost/animal per grazing day. The average daily gain (ADG) was calculated for each NWSG to develop 3 harvested feed rations that would result in the same ADG over the same number of grazing day as each NWSG treatment. The average cost/animal per grazing day was lowest for SG ($0.48/animal/grazing d) and highest for BBIG+RC ($1.10/animal/grazing d). For both BBIG and SG, legumes increased the average cost/animal per grazing day because grazing days did not increase enough to account for the additional cost of the legumes. No difference was observed in ADG for heifers grazing BBIG (0.85 kg/d) and BBIG+RC (0.94 kg/d), and no difference was observed in ADG for heifers grazing SG (0.71 kg/d) and SG+RC (0.70 kg/d). However, the ADG for heifers grazing SG and SG+RC was lower than the ADG for heifers grazing either BBIG or BBIG+RC. The average cost/animal per grazing day was lower for all NWSG treatments than the average cost/animal per day for all comparable feed rations at a low, average, and high yardage fee. Results of this study suggest that SG was the most cost-effective NWSG alternative to harvested feeds for bred dairy heifer rearing. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Dispersal limitation does not control high elevational distribution of alien plant species in the southern Sierra Nevada, California

USGS Publications Warehouse

Rundel, Philip W.; Keeley, Jon E.

2016-01-01

Patterns of elevational distribution of alien plant species in the southern Sierra Nevada of California were used to test the hypothesis that alien plant species invading high elevations around the world are typically climate generalists capable of growing across a wide elevational range. The Sierra Nevada has been heavily impacted for more than a century and a half, first by heavy grazing up into high elevation meadows, followed by major logging, and finally, by impacts associated with recreational use. The comparative elevational patterns of distribution and growth form were compared for native and alien plant species in the four families (Asteraceae, Brassicaceae, Fabaceae, and Poaceae) that contribute the majority of naturalized aliens in the study area. The distribution of realized climatic niche breadth, as measured by elevational range of occurrence, was virtually identical for alien and native species, with both groups showing a roughly Gaussian distribution peaking with species whose range covers a span of 1500–1999 m. In contrast to alien species, which only rarely occurred at higher elevations, native species showed a distribution of upper elevation limits peaking at 3000–3499 m, an elevation that corresponds to the zone of upper montane and subalpine forests. Consistent with a hypothesis of abiotic limitations, only a few alien species have been ecologically successful invaders at subalpine and alpine elevations above 2500 m. The low diversity of aliens able to become established in these habitats is unlikely due to dispersal limitations, given the long history of heavy grazing pressure at high elevations across this region. Instead, this low diversity is hypothesized to be a function of life history traits and multiple abiotic stresses that include extremes of cold air and soil temperature, heavy snowfall, short growing seasons, and low resource availability. These findings have significant implications for resource managers.

Cattle grazing in semiarid forestlands: Habitat selection during periods of drought

Treesearch

C. L. Roever; T. DelCurto; M. Rowland; M. Vavra; M. Wisdom

2015-01-01

Climate change models are predicting increased frequency and severity of droughts in arid and semiarid environments, and these areas are responsible for much of the world’s livestock production. Because cattle (Bos Taurus) grazing can impact the abundance, distribution, and ecological function of native plant and animal communities, it is important...

Vole-driven restoration of a parariparian meadow complex on the Colorado Plateau (south-central Utah)

Treesearch

Dennis M. Bramble; Jean C. Bramble

2008-01-01

Rapid and substantial reductions in the local density of invasive rubber rabbitbrush (Chrysothamnus nauseosus) have been achieved on a shrub-infested meadow complex solely by manipulating grazing so as to benefit the native meadow vole, Microtus montanus. The key adjustment has been a shift from spring-summer to late season grazing...

Effects of a blended garlic and cinnamon essential oil extract with and without monensin sodium on the performance of grazing steers

USDA-ARS?s Scientific Manuscript database

A series of stocker grazing experiments were conducted with the objective to determine the efficacy of supplementing growing calf diets with essential oils from garlic and cinnamon extracts (GCOE) in promoting growth on cool-season annuals in Arkansas (SWREC) and Oklahoma (SPRRS), or native rangelan...

Conversion of native terrestrial ecosystems in Hawai‘i to novel grazing systems: a review

USGS Publications Warehouse

Leopold, Christina R.; Hess, Steven C.

2017-01-01

The remote oceanic islands of Hawai‘i exemplify the transformative effects that non-native herbivorous mammals can bring to isolated terrestrial ecosystems. We reviewed published literature containing systematically collected, analyzed, and peer-reviewed original data specifically addressing direct effects of non-native hoofed mammals (ungulates) on terrestrial ecosystems, and indirect effects and interactions on ecosystem processes in Hawai‘i. The effects of ungulates on native vegetation and ecosystems were addressed in 58 original studies and mostly showed strong short-term regeneration of dominant native trees and understory ferns after ungulate removal, but unassisted recovery was dependent on the extent of previous degradation. Ungulates were associated with herbivory, bark-stripping, disturbance by hoof action, soil erosion, enhanced nutrient cycling from the interaction of herbivory and grasses, and increased pyrogenicity and competition between native plants and pasture grasses. No studies demonstrated that ungulates benefitted native ecosystems except in short-term fire-risk reduction. However, non-native plants became problematic and continued to proliferate after release from herbivory, including at least 11 species of non-native pasture grasses that had become established prior to ungulate removal. Competition from non-native grasses inhibited native species regeneration where degradation was extensive. These processes have created novel grazing systems which, in some cases, have irreversibly altered Hawaii’s terrestrial ecology. Non-native plant control and outplanting of rarer native species will be necessary for recovery where degradation has been extensive. Lack of unassisted recovery in some locations should not be construed as a reason to not attempt restoration of other ecosystems.

The ability of winter grazing to reduce wildfire size, intensity, and fire-induced plant mortality was not demonstrated: A comment on Davies et al. (2015)

EPA Science Inventory

A recent study by Davies et al. sought to test whether winter grazing could reduce wildfire size, fire behavior metrics, and fire-induced plant mortality in shrub-grasslands. The authors concluded that ungrazed rangelands may experience more fire-induced mortality of native peren...

The ability of winter grazing to reduce wildfire size, intensity, and fire-induced plant mortality was not demonstrated: a comment on Davies et al. (2015)

USDA-ARS?s Scientific Manuscript database

A recent study by Davies et al. sought to test whether winter grazing could reduce wildfire size, fire behavior and intensity metrics, and fire-induced plant mortality in shrub-grasslands. The authors concluded that ungrazed rangelands may experience fire-induced mortality of native perennial bunchg...

Cattle, deer, and elk grazing of the invasive plant sulfur cinquefoil

Treesearch

Catherine G. Parks; Bryan A. Endress; Martin Vavra; Michael L. McInnis; Bridgett J. Naylor

2008-01-01

The role of ungulates as contributors to establishment and spread of non-native invasive plants in natural areas is not well known. The objectives of this study were to document whether or not sulfur cinquefoil (Potentilia recta L.) is grazed by ungulates and to quantify the effects of ungulate herbivory on the density and demography of sulfur...

Western land managers will need all available tools for adapting to climate change, including grazing: A critique of Beschta et al

USDA-ARS?s Scientific Manuscript database

In a previous article, Beschta et al. (2013) argue that grazing by large ungulates (both native and domestic) should be eliminated or greatly reduced on western public lands to reduce potential climate change impacts. The authors were selective in their use of the scientific literature, and their p...

Restoring Native California Oaks on Grazed Rangelands

Treesearch

Douglas D. McCreary; Jerry Tecklin

2005-01-01

Efforts to regenerate oaks on California’s oak woodlands often must address how to establish seedlings in areas grazed by livestock. Research indicates that damage to young oak seedlings from cattle varies by season, with less damage during the winter when deciduous oaks do not have leaves. While exclusion of cattle from planted areas does result in reduced damage, the...

Some wood of Hawaii... properties and uses of 16 commercial species

Treesearch

Roger G. Skolmen

1974-01-01

Koa is Hawaii's finest native timber tree. Unfortunately, it grows best in areas that can be converted into good grazing land, and most of the best koa forests have been cleared to develop pasture. Consequently, not much koa is left. Koa seedlings are also palatable to grazing animals, so that the number of young, vigorous koa trees is small.

Butterfly responses to prairie restoration through fire and grazing

USGS Publications Warehouse

Vogel, Jennifer A.; Debinski, Diane M.; Koford, Rolf R.; Miller, J.R.

2007-01-01

The development of land for modern agriculture has resulted in losses of native prairie habitat. The small, isolated patches of prairie habitat that remain are threatened by fire suppression, overgrazing, and invasion by non-native species. We evaluated the effects of three restoration practices (grazing only, burning only, and burning and grazing) on the vegetation characteristics and butterfly communities of remnant prairies. Total butterfly abundance was highest on prairies that were managed with burning and grazing and lowest on those that were only burned. Butterfly species richness did not differ among any of the restoration practices. Butterfly species diversity was highest on sites that were only burned. Responses of individual butterfly species to restoration practices were highly variable. In the best predictive regression model, total butterfly abundance was negatively associated with the percent cover of bare ground and positively associated with the percent cover of forbs. Canonical correspondence analysis revealed that sites with burned only and grazed only practices could be separated based on their butterfly community composition. Butterfly communities in each of the three restoration practices are equally species rich but different practices yield compositionally different butterfly communities. Because of this variation in butterfly species responses to different restoration practices, there is no single practice that will benefit all species or even all species within habitat-specialist or habitat-generalist habitat guilds. ?? 2007 Elsevier Ltd. All rights reserved.

Using packrat middens to assess how grazing influences vegetation change in Glen Canyon National Recreation Area, Utah

USGS Publications Warehouse

Fisher, Jessica F.; Cole, Kenneth L.; Anderson, R. Scott

2006-01-01

The fossil and sub-fossil plant macrofossils and pollen grains found in packrat middens can serve as important proxies for climate and vegetation change in the arid Southwestern United States. A new application for packrat midden research is in understanding post-settlement vegetation changes caused by the grazing of domesticated animals. This work examines a series of 27 middens from Glen Canyon National Recreation Area (GLCA), spanning from 995 yr BP to the present, which detail vegetation during the periods just prior to, and following, the introduction of domesticated grazers. By comparing middens deposited before and after the start of grazing by domesticated sheep and cattle, the effect on the native plant communities through time can be determined. This analysis of change through time is augmented by measurements of change through space by contrasting contemporaneous middens from nearby similar grazed and ungrazed sites. These comparisons are only made possible by the presence of inaccessible ungrazed areas surrounded by steep cliffs. Multivariate ordinations of the plant assemblages from packrat middens demonstrated that even though all middens were selected from similar geologic substrates, soils, and vegetation type, their primary variability was site-to-site. This suggests that selecting comparable grazed versus ungrazed study treatments would be difficult, and that two similar sites several kilometers apart should not be assumed to have been the same prior to grazing without pre-grazing data. But, the changes through time on grazed areas, as well as the differences between grazed and ungrazed areas in the diversity of certain taxonomic groups, both suggest that grazing by domesticated ungulates has had a noticeable effect on the vegetation. The changes seen through time suggested that grazing lowered the number of taxa recorded and lessened the pre-existing differences within sites, homogenizing the resultant plant associations. Late Holocene pre-settlement middens, and modern middens from ungrazed areas, contained more native grasses, skunkbush sumac (Rhus trilobata), blackbrush (Coleogyne ramosissima), winterfat (Krascheninnikovia lanata), Utah serviceberry (Amelanchier utahensis), and roundleaf buffaloberry (Shepherdia rotundifolia) than modern middens from grazed areas. Pollen data supported the macrofossil data, recording decreases in pollen of the goosefoot family (Chenopodiaceae), grass family (Poaceae), and globemallow (Sphaeralcea spp.) from pre- to post-settlement.

Carbon and Water Vapor Fluxes of Different Ecosystems in Oklahoma

NASA Astrophysics Data System (ADS)

Wagle, P.; Gowda, P. H.; Northup, B. K.

2016-12-01

Information on exchange of energy, carbon dioxide (CO2), and water vapor (H2O) for major terrestrial ecosystems is vital to quantify carbon and water balances on a large-scale. It is also necessary to develop, test, and improve crop models and satellite-based production efficiency and evapotranspiration (ET) models, and to better understand the potential of terrestrial ecosystems to mitigate rising atmospheric CO2 concentration and climate change. A network (GRL-FLUXNET) of nine eddy flux towers has been established over a diverse range of terrestrial ecosystems, including native and improved perennial grasslands [unburned and grazed tallgrass prairie, burned and grazed tallgrass prairie, and burned Bermuda grass (Cynodon dactylon L.)], grazed and non-grazed winter wheat (Triticum aestivum L.), till and no-till winter wheat and canola (Brassica napus L.), alfalfa (Medicago sativa L.), and soybean (Glycine max L.), at the USDA-ARS, Grazinglands Research Laboratory, El Reno, OK. In this presentation, we quantify and compare net ecosystem CO2 exchange (NEE) and ET between recently burned and grazed tallgrass prairie and burned and non-grazed Bermuda grass pastures, alfalfa, and soybean. Preliminary results show monthly ensembles average NEE reached seasonal peak values of -29, -35, -25, and -20 µmol m-2 s-1 in burned tallgrass prairie pasture, burned Bermuda grass pasture, alfalfa, and soybean, respectively. Similarly, monthly ensembles average ET reached seasonal peak values of 0.22, 0.27, 0.25, 0.28 mm 30-min-1 in burned tallgrass prairie pasture, burned Bermuda grass pasture, alfalfa, and soybean, respectively. Seasonal patterns and daily magnitudes of NEE and ET and their responses to the similar climatic conditions will be further investigated.

Soil conditions moderate the effects of herbivores, but not mycorrhizae, on a native bunchgrass

NASA Astrophysics Data System (ADS)

Connolly, Brian M.; Orrock, John L.; Witter, Martha S.

2016-11-01

Herbivores, microbial mutualists, and soil nutrients can affect plant survival, growth, and reproduction, demographic parameters that are essential to plant restoration. In this study we ask: 1) whether native plants that form early associations with mycorrhizal fungi are more tolerant of mammalian grazers, and 2) how early plant associations with mycorrhizal fungi influence mammalian grazing across gradients in soil nutrients. In eight grassland sites in California (USA), we transplanted seedlings of a native bunchgrass, Stipa pulchra, that were or were not pretreated with mycorrhizal fungi in exclosures designed to exclude different guilds of vertebrate grazers. Pretreated plants had greater establishment eight months after transplantation than untreated plants. Mycorrhizal inoculation resulted in twofold greater biomass and fourfold greater seed production when plants were protected from herbivores; inoculation with mycorrhizae resulted in twofold greater biomass and seed production when plants were accessible by all herbivores. Soil phosphate and potassium concentrations influenced herbivory: vertebrate grazing had less effect on transplant biomass and seed production at sites with high phosphate - low potassium soils, but the effects of grazing were more severe in low phosphate - high potassium soils. Pretreatment with mycorrhizal fungi can result in greater survival, growth, and reproduction of transplanted seedlings of native bunchgrass S. pulchra. Our results also illustrate that soil conditions may influence the extent to which the vertebrate herbivore community limits restoration of S. pulchra: the effects of some small mammalian herbivores (e.g., voles) was little affected by soil conditions, but grazing by larger herbivores had a greater effect on S. pulchra performance at sites with low phosphate - high potassium soils. In helping identify the contribution of soil nutrients, herbivores, and mycorrhizae to establishment and performance, our work has implications for the restoration of a species that is likely a fundamental component of pristine California grassland ecosystems.

Comparison of Grazing Intensity & Diets of Native and Invasive Amphipods in Lake Erie

NASA Astrophysics Data System (ADS)

Duggan, J. P.; Francouer, S. N.

2005-05-01

Echinogammarus ischnus, an invasive amphipod originating from the Ponto Caspian Basin, was first discovered in the Detroit River in 1995 and has migrated through the lower Great Lakes displacing the native amphipod, Gammarus fasciatus. Both amphipods seek food and refuge by inhabiting substrata encrusted with zebra mussels and/or filamentous macro-algae. The filamentous green alga Cladophora, along with its epiphytic communities, are an important food source and refuge from predators and physical stresses. We examined the gut content of both amphipod species to determine their preferred food in their natural habitats, and conducted a laboratory experiment to determine each amphipod's grazing effects on algal biomass. Gut analysis was completed by taking grab samples from 4 study sites located along the western shore of Lake Erie every two weeks July through September, 2004. Amphipods were separated by species and preserved in 90% alcohol for later dissection. Algal taxa from amphipod guts were identified and enumerated using brightfield microscopy. In the lab experiment, algal biomass prior to and after two weeks of amphipod grazing was determined using ash-free dry mass and chlorophyll-a. Preliminary results indicate that E. ischnus and G. fasciatus exert approximately equal grazing pressure on the Great Lakes food web.

Use of ecological sites in managing wildlife and livestock: An example with prairie dogs

USDA-ARS?s Scientific Manuscript database

Prairie dogs are a native rodent found in the mixed grass prairie of the northern Great Plains. Prairie dogs can have an adverse impact on the amount of forages available for grazing livestock. In the Native American community, prairie dogs are often valued as a cultural resource and as an importan...

Herbivory and drought generate short-term stochasticity and long-term stability in a savanna understory community.

PubMed

Riginos, Corinna; Porensky, Lauren M; Veblen, Kari E; Young, Truman P

2018-03-01

Rainfall and herbivory are fundamental drivers of grassland plant dynamics, yet few studies have examined long-term interactions between these factors in an experimental setting. Understanding such interactions is important, as rainfall is becoming increasingly erratic and native wild herbivores are being replaced by livestock. Livestock grazing and episodic low rainfall are thought to interact, leading to greater community change than either factor alone. We examined patterns of change and stability in herbaceous community composition through four dry periods, or droughts, over 15 years of the Kenya Long-term Exclosure Experiment (KLEE), which consists of six different combinations of cattle, native wild herbivores (e.g., zebras, gazelles), and mega-herbivores (giraffes, elephants). We used principal response curves to analyze the trajectory of change in each herbivore treatment relative to a common initial community and asked how droughts contributed to community change in these treatments. We examined three measures of stability (resistance, variability, and turnover) that correspond to different temporal scales and found that each had a different response to grazing. Treatments that included both cattle and wild herbivores had higher resistance (less net change over 15 years) but were more variable on shorter time scales; in contrast, the more lightly grazed treatments (no herbivores or wild herbivores only) showed lower resistance due to the accumulation of consistent, linear, short-term change. Community change was greatest during and immediately after droughts in all herbivore treatments. But, while drought contributed to directional change in the less grazed treatments, it contributed to both higher variability and resistance in the more heavily grazed treatments. Much of the community change in lightly grazed treatments (especially after droughts) was due to substantial increases in cover of the palatable grass Brachiaria lachnantha. These results illustrate how herbivory and drought can act together to cause change in grassland communities at the moderate to low end of a grazing intensity continuum. Livestock grazing at a moderate intensity in a system with a long evolutionary history of grazing contributed to long-term stability. This runs counter to often-held assumptions that livestock grazing leads to directional, destabilizing shifts in grassland systems. © 2017 by the Ecological Society of America.

Vegetation changes over 12 years in ungrazed and grazed Conservation Reserve Program Grasslands in the central and southern plains

USGS Publications Warehouse

Cade, Brian S.; Vandever, Mark W.; Allen, Arthur W.; Terrell, James W.

2005-01-01

The Conservation Reserve Program (CRP) established under the 1985 Food Security Act has the fundamental objectives of jointly providing economic support to segments of the agricultural community and conservation of natural resources (Osborn, 1997; Heard and others, 2000). Although soil loss on highly erodable lands was the principal natural resource conservation issue addressed in the 1985 CRP, improving water quality and wildlife habitat both became important considerations as the program evolved (Farmer and others, 1988). For example, Best and others (1997) found that production of young birds on CRP fields in the Midwest was ≥15 times the production on row-crop fields because of improved habitat. The increasing importance of wildlife habitat is reflected in continuing refinement of the Environmental Benefits Index (EBI) used by the U.S. Department of Agriculture (USDA) to quantify the potential benefits of enrolling lands in CRP (Osborn, 1997; Ribaudo and others, 2001). The refinements reflect input furnished by federal, state, and non-government organizations seeking greater wildlife habitat quality on CRP lands (Roseberry and David, 1994; Hughes and others, 1995; Millenbah and others, 1996; Patterson and Best, 1996; Rodgers, 1999; Allen and others, 2001).Refinement in the EBI has changed the types of grasses planted on newly enrolled land. In early CRP signups (1 through 11), 71% of new grassland acres were planted to introduced grasses and legumes [Conservation Practice (CP) 1] while 29% of the acres were planted to native grasses (CP2) (Osborn and others, 1992). By the 27th signup in July 2004, over 34.8 million acres (14 million ha) were enrolled in the CRP. More than 73% of these lands were planted to various mixtures of introduced (CP1) or native (CP2) grasses for a minimal contract period of 10 years (USDA, 2004). Continuation of grass plantings under the 2002 Farm Bill may result in CRP lands furnishing grass dominated cover for 20 or more consecutive years. The species of grass established in seeded grasslands can have a major influence on the potential quality of wildlife habitat where vegetation is maintained over a multi-year period. Different species of grass may have comparable abilities to alleviate soil erosion but furnish dissimilar qualities of wildlife habitat (fig. 1). For example, smooth brome, an introduced cool-season grass (grass species and scientific names are presented in table 1), is highly valued for its erosion control and forage attributes (Casler and Carlson, 1995). Switchgrass, a native warm-season grass, also is valued for its soil and water conservation qualities (Moser and Vogel, 1995) but provides greater benefits for some species of wildlife (Clubine, 1995). The quality of nesting and winter cover for ring-necked pheasants (Phasianus colchicus) furnished by smooth brome on northeastern Colorado CRP lands is inferior to that provided by the taller, more robust switchgrass (Allen, 1994). Characteristics of the agricultural landscape surrounding individual CRP fields also play a role in the wildlife habitat potential of CRP plantings (Weber and others, 2002; Nusser and others, 2004). of native and seeded grasslands change in response to the presence (and absence) of physical disturbances such as fire, grazing, tillage, and haying (Hobbs and Huenneke, 1992; Millenbah and others, 1996; Allen and others, 2001; Renfrew and Ribic, 2001; Swengel and Swengel, 2001). The perpetuation of diversity in species composition and vegetation structure following disturbance sustains desirable habitat for a variety of grassland-dependent wildlife (Hall and Willig, 1994; Barnes and others, 1995; King and Savidge, 1995; Granfors and others, 1996; Herkert and others, 1996; Kurzejeski, 1996; Patterson and Best, 1996; Klute and others, 1997). Undisturbed grasslands have lower grass and forb species diversity, greater amounts of dead plant material, decreased as well as seasonally delayed productivity, and diminished structural diversity of vegetation (Peet and others, 1975; Rice and Parenti, 1978; Butler and Briske, 1988; Campa and Winterstein, 1992). Recommendations for the timing of disturbance to increase grass and forb species diversity range from 3 to 8 years following establishment of seeded grasslands in the northern Great Plains and Midwest (Duebbert and others, 1981; Higgens, 1987; Millenbah and others, 1996). The management interval, however, is affected by climatic conditions, soils, grass species, and management history of the individual stand. We quantified changes in vegetation structure and species composition across the typical 10-year contract period in undisturbed southern and central Great Plains CRP fields (fig. 2) planted to introduced and native grasses. In addition, we compared changes in vegetation in fields grazed during the emergency release of 1996 by comparing conditions prior to grazing and two and four years post grazing relative to changes in similar fields that were not grazed. Documentation of long-term changes in vegetation structure and composition for fields planted to common grass seed mixtures across a wide range of environmental conditions provides information to improve long-term wildlife habitat potential, guide program administration, and define management practices that yield economic benefits to operators while still meeting wildlife and conservation objectives. Emergency grazing provisions of the CRP are controversial. Although grazing can alter vegetative characteristics and reduce habitat quality in the short-term (Temple and others, 1999), periodic disturbance may be necessary to maintain habitat quality, and more information is needed assessing long-term effects of emergency grazing on vegetative structure and species composition. 

Market access and community size influence pastoral management of native and exotic livestock species: A case study in communities of the Cordillera Real in Bolivia's high Andean wetlands.

PubMed

Struelens, Quentin; Gonzales Pomar, Karina; Loza Herrera, Susi; Nina Huanca, Gaby; Dangles, Olivier; Rebaudo, François

2017-01-01

Grazing areas management is of utmost importance in the Andean region. In the valleys of the Bolivian Cordillera Real near La Paz, pastoralism constitutes the traditional way for people to insure food security and economical sustainability. In these harsh mountains, unique and productive wetlands sustained by glacial water streams are of utmost importance for feeding cattle herds during the dry season. After the colonization by the Spanish, a shift in livestock species has been observed, with the introduction of exotic species such as cows and sheep, resulting in a different impact on pastures compared to native camelid species-llamas and alpacas. Here we explored some of the social-economical and environmental drivers that motivate Bolivian pastoralists to prefer exotic over native livestock species, based on 36 household surveys in the Cordillera Real. We constructed a Partial Least Squares Structural Equation Model in order to assess the relationships between these drivers. Our results suggest that the access to market influenced pastoralists to reshape their herd composition, by increasing the number of sheep. They also suggest that community size increased daily grazing time in pastures, therefore intensifying the grazing pressure. At a broader scale, this study highlights the effects of some social-economical and environmental drivers on mountain herding systems.

Market access and community size influence pastoral management of native and exotic livestock species: A case study in communities of the Cordillera Real in Bolivia's high Andean wetlands

PubMed Central

Struelens, Quentin; Gonzales Pomar, Karina; Loza Herrera, Susi; Nina Huanca, Gaby; Dangles, Olivier

2017-01-01

Grazing areas management is of utmost importance in the Andean region. In the valleys of the Bolivian Cordillera Real near La Paz, pastoralism constitutes the traditional way for people to insure food security and economical sustainability. In these harsh mountains, unique and productive wetlands sustained by glacial water streams are of utmost importance for feeding cattle herds during the dry season. After the colonization by the Spanish, a shift in livestock species has been observed, with the introduction of exotic species such as cows and sheep, resulting in a different impact on pastures compared to native camelid species—llamas and alpacas. Here we explored some of the social-economical and environmental drivers that motivate Bolivian pastoralists to prefer exotic over native livestock species, based on 36 household surveys in the Cordillera Real. We constructed a Partial Least Squares Structural Equation Model in order to assess the relationships between these drivers. Our results suggest that the access to market influenced pastoralists to reshape their herd composition, by increasing the number of sheep. They also suggest that community size increased daily grazing time in pastures, therefore intensifying the grazing pressure. At a broader scale, this study highlights the effects of some social-economical and environmental drivers on mountain herding systems. PMID:29228062

Grassland birds: An overview of threats and recommended management strategies

USGS Publications Warehouse

Vickery, P.D.; Herkert, J.R.; Knopf, F.L.; Ruth, J.; Keller, C.E.; Bonney, Rick; Pashley, David N.; Cooper, Robert; Niles, Larry

2000-01-01

Grassland ecosystems are dependent on periodic disturbance for habitat maintenance. Historically, grazing by native herbivores and prairie fires were the agents principally responsible for maintaining grassland areas. However, elimination of native herbivores, wide-spread fire suppression, and conversion for agriculture have greatly altered grasslands in the United States and Canada. Because of these landscape changes, many grassland birds are increasingly dependent on land managers for habitat creation, maintenance, and health. Grazing, prescribed burning, and mowing/haying are the most frequently used, and versatile, grassland management techniques. Grassland birds prefer a wide range of grass heights and densities, with some species preferring short sparse vegetation, and others preferring taller, more dense vegetation. Due to differences in species habitat preferences and regional differences in soils and floristics, the responses of individual grassland species to specific grassland management practices can be variable and often are regionally dependent. As a result, management of grassland areas is best directed toward the creation of a mosaic of grassland habitat types. This habitat mosaic is probably best maintained through some type of rotational management system in which sections of large grassland areas receive management on a regular schedule. Such a rotational system would provide a variety of habitat types in every year, would ensure the availability of suitable habitat for birds at either end of the grassland management spectrum, and also would provide habitat for birds whose preferences lie between these extremes.

76 FR 10299 - Endangered and Threatened Wildlife and Plants: 90-Day Finding on a Petition To List the Wild...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-24

... conversion, woody plant invasion, and cattle grazing have altered native grasslands (Ricketts et al. 2008, pp... rapid recovery of these degraded grasslands (Ricketts et al. 2008, p. 288). Boyd (2003, pp. 95, 148-151... (Olson 1997, p. 4; Ricketts et al. 2008, p. 275). Native American Tribes also have large tracts of...

Effect of cultural treatments on regeneration of native woodlands on the Northern Great Plains

Treesearch

Daniel W. Uresk; Charles E. Boldt

1986-01-01

Two cultural treatments were evaluated over a 6-year post-treatment period to determine their effect on regeneration of native woodlands in southwestern North Dakota. Cultural treatments included livestock exclusion and the combination of felling and removal of low-vigor trees and transplanting of woody plants. Shrub density varied by species when grazed and ungrazed...

Livestock grazing not detrimental to meadow wildflowers

Treesearch

Raymond D. Ratliff

1972-01-01

Wildflower growth, meadow conditions, and grazing methods were compared in the Bogard area, Lassen National Forest, northeastern California. The two grazing methods were rest-rotation, in which range units are periodically rested from grazing, and free-choice, in which range units are not provided any rest periods from use. The results suggest that grazing per se need...

43 CFR 2610.0-5 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

.... Lands which produce native grasses sufficient in quantity, if ungrazed by grazing animals, to make an... which a profitable crop may be harvested. (h) Reclamation means the establishment of works for...

Dining local: the microbial diet of a snail that grazes microbial communities is geographically structured.

PubMed

O'Rorke, Richard; Cobian, Gerald M; Holland, Brenden S; Price, Melissa R; Costello, Vincent; Amend, Anthony S

2015-05-01

Achatinella mustelina is a critically endangered tree snail that subsists entirely by grazing microbes from leaf surfaces of native trees. Little is known about the fundamental aspects of these microbe assemblages: not taxonomic composition, how this varies with host plant or location, nor whether snails selectively consume microbes. To address these questions, we collected 102 snail faecal samples as a proxy for diet, and 102 matched-leaf samples from four locations. We used Illumina amplicon sequencing to determine bacterial and fungal community composition. Microbial community structure was significantly distinct between snail faeces and leaf samples, but the same microbes occurred in both. We conclude that snails are not 'picky' eaters at the microbial level, but graze the surface of whatever plant they are on. In a second experiment, the gut was dissected from non-endangered native tree snails in the same family as Achatinella to confirm that faecal samples reflect gut contents. Over 60% of fungal reads were shared between faeces, gut and leaf samples. Overall, location, sample type (faeces or leaf) and host plant identity all significantly explained the community composition and variation among samples. Understanding the microbial ecology of microbes grazed by tree snails enables effective management when conservation requires captive breeding or field relocation. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

Species-environment interactions changed by introduced herbivores in an oceanic high-mountain ecosystem.

PubMed

Seguí, Jaume; López-Darias, Marta; Pérez, Antonio J; Nogales, Manuel; Traveset, Anna

2017-01-05

Summit areas of oceanic islands constitute some of the most isolated ecosystems on earth, highly vulnerable to climate change and introduced species. Within the unique high-elevation communities of Tenerife (Canary Islands), reproductive success and thus long-term survival of species may depend on environmental suitability as well as threat by introduced herbivores. By experimentally modifying the endemic and vulnerable species Viola cheiranthifolia along its entire altitudinal occurrence range, we studied plant performance, autofertility, pollen limitation and visitation rate and the interactive effect of grazing by non-native rabbits on them. We assessed the grazing effects by recording (1) the proportion of consumed plants and flowers along the gradient, (2) comparing fitness traits of herbivore-excluded plants along the gradient, and (3) comparing fitness traits, autofertility and pollen limitation between plants excluded from herbivores with unexcluded plants at the same locality. Our results showed that V. cheiranthifolia performance is mainly affected by inter-annual and microhabitat variability along the gradient, especially in the lowest edge. Despite the increasingly adverse environmental conditions, the plant showed no pollen limitation with elevation, which is attributed to the increase in autofertility levels (≥ 50% of reproductive output) and decrease in competition for pollinators at higher elevations. Plant fitness is, however, extremely reduced owing to the presence of non-native rabbits in the area (consuming more than 75% of the individuals in some localities), which in turn change plant trait-environment interactions along the gradient. Taken together, these findings indicate that the elevational variation found on plant performance results from the combined action of non-native rabbits with the microhabitat variability, exerting intricate ecological influences that threaten the survival of this violet species. Published by Oxford University Press on behalf of the Annals of Botany Company.

Effect of yearling steer sequence grazing of perennial and annual forages in an integrated crop and livestock system on grazing performance, delayed feedlot entry, finishing performance, carcass measurements, and systems economics.

PubMed

Sentürklü, Songul; Landblom, Douglas G; Maddock, Robert; Petry, Tim; Wachenheim, Cheryl J; Paisley, Steve I

2018-06-04

In a 2-yr study, spring-born yearling steers (n = 144), previously grown to gain <0.454 kg·steer-1·d-1, following weaning in the fall, were stratified by BW and randomly assigned to three retained ownership rearing systems (three replications) in early May. Systems were 1) feedlot (FLT), 2) steers that grazed perennial crested wheatgrass (CWG) and native range (NR) before FLT entry (PST), and 3) steers that grazed perennial CWG and NR, and then field pea-barley (PBLY) mix and unharvested corn (UC) before FLT entry (ANN). The PST and ANN steers grazed 181 d before FLT entry. During grazing, ADG of ANN steers (1.01 ± SE kg/d) and PST steers (0.77 ± SE kg/d) did not differ (P = 0.31). But even though grazing cost per steer was greater (P = 0.002) for ANN vs. PST, grazing cost per kg of gain did not differ (P = 0.82). The ANN forage treatment improved LM area (P = 0.03) and percent i.m. fat (P = 0.001). The length of the finishing period was greatest (P < 0.001) for FLT (142 d), intermediate for PST (91 d), and least for ANN (66 d). Steer starting (P = 0.015) and ending finishing BW (P = 0.022) of ANN and PST were greater than FLT steers. Total FLT BW gain was greater for FLT steers (P = 0.017), but there were no treatment differences for ADG, (P = 0.16), DMI (P = 0.21), G: F (P = 0.82), and feed cost per kg of gain (P = 0.61). However, feed cost per steer was greatest for FLT ($578.30), least for ANN ($276.12), and intermediate for PST ($381.18) (P = 0.043). There was a tendency for FLT steer HCW to be less than ANN and PST, which did not differ (P = 0.076). There was no difference between treatments for LM area (P = 0.094), backfat depth (P = 0.28), marbling score (P = 0.18), USDA yield grade (P = 0.44), and quality grade (P = 0.47). Grazing steer net return ranged from an ANN system high of $9.09/steer to a FLT control system net loss of -$298 and a PST system that was slightly less than the ANN system (-$30.10). Ten-year (2003 to 2012) hedging and net return sensitivity analysis revealed that the FLT treatment underperformed 7 of 10 yr and futures hedging protection against catastrophic losses were profitable 40, 30, and 20% of the time period for ANN, PST, and FLT, respectively. Retained ownership from birth through slaughter coupled with delayed FLT entry grazing perennial and annual forages has the greatest profitability potential.

Population trends of forest birds at Hakalau Forest National Wildlife Refuge, Hawai'i

USGS Publications Warehouse

Camp, Richard J.; Pratt, Thane K.; Gorresen, P. Marcos; Jeffrey, John J.; Woodworth, Bethany L.

2010-01-01

The Hakalau Forest National Wildlife Refuge was established to protect native Hawaiian forest birds, particularly endangered species. Management for forest restoration on the refuge has consisted mainly of removing feral ungulates, controlling invasive alien plants, and reforesting former pastures. To assess effects of this habitat improvement for forest birds, we estimated density annually by distance sampling and examined population trends for native and alien passerines over the 21 years since the refuge was established. We examined long-term trends and recent short-term trajectories in three study areas: (1) reforested pastureland, (2) heavily grazed open forest that was recovering, and (3) lightly grazed closed forest that was relatively intact. Three species of native birds and two species of alien birds had colonized the reforested pasture and were increasing. In the open forest, densities of all eight native species were either stable or increasing. Long-term trends for alien birds were also generally stable or increasing. Worryingly, however, during the most recent 9 years, in the open forest trajectories of native species were decreasing or inconclusive, but in the reforested pasture they generally increased. The closed forest was surveyed in only the most recent 9 years, and trajectories of native species there were mixed. Overall, long-term population trends in Hakalau are stable or increasing, contrasting with declines in most other areas of Hawai'i over the same period. However, more recent mixed results may indicate emergent problems for this important bird area.

Multi-decadal impacts of grazing on soil physical and biogeochemical properties in southeast Utah

USGS Publications Warehouse

Neff, J.C.; Reynolds, R.L.; Belnap, J.; Lamothe, P.

2005-01-01

Many soils in southeastern Utah are protected from surface disturbance by biological soil crusts that stabilize soils and reduce erosion by wind and water. When these crusts are disturbed by land use, soils become susceptible to erosion. In this study, we compare a never-grazed grassland in Canyonlands National Park with two historically grazed sites with similar geologic, geomorphic, and geochemical characteristics that were grazed from the late 1800s until 1974. We show that, despite almost 30 years without livestock grazing, surface soils in the historically grazed sites have 38-43% less silt, as well as 14-51% less total elemental soil Mg, Na, P, and Mn content relative to soils never exposed to livestock disturbances. Using magnetic measurement of soil magnetite content (a proxy for the stabilization of far-traveled eolian dust) we suggest that the differences in Mg, Na, P, and Mn are related to wind erosion of soil fine particles after the historical disturbance by livestock grazing. Historical grazing may also lead to changes in soil organic matter content including declines of 60-70% in surface soil C and N relative to the never-grazed sites. Collectively, the differences in soil C and N content and the evidence for substantial rock-derived nutrient loss to wind erosion implies that livestock grazing could have long-lasting effects on the soil fertility of native grasslands in this part of southeastern Utah. This study suggests that nutrient loss due to wind erosion of soils should be a consideration for management decisions related to the long-term sustainability of grazing operations in arid environments.

Non-grazing and gophers lower bulk density and acidity in annual-plant soil

Treesearch

Raymond D. Ratliff; Stanley E. Westfall

1971-01-01

The effects of non-grazing on Ahwahnee coarse sandy loam were studied at the San Joaquin Experimental Range in central California. An exclosure, on which there had been no livestock grazing for 34 years, had a lower surface bulk density and lower acidity than an adjacent range that had been grazed. Bulk density averaged 1.08 gm./cc. on the ungrazed range, and 1.43 gm./...

25 CFR 700.725 - Livestock trespass.

Code of Federal Regulations, 2010 CFR

2010-04-01

... according to the range unit Range Management Plan. (c) The grazing of livestock upon any land withdrawn from... approved by the Commissioner. (e) Grazing of livestock whose brand is not recorded in the range unit Range Management Plan. The owner of any livestock grazing in trespass on the New Lands is liable to a civil penalty...

Effects of livestock exclusion on density, survival and biomass of the perennial sagebrush grass Hymenachne pernambucense (Poaceae) from a temperate fluvial wetland

NASA Astrophysics Data System (ADS)

Magnano, Andrea L.; Nanni, Analía S.; Krug, Pamela; Astrada, Elizabeth; Vicari, Ricardo; Quintana, Rubén D.

2018-01-01

In Argentina, the intensification of soybean production has displaced a substantial proportion of cattle ranching to fluvial wetlands such as those in the Delta of the Paraná River. Cattle grazing affects structure and dynamics of native forage plants but there is little information on this impact in populations from fluvial wetlands. This study addresses the effect of cattle ranching on density, survival, mean life-span and aerial biomass of Hymenachne pernambucense (Poaceae), an important forage species in the region. The study was carried out monthly for one year in permanents plots subject to continuous grazing and plots excluded from grazing in the Middle Delta of the Paraná River. In plots excluded from grazing, tillers showed significantly higher population density and survival, and a two-fold increase in mean life-span, while continuous grazing decreased survival of cohorts. The largest contribution to tiller density in ungrazed and grazed populations was made by spring and summer cohorts, respectively. Total and green biomass were significantly higher in the ungrazed population, with highest differences in late spring-early summer. Cattle grazing affected the relationship between tiller density and green biomass suggesting that cattle prefer sprouts because they are more palatable and nutritious than older tissue.

Effect of Mixed Systems on Crop Productivity

NASA Astrophysics Data System (ADS)

Senturklu, Songul; Landblom, Douglas; Cihacek, Larry; Brevik, Eric

2017-04-01

The goals of this non-irrigated research has been to determine the effect of mixed systems integration on crop, soil, and beef cattle production in the northern Great Plains region of the United States. Over a 5-year period, growing spring wheat (HRSW-C) continuously year after year was compared to a 5-year crop rotation that included spring wheat (HRSW-R), cover crop (dual crop consisting of winter triticale/hairy vetch seeded in the fall and harvested for hay followed by a 7-species cover crop that was seeded in June after hay harvest), forage corn, field pea/barley, and sunflower. Control 5-year HRSW yield was 2690 kg/ha compared to 2757 kg/ha for HRSW grown in rotation. Available soil nitrogen (N) is often the most important limitation for crop production. Expensive fertilizer inputs were reduced in this study due to the mixed system's complementarity in which the rotation system that included beef cattle grazing sustained N availability and increased nutrient cycling, which had a positive effect on all crops grown in the rotation. Growing HRSW continuously requires less intensive management and in this research was 14.5% less profitable. Whereas, when crop management increased and complementing crops were grown in rotation to produce crops and provide feed for grazing livestock, soil nutrient cycling improved. Increased nutrient cycling increased crop rotation yields and yearling beef cattle steers that grazing annual forages in the rotation gain more body weight than similar steers grazing NGP native range. Results of this long-term research will be presented in a PICO format for participant discussion.

36 CFR 222.53 - Grazing fees in the East-noncompetitive procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... current period's hay price index, less the value of any agency required range improvements. (ii) Grazing Fee Credits for Range Improvements. Any requirements for permittee construction or development of range improvements shall be identified through an agreement and incorporated into the grazing permit...

Teasing Apart the Effects of Atmospheric Nitrogen Deposition from Grazing and Drought in Vernal Pool Wetlands and Adjacent Grassland

NASA Astrophysics Data System (ADS)

Fogel, M. L.; Araiza, D. N.; Nakamoto, B. J.; Vega, M. C.; Bradley, C. J.; Swarth, C. W.

2014-12-01

The remaining vernal pools flanking California's Central Valley may be protected from development, but they are not pristine environments. At UC Merced's Vernal Pools and Grassland Reserve, dairy cattle grazing is a fact of life, needed to keep non-native grasses from encroaching on and dominating these low lying, ephemeral pools. In addition to grazing, atmospheric deposition of nitrogen from adjacent agricultural farms and dairies has affected the biogeochemical cycling here, in particular because the area has never been ploughed and is essentially a terminal, interior catchment with almost no outputs. For the past two years, the region has been subjected to extreme drought resulting in altered patterns in vernal pool development and nutrient exchange. We are using stable nitrogen, carbon, and hydrogen isotopes in organic and inorganic reservoirs to understand which of the three stressors (e.g. N loading, grazing, or drought) affects the ecosystem functioning the most. Simple measurements of residual dry matter (the rancher's standard) coupled with soil analyses and plant distribution, isotopic composition, and productivity will be presented at a landscape scale. Atmospheric deposition, as rain in winter and early spring and as dust in summer and fall, delivers substantial ammonium and nitrate to the Reserve and could be traced back to nearby hotspots, as well as from major storm systems. Concentrations and compositions of N in precipitation were highly variable depending on when the last storm event had occurred. Ammonia/ammonium in rainwater ranged from δ15N= -24 to +7‰, probably explaining the large range in the δ15N of plant tissues collected in winter/spring (-4.3 to +10.9‰,) and that of extractable ammonium from surface soils (δ15N = -7 to +13‰). Interior grassland and vernal pool ecosystems, with substantial inputs and little to no outputs, host biogeochemical processes that amplify heterogeneity on relative small scales.

Preserving prairies: Understanding temporal and spatial patterns of invasive annual bromes in the Northern Great Plains

USGS Publications Warehouse

Ashton, Isabel; Symstad, Amy J.; Davis, Christopher; Swanson, Daniel J.

2016-01-01

Two Eurasian invasive annual brome grasses, cheatgrass (Bromus tectorum) and Japanese brome (Bromus japonicus), are well known for their impact in steppe ecosystems of the western United States where these grasses have altered fire regimes, reduced native plant diversity and abundance, and degraded wildlife habitat. Annual bromes are also abundant in the grasslands of the Northern Great Plains (NGP), but their impact and ecology are not as well studied. It is unclear whether the lessons learned from the steppe will translate to the mixed-grass prairie where native plant species are adapted to frequent fires and grazing. Developing a successful annual brome management strategy for National Park Service units and other NGP grasslands requires better understanding of (1) the impact of annual bromes on grassland condition; (2) the dynamics of these species through space and time; and (3) the relative importance of environmental factors within and outside managers' control for these spatiotemporal dynamics. Here, we use vegetation monitoring data collected from 1998 to 2015 in 295 sites to relate spatiotemporal variability of annual brome grasses to grassland composition, weather, physical environmental characteristics, and ecological processes (grazing and fire). Concern about the impact of these species in NGP grasslands is warranted, as we found a decline in native species richness with increasing annual brome cover. Annual brome cover generally increased over the time of monitoring but also displayed a 3- to 5-yr cycle of reduction and resurgence. Relative cover of annual bromes in the monitored areas was best predicted by park unit, weather, extant plant community, slope grade, soil composition, and fire history. We found no evidence that grazing reduced annual brome cover, but this may be due to the relatively low grazing pressure in our study. By understanding the consequences and patterns of annual brome invasion, we will be better able to preserve and restore these grassland landscapes for future generations.

Heifer body weight gain and reproductive achievement in response to protein and energy supplementation while grazing dormant range forage

USDA-ARS?s Scientific Manuscript database

Heifers grazing winter range require supplemental nutrients to compliment dormant forage to achieve optimal growth and performance. A study was conducted to evaluate nutritional environment and effect of different supplementation strategies for developing heifers grazing dormant winter range. Eigh...

75 FR 38539 - Notice of Availability of Final Supplemental Environmental Impact Statement Updating Cumulative...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-02

... impacts to air quality, minerals, Native American and cultural resources, water, vegetation, grazing..., including construction of five shafts to access the ore bodies, shaft hoists, a waste rock disposal facility...

Chemical Composition, In vitro Gas Production, Ruminal Fermentation and Degradation Patterns of Diets by Grazing Steers in Native Range of North Mexico

PubMed Central

Murillo, M.; Herrera, E.; Carrete, F. O.; Ruiz, O.; Serrato, J. S.

2012-01-01

The objective of the study was to quantify annual and seasonal differences in the chemical composition, in vitro gas production, in situ degradability and ruminal fermentation of grazing steers’ diets. Diet samples were collected with four esophageal cannulated steers (350±3 kg BW); and four ruminally cannulated heifers (342±1.5 kg BW) were used to study the dry matter degradation and fermentation in rumen. Data were analyzed with repeated measurements split plot design. The crude protein, in vitro dry matter digestibility and metabolizable energy were higher during the first year of trial and in the summer (p<0.01). The values of calcium, phosphorus, magnesium, zinc and copper were higher in summer (p<0.05). The gas produced by the soluble and insoluble fractions, as well as the constant rate of gas production were greater in summer and fall (p<0.01). The ammonia nitrogen (NH3N) and total volatile fatty acids concentrations in rumen, the soluble and degradable fractions, the constant rate of degradation and the effective degradability of DM and NDF were affected by year (p<0.05) and season (p<0.01). Our study provides new and useful knowledge for the formulation of protein, energetic and mineral supplements that grazing cattle need to improve their productive and reproductive performance. PMID:25049495

43 CFR 4130.5 - Free-use grazing permits.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Free-use grazing permits. 4130.5 Section... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.5 Free-use grazing permits. (a) A free-use grazing permit shall be issued to...

43 CFR 4130.5 - Free-use grazing permits.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Free-use grazing permits. 4130.5 Section... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.5 Free-use grazing permits. (a) A free-use grazing permit shall be issued to...

43 CFR 4130.5 - Free-use grazing permits.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Free-use grazing permits. 4130.5 Section... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.5 Free-use grazing permits. (a) A free-use grazing permit shall be issued to...

43 CFR 4130.5 - Free-use grazing permits.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Free-use grazing permits. 4130.5 Section... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.5 Free-use grazing permits. (a) A free-use grazing permit shall be issued to...

Perennial grass establishment following cheatgrass control using herbicides

USDA-ARS?s Scientific Manuscript database

The introduction and subsequent invasion of Cheatgrass (Bromus tectorum) onto Intermountain rangelands has resulted in increased frequencies of wildfires and severely altered native plant communities. These destructive wildfires have negatively impacted wildlife and grazing resources as well as har...

Imazapic, rimsulfuron, and sulfometuron methyl effectiveness at controlling cheatgrass

USDA-ARS?s Scientific Manuscript database

The introduction and subsequent invasion of cheatgrass (Bromus tectorum) onto Intermountain rangelands has resulted in increased frequencies of wildfires and severely altered native plant communities. These destructive wildfires have negatively impacted wildlife and grazing resources. The ability o...

Long-term Effects of Shrub Encroachment and Grazing on Soil Microbial Composition and Function

NASA Astrophysics Data System (ADS)

Gallery, R. E.; O'Shea, C.; Kwiecien, A.; Predick, K.; Archer, S. R.

2014-12-01

Drylands account for ca. 35% of terrestrial net primary productivity and thus play a significant role in global water and biogeochemical cycles. Replacement of grasses by shrubs has been widespread in these systems and has altered rates of erosion and native plant biodiversity and productivity. The net effect of these changes on biogeochemical cycling is not well understood. Projected warmer and drier conditions may further alter the function and stability of these ecosystems and soil resources through direct effects on soil microbiota and plant-microbe interactions. We quantified microbial community responses to long-term livestock grazing and shrub encroachment in a Sonoran Desert grassland. We sought to characterize tipping points where biotic controls over ecosystem processes shift from being 'grass-driven' to 'shrub-driven.' We asked: How do livestock grazing (the predominant land use in dryland ecosystems) and shrub invasion (a predominant land cover change) interact to influence microbial biomass and the relative abundance of bacteria, archaea, and fungi and their extracellular enzyme activities? Surface soil from bare-ground patches, native and invasive grass rhizospheres, and bole and canopy dripline locations in patches of mature mesquite trees in long-term grazed and long-term (70+ y) protected pastures were collected and analyzed for microbial community composition, biomass, potential exoenzyme activities, and a suite of biogeochemical characteristics. We found no differences in microbial communities or the soils associated with native vs. exotic grasses. Overall, mesquite bole patches differed from other patches in all soil characteristics except potential enzyme activity: soil temperature was significantly lower, and total carbon (C) and soil moisture were significantly higher. Potential activities were lowest for bare ground and highest at shrub dripline patches for all seven exoenzymes tested. Mean potential activities for C and phosphorous (P) hydrolyzing enzymes in long-term protected pastures (C: 21.4 ug activity g-1 h-1 ± 2.3; P: 29.8 ug activity g-1 h-1 ± 3.5) were significantly higher than those in grazed pastures (C: 16.6 ug activity g-1 h-1 ± 2.1; P: 15.8 ug activity g-1 h-1 ± 2.5), suggesting long-term effects of past land use on current soil microbial populations.

Fire and grazing influence site resistance to Bromus tectorum through their effects on shrub, bunchgrass and biocrust communities in the Great Basin (USA)

USGS Publications Warehouse

Condon, Lea A.; Pyke, David A.

2018-01-01

Shrubs, bunchgrasses and biological soil crusts (biocrusts) are believed to contribute to site resistance to plant invasions in the presence of cattle grazing. Although fire is a concomitant disturbance with grazing, little is known regarding their combined impacts on invasion resistance. We are the first to date to test the idea that biotic communities mediate the effects of disturbance on site resistance. We assessed cover of Bromus tectorum, shrubs, native bunchgrasses, lichens and mosses in 99 burned and unburned plots located on similar soils where fires occurred between 12 and 23 years before sampling. Structural equation modeling was used to test hypothesized relationships between environmental and disturbance characteristics, the biotic community and resistance to B. tectorum cover. Characteristics of fire and grazing did not directly relate to cover of B. tectorum. Relationships were mediated through shrub, bunchgrass and biocrust communities. Increased site resistance following fire was associated with higher bunchgrass cover and recovery of bunchgrasses and mosses with time since fire. Evidence of grazing was more pronounced on burned sites and was positively correlated with the cover of B. tectorum, indicating an interaction between fire and grazing that decreases site resistance. Lichen cover showed a weak, negative relationship with cover of B. tectorum. Fire reduced near-term site resistance to B. tectorum on actively grazed rangelands. Independent of fire, grazing impacts resulted in reduced site resistance to B. tectorum, suggesting that grazing management that enhances plant and biocrust communities will also enhance site resistance.

Reforestation efforts reshape Hawaii's soil hydrology

NASA Astrophysics Data System (ADS)

Schultz, Colin

2012-04-01

Starting with the arrival in Hawaii of Polynesian settlers in the fourth century and peaking in the mid-1800s, the destructive forces of wildfires and pests and the grazing of feral pigs, goats, and cattle reduced the native forests of Maui to just one tenth of their original extent. Maui's native vegetation was replaced largely by imported or invasive species. Over time, the invasive grasses that took root reshaped the hydrological properties of the soil, reducing the viability of native plant species, which had evolved to thrive under Hawaii's previous hydrological dynamics. Maui's ecosystem had been changed for so long that scientists were uncertain whether the region could actually again support the native flora

Increase in plasma total antioxidant capacity of grazing Japanese Black heifers and cows in forestland in Japan.

PubMed

Haga, Satoshi; Ishizaki, Hiroshi; Nakano, Miwa; Nakao, Seiji; Hirano, Kiyoshi; Yamamoto, Yoshito; Kitagawa, Miya; Sasaki, Hiroyuki; Kariya, Yoshihiro

2014-02-01

Blood total antioxidant capacity (TAC) has become a key bio-marker for animal health. Forest-grazing cattle are known to forage various native plants that have high TAC. This study evaluated differences of plasma TAC between forest-grazing (FG) and pasture-grazing cattle (PG). Experiment 1 monitored the plasma TAC levels of 32 Japanese Black cattle. The level in PG did not change throughout the grazing period. However, that in FG, which increased from summer, was significantly higher than that in PG through fall (P < 0.05). In experiment 2, we used nine Japanese Black heifers and investigated their blood antioxidant parameters and the TAC in plants that the cattle consumed in late June and September. The plasma TAC levels in FG were significantly higher than those in PG in both periods (P < 0.05). Plasma levels of lipid peroxidation in FG tended to be lower than that in PG (P = 0.098). Furthermore, the TAC levels in various species of shrubs and trees consumed by FG were higher than those in pasture grasses. Results of this study show that plasma TAC of grazing Japanese Black cattle in forestland increase from summer through fall. © 2013 Japanese Society of Animal Science.

Greenhouse gas fluxes of grazed and hayed wetland catchments in the U.S. Prairie Pothole Ecoregion

USGS Publications Warehouse

Finocchiaro, Raymond G.; Tangen, Brian A.; Gleason, Robert A.

2014-01-01

Wetland catchments are major ecosystems in the Prairie Pothole Region (PPR) and play an important role in greenhouse gases (GHG) flux. However, there is limited information regarding effects of land-use on GHG fluxes from these wetland systems. We examined the effects of grazing and haying, two common land-use practices in the region, on GHG fluxes from wetland catchments during 2007 and 2008. Fluxes of methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2), along with soil water content and temperature, were measured along a topographic gradient every other week during the growing season near Ipswich, SD, USA. Closed, opaque chambers were used to measure fluxes of soil and plant respiration from native sod catchments that were grazed or left idle, and from recently restored catchments which were seeded with native plant species; half of these catchments were hayed once during the growing season. Catchments were adjacent to each other and had similar soils, soil nitrogen and organic carbon content, precipitation, and vegetation. When compared with idle catchments, grazing as a land-use had little effect on GHG fluxes. Likewise, haying had little effect on fluxes of CH4 and N2O compared with non-hayed catchments. Haying, however, did have a significant effect on combined soil and vegetative CO2 flux in restored wetland catchments owing to the immediate and comprehensive effect haying has on plant productivity. This study also examined soil conditions that affect GHG fluxes and provides cumulative annual estimates of GHG fluxes from wetland catchment in the PPR.

Aridity and grazing as convergent selective forces: an experiment with an Arid Chaco bunchgrass.

PubMed

Quiroga, R Emiliano; Golluscio, Rodolfo A; Blanco, Lisandro J; Fernández, Roberto J

2010-10-01

It has been proposed that aridity and grazing are convergent selective forces: each one selects for traits conferring resistance to both. However, this conceptual model has not yet been experimentally validated. The aim of this work was to experimentally evaluate the effect of aridity and grazing, as selective forces, on drought and grazing resistance of populations of Trichloris crinita, a native perennial forage grass of the Argentinean Arid Chaco region. We collected seeds in sites with four different combinations of aridity and grazing history (semiarid/ subhumid x heavily grazed/lightly grazed), established them in pots in a common garden, and subjected the resulting plants to different combinations of drought and defoliation. Our results agreed with the convergence model. Aridity has selected T. crinita genotypes that respond better to drought and defoliation in terms of sexual reproduction and leaf growth, and that can evade grazing due to a lower shoot: root ratio and a higher resource allocation to reserves (starch) in stem bases. Similarly, grazing has selected genotypes that respond better to drought and defoliation in terms of sexual reproduction and that can evade grazing due to a lower digestibility of leaf blades. These results allow us to extend concepts of previous models in plant adaptation to herbivory to models on plant adaptation to drought. The only variable in which we obtained a result opposite to predictions was plant height, as plants from semiarid sites were taller (and with more erect tillers) than plants from subhumid sites; we hypothesize that this result might have been a consequence of the selection exerted by the high solar radiation and soil temperatures of semiarid sites. In addition, our work allows for the prediction of the effects of dry or wet growing seasons on the performance of T. crinita plants. Our results suggest that we can rely on dry environments for selecting grazing-resistant genotypes and on high grazing pressure history environments for selecting drought-resistant ones.

Effects of ungulate management on vegetation at Hakalau Forest National Wildlife Refuge, Hawai'i Island

USGS Publications Warehouse

Hess, S.C.; Jeffrey, J.J.; Pratt, L.W.; Ball, D.L.

2010-01-01

We compiled and analysed data from 1987-2004 on vegetation monitoring during feral ungulate management at Hakalau Forest National Wildlife Refuge, a tropical montane rainforest on the island of Hawai'i All areas in the study had previously been used by ungulates, but cattle (Bos taurus) were removed and feral pig (Sus scrofa) populations were reduced during the study period. We monitored six line-intercept transects, three in previously high ungulate use areas and three in previously low ungulate use areas. We measured nine cover categories with the line-intercept method: native ferns; native woody plants; bryophytes; lichens; alien grasses; alien herbs; litter; exposed soil; and coarse woody debris. Vegetation surveys were repeated four times over a 16-year period. Vegetation monitoring revealed a strong increase in native fern cover and slight decreases in cover of bryophytes and exposed soil. Mean cover of native plants was generally higher in locations that were formerly lightly grazed, while alien grass and herb cover was generally higher in areas that were heavily grazed, although these effects were not statistically significant. These responses may represent early serai processes in forest regeneration following the reduction of feral ungulate populations. In contrast to many other Hawaiian forests which have become invaded by alien grasses and herbs after ungulate removal, HFNWR has not experienced this effect.

AmeriFlux US-AR1 ARM USDA UNL OSU Woodward Switchgrass 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Billesbach, Dave; Bradford, James

This is the AmeriFlux version of the carbon flux data for the site US-AR1 ARM USDA UNL OSU Woodward Switchgrass 1. Site Description - The ARM USDA UNL OSU Woodward Switchgrass 1 tower is located on public land owned by the USDA-ARS Southern Plains Range Research Station in Woodward, Oklahoma. The site is on a former native prairie that is in the process of changing to switchgrass. A second companion site (ARM USDA UNL OSU Woodward Switchgrass 2) is on a former wheat field. In Spring 2009, the former native prairie site was burned, cattle were put on the pasturemore » to graze down emergent grass, and broadleaf herbicide was sprayed. In Summer 2009, the cattle were removed from the pasture, and the site was sprayed with herbicide to kill all grass. In Spring 2010, prior to the planting of switchgrass, final herbicide was sprayed to kill cheat grass and to control broadleaf plants.« less

AmeriFlux US-Cop Corral Pocket

DOE Data Explorer

Bowling, David [University of Utah

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site US-Cop Corral Pocket. Site Description - The Corral Pocket site is located in a semi-arid grassland in southeastern Utah, just east of Canyonlands National park. For the greater part of the year, 38-80% of the ground is essentially bare. Vegetation is primarily native perennial C3/C4 grasses with annual ground converge ranging from 8-35%. Leaving the remaining 0-15% coverage to interspersed annual grasses, the remaining 0-15% coverage is occupied by annual grasses. 6-8 weeks during the late fall or winter, Livestock grazing is responsible for the majority of aboveground vegetation loss and subsequent high variability of ground coverage.

Effect of Supplemental Corn Dried Distillers Grains with Solubles Fed to Beef Steers Grazing Native Rangeland during the Forage Dormant Season

PubMed Central

Murillo, M.; Herrera, E.; Ruiz, O.; Reyes, O.; Carrete, F. O.; Gutierrez, H.

2016-01-01

Two experiments were conducted to evaluate the effects of the level of corn dry distillers grains with solubles (CDDGS) supplementation on growing performance, blood metabolites, digestion characteristics and ruminal fermentation patterns in steers grazing dormant forage. In Exp. 1, of growth performance, 120 steers (204±5 kg initial body weight [BW]) were distributed randomly into 3 groups (each of 40 steers), which were provided with the following levels of CDDGS supplement: 0%, 0.25%, or 0.50% BW. All groups of steers were grazed for 30 days in each of 3 grazing periods (March, April, and May). Approximately 1,000 ha of the land was divided with electric fencing into 3 equally sized pastures (333 ha in size). Blood samples were collected monthly from 20 steers in each grazing group for analysis of glucose (G), urea-nitrogen (UN) and non-esterified fatty acids. Final BW, average daily gain (ADG) and supplement conversion (CDDGS-C) increased with increasing levels of CDDGS supplementation (p<0.05).The CDDGS supplementation also increased the plasma G and UN concentrations (p<0.05). In Exp. 2, of digestive metabolism, 9 ruminally cannulated steers (BW = 350±3 kg) were distributed, following a completely randomized design, into groups of three in each pasture. The ruminally cannulated steers were provided the same levels of CDDGS supplementation as in the growing performance study (0%, 0.25%, and 0.50% BW), and they grazed along with the other 40 steers throughout the grazing periods. The dry matter intake, crude protein intake, neutral detergent fiber intake (NDFI), apparent digestibility of dry matter (ADDM), crude protein (ADCP) and neutral detergent fiber (ADNDF) increased with increasing levels of CDDGS supplementation (p<0.05). The ruminal degradation rates of CP (kdCP), NDF (kdNDF) and passage rate (kp) also increased with increasing levels of CDDGS supplementation (p<0.05). Ruminal ammonia nitrogen (NH3-N) and propionate concentrations also increased with increasing levels of CDDGS supplementation (p<0.05). However, acetate concentrations decreased with increasing levels of CDDGS supplementation (p<0.05). Liquid dilution rate increased with increasing levels of CDDGS supplementation but ruminal liquid volume decreased (p<0.05). On the basis of these findings, we can conclude that CDDGS supplementation enhanced the productive performance of cattle grazing native rangeland without negatively affecting forage intake, glucose and urea-nitrogen blood concentrations, ruminal degradation and ruminal fermentation patterns. PMID:26954168

Effect of Supplemental Corn Dried Distillers Grains with Solubles Fed to Beef Steers Grazing Native Rangeland during the Forage Dormant Season.

PubMed

Murillo, M; Herrera, E; Ruiz, O; Reyes, O; Carrete, F O; Gutierrez, H

2016-05-01

Two experiments were conducted to evaluate the effects of the level of corn dry distillers grains with solubles (CDDGS) supplementation on growing performance, blood metabolites, digestion characteristics and ruminal fermentation patterns in steers grazing dormant forage. In Exp. 1, of growth performance, 120 steers (204±5 kg initial body weight [BW]) were distributed randomly into 3 groups (each of 40 steers), which were provided with the following levels of CDDGS supplement: 0%, 0.25%, or 0.50% BW. All groups of steers were grazed for 30 days in each of 3 grazing periods (March, April, and May). Approximately 1,000 ha of the land was divided with electric fencing into 3 equally sized pastures (333 ha in size). Blood samples were collected monthly from 20 steers in each grazing group for analysis of glucose (G), urea-nitrogen (UN) and non-esterified fatty acids. Final BW, average daily gain (ADG) and supplement conversion (CDDGS-C) increased with increasing levels of CDDGS supplementation (p<0.05).The CDDGS supplementation also increased the plasma G and UN concentrations (p<0.05). In Exp. 2, of digestive metabolism, 9 ruminally cannulated steers (BW = 350±3 kg) were distributed, following a completely randomized design, into groups of three in each pasture. The ruminally cannulated steers were provided the same levels of CDDGS supplementation as in the growing performance study (0%, 0.25%, and 0.50% BW), and they grazed along with the other 40 steers throughout the grazing periods. The dry matter intake, crude protein intake, neutral detergent fiber intake (NDFI), apparent digestibility of dry matter (ADDM), crude protein (ADCP) and neutral detergent fiber (ADNDF) increased with increasing levels of CDDGS supplementation (p<0.05). The ruminal degradation rates of CP (kdCP), NDF (kdNDF) and passage rate (kp) also increased with increasing levels of CDDGS supplementation (p<0.05). Ruminal ammonia nitrogen (NH3-N) and propionate concentrations also increased with increasing levels of CDDGS supplementation (p<0.05). However, acetate concentrations decreased with increasing levels of CDDGS supplementation (p<0.05). Liquid dilution rate increased with increasing levels of CDDGS supplementation but ruminal liquid volume decreased (p<0.05). On the basis of these findings, we can conclude that CDDGS supplementation enhanced the productive performance of cattle grazing native rangeland without negatively affecting forage intake, glucose and urea-nitrogen blood concentrations, ruminal degradation and ruminal fermentation patterns.

36 CFR 222.4 - Changes in grazing permits.

Code of Federal Regulations, 2010 CFR

2010-07-01

... RANGE MANAGEMENT Grazing and Livestock Use on the National Forest System § 222.4 Changes in grazing... use permits in whole or in part as follows: (1) Cancel permits where lands grazed under the permit are... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Changes in grazing permits...

The Corps of Engineers and Prairie Restoration: Synopsis of the First Corps Prairie Workshop, Follow-up Actions, and Thoughts on the Future of Prairie Restoration and Management on Operational Projects

DTIC Science & Technology

2009-06-01

Corps super- vision regarding management practices such as cropping systems and cattle grazing. Also, the Corps’ focus at the time was on tree planting...on crop rotation and removal of grazing. Changes included the installation of 100-ft-wide warm-season native grass strips between each agricultural...brood-rearing habitat, but it was not always possible to put that much land aside. Idle fields consisted of 5- to 15-acre blocks centered in row crop

Multiscale responses of soil stability and invasive plants to removal of non-native grazers from an arid conservation reserve

USGS Publications Warehouse

Beever, E.A.; Huso, M.; Pyke, D.A.

2006-01-01

Disturbances and ecosystem recovery from disturbance both involve numerous processes that operate on multiple spatial and temporal scales. Few studies have investigated how gradients of disturbance intensity and ecosystem responses are distributed across multiple spatial resolutions and also how this relationship changes through time during recovery. We investigated how cover of non-native species and soil-aggregate stability (a measure of vulnerability to erosion by water) in surface and subsurface soils varied spatially during grazing by burros and cattle and whether patterns in these variables changed after grazer removal from Mojave National Preserve, California, USA. We compared distance from water and number of ungulate defecations - metrics of longer-term and recent grazing intensity, respectively, - as predictors of our response variables. We used information-theoretic analyses to compare hierarchical linear models that accounted for important covariates and allowed for interannual variation in the disturbance-response relationship at local and landscape scales. Soil stability was greater under perennial vegetation than in bare interspaces, and surface soil stability decreased with increasing numbers of ungulate defecations. Stability of surface samples was more affected by time since removal of grazers than was stability of subsurface samples, and subsurface soil stability in bare spaces was not related to grazing intensity, time since removal, or any of our other predictors. In the high rainfall year (2003) after cattle had been removed for 1-2 years, cover of all non-native plants averaged nine times higher than in the low-rainfall year (2002). Given the heterogeneity in distribution of large-herbivore impacts that we observed at several resolutions, hierarchical analyses provided a more complete understanding of the spatial and temporal complexities of disturbance and recovery processes in arid ecosystems. ?? 2006 Blackwell Publishing Ltd.

Multi-scale responses of soil stability and invasive plants to removal of non-native grazers from an arid conservation reserve

USGS Publications Warehouse

Beever, Erik A.; Huso, Manuela M. P.; Pyke, David A.

2006-01-01

Disturbances and ecosystem recovery from disturbance both involve numerous processes that operate on multiple spatial and temporal scales. Few studies have investigated how gradients of disturbance intensity and ecosystem responses are distributed across multiple spatial resolutions and also how this relationship changes through time during recovery. We investigated how cover of non-native species and soil-aggregate stability (a measure of vulnerability to erosion by water) in surface and subsurface soils varied spatially during grazing by burros and cattle and whether patterns in these variables changed after grazer removal from Mojave National Preserve, California, USA. We compared distance from water and number of ungulate defecations — metrics of longer-term and recent grazing intensity, respectively, — as predictors of our response variables. We used information-theoretic analyses to compare hierarchical linear models that accounted for important covariates and allowed for interannual variation in the disturbance–response relationship at local and landscape scales. Soil stability was greater under perennial vegetation than in bare interspaces, and surface soil stability decreased with increasing numbers of ungulate defecations. Stability of surface samples was more affected by time since removal of grazers than was stability of subsurface samples, and subsurface soil stability in bare spaces was not related to grazing intensity, time since removal, or any of our other predictors. In the high rainfall year (2003) after cattle had been removed for 1–2 years, cover of all non-native plants averaged nine times higher than in the low-rainfall year (2002). Given the heterogeneity in distribution of large-herbivore impacts that we observed at several resolutions, hierarchical analyses provided a more complete understanding of the spatial and temporal complexities of disturbance and recovery processes in arid ecosystems.

Effects of Grazing and Fire Frequency on Floristic Quality and its Relationship to Indicators of Soil Quality in Tallgrass Prairie

NASA Astrophysics Data System (ADS)

Manning, George C.; Baer, Sara G.; Blair, John M.

2017-12-01

Fire and grazing are widely used to manage grasslands for conservation purposes, but few studies have evaluated the effects of these drivers on the conservation value of plant communities measured by the floristic quality index (FQI). Further, the influence of fire and grazing on soil properties and functions are difficult for land managers and restoration practitioners to assess. The objectives of this study were to: (1) quantify the independent and interactive effects of grazing and fire frequency on floristic quality in native tallgrass prairie to provide potential benchmarks for community assessment, and (2) to explore whether floristic quality can serve as an indicator of soil structure and function for more holistic ecosystem assessments. A factorial combination of fire frequencies (1-2, 4, and 20 years return intervals) and grazing (by bison or ungrazed) treatments were sampled for plant species composition, and for several indicators of soil quality in lowland tallgrass prairie. Floristic quality, diversity, and richness were higher in grazed than ungrazed prairie over all fire frequencies ( P < 0.05). Available inorganic N, microbial biomass N, total N, and soil bulk density were also higher in grazed prairie soil over all fire frequencies ( P < 0.05). Microbial biomass C, total organic C, and total soil N were positively correlated with FQI ( P < 0.05). This study shows that floristic quality and soil N pools are more strongly influenced by grazing than fire and that floristic quality can be an indicator of total soil C and N stocks in never cultivated lowland prairie.

Effects of Grazing and Fire Frequency on Floristic Quality and its Relationship to Indicators of Soil Quality in Tallgrass Prairie.

PubMed

Manning, George C; Baer, Sara G; Blair, John M

2017-12-01

Fire and grazing are widely used to manage grasslands for conservation purposes, but few studies have evaluated the effects of these drivers on the conservation value of plant communities measured by the floristic quality index (FQI). Further, the influence of fire and grazing on soil properties and functions are difficult for land managers and restoration practitioners to assess. The objectives of this study were to: (1) quantify the independent and interactive effects of grazing and fire frequency on floristic quality in native tallgrass prairie to provide potential benchmarks for community assessment, and (2) to explore whether floristic quality can serve as an indicator of soil structure and function for more holistic ecosystem assessments. A factorial combination of fire frequencies (1-2, 4, and 20 years return intervals) and grazing (by bison or ungrazed) treatments were sampled for plant species composition, and for several indicators of soil quality in lowland tallgrass prairie. Floristic quality, diversity, and richness were higher in grazed than ungrazed prairie over all fire frequencies (P < 0.05). Available inorganic N, microbial biomass N, total N, and soil bulk density were also higher in grazed prairie soil over all fire frequencies (P < 0.05). Microbial biomass C, total organic C, and total soil N were positively correlated with FQI (P < 0.05). This study shows that floristic quality and soil N pools are more strongly influenced by grazing than fire and that floristic quality can be an indicator of total soil C and N stocks in never cultivated lowland prairie.

Simulating the effects of soil organic nitrogen and grazing on arctic tundra vegetation dynamics on the Yamal Peninsula, Russia

NASA Astrophysics Data System (ADS)

Yu, Q.; Epstein, H. E.; Walker, D. A.

2009-12-01

Sustainability of tundra vegetation under changing climate on the Yamal Peninsula, northwestern Siberia, home to the world’s largest area of reindeer husbandry, is of crucial importance to the local native community. An integrated investigation is needed for better understanding of the effects of soils, climate change and grazing on tundra vegetation in the Yamal region. In this study we applied a nutrient-based plant community model (ArcVeg) to evaluate how two factors (soil organic nitrogen [SON] levels and grazing) interact to affect tundra responses to climate warming across a latitudinal climatic gradient on the Yamal Peninsula. Model simulations were driven by field-collected soil data and expected grazing patterns along the Yamal Arctic Transect (YAT), within bioclimate subzones C (High Arctic), D (northern Low Arctic) and E (southern Low Arctic). Plant biomass and NPP (net primary productivity) were significantly increased with warmer bioclimate subzones, greater soil nutrient levels and temporal climate warming, while they declined with higher grazing frequency. Temporal climate warming of 2 °C caused an increase of 665 g/m2 in total biomass at the high SON site in subzone E, while only 298 g/m2 in the low SON site. When grazing frequency was also increased, total biomass increased by only 369 g/m2 in the high SON site in contrast to 184 g/m2 in the low SON site in subzone E. When comparing low grazing to high grazing effects on soil organic nitrogen pools over time (Figure 1), higher grazing frequency led to either slower SON accumulation rates or more rapid SON depletion rates. Warming accentuated these differences caused by grazing, suggesting the interaction between grazing and warming may yield greater differences in SON levels across sites. Our results suggest that low SON and grazing may limit plant response to climate change. Interactions among bioclimate subzones, soils, grazing and warming significantly affect plant biomass and productivity in the arctic tundra and should not be ignored in regional scale studies.

Effects of nitrogen deposition and cattle grazing on productivity, invasion impact, and soil microbial processes in a serpentine grassland

NASA Astrophysics Data System (ADS)

Pasari, J.; Hernandez, D.; Selmants, P. C.; Keck, D.

2010-12-01

In recent decades, human activities have vastly increased the amount of biologically available nitrogen (N) in the biosphere. The resulting increase in N availability has broadly affected ecosystems through increased productivity, changes in species composition, altered nutrient cycles, and increases in invasion by exotic plant species, especially in systems that were historically low in N. California serpentine grasslands are N-limited ecosystems historically dominated by native species including several threatened and endangered plants and animals. Cattle grazing has emerged as the primary tool for controlling the impact of nitrophilic exotic grasses whose increased abundance has paralleled the regional traffic-derived increase in atmospheric N deposition. We examined the interactive effects of cattle grazing and N deposition on plant community composition, productivity, invasion resistance, and microbial processes in the Bay Area's largest serpentine grassland to determine the efficacy of current management strategies as well as the biogeochemical consequences of exotic species invasion. In the first two years of the study, aboveground net primary productivity decreased in response to grazing and increased in response to nitrogen addition. However, contrary to our hypotheses the change in productivity was not due to an increase in exotic species cover as there was little overall effect of grazing or N addition on species composition. Microbial activity was more responsive to grazing and N. Potential net N mineralization rates increased with N addition, but were not affected by grazing. In contrast, soil respiration rates were inhibited by grazing, but were not affected by N addition; suggesting strong carbon-limitation of soil microbial activity, particularly under grazing. Site differences in soil depth and grazing intensity were often more important than treatment effects. We suspect that the unusually dry conditions in the first two growing seasons inhibited the growth of exotic species and minimized the effects of cattle exclusion and N addition on species composition.

The effects of burning and grazing on survival, home range, and prey dynamics of the Texas horned lizard in a thornscrub ecosystem

Treesearch

Anna L. Burrow; Richard T. Kazmaier; Eric C. Hellgren; Donald C. Ruthven, III

2002-01-01

We examined the effects of rotational livestock grazing and prescribed winter burning on the state threatened Texas horned lizard, Phrynosoma cornutum, by comparing home range sizes, survival estimates and prey abundance across burning and grazing treatments in southern Texas. Adult lizards were fitted with backpacks carrying radio transmitters and...

Stream chemistry responses to four range management strategies in eastern Oregon.

Treesearch

A.R. Tiedemann; D.A. Higgins; T.M. Quigley; H.R. Sanderson

1989-01-01

Responses of stream chemistry parameters, nitrate-N (NO3-N), phosphate (PO4), calcium (Ca), magnesium (Mg), potassium (K), sodium (Na), and hydrogen ion activity (pH) were measured on 13 wildland watersheds managed at four different grazing strategies. Range management strategies tested were (A) no grazing, (B) grazing without control of livestock distribution (8.2 ha/...

Biologic surveys for the Sandia National Laboratories, Coyote Canyon Test Complex, Kirtland Air Force Base, Albuquerque, New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, R.M.; Knight, P.J.

This report provides results of a comprehensive biologic survey performed in Coyote Canyon Test Complex (CCTC), Sandia National Laboratories (SNL), Bernalillo County, New Mexico, which was conducted during the spring and summer of 1992 and 1993. CCTC is sited on land owned by the Department of Energy (DOE) and Kirtland Air Force Base and managed by SNL. The survey covered 3,760 acres of land, most of which is rarely disturbed by CCTC operations. Absence of grazing by livestock and possibly native ungulates, and relative to the general condition of private range lands throughout New Mexico, and relative to other grazingmore » lands in central New Mexico. Widely dispersed, low intensity use by SNL as well as prohibition of grazing has probably contributed to abundance of special status species such as grama grass cactus within the CCTC area. This report evaluates threatened and endangered species found in the area, as well as comprehensive assessment of biologic habitats. Included are analyses of potential impacts and mitigative measures designed to reduce or eliminate potential impacts. Included is a summary of CCTC program and testing activities.« less

Free-grazing Ducks and Highly Pathogenic Avian Influenza, Thailand

PubMed Central

Chaitaweesub, Prasit; Parakamawongsa, Tippawon; Premashthira, Sith; Tiensin, Thanawat; Kalpravidh, Wantanee; Wagner, Hans; Slingenbergh, Jan

2006-01-01

Thailand has recently had 3 epidemic waves of highly pathogenic avian influenza (HPAI); virus was again detected in July 2005. Risk factors need to be identified to better understand disease ecology and assist HPAI surveillance and detection. This study analyzed the spatial distribution of HPAI outbreaks in relation to poultry, land use, and other anthropogenic variables from the start of the second epidemic wave (July 2004–May 2005). Results demonstrate a strong association between H5N1 virus in Thailand and abundance of free-grazing ducks and, to a lesser extent, native chickens, cocks, wetlands, and humans. Wetlands used for double-crop rice production, where free-grazing duck feed year round in rice paddies, appear to be a critical factor in HPAI persistence and spread. This finding could be important for other duck-producing regions in eastern and southeastern Asian countries affected by HPAI. PMID:16494747

Purple threeawn in vitro fermentation and gas production response to nitrogen fertilization and fire

USDA-ARS?s Scientific Manuscript database

Purple threeawn (Aristida purpurea) is a native perennial bunchgrass with poor forage quality. It often dominates sites with disturbed soils and persists with continued severe grazing. Nitrogen fertilization and fire have each been used to reduce threeawn, however, greater utilization of threeawn ...

Fire and nitrogen fertilization effects on Purple Threeawn in vitro fermentation and gas production

USDA-ARS?s Scientific Manuscript database

Purple threeawn (Aristida purpurea) is a native perennial bunchgrass with poor forage quality. The grass often dominates sites where soils have been disturbed and persists with continued severe grazing of preferred species due to livestock avoidance of threeawn. Nitrogen fertilization and fire hav...

Consequences of prescribed fire and grazing on grassland ant communities.

PubMed

Underwood, Emma C; Christian, Caroline E

2009-04-01

Prescribed fire and livestock grazing are used for the management and restoration of native grasslands the world over; however, the effects of these management techniques on ant communities are unclear. We examined the response of ants to these disturbances in grasslands in northern California. Twenty-four 30 by 30 m plots were established across two sites that received one of four treatments: grazing, fire, grazing and fire, or no treatment. Ants were censused using 240 pitfall traps with one preburn and two postburn samples (14 d and 1 yr after burning). We analyzed ant abundance using broadly defined groups based on feeding habit and/or habitat use and detected no grazing effect but a significant fire effect that differed by group. Immediate postfire sampling showed an increase in cryptic species (particularly Brachymyrmex depilis). One year after the fire, no response was detected for cryptic species, but burned plots had greater abundance of seed harvesters. Analysis of vegetation showed burned plots had significantly greater forb cover, which might have provided greater food resources, and also lower biomass, which might have facilitated foraging. Understanding the effects of these management tools on ant abundance complements our understanding of their effect on vegetation and assists conservation practitioners effectively manage grassland ecosystems both in California and beyond.

Management practices and controls on methane emissions from sub-tropical wetlands

NASA Astrophysics Data System (ADS)

DeLucia, Nicholas; Casa-Nova Gomez, Nuri; Bernacchi, Carl

2015-04-01

It is well documented that green house gas concentrations have risen at unequivocal rates since the industrial revolution but the disparity between anthropogenic sources and natural sources is uncertain. Wetlands are one example of a natural ecosystem that can be a substantial source or sink for methane (CH4) depending on any combination of climate conditions, natural and anthropogenic disturbances, or ecosystem perturbations. Due to strict anaerobic conditions required for CH4-generating microorganisms, natural wetlands are the main source for biogenic CH4. Although wetlands occupy less than 5% of total land surface area, they contribute approximately 20% of total CH4 emissions to the atmosphere. CH4 is one of the most damaging green house gases with current emission estimates ranging from 55 to 231 Tg CH4 yr-1. The processes regulating CH4 emissions are sensitive to land use and management practices of areas surrounding wetlands. Variation in adjacent vegetation or grazing intensity by livestock can, for example, alter CH4 fluxes from wetland soils by altering nutrient balance, carbon inputs and hydrology. Therefore, understanding how these changes will affect wetland source strength is essential to understand the impact of wetland management practices on the global climate system. In this study we quantify wetland methane fluxes from subtropical wetlands on a working cattle ranch in central Florida near Okeechobee Lake (27o10'52.04"N, 81o21'8.56"W). To determine differences in CH4 fluxes associated with land use and management, a replicated (n = 4) full factorial experiment was designed for wetlands where the surrounding vegetation was (1) grazed or un-grazed and (2) composed of native vegetation or improved pasture. Net exchange of CH4 and CO2 between the land surface and the atmosphere were sampled with a LICOR Li-7700 open path CH4 analyzer and Li-7500A open path CO2/H20 analyzer mounted in a 1-m3 static gas-exchange chamber. Our results showed and verified that CH4 emissions from subtropical wetlands were larger when high soil moisture was coupled with high temperatures. Grazing alone, does not appear to alter net ecosystem CH4 emissions from subtropical semi-native and improved wetlands. Pasture type is a stronger indicator of wetland methane potential. Wetlands embedded in improved pastures exhibited periods of increased methane emission that was particularly noticeable during the wet season (July- Nov). These results help quantify GHG emissions from subtropical wetlands under different management practices while demonstrating the differences in these fluxes based on the surrounding ecosystem.

Microzooplankton grazing and selective feeding during bloom periods in the Tolo Harbour area as revealed by HPLC pigment analysis

NASA Astrophysics Data System (ADS)

Liu, Xiangjiang; Tang, Chi Hung; Wong, Chong Kim

2014-07-01

Dilution experiments were conducted to investigate microzooplankton grazing impact on phytoplankton of different taxonomic groups and size fractions (< 5, 5-20, 20-200 μm) during spring and summer bloom periods at two different sites (inner Tolo Harbour and Tolo Channel) in the Tolo Harbour area, the northeastern coastal area of Hong Kong. Experiments combined with HPLC pigment analysis in three phytoplankton size fractions measured pigment and size specific phytoplankton growth rates and microzooplankton grazing rates. Pigment-specific phytoplankton growth rates ranged between 0.08 and 3.53 d- 1, while specific grazing rates of microzooplankton ranged between 0.07 and 2.82 d- 1. Highest specific rates of phytoplankton growth and microzooplankton grazing were both measured in fucoxanthin in 5-20 μm size fraction in inner Tolo Harbour in summer, which coincided with the occurrence of diatom bloom. Results showed significant correlations between phytoplankton growth and microzooplankton grazing rates. Microzooplankton placed high grazing pressure on phytoplankton community. High microzooplankton grazing impact on alloxanthin (2.63-5.13) suggested strong selection toward cryptophytes. Our results provided no evidence for size selective grazing on phytoplankton by microzooplankton.

Home on the range: might the cattle peacefully graze?

Treesearch

Sally Duncan

1999-01-01

Grazing and how it impacts the landscape is a concern for public and private land managers. This issue of "Science Findings" examines the issue of cattle and grazing and provides some background, perspective, and research results on various grazing systems. Researchers Jim McIver, of the Forest Service's Blue Mountains Natural Resources Institute, and...

Doublethink and scale mismatch polarize policies for an invasive tree

PubMed Central

Roberts, Caleb P.; Uden, Daniel R.; Allen, Craig R.; Twidwell, Dirac

2018-01-01

Mismatches between invasive species management policies and ecological knowledge can lead to profound societal consequences. For this reason, natural resource agencies have adopted the scientifically-based density-impact invasive species curve to guide invasive species management. We use the density-impact model to evaluate how well management policies for a native invader (Juniperus virginiana) match scientific guidelines. Juniperus virginiana invasion is causing a sub-continental regime shift from grasslands to woodlands in central North America, and its impacts span collapses in endemic diversity, heightened wildfire risk, and crashes in grazing land profitability. We (1) use land cover data to identify the stage of Juniperus virginiana invasion for three ecoregions within Nebraska, USA, (2) determine the range of invasion stages at individual land parcel extents within each ecoregion based on the density-impact model, and (3) determine policy alignment and mismatches relative to the density-impact model in order to assess their potential to meet sustainability targets and avoid societal impacts as Juniperus virginiana abundance increases. We found that nearly all policies evidenced doublethink and policy-ecology mismatches, for instance, promoting spread of Juniperus virginiana regardless of invasion stage while simultaneously managing it as a native invader in the same ecoregion. Like other invasive species, theory and literature for this native invader indicate that the consequences of invasion are unlikely to be prevented if policies fail to prioritize management at incipient invasion stages. Theory suggests a more realistic approach would be to align policy with the stage of invasion at local and ecoregion management scales. There is a need for scientists, policy makers, and ecosystem managers to move past ideologies governing native versus non-native invader classification and toward a framework that accounts for the uniqueness of native species invasions, their anthropogenic drivers, and their impacts on ecosystem services. PMID:29513675

An audit of non-fatal assault injuries treated in Federal Medical Center (FMC), Nguru, north east Nigeria.

PubMed

Eni, U E; Na'aya, H U; Musa, A M; Lawan, M A; Chinda, J Y

2009-01-01

Violent assault injuries are a frequent occurrence in the native communities of the North Eastern Nigeria. The injuries are mostly unreported, and therefore no policy towards prevention. We hope to highlight the common causes and pattern of such injuries, as well as suggest control measures in order to reduce the incidence. A retrospective review of 208 assault injury cases seen at the Accident and Emergency department of the Federal Medical Center, Nguru, between January 2002 and December 2006. All but 12 were males, giving a male to female ratio of 16:1. Most of the patients are illiterate herdsmen and farmers. The age ranged from 12 to 70 years, with a mean of 30.9 +/- 11.2 years. The peak age incidence was 30-40 years. Fighting was the most common cause, accounting for 124 (59.6%), followed by armed robbery assaults, which accounted for 75 (36.1%). Domestic abuse was the cause in 9 cases (4.3%). Arrow shot was the commonest form of assault injury in 55 (26.4%) cases, followed by matchet in 49 (23.6%), gunshot in 37 (17.8%), club/stick in 32 (15.4%) and stab wounds in 26 (12.5 %). Quarrel over farmlands used for grazing by herdsmen was the leading cause of fighting resulting in assault injuries (87), followed by quarrel over women (32)! Assault injuries are a common occurrence in the native communities of the North Eastern Nigeria. Addressing the root causes such as mapping out grazing lands in the region, community policing as well as mandatory reporting of all assault injuries to the police for appropriate legal action, will help reduce the incidence of assault injuries.

Traditional vs Modern: Role of Breed Type in Determining Enteric Methane Emissions from Cattle Grazing as Part of Contrasting Grassland-Based Systems

PubMed Central

Fraser, Mariecia D.; Fleming, Hannah R.; Moorby, Jon M.

2014-01-01

Ruminant livestock turn forages and poor-quality feeds into human edible products, but enteric methane (CH4) emissions from ruminants are a significant contributor to greenhouse gases (GHGs) and hence to climate change. Despite the predominance of pasture-based beef production systems in many parts of Europe there are little data available regarding enteric CH4 emissions from free-ranging grazing cattle. It is possible that differences in physiology or behaviour could influence comparative emissions intensities for traditional and modern breed types depending on the nutritional characteristics of the herbage grazed. This study investigated the role of breed type in influencing CH4 emissions from growing beef steers managed on contrasting grasslands typical of intensive (lowland) and extensive (upland) production systems. Using the SF6 dilution technique CH4 emissions were estimated for a modern, fast-growing crossbred (Limousin cross) and a smaller and hardier native breed (Welsh Black) when grazing lowland perennial ryegrass (high nutritional density, low sward heterogeneity) and semi-improved upland pasture (low/medium nutritional density, high sward heterogeneity). Live-weight gain was substantially lower for steers on the upland system compared to the lowland system (0.31 vs. 1.04 kg d−1; s.e.d. = 0.085 kg d−1; P<0.001), leading to significant differences in estimated dry matter intakes (8.0 vs. 11.1 kg DM d−1 for upland and lowland respectively; s.e.d. = 0.68 kg DM d−1; P<0.001). While emissions per unit feed intake were similar for the lowland and upland systems, CH4 emissions per unit of live-weight gain (LWG) were substantially higher when the steers grazed the poorer quality hill pasture (760 vs 214 g kg−1 LWG; s.e.d. = 133.5 g kg−1 LWG; P<0.001). Overall any effects of breed type were relatively small relative to the combined influence of pasture type and location. PMID:25259617

Effect of forage energy intake and supplementation on marbling deposition in growing beef cattle.

USDA-ARS?s Scientific Manuscript database

Glucose is the primary carbon source for fatty acid synthesis in intramuscular fat, whereas, acetate is primarily utilized by subcutaneous fat. Our objective was to examine the effect of forage energy intake and type of fermentation on marbling deposition by stocker cattle grazing dormant native ra...

Using state-and-transition models to project cheatgrass and juniper invasion in Southeastern Oregon sagebrush steppe

Treesearch

Megan K. Creutzburg; Joshua S. Halofsky; Miles A. Hemstrom

2012-01-01

Many threats are jeopardizing the sagebrush steppe of the Columbia Basin, including the spread of invasive species such as cheatgrass (Bromus tectorum L.) and the expansion of western juniper (Juniperus occidentalis Hook.) into historic shrub steppe. Native sagebrush steppe provides productive grazing lands and important...

Historical and pictorial perspective of the Upper Verde River [Chapter 2

Treesearch

Alvin L. Medina; Daniel G. Neary

2012-01-01

The UVR corridor is a diverse riverine ecosystem in central Arizona (see Chapter 1). Since European settlement, it has witnessed many events such as droughts, floods, construction of Sullivan Dam, groundwater withdrawals, cattle grazing, mining, nonnative fish introductions, native fish extinctions, and urbanization that are not fully understood. Geologically, the UVR...

Establishing native plants in crested wheatgrass stands using successional management

Treesearch

Valerie A. Fansler

2007-01-01

Crested wheatgrass (Agropyron cristatum (L.) Gaertn.) is a nonindigenous perennial grass that was introduced to North America to improve the condition of degraded rangelands. It has proven to be a successful revegetation species due to its superior ease of establishment, strong competitive ability, and ability to tolerate grazing. However, crested...

75 FR 42489 - Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Limnanthes...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-21

... increase species' richness and native plant cover in this edge habitat. In a grazing report prepared for... Lomatium cookii. Excluding overlapping critical habitat units for the two species, a total of approximately... of mining activities can result in direct habitat loss for the species and limit recovery. Indirect...

Deforestation of "degraded" rangelands: The Argentine Chaco enters the next stage of the Anthropocene

USDA-ARS?s Scientific Manuscript database

Twenty years ago I completed my Master’s work in the Chaco forests of northern Argentina. The native forests are, in fact, rangelands. In addition to livestock grazing, there is timber extraction, wildlife harvest (think tegu lizard cowboy boots), and charcoal production. I took part in a project co...

Vulnerability of crops and native grasses to summer drying in the U.S. Southern Great Plains

DOE PAGES

Raz-Yaseef, Naama; Billesbach, Dave P.; Fischer, Marc L.; ...

2015-08-31

The Southern Great Plains are characterized by a fine-scale mixture of different land-cover types, predominantly winter-wheat and grazed pasture, with relatively small areas of other crops, native prairie, and switchgrass. Recent droughts and predictions of increased drought in the Southern Great Plains, especially during the summer months, raise concern for these ecosystems. We measured ecosystem carbon and water fluxes with eddy-covariance systems over cultivated cropland for 10 years, and over lightly grazed prairie and new switchgrass fields for 2 years each. Growing-season precipitation showed the strongest control over net carbon uptake for all ecosystems, but with a variable effect: grassesmore » (prairie and switchgrass) needed at least 350 mm of precipitation during the growing season to become net carbon sinks, while crops needed only 100 mm. In summer, high temperatures enhanced evaporation and led to higher likelihood of dry soil conditions. Therefore, summer-growing native prairie species and switchgrass experienced more seasonal droughts than spring-growing crops. For wheat, the net reduction in carbon uptake resulted mostly from a decrease in gross primary production rather than an increase in respiration. Flux measurements suggested that management practices for crops were effective in suppressing evapotranspiration and decomposition (by harvesting and removing secondary growth), and in increasing carbon uptake (by fertilizing and conserving summer soil water). In light of future projections for wetter springs and drier and warmer summers in the Southern Great Plains, our study indicates an increased vulnerability in native ecosystems and summer crops over time.« less

Evidence of Physiological Decoupling from Grassland Ecosystem Drivers by an Encroaching Woody Shrub

PubMed Central

Nippert, Jesse B.; Ocheltree, Troy W.; Orozco, Graciela L.; Ratajczak, Zak; Ling, Bohua; Skibbe, Adam M.

2013-01-01

Shrub encroachment of grasslands is a transformative ecological process by which native woody species increase in cover and frequency and replace the herbaceous community. Mechanisms of encroachment are typically assessed using temporal data or experimental manipulations, with few large spatial assessments of shrub physiology. In a mesic grassland in North America, we measured inter- and intra-annual variability in leaf δ13C in Cornus drummondii across a grassland landscape with varying fire frequency, presence of large grazers and topographic variability. This assessment of changes in individual shrub physiology is the largest spatial and temporal assessment recorded to date. Despite a doubling of annual rainfall (in 2008 versus 2011), leaf δ13C was statistically similar among and within years from 2008-11 (range of −28 to −27‰). A topography*grazing interaction was present, with higher leaf δ13C in locations that typically have more bare soil and higher sensible heat in the growing season (upland topographic positions and grazed grasslands). Leaf δ13C from slopes varied among grazing contrasts, with upland and slope leaf δ13C more similar in ungrazed locations, while slopes and lowlands were more similar in grazed locations. In 2011, canopy greenness (normalized difference vegetation index – NDVI) was assessed at the centroid of individual shrubs using high-resolution hyperspectral imagery. Canopy greenness was highest mid-summer, likely reflecting temporal periods when C assimilation rates were highest. Similar to patterns seen in leaf δ13C, NDVI was highest in locations that typically experience lowest sensible heat (lowlands and ungrazed). The ability of Cornus drummondii to decouple leaf physiological responses from climate variability and fire frequency is a likely contributor to the increase in cover and frequency of this shrub species in mesic grassland and may be generalizable to other grasslands undergoing woody encroachment. PMID:24339950

Livestock grazing and wildlife: developing compatabilities.

Treesearch

Martin Vavra

2005-01-01

Livestock grazing has been considered detrimental to wildlife habitat. Managed gazing programs, however, have the potential to maintain habitat diversity and quality. In cases in which single-species management predominates (sage-grouse [Centrocercus urophasianus] or elk [Cervus elaphus nelsoni] winter range), grazing systems...

Building beef cow nutritional programs with the 1996 NRC beef cattle requirements model.

PubMed

Lardy, G P; Adams, D C; Klopfenstein, T J; Patterson, H H

2004-01-01

Designing a sound cow-calf nutritional program requires knowledge of nutrient requirements, diet quality, and intake. Effectively using the NRC (1996) beef cattle requirements model (1996NRC) also requires knowledge of dietary degradable intake protein (DIP) and microbial efficiency. Objectives of this paper are to 1) describe a framework in which 1996NRC-applicable data can be generated, 2) describe seasonal changes in nutrients on native range, 3) use the 1996NRC to predict nutrient balance for cattle grazing these forages, and 4) make recommendations for using the 1996NRC for forage-fed cattle. Extrusa samples were collected over 2 yr on native upland range and subirrigated meadow in the Nebraska Sandhills. Samples were analyzed for CP, in vitro OM digestibility (IVOMD), and DIP. Regression equations to predict nutrients were developed from these data. The 1996NRC was used to predict nutrient balances based on the dietary nutrient analyses. Recommendations for model users were also developed. On subirrigated meadow, CP and IVOMD increased rapidly during March and April. On native range, CP and IVOMD increased from April through June but decreased rapidly from August through September. Degradable intake protein (DM basis) followed trends similar to CP for both native range and subirrigated meadow. Predicted nutrient balances for spring- and summer-calving cows agreed with reported values in the literature, provided that IVOMD values were converted to DE before use in the model (1.07 x IVOMD - 8.13). When the IVOMD-to-DE conversion was not used, the model gave unrealistically high NE(m) balances. To effectively use the 1996NRC to estimate protein requirements, users should focus on three key estimates: DIP, microbial efficiency, and TDN intake. Consequently, efforts should be focused on adequately describing seasonal changes in forage nutrient content. In order to increase use of the 1996NRC, research is needed in the following areas: 1) cost-effective and accurate commercial laboratory procedures to estimate DIP, 2) reliable estimates or indicators of microbial efficiency for various forage types and qualities, 3) improved estimates of dietary TDN for forage-based diets, 4) validation work to improve estimates of DIP and MP requirements, and 5) incorporation of nitrogen recycling estimates.

Evaluation of Central North American prairie management based on species diversity, life form, and individual species metrics.

PubMed

Brudvig, Lars A; Mabry, Catherine M; Miller, James R; Walker, Tracy A

2007-06-01

Reintroduction of fire and grazing, alone or in combination, has increasingly been recognized as central to the restoration of North American mixed-grass and tallgrass prairies. Although ecological studies of these systems are abundant, they have generally been observational, or if experimental, have focused on plant species diversity. Species diversity measures alone are not sufficient to inform management, which often has goals associated with life-form groups and individual species. We examined the effects of prescribed fire, light cattle grazing, and a combination of fire and grazing on three vegetation components: species diversity, groups of species categorized by life-form, and individual species. We evaluated how successful these three treatments were in achieving specific management goals for prairies in the Iowa Loess Hills (U.S.A.). The grazing treatment promoted the greatest overall species richness, whereas grazing and burning and grazing treatments resulted in the lowest cover by woody species. Burning alone best achieved the management goals of increasing the cover and diversity of native species and reducing exotic forb and (predominantly exotic) cool-season grass cover. Species-specific responses to treatments appeared idiosyncratic (i.e., within each treatment there existed a set of species attaining their highest frequency) and nearly half of uncommon species were present in only one treatment. Because all management goals were not achieved by any one treatment, we conclude that management in this region may need refining. We suggest that a mosaic of burning and grazing (alone and in combination) may provide the greatest landscape-level species richness; however, this strategy would also likely promote the persistence of exotic species. Our results support the need to consider multiple measures, including species-specific responses, when planning and evaluating management.

Eutrophication and Dreissena invasion as drivers of biodiversity: a century of change in the mollusc community of Oneida Lake.

PubMed

Karatayev, Vadim A; Karatayev, Alexander Y; Burlakova, Lyubov E; Rudstam, Lars G

2014-01-01

Changes in nutrient loading and invasive species are among the strongest human-driven disturbances in freshwater ecosystems, but our knowledge on how they affect the biodiversity of lakes is still limited. We conducted a detailed historical analysis of the mollusc community of Oneida Lake based on our comprehensive lakewide study in 2012 and previous surveys dating back to 1915. In the early 20th century, the lake had a high water clarity, with abundant macrophytes and benthic algae, and hosted the most diverse molluscan community in New York State, including 32 gastropod and 9 unionid species. By the 1960s, lake turbidity increased during a period of anthropogenic eutrophication, resulting in a 38% decline in species richness and a 95% reduction in abundance of native gastropods grazing on benthic algae. Following the invasion of Dreissena spp. in 1991 and subsequent increases in water clarity, native gastropod species richness expanded by 37% and abundance increased 20-fold by 2012. In contrast, filter-feeding unionids were unaffected by increased turbidity during the period of eutrophication but were extirpated by dreissenids. Through contrasting effects on turbidity, eutrophication and Dreissena spp. have likely driven the observed changes in native grazing gastropods by affecting the abundance of light-limited benthic algae. Given the high species richness and ecological importance of benthic grazers, monitoring and managing turbidity is important in preserving molluscan diversity.

[Effect of herbivorous and corallivorous fishes on the survival of transplanted corals in the Colombian Caribbean].

PubMed

Chasqui-Velasco, Luis; Alvarado Ch, Elvira; Acero, Arturo; Zapata, Fernando A

2007-01-01

To examine the effects of herbivorous and corallivorous fishes on the survival of transplanted colonies of Montastraea annularis, Diploria labyrinthiformis and Porites astreoides, both transplanted and native colonies were full-cage enclosed and compared to open (uncaged) colonies, while caging effects were assessed with a partial-cage (roof treatment). To evaluate if transplant stress increased the corals availability to fish predation, comparisons of fish foraging intensity among transplanted versus native colonies were made. To determine the density of herbivorous and corallivorous fishes on the transplants area visual censuses were made. The transient herbivorous fishes (Scaridae and Acanthuridae) were the most abundant fishes, and the corallivorous fishes (mainly Chaetodontidae) were the scarcest. A negative effect of territorial herbivorous fishes on M annularis transplants survival was observed, mainly early on the study. Fish foraging intensity was similar on transplanted and native colonies, but differed among coral species, being lowest on D. labyrinthiformis. Fast macroalgal growth inside full-cages due to reduced fish grazing was observed. This caused partial bleaching and partial mortality in some colonies, mainly of P. astreoides. No significant difference in healthy tissue percentages among full-cage and uncaged colonies on M. annularis and D. labyrinthiformis was found, while in P. astreoides there were evilent differences. The results indicate a damselfish negative effect on transplants survival early on the study, which can change depending on the fish and coral species involved. Results also indicate a fish grazing positive effect, caused by the reduction of coral-algae competition pressure, mainly on P. astreoides. Parrotfishes seem to affect corals survival both negatively through direct biting, and positively by controlling algal growth. Overall, coral transplant success was almost unaffected by fish foraging activity although several differences among coral species were obvious in relation to colony shape. Additionally, the interaction among herbivorous fish grazing and coral-algae competition balance appear important in determining transplant survival.

The status and importance of crude protein and macro minerals in native pastures growing on Vertisols of the central highlands of Ethiopia.

PubMed

Gizachew, Lemma; Smit, G N

2012-01-01

The effects of pasture management, season and soil nutrient status on crude protein (CP) and macro mineral concentration of native pasture was studied in the Vertisol areas of the central Ethiopian highland. Soil and herbage samples from 18 continuously grazed (CG) and 12 seasonally grazed (SG) pasture sites were analyzed for N, P, Ca, Mg, K and Na. Soil and dry season CG pasture samples were collected in January and February 2001 (dry season: November-February), while wet season CG and SG pasture samples were collected during September 2001 (wet season: April-October). The Potassium concentration (2.55%) of mixed herbage samples from SG pasture exceeded the K values (1.80%) from CG pasture (P < 0.01). Significant (P < 0.01) differences of CP and macro minerals concentrations were noted among forage species. The mean CP and K concentrations of herbage from CG pasture were higher (P < 0.01) during the wet than during the dry season (5.97 and 1.80% vs. 3.18 and 0.79%), while the opposite was true for Ca (0.49% vs. 0.61%) (P < 0.05). Regarding soil macro minerals and the corresponding herbage macro mineral concentrations, significant (P < 0.05) but inconsistent correlations were found for Ca, P, Mg and Na. The results suggest that pasture management, season and to some extend soil nutrient status, can affect herbage CP and macro mineral composition. The levels of CP in CG pasture and that of P and Na in both CG and SG pastures may fall below the requirements of grazing livestock. Resting at critical stages of the growth cycle of the forage species encouraged the recovery of desirable species. For this reason resting of pasture can contribute significantly to the quality of the native pastures of the Vertisols of the central Ethiopian highlands and should be encouraged. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effects of soils and grazing on breeding birds of uncultivated upland grasslands of the Northern Great Plains

USGS Publications Warehouse

Kantrud, H.A.; Kologiski, R.L.

1982-01-01

The principal use of uncultivated upland grasslands in the northern Great Plains is for livestock production. However, on lands set aside for wildlife or for scientific or recreational use, grazing by livestock may be used as a management measure to enhance populations of game species or to create conditions that increase the diversity of plant or animal species. To determine the effects of grazing on the avifauna of various types of Great Plains grasslands, we conducted bird censuses and plant surveys during 1974-78 on 615 plots of lightly, moderately, or heavily grazed native rangeland.Numbers of horned lark (Eremophila alpestris), western meadowlark (Sturnella neglecta), lark bunting (Calamospiza melanocorys), and chestnut-collared longspur (Calcarius ornatus) accounted for 65-75% of the total bird population, regardless of grazing intensity. For the entire area sampled (600,000 km2), horned lark, western meadowlark, and chestnut-collared longspur were the dominant birds. Major differences in composition of the dominant species and species richness occurred among the major soils. Increased mean annual soil temperature seemingly had a greater negative influence on avian species richness than did decreased soil moisture or organic matter content. Differences in total bird density were not significant among soils and among grazing intensities within most soils. For the area as a whole, light or moderate grazing resulted in increased species richness. Of the 29 species studied, 2 responded significantly to grazing for the area as a whole and 6 others to grazing on the soil in which peak densities occurred. Response of several other species to grazing effects evidently varied among strata.A list of plants with mean cover values of more than 1% in any of the 18 combinations of soils and grazing intensities contained less than 25 species, attesting to the relative simplicity of the grassland vegetation in the northern Great Plains. Agropyron spp. and Bouteloua gracilis were the dominant plants that provided greater than average cover on the best habitat for the most bird species. Optimum habitat for each bird species is given in terms of grazing, soils, and dominant plant species. Increased soil temperature probably had a negative effect on plant species richness, especially among soils with a high organic matter content that supported perennial grasses and other mesophytes.

Effects of grazing and burning on densities and habitats of breeding ducks in North Dakota

USGS Publications Warehouse

Kruse, Arnold D.; Bowen, Bonnie S.

1996-01-01

Native grassland communities controlled by public agencies become increasingly important to the maintenance of many wildlife species as privately owned grasslands are destroyed or degraded for farming, mining, and development. In turn, wildlife on publicly owned grasslands are affected by the management techniques practiced by local managers. We studied the effects of grazing and prescribed burning on upland-nesting ducks and the structure and type of vegetation from 1980 to 1988 at the Lostwood National Wildlife Refuge (NWR) in northwestern North Dakota. Mallard (Anas platyrhynchos), the most abundant species at Lostwood NWR, had lower (P < 0.05) annual nest densities on experimental and control fields in the later years than in the early years of the study. Spring burning reduced (P = 0.016) nest densities of gadwall (A. strepera). Spring grazing reduced nest densities of gadwall (P = 0.014), and blue-winged teal (A. discors, P = 0.023). Nest density of gadwall increased (P = 0.018) after spring grazing was terminated. On the summer burn/spring graze fields, blue-winged teal had lower (P = 0.010) nest densities after treatments (1987-88) than before treatments (1980-81). Nest success was high (mallard 34%, gadwall 45%, blue-winged teal 31%) but was not influenced (P 0.16) by the burning and grazing treatments. During the study, the amount of grass/brush increased, whereas the amount of brush and brush/grass decreased on control and treatment fields. During the years with burning and grazing, short vegetation increased and tall vegetation decreased. On the spring graze fields, 1 year after grazing ended the vegetation was similar to that on the control fields. The spring burn and summer burn/spring graze fields recovered more slowly. Brushy species such as western snowberry (Symphoricarpos occidentalis) provided attractive nesting habitat for many upland-nesting waterfowl species, especially mallard, gadwall, American wigeon (A. americana), and northern pintail (A. acuta). Habitat needs of additional species of wildlife that depend on grasslands may need to be considered when deciding how to manage habitat.

76 FR 80329 - Information Collection; Grazing Permit Administration Forms

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-23

... to another account Information on the allotment; number of cattle, horses, or sheep; Period range not... DEPARTMENT OF AGRICULTURE Forest Service Information Collection; Grazing Permit Administration... organizations on the extension with no revision of a currently approved information collection, Grazing Permit...

75 FR 29572 - Information Collection; Grazing Management

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-26

... Control Number 1004-0019] Information Collection; Grazing Management AGENCY: Bureau of Land Management... submitted an information collection request to the Office of Management and Budget (OMB) for a 3-year... INFORMATION: Title: Grazing Management (43 CFR 4120). OMB Number: 1004-0019. Forms: 4120-6 (Cooperative Range...

Eating beef: cattle, methane and food production.

PubMed

Wahlquist, Åsa K

2013-01-01

A number of prominent people have advocated eating less meat or becoming a vegetarian to reduce global warming, because cattle produce the greenhouse gas methane. This raises a number of questions including: what will happen to the grasslands that much of the world's cattle currently graze; how will alternate protein be produced, and what will the greenhouse consequences of that production be? It comes down to production systems. About 70 per cent of the world's agricultural land is grassland, and the only way to produce food from grasslands is to graze ruminants on it. If domesticated animals do not graze the grasslands, native or feral ruminants, which also produce methane, tend to move in. Feeding high quality grain to cattle is much less defensible. Replacing animal protein with plant proteins like soybeans necessitates more cropping land, water, fuel and chemicals being used. A more rational food system would raise cattle on grasslands but not feed them high quality grains. Instead more of the currently grown crop could be devoted to human consumption.

Removal of perennial herbaceous species affects response of cold desert scrublands to fire

Treesearch

Jeanne C. Chambers; David I. Board; Bruce A. Roundy; Peter J. Weisberg

2017-01-01

Our results show that loss of perennial herbaceous species, which can result from inappropriate livestock grazing, and loss of shrubs, which often results from fire, interact to affect key functional groups. The implications are that ecosystem resilience to disturbance in Cold Desert shrublands decreases when competition from perennial native grasses and forbs for...

Riparian restoration of Seiiorito Canyon, a tributary of the Rio Puerco

Treesearch

Dwain W. Vincent

1996-01-01

Seiiorito Canyon, a non-functional, degraded tributary stream of the Rio Puerto in New Mexico, has begun to respond to management strategies by the Bureau of Land Management. Restoration of the riparian ecosystem has been accomplished principally through livestock grazing management and planting and reestablishment of the native cottonwood/willow communities. The use...

The Importance and Future Condition of Western Riparian Ecosystems as Migratory Bird Habitat

Treesearch

Susan K. Skagen; Rob Hazlewood; Michael L. Scott

2005-01-01

Riparian forests have long been considered important habitats for breeding western landbirds, and growing evidence reinforces their importance during the migratory period as well. Extensive modification of natural flow regimes, grazing, and forest clearing along many rivers in the western U.S. have led to loss and simplification of native riparian forests and to...

78 FR 59 - Endangered and Threatened Wildlife and Plants; Listing the Honduran Emerald Hummingbird

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-02

...-owned land and is often planted with non-native grasses for cattle foraging (Perez and Thorn 2012, pers... invasive grass species ( http://www.birdlist.org/cam/honduras/hn_ecosystems.htm , accessed May 22, 2012... private landowners in order to plant pasture grass for grazing cattle (Hyman 2012 pers. comm.). In the...

The history of human disturbance in forest ecosystems of southern Indiana

Treesearch

Michael A. Jenkins

2013-01-01

The forests of southern Indiana have been shaped and defined by anthropogenic disturbance. Native Americans influenced composition and structure through land clearing and burning, but the scale and rate of human disturbance intensified with European settlement. Sustained settlement led to the loss of forest land to agriculture and livestock grazing. Forests were also...

Grassland bird responses to land management in the largest remaining tallgrass prairie.

PubMed

Rahmig, Corina J; Jensen, William E; With, Kimberly A

2009-04-01

Extensive habitat loss and changing agricultural practices have caused widespread declines in grassland birds throughout North America. The Flint Hills of Kansas and Oklahoma--the largest remaining tallgrass prairie--is important for grassland bird conservation despite supporting a major cattle industry. In 2004 and 2005, we assessed the community, population, and demographic responses of grassland birds to the predominant management practices (grazing, burning, and haying) of the region, including grasslands restored under the Conservation Reserve Program (CRP). We targeted 3 species at the core of this avian community: the Dickcissel (Spiza americana), Grasshopper Sparrow (Ammodramus savannarum), and Eastern Meadowlark (Sturnella magna). Bird diversity was higher in native prairie hayfields and grazed pastures than CRP fields, which were dominated by Dickcissels. Although Dickcissel density was highest in CRP, their nest success was highest and nest parasitism by Brown-headed Cowbirds (Moluthrus ater) lowest in unburned hayfields (in 2004). Conversely, Grasshopper Sparrow density was highest in grazed pastures, but their nest success was lowest in these pastures and highest in burned hayfields, where cowbird parasitism was also lowest (in 2004). Management did not influence density and nest survival of Eastern Meadowlarks, which were uniformly low across the region. Nest success was extremely low (5-12%) for all 3 species in 2005, perhaps because of a record spring drought. Although the CRP has benefited grassland birds in agricultural landscapes, these areas may have lower habitat value in the context of native prairie. Hayfields may provide beneficial habitat for some grassland birds in the Flint Hills because they are mowed later in the breeding season than elsewhere in the Midwest. Widespread grazing and annual burning have homogenized habitat-and thus grassland-bird responses-across the Flint Hills. Diversification of management practices could increase habitat heterogeneity and enhance the conservation potential of the Flint Hills for grassland birds.

Interactions between non-native armored suckermouth catfish (Loricariidae: Pterygoplichthys) and native Florida manatee (Trichechus manatus latirostris) in artesian springs

USGS Publications Warehouse

Nico, Leo G.; Loftus, William F.; Reid, James P.

2009-01-01

Non-native suckermouth armored catfishes (Loricariidae) of the genus Pterygoplichthys are now common throughout much of peninsular Florida. In this paper, we present preliminary observations on interactions between a Pterygoplichthys species, tentatively identified as P. disjunctivus (Weber, 1991), and endangered native Florida manatees, Trichechus manatus latirostris (Harlan, 1824), in artesian spring systems in Florida's St. Johns River drainage. The introduced catfish have become abundant in spring habitats, sites used by manatees as winter thermal refuges. In the spring runs, Pterygoplichthys regularly attaches to manatees and grazes the epibiota on their skin. On occasion, dozens of Pterygoplichthys congregate on individual manatees. Manatee responses varied widely; some did not react visibly to attached catfish whereas others appeared agitated and attempted to dislodge the fish. The costs and/or benefits of this interaction to manatees remain unclear.

Molecular footprints of the Holocene retreat of dwarf birch in Britain

PubMed Central

Wang, Nian; Borrell, James S; Bodles, William J A; Kuttapitiya, Anasuya; Nichols, Richard A; Buggs, Richard J A

2014-01-01

Past reproductive interactions among incompletely isolated species may leave behind a trail of introgressed alleles, shedding light on historical range movements. Betula pubescens is a widespread native tetraploid tree species in Britain, occupying habitats intermediate to those of its native diploid relatives, B. pendula and B. nana. Genotyping 1134 trees from the three species at 12 microsatellite loci, we found evidence of introgression from both diploid species into B. pubescens, despite the ploidy difference. Surprisingly, introgression from B. nana, a dwarf species whose present range is highly restricted in northern, high-altitude peat bogs, was greater than introgression from B. pendula, which is morphologically similar to B. pubescens and has a substantially overlapping range. A cline of introgression from B. nana was found extending into B. pubescens populations far to the south of the current B. nana range. We suggest that this genetic pattern is a footprint of a historical decline and/or northwards shift in the range of B. nana populations due to climate warming in the Holocene. This is consistent with pollen records that show a broader, more southerly distribution of B. nana in the past. Ecological niche modelling predicts that B. nana is adapted to a larger range than it currently occupies, suggesting additional factors such as grazing and hybridization may have exacerbated its decline. We found very little introgression between B. nana and B. pendula, despite both being diploid, perhaps because their distributions in the past have rarely overlapped. Future conservation of B. nana may partly depend on minimization of hybridization with B. pubescens, and avoidance of planting B. pendula near B. nana populations. PMID:24762172

Estimating influence of stocking regimes on livestock grazing distributions

USDA-ARS?s Scientific Manuscript database

Ungulates often concentrate grazing at small hotspots in the larger landscape, and dispersing livestock away from these intensively grazed areas is one of the central challenges in range management. We evaluated a technique based on shifting the stocking date to prevent overgrazing of small areas co...

78 FR 52782 - Renewal of Approved Information Collection

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-26

... maintaining range improvement projects that enhance or improve livestock grazing management, improve watershed... Interior, Bureau of Land Management, 1849 C Street NW., Room 2134LM, Attention: Jean Sonneman, Washington... by the BLM. Range improvements enhance or improve livestock grazing management, improve watershed...

MICROTOPOGRAPHY AND GRAZING IN DESERT RANGE LAND: A LESSON IN STATISTICS VERSUS REALITY IN THE FIELD

EPA Science Inventory

This presentation summarizes two experiments on the effects of grazing on soil microtopography in a Chihuahuan Desert rangeland. In the first experiment, we measured the effect of three consecutive years of short duration <48 hours per year) intense grazing (20--40 yearling cows ...

Community responses of arthropods to a range of traditional and manipulated grazing in shortgrass steppe

USDA-ARS?s Scientific Manuscript database

Livestock grazing has context-dependent impacts on grassland plant and animal communities. In grassland ecosystems that have evolved with large herbivores, such as the North American Great Plains with bison (Bison bison), responses of plants to grazing are better understood, and more predictable, th...

78 FR 21147 - Renewal of Approved Information Collection

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-09

... maintaining range improvement projects that enhance or improve livestock grazing management, improve watershed.... Department of the Interior, Bureau of Land Management, 1849 C Street NW., Room 2134LM, Attention: Jean... lands managed by the BLM. Range improvements enhance or improve livestock grazing management, improve...

Multifunctional Dryland Forestry: Accumulating Experience From the East-Mediterranean

NASA Astrophysics Data System (ADS)

Osem, Y.; Shachack, M.; Moshe, I.

2014-12-01

Although small in size the landscapes of East Mediterranean Israel extend over a wide geo-climatic gradient ranging from dry sub-humid to hyper-arid lands. Thousands of years under intense human exploitation in this region, involving cutting, livestock grazing, agricultural practice and fire have resulted in severe degradation of these water limited ecosystems. The highly degraded state of the native vegetation as found by the new settlers coming to Israel in the beginning of the previous century, has provided the basic motivation for an extensive afforestation enterprise carried out during the last 100 years. This talk will present an overview on the accumulating experience in establishing and managing multifunctional forests in this dryland region. Given their very limited timber value, dryland forests are designed and managed under various goals the important of which are landscape aesthetics, recreation opportunities, grazing land, ecosystem restoration and soil conservation. Being subjected to water scarcity of high temporal and spatial variation, these manmade systems are managed to withstand water deficiency of unpredictable magnitude through the manipulation of both water input and water consumption. In the dry subhumid regions, forest management focuses mainly on controlling water consumption through the manipulation of vegetation structure using thinning and livestock grazing as primary silvicultural tools. Going into the semiarid zone, practices of rainfall redistribution and runoff harvesting become crucial for tree establishment and growth. The implementation of these practices varies depending on topography, rainfall amount and forest goals. The talk will provide a brief description of these unique silvicultural systems, review some of the recent scientific work in them and refer to critical gaps in knowledge. The relevancy to intercrop agroforestry in rainfed ecosystems will be discussed.

Fire history of the San Francisco East Bay region and implications for landscape patterns

USGS Publications Warehouse

Keeley, J.E.

2005-01-01

The San Francisco East Bay landscape is a rich mosaic of grasslands, shrublands and woodlands that is experiencing losses of grassland due to colonization by shrubs and succession towards woodland associations. The instability of these grasslands is apparently due to their disturbance-dependent nature coupled with 20th century changes in fire and grazing activity. This study uses fire history records to determine the potential for fire in this region and for evidence of changes in the second half of the 20th century that would account for shrubland expansion. This region has a largely anthropogenic fire regime with no lightning-ignited fires in most years. Fire suppression policy has not excluded fire from this region; however, it has been effective at maintaining roughly similar burning levels in the face of increasing anthropogenic fires, and effective at decreasing the size of fires. Fire frequency parallels increasing population growth until the latter part of the 20th century, when it reached a plateau. Fire does not appear to have been a major factor in the shrub colonization of grasslands, and cessation of grazing is a more likely immediate cause. Because grasslands are not under strong edaphic control, rather their distribution appears to be disturbance-dependent, and natural lightning ignitions are rare in the region, I hypothesize that, before the entrance of people into the region, grasslands were of limited extent. Native Americans played a major role in creation of grasslands through repeated burning and these disturbance-dependent grasslands were maintained by early European settlers through overstocking of these range lands with cattle and sheep. Twentieth century reduction in grazing, coupled with a lack of natural fires and effective suppression of anthropogenic fires, have acted in concert to favor shrubland expansion.

Vascular Plant and Vertebrate Inventory of Coronado National Memorial

USGS Publications Warehouse

Schmidt, Cecilia A.; Powell, Brian F.; Swann, Don E.; Halvorson, William L.

2007-01-01

We conducted inventories for amphibians and reptiles, birds, and mammals; and summarized past inventories for vascular plants at Coronado National Memorial (NM) in Arizona. We used our data as well as data from previous research to compile species lists for the memorial, assess inventory completeness, and make suggestions on future monitoring efforts. There have been 940 species of plants and vertebrates recorded at Coronado NM (Table 1), of which 46 (5%) are non-native. The species richness of the memorial is one of the highest in the Sonoran Desert Network of park units, third only to park units that are two and one-half (Chiricahua National Monument), 19 (Saguaro National Park) and 70 (Organ Pipe Cactus National Monument) times larger in area. The high species diversities are due to the large elevational gradient, overlap of bigeographical regions, wide range of geology and soils, and diverse vegetation communities present at the memorial. Changes in species composition have occurred at the memorial over the last 20 years in all major taxonomic groups. These changes are likely due to increases in grassy plant species (both native and non-native) at the lower elevations of the memorial. We suspect that grassy plant cover has increased because of changes in grazing intensity, introduction of some non-native species, and a recent fire. All recent vertebrate inventories have yielded grassland obligate species not previously recorded at the memorial. Based on the review of past studies, we believe the inventory for most taxa, except bats, is nearly complete, though some rare or elusive species will likely be added with additional survey effort.

Nitrogen deposition effects on coastal sage vegetation of southern California

Treesearch

Edith B. Allen; Pamela E. Padgett; Andrzej Bytnerowicz; Richard Minnich

1998-01-01

The coastal sage scrub (CSS) vegetation of southern California has been declining in land area and in shrub density over the past 60 years or more, and is being replaced by Mediterranean annual grasses in many areas. Although much of this loss is attributable to agriculture, grazing, urbanization and frequent fire, even protected areas have experienced a loss in native...

Long-term response of the mamane forest to feral herbivore management on Mauna Kea, Hawaii

Treesearch

E. Reddy; D. H. Van Vuren; P. G. Scowcroft; J. B. Kauffman; L. Perry

2012-01-01

Seven exclosure sites located on Mauna Kea, Hawaii and established in the 1960s and 70s were sampled to characterize long-term response of the mamane (Sophora chrysophylla) forest to protection from feral sheep grazing, and to assess impacts of non-native plant species and recurrent sheep presence on forest recovery. The forest provides essential...

AmeriFlux US-Shd Shidler- Oklahoma

DOE Data Explorer

Verma, Shashi [University of Nebraska - Lincoln

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site US-Shd Shidler- Oklahoma. Site Description - Native tall grass prairie. A prairie management prescribed burn was conducted in the spring of 1997, but not in 1996. The site was not grazed from early August 1996-September 1997. almost all plants are warm season C4 species, grasslands, temperate continental climate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raz-Yaseef, Naama; Billesbach, Dave P.; Fischer, Marc L.

The Southern Great Plains are characterized by a fine-scale mixture of different land-cover types, predominantly winter-wheat and grazed pasture, with relatively small areas of other crops, native prairie, and switchgrass. Recent droughts and predictions of increased drought in the Southern Great Plains, especially during the summer months, raise concern for these ecosystems. We measured ecosystem carbon and water fluxes with eddy-covariance systems over cultivated cropland for 10 years, and over lightly grazed prairie and new switchgrass fields for 2 years each. Growing-season precipitation showed the strongest control over net carbon uptake for all ecosystems, but with a variable effect: grassesmore » (prairie and switchgrass) needed at least 350 mm of precipitation during the growing season to become net carbon sinks, while crops needed only 100 mm. In summer, high temperatures enhanced evaporation and led to higher likelihood of dry soil conditions. Therefore, summer-growing native prairie species and switchgrass experienced more seasonal droughts than spring-growing crops. For wheat, the net reduction in carbon uptake resulted mostly from a decrease in gross primary production rather than an increase in respiration. Flux measurements suggested that management practices for crops were effective in suppressing evapotranspiration and decomposition (by harvesting and removing secondary growth), and in increasing carbon uptake (by fertilizing and conserving summer soil water). In light of future projections for wetter springs and drier and warmer summers in the Southern Great Plains, our study indicates an increased vulnerability in native ecosystems and summer crops over time.« less

Eutrophication and Dreissena Invasion as Drivers of Biodiversity: A Century of Change in the Mollusc Community of Oneida Lake

PubMed Central

Karatayev, Vadim A.; Karatayev, Alexander Y.; Burlakova, Lyubov E.; Rudstam, Lars G.

2014-01-01

Changes in nutrient loading and invasive species are among the strongest human-driven disturbances in freshwater ecosystems, but our knowledge on how they affect the biodiversity of lakes is still limited. We conducted a detailed historical analysis of the mollusc community of Oneida Lake based on our comprehensive lakewide study in 2012 and previous surveys dating back to 1915. In the early 20th century, the lake had a high water clarity, with abundant macrophytes and benthic algae, and hosted the most diverse molluscan community in New York State, including 32 gastropod and 9 unionid species. By the 1960s, lake turbidity increased during a period of anthropogenic eutrophication, resulting in a 38% decline in species richness and a 95% reduction in abundance of native gastropods grazing on benthic algae. Following the invasion of Dreissena spp. in 1991 and subsequent increases in water clarity, native gastropod species richness expanded by 37% and abundance increased 20-fold by 2012. In contrast, filter-feeding unionids were unaffected by increased turbidity during the period of eutrophication but were extirpated by dreissenids. Through contrasting effects on turbidity, eutrophication and Dreissena spp. have likely driven the observed changes in native grazing gastropods by affecting the abundance of light-limited benthic algae. Given the high species richness and ecological importance of benthic grazers, monitoring and managing turbidity is important in preserving molluscan diversity. PMID:25010705

Fatty acid composition of polar and neutral meat lipids of goats browsing in native pasture of Brazilian Semiarid.

PubMed

Fonteles, Natália L O; Alves, Susana P; Madruga, Marta Suely; Queiroga, Rita R E; Andrade, Albericio P; Silva, Divan S; Leal, Amanda P; Bessa, Rui J B; Medeiros, Ariosvaldo N

2018-05-01

Thirty six male goats grazing Caatinga native pasture were randomly assigned to 4 concentrate supplementation levels (0, 5, 10 and 15g/kg of body weight) and slaughtered after 120days. Longissimus muscle meat lipids were extracted and fractionated into neutral (NL) and polar (PL) lipids. Supplementation of grazing goats increased linearly (P<0.05) intramuscular fat (1 to 1.5% of meat) and NL (0.3 to 1% of meat) but decreased linearly (P=0.044) the PL (0.66 to 0.50% of meat). On NL, supplementation increased linearly (P=0.047) the proportion of c9-18:1 (31 to 40% of FA) with supplementation. On PL, supplementation reduced linearly (P<0.03) the dimethyl acetals, 18:3n-3 and most of long chain polyunsaturated FA (PUFA) proportions but increased linearly (P<0.001) the c9-18:1. Considering the total meat FA, supplementation led to an increase of the saturated and monounsaturated FA contents and a decrease of the long chain n-6 and n-3 PUFA contents. Copyright © 2018 Elsevier Ltd. All rights reserved.

Beneficial effects of restoration practices can be thwarted by climate extremes.

PubMed

Maccherini, Simona; Bacaro, Giovanni; Marignani, Michela

2018-06-01

The impacts of climate extremes on species, communities and ecosystems have become critical concerns to science and society. Under a changing climate, how restoration outcomes are affected by extreme climate variables is a largely unknown topic. We analyzed the effects of experimental factors (grazing and sowing of native species), extreme climate events (intense precipitation and extreme temperatures indexes) and their combination on the restoration progress of a dry, calcareous grassland in Tuscany (Italy) with a 1 year before/15 years continuous annual monitoring after, control/impact (BACI) experiment. Grazing had a beneficial effect on the diversity of the grassland, while sowing had a limited impact. The climatic index that most affected the entire plant community composition was the number of very heavy precipitation days. The interaction of grazing and extreme climatic indexes had a significant detrimental effect on restoration outcomes, increasing the cover of synanthropic and Cosmopolitan-Subcosmopolitan generalist species and decreasing the cover of more valuable species such endemic species. In the richest grazed plots, species richness showed a lower sensitivity to the average precipitation per wet day but in grazed site, restoration outcomes can be negatively influenced by the intensification of precipitation and temperature extremes. In a context of progressive tropicalization of the Mediterranean area, to assist managers setting achievable restoration goals, restoration practitioners should consider that climate extremes might interfere with the beneficial effects of restoration practices. Copyright © 2018 Elsevier B.V. All rights reserved.

Livestock grazing and the desert tortoise in the Mojave Desert

USGS Publications Warehouse

Oldemeyer, John L.

1994-01-01

A large part of the Mojave Desert is not in pristine condition, and some current conditions can be related to past grazing-management practices. No information could be found on densities of the desert tortoise (Gopherus agassizii) or on vegetative conditions of areas that had not been grazed to allow managers a comparison of range conditions with data on tortoises. Experimental information to assess the effect of livestock grazing on tortoises is lacking, and researchers have not yet examined whether the forage that remains after grazing is sufficient to meet the nutritional needs of desert tortoises.

Wild sheep and deer in Hawai'i: a threat to fragile ecosystems

USGS Publications Warehouse

Hess, Steven C.

2008-01-01

The unique native flora of the Hawaiian Islands, which evolved in the absence of ungulates (grazing animals), is highly vulnerable to damage by trampling and browsing. Wild ungulates introduced into Hawai'i in the past 150 years, including mouflon, axis deer, and mule deer, have severely harmed the native flora. Control measures used against feral animals do not work as well against these wild animals. Trophy hunting tends to alter sex ratios and increase population growth. U.S. Geological Survey scientists are studying these wild ungulates in order to develop more effective control measures that help protect Hawai'i's endemic flora.

Combining Restricted Grazing and Nitrification Inhibitors to Reduce Nitrogen Leaching on New Zealand Dairy Farms.

PubMed

Romera, Alvaro J; Cichota, Rogerio; Beukes, Pierre C; Gregorini, Pablo; Snow, Val O; Vogeler, Iris

2017-01-01

Intensification of pastoral dairy systems often means more nitrogen (N) leaching. A number of mitigation strategies have been proposed to reduce or reverse this trend. The main strategies focus on reducing the urinary N load onto pastures or reducing the rate of nitrification once the urine has been deposited. Restricted grazing is an example of the former and the use of nitrification inhibitors an example of the latter. A relevant concern is the cost effectiveness of these strategies, independently and jointly. To address this concern, we employed a modeling approach to estimate N leaching with and without the use of these mitigation options from a typical grazing dairy farm in New Zealand. Three restricted grazing options were modeled with and without a nitrification inhibitor (dicyandiamide, DCD) and the results were compared with a baseline farm (no restricted grazing, no inhibitor). Applying DCD twice a year, closely following the cows after an autumn and winter grazing round, has the potential to reduce annualized and farm-scale N leaching by ∼12%, whereas restricted grazing had leaching reductions ranging from 23 to 32%, depending on the timing of restricted grazing. Combining the two strategies resulted in leaching reductions of 31 to 40%. The abatement cost per kilogram of N leaching reduction was NZ$50 with DCD, NZ$32 to 37 for restricted grazing, and NZ$40 to 46 when the two were combined. For the range analyzed, all treatments indicated similar cost per percentage unit of mitigated N leaching, demonstrating that restricted grazing and nitrification inhibitors can be effective when used concurrently. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Doublethink and scale mismatch polarize policies for an invasive tree

USGS Publications Warehouse

Roberts, Caleb P.; Uden, Daniel R.; Allen, Craig R.; Twidwell, Dirac

2018-01-01

Mismatches between invasive species management policies and ecological knowledge can lead to profound societal consequences. For this reason, natural resource agencies have adopted the scientifically-based density-impact invasive species curve to guide invasive species management. We use the density-impact model to evaluate how well management policies for a native invader (Juniperus virginiana) match scientific guidelines. Juniperus virginiana invasion is causing a sub-continental regime shift from grasslands to woodlands in central North America, and its impacts span collapses in endemic diversity, heightened wildfire risk, and crashes in grazing land profitability. We (1) use land cover data to identify the stage of Juniperus virginiana invasion for three ecoregions within Nebraska, USA, (2) determine the range of invasion stages at individual land parcel extents within each ecoregion based on the density-impact model, and (3) determine policy alignment and mismatches relative to the density-impact model in order to assess their potential to meet sustainability targets and avoid societal impacts as Juniperus virginiana abundance increases. We found that nearly all policies evidenced doublethink and policy-ecology mismatches, for instance, promoting spread of Juniperus virginiana regardless of invasion stage while simultaneously managing it as a native invader in the same ecoregion. Like other invasive species, theory and literature for this native invader indicate that the consequences of invasion are unlikely to be prevented if policies fail to prioritize management at incipient invasion stages. Theory suggests a more realistic approach would be to align policy with the stage of invasion at local and ecoregion management scales. There is a need for scientists, policy makers, and ecosystem managers to move past ideologies governing native versus non-native invader classification and toward a framework that accounts for the uniqueness of native species invasions, their anthropogenic drivers, and their impacts on ecosystem services.

Landscape variation in the diet and productivity of reindeer in Alaska based on stable isotope analyses

Treesearch

Gregory L. Finstad; Knut Kielland

2011-01-01

Productivity of a managed grazing system is dependent upon both the grazing strategy of ungulates and decisions made by humans. Herds of domestic reindeer (Rangifer tarandus tarandus) graze on discrete ranges of the Seward Peninsula, Alaska with variable production rates. We show that the 15N natural abundance of reindeer...

Relationship between body condition score at calving and reproductive performance in young postpartum cows grazing native range.

PubMed

Mulliniks, J T; Cox, S H; Kemp, M E; Endecott, R L; Waterman, R C; Vanleeuwen, D M; Petersen, M K

2012-08-01

Body condition score is used as a management tool to predict competency of reproduction in beef cows. Therefore, a retrospective study was performed to evaluate association of BCS at calving with subsequent pregnancy rate, days to first postpartum ovulation, nutrient status (assessed by blood metabolites), and calf BW change in 2- and 3-yr-old cows (n = 351) managed and selected to fit their environment of grazing native range over 6 yr at the Corona Range and Livestock Research Center, Corona, NM. Cows were managed similarly before calving, without manipulation of management, to achieve predetermined BCS at parturition. Palpable BCS (scale of 1 to 9) were determined by 2 experienced technicians before calving. Cows were classified to 1 of 3 BCS groups prior calving: BCS 4 (mean BCS = 4.3 ± 0.02), 5 (mean BCS = 5.0 ± 0.03), or 6 (mean BCS = 5.8 ± 0.06). Cows were weighed weekly after calving and serum was collected once weekly (1 yr) or twice weekly (5 yr) for progesterone analysis to estimate first postpartum ovulation beginning 35 d postpartum. Year effects also were evaluated, with years identified as either above or below average precipitation. Days to first postpartum ovulation did not differ among calving BCS groups (P = 0.93). Pregnancy rates were not influenced by calving BCS (P = 0.83; 92%, 91%, 90% for BCS 4, 5, and 6, respectively). Days to BW nadir was not influenced by BCS at calving (P = 0.95). Cow BW was different at all measuring points (P < 0.01) with BCS 6 cows having the heaviest BW and cows with BCS 4 the lightest. Cows with calving BCS 4 and 5 lost more (P = 0.06) BW from the initiation of the study to the end of breeding than cows with BCS 6. However, cow BW change at all other measurement periods was not different (P ≥ 0.49) among calving BCS groups. Serum glucose and NEFA concentrations were not influenced by calving BCS (P ≥ 0.51). Calf BW at birth (P = 0.60), branding (55-d BW; P = 0.76), and weaning (205-d BW; P = 0.60) were not impacted by cow calving BCS. Body condition score did not influence overall pregnancy rates, indicating that young cows can have a reduced BCS and still be reproductively punctual. Therefore, these results indicate that reproductive performance of young cows with reduced BCS may not be affected when managed in extensive range conditions.

Bitterbrush ecology - some recent findings

Treesearch

Eamor C. Nord

1959-01-01

Bitterbrush (Purshia ssp. ) is an important element of range grazing capacity in the West . This browse shrub provides premium forage on many important winter-deer ranges and is a valuable part of the diet of many animals. But the shrubs have been destroyed or damaged over large areas by fire, heavy grazing by livestock and game, insect defoliation...

25 CFR 700.711 - Grazing permits.

Code of Federal Regulations, 2010 CFR

2010-04-01

... OFFICE OF NAVAJO AND HOPI INDIAN RELOCATION COMMISSION OPERATIONS AND RELOCATION PROCEDURES New Lands... residency on the New Lands Range Unit of permit issue, and (4) Own livestock which graze on the range unit of permit issue. (c) Permits will be issued for a base of 80 SUYL (20 AU) and may not be divided or...

43 CFR 4120.5-2 - Cooperation with Tribal, state, county, and Federal agencies.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING..., to the extent such cooperation does not conflict with the Wild Free-Roaming Horse and Burro Act of... grazing boards in reviewing range improvements and allotment management plans on public lands. [60 FR 9965...

43 CFR 4120.5-2 - Cooperation with Tribal, state, county, and Federal agencies.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING..., to the extent such cooperation does not conflict with the Wild Free-Roaming Horse and Burro Act of... grazing boards in reviewing range improvements and allotment management plans on public lands. [60 FR 9965...

43 CFR 4120.5-2 - Cooperation with Tribal, state, county, and Federal agencies.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING..., to the extent such cooperation does not conflict with the Wild Free-Roaming Horse and Burro Act of... grazing boards in reviewing range improvements and allotment management plans on public lands. [60 FR 9965...

A Survey of the Educational and Training Needs of the Pastoral Industry of South Australia. Final Report.

ERIC Educational Resources Information Center

Raftery, John; And Others

In late 1979 and 1980 a survey was conducted of 207 pastoral lease owners and managers in the north of South Australia to determine their education and training requirements. The pastoral industry grazes sheep and cattle on native pastures and shrubs, is beset by widely fluctuating rainfall and production, sells its products of wool and meat on a…

Land uses, fire, and invasion: Exotic annual Bromus and human dimensions [Chapter 11

Treesearch

David A. Pyke; Jeanne C. Chambers; Jeffrey L. Beck; Matthew L. Brooks; Brian A. Mealor

2016-01-01

Human land uses are the primary cause of the introduction and spread of exotic annual Bromus species. Initial introductions were likely linked to contaminated seeds used by homesteading farmers in the late 1880s and early 1900s. Transportation routes aided their spread. Unrestricted livestock grazing from the 1800s through the mid-1900s reduced native plant competitors...

Toward a woody plant list for Antigua and Barbuda: past and present.

Treesearch

John Francis; Carlos Rivera; Julio Figureroa

1994-01-01

Beginning in the 17th century, the forest lands of Antigua and Barbuda were cleared for agriculture, burned, cut over, and grazed severely. A survey by personnel of the USDA Forest Service, International Institute of Tropical Forestry and previous surveys were used to assemble lists of native and exotic woody plants. A large majority of the original woody flora still...

Assessing herbivore foraging behavior with GPS collars in a semiarid grassland.

PubMed

Augustine, David J; Derner, Justin D

2013-03-15

Advances in global positioning system (GPS) technology have dramatically enhanced the ability to track and study distributions of free-ranging livestock. Understanding factors controlling the distribution of free-ranging livestock requires the ability to assess when and where they are foraging. For four years (2008-2011), we periodically collected GPS and activity sensor data together with direct observations of collared cattle grazing semiarid rangeland in eastern Colorado. From these data, we developed classification tree models that allowed us to discriminate between grazing and non-grazing activities. We evaluated: (1) which activity sensor measurements from the GPS collars were most valuable in predicting cattle foraging behavior, (2) the accuracy of binary (grazing, non-grazing) activity models vs. models with multiple activity categories (grazing, resting, traveling, mixed), and (3) the accuracy of models that are robust across years vs. models specific to a given year. A binary classification tree correctly removed 86.5% of the non-grazing locations, while correctly retaining 87.8% of the locations where the animal was grazing, for an overall misclassification rate of 12.9%. A classification tree that separated activity into four different categories yielded a greater misclassification rate of 16.0%. Distance travelled in a 5 minute interval and the proportion of the interval with the sensor indicating a head down position were the two most important variables predicting grazing activity. Fitting annual models of cattle foraging activity did not improve model accuracy compared to a single model based on all four years combined. This suggests that increased sample size was more valuable than accounting for interannual variation in foraging behavior associated with variation in forage production. Our models differ from previous assessments in semiarid rangeland of Israel and mesic pastures in the United States in terms of the value of different activity sensor measurements for identifying grazing activity, suggesting that the use of GPS collars to classify cattle grazing behavior will require calibrations specific to the environment and vegetation being studied.

A spatial risk assessment of bighorn sheep extirpation by grazing domestic sheep on public lands.

PubMed

Carpenter, Tim E; Coggins, Victor L; McCarthy, Clinton; O'Brien, Chans S; O'Brien, Joshua M; Schommer, Timothy J

2014-04-01

Bighorn sheep currently occupy just 30% of their historic distribution, and persist in populations less than 5% as abundant overall as their early 19th century counterparts. Present-day recovery of bighorn sheep populations is in large part limited by periodic outbreaks of respiratory disease, which can be transmitted to bighorn sheep via contact with domestic sheep grazing in their vicinity. In order to assess the viability of bighorn sheep populations on the Payette National Forest (PNF) under several alternative proposals for domestic sheep grazing, we developed a series of interlinked models. Using telemetry and habitat data, we characterized herd home ranges and foray movements of bighorn sheep from their home ranges. Combining foray model movement estimates with known domestic sheep grazing areas (allotments), a Risk of Contact Model estimated bighorn sheep contact rates with domestic sheep allotments. Finally, we used demographic and epidemiologic data to construct population and disease transmission models (Disease Model), which we used to estimate bighorn sheep persistence under each alternative grazing scenario. Depending on the probability of disease transmission following interspecies contact, extirpation probabilities for the seven bighorn sheep herds examined here ranged from 20% to 100%. The Disease Model allowed us to assess the probabilities that varied domestic sheep management scenarios would support persistent populations of free-ranging bighorn sheep. Copyright © 2014 Elsevier B.V. All rights reserved.

43 CFR 4710.5 - Closure to livestock grazing.

Code of Federal Regulations, 2011 CFR

2011-10-01

... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) PROTECTION, MANAGEMENT, AND CONTROL OF WILD FREE-ROAMING HORSES AND BURROS Management Considerations § 4710.5 Closure to livestock grazing. (a) If...

43 CFR 4710.5 - Closure to livestock grazing.

Code of Federal Regulations, 2013 CFR

2013-10-01

... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) PROTECTION, MANAGEMENT, AND CONTROL OF WILD FREE-ROAMING HORSES AND BURROS Management Considerations § 4710.5 Closure to livestock grazing. (a) If...

43 CFR 4710.5 - Closure to livestock grazing.

Code of Federal Regulations, 2014 CFR

2014-10-01

... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) PROTECTION, MANAGEMENT, AND CONTROL OF WILD FREE-ROAMING HORSES AND BURROS Management Considerations § 4710.5 Closure to livestock grazing. (a) If...

43 CFR 4710.5 - Closure to livestock grazing.

Code of Federal Regulations, 2012 CFR

2012-10-01

... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) PROTECTION, MANAGEMENT, AND CONTROL OF WILD FREE-ROAMING HORSES AND BURROS Management Considerations § 4710.5 Closure to livestock grazing. (a) If...

The importance of federal grazing allotments to central Sierran oak woodland permittees: a first approximation

Treesearch

Adriana Sulak; Lynn Huntsinger

2002-01-01

The interlinkage of privately owned foothill oak woodlands and federal grazing permits in the central Sierra Nevada is examined. Knowledge of the viability of the range livestock industry is important to large-scale conservation of hardwood rangelands in the Sierran foothills. Because ranches in the Sierra often use USDA Forest Service grazing allotments, efforts at...

43 CFR 4120.3-9 - Water rights for the purpose of livestock grazing on public lands.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Water rights for the purpose of livestock grazing on public lands. 4120.3-9 Section 4120.3-9 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA...

Rest-rotation grazing at Harvey Valley. . .range health, cattle gains, costs

Treesearch

Raymond D. Ratliff; Jack N. Reppert; Richard J. McConnen

1972-01-01

A trial of rest-rotation grazing was started in 1954 on the Harvey Valley allotment of the Lassen National Forest, northern California. This paper evaluates progress observed to 1966. Ecologically the program is considered sound. And after only a decade, the allotment was in better condition than allotments grazed season-long. Cattle weight gains were acceptable, and...

75 FR 22617 - Notice of Intent To Prepare an Environmental Assessment for Domestic Sheep Grazing on the Dog...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-29

... Intent To Prepare an Environmental Assessment for Domestic Sheep Grazing on the Dog Creek and Green Creek... that will evaluate a range of alternatives for grazing domestic sheep on the Dog Creek and Green Creek... to the Bishop RMP, and would therefore require a plan amendment. The Dog Creek allotment consists of...

Mollusc assemblages associated with invasive and native Sargassum species

NASA Astrophysics Data System (ADS)

Veiga, Puri; Torres, Ana Catarina; Besteiro, Celia; Rubal, Marcos

2018-06-01

Molluscs associated with the native macroalga Sargassum flavifolium and the invasive S. muticum were compared. The influence of habitat complexity provided by each macroalga was considered using biomass and fractal measures as proxies of habitat size and architecture, respectively. Results showed that biomass and fractal area of the alga and abundance, specific richness and diversity of the mollusc assemblages were significantly lower in the invasive macroalga and that mollusc assemblage differed significantly between macroalgae. Among species responsible for dissimilarity between macroalgae, microphytobenthos-grazing gastropods were more abundant in the native seaweed whereas two filter-feeding bivalves were more abundant in the invasive. Results also revealed significant correlations between biomass and fractal area with mollusc assemblages. However, the largest correlation coefficients for fractal area suggest more relevance of habitat architecture. Despite being two closely taxonomically macroalgae, of similar morphology, our findings suggest that the function of invasive macroalga as habitat provider differs from the native and induces changes in its associated fauna, which could imply food web modifications.

Does prescribed burning result in biotic homogenization of coastal heathlands?

PubMed

Velle, Liv Guri; Nilsen, Liv Sigrid; Norderhaug, Ann; Vandvik, Vigdis

2014-05-01

Biotic homogenization due to replacement of native biodiversity by widespread generalist species has been demonstrated in a number of ecosystems and taxonomic groups worldwide, causing growing conservation concern. Human disturbance is a key driver of biotic homogenization, suggesting potential conservation challenges in seminatural ecosystems, where anthropogenic disturbances such as grazing and burning are necessary for maintaining ecological dynamics and functioning. We test whether prescribed burning results in biotic homogenization in the coastal heathlands of north-western Europe, a seminatural landscape where extensive grazing and burning has constituted the traditional land-use practice over the past 6000 years. We compare the beta-diversity before and after fire at three ecological scales: within local vegetation patches, between wet and dry heathland patches within landscapes, and along a 470 km bioclimatic gradient. Within local patches, we found no evidence of homogenization after fire; species richness increased, and the species that entered the burnt Calluna stands were not widespread specialists but native grasses and herbs characteristic of the heathland system. At the landscapes scale, we saw a weak homogenization as wet and dry heathland patches become more compositionally similar after fire. This was because of a decrease in habitat-specific species unique to either wet or dry habitats and postfire colonization by a set of heathland specialists that established in both habitat types. Along the bioclimatic gradient, species that increased after fire generally had more specific environmental requirements and narrower geographical distributions than the prefire flora, resulting in a biotic 'heterogenisation' after fire. Our study demonstrates that human disturbance does not necessarily cause biotic homogenization, but that continuation of traditional land-use practices can instead be crucial for the maintenance of the diversity and ecological function of a seminatural ecosystem. The species that established after prescribed burning were heathland specialists with relatively narrow geographical ranges. © 2013 John Wiley & Sons Ltd.

Indirect effects of habitat disturbance on invasion: nutritious litter from a grazing resistant plant favors alien over native Collembola.

PubMed

Leinaas, Hans Petter; Bengtsson, Jan; Janion-Scheepers, Charlene; Chown, Steven L

2015-08-01

Biological invasions are major threats to biodiversity, with impacts that may be compounded by other forms of environmental change. Observations of high density of the invasive springtail (Collembola), Hypogastrura manubrialis in heavily grazed renosterveld vegetation in the Western Cape, South Africa, raised the question of whether the invasion was favored by changes in plant litter quality associated with habitat disturbance in this vegetation type. To examine the likely mechanisms underlying the high abundance of H. manubrialis, cages with three types of naturally occurring litter with different nutrient content were placed out in the area and collected after different periods of time. Hypogastrura manubrialis was mainly found in the nutrient-rich litter of the yellowbush (Galenia africana), which responds positively to disturbance in the form of overgrazing. This suggests that invasion may have been facilitated by a positive interaction with this grazing resistant plant. By contrast, indigenous Collembola were least abundant in yellowbush litter. Negative correlations between high abundance of H. manubrialis and the abundance and diversity of other species suggest that competitive interactions might underlie low abundance of these other species at the patch level. Group behavior enables H. manubrialis to utilize efficiently this ephemeral, high quality resource, and might improve its competitive ability. The results suggest that interactions among environmental change drivers may lead to unforeseen invasion effects. H. manubrialis is not likely to be very successful in un-grazed renosterveld, but in combination with grazing, favoring the nutrient-rich yellowbush, it may become highly invasive. Field manipulations are required to fully verify these conclusions.

Indirect effects of habitat disturbance on invasion: nutritious litter from a grazing resistant plant favors alien over native Collembola

PubMed Central

Leinaas, Hans Petter; Bengtsson, Jan; Janion-Scheepers, Charlene; Chown, Steven L

2015-01-01

Biological invasions are major threats to biodiversity, with impacts that may be compounded by other forms of environmental change. Observations of high density of the invasive springtail (Collembola), Hypogastrura manubrialis in heavily grazed renosterveld vegetation in the Western Cape, South Africa, raised the question of whether the invasion was favored by changes in plant litter quality associated with habitat disturbance in this vegetation type. To examine the likely mechanisms underlying the high abundance of H. manubrialis, cages with three types of naturally occurring litter with different nutrient content were placed out in the area and collected after different periods of time. Hypogastrura manubrialis was mainly found in the nutrient-rich litter of the yellowbush (Galenia africana), which responds positively to disturbance in the form of overgrazing. This suggests that invasion may have been facilitated by a positive interaction with this grazing resistant plant. By contrast, indigenous Collembola were least abundant in yellowbush litter. Negative correlations between high abundance of H. manubrialis and the abundance and diversity of other species suggest that competitive interactions might underlie low abundance of these other species at the patch level. Group behavior enables H. manubrialis to utilize efficiently this ephemeral, high quality resource, and might improve its competitive ability. The results suggest that interactions among environmental change drivers may lead to unforeseen invasion effects. H. manubrialis is not likely to be very successful in un-grazed renosterveld, but in combination with grazing, favoring the nutrient-rich yellowbush, it may become highly invasive. Field manipulations are required to fully verify these conclusions. PMID:26380678

Range Ecosystems

USDA-ARS?s Scientific Manuscript database

After 200 years, livestock grazing remains California’s most extensive land use. Contemporary rangelands are managed for multiple outcomes, including livestock production, biodiversity conservation, fuels management, and soil, water, and air quality protection. The requirements of grazing management...

Profitability of grazing versus mechanical forage harvesting on New York dairy farms.

PubMed

Gloy, B A; Tauer, L W; Knoblauch, W

2002-09-01

The profitability of rotational grazing versus mechanical harvesting of forages was estimated using data from 237 nongrazing and 57 grazing farms participating in the New York farm business summary program in the year 2000. The objective was to perform an empirical comparison of the profitability of grazing versus mechanical forage harvesting systems. A regression analysis technique that controls for treatment selection bias is used to determine the impact of grazing on the rate of return on assets. This is accomplished by joint maximum likelihood estimation of a probit adoption function and a profit function. The results indicate that treatment selection does not have an important impact on the estimate of the profitability of grazing. There were wide ranges and overlap of profitability among herds using the two systems. However, other things equal, farmers utilizing grazing systems were at least if not more profitable than farmers not using grazing systems. After controlling for the factors influencing the decision to graze, we found that herd size, rate of milk production per cow, and prices received for milk have a strong positive impact on profitability. Farmers who perceive potential lifestyle benefits that might be obtained by implementing a grazing system likely do not have to pay an income penalty for adopting a grazing system.

Influence of domestic livestock grazing on American Pika (Ochotona princeps) forage and haypiling behavior in the Great Basin. Western North American Naturalist.

Treesearch

Constance I. Millar

2011-01-01

In a pilot study, I observed a relationship between domestic livestock grazing and location of American pika (Ochotona princeps) haypiles in the eastern Sierra Nevada and several Great Basin mountain ranges. Where vegetation communities adjacent to talus bases (forefields) were grazed, mean distance from the talus borders to the closest fresh...

Changes in vegetative cover on Western Arctic Herd winter range from 1981 to 2005: potential effects of grazing and climate change

Treesearch

Kyle Joly; Randi R. Jandt; Cynthia R. Meyers; Martha J. Cole

2007-01-01

The population of the Western Arctic Herd, estimated at 490,000 caribou (Rangifer tarandus granti) in 2003, is at its highest level in 30 years. Twenty permanent range transects were established in the winter range of the Western Arctic Herd in 1981 to assess the impacts of grazing. These transects were revisited in 1995 and 1996 (1995/96). Only 18...

The ability of winter grazing to reduce wildfire size, intensity ...

EPA Pesticide Factsheets

A recent study by Davies et al. sought to test whether winter grazing could reduce wildfire size, fire behavior metrics, and fire-induced plant mortality in shrub-grasslands. The authors concluded that ungrazed rangelands may experience more fire-induced mortality of native perennial bunchgrasses. The authors also presented several statements regarding the benefits of winter grazing on post-fire plant community responses. However, this commentary will show that the study by Davies et al. has underlying methodological flaws, lacks data necessary to support their conclusions, and does not provide an accurate discussion on the effect of grazing on rangeland ecosystems. Importantly, Davies et al. presented no data on the post-fire mortality of the perennial bunchgrasses or on the changes in plant community composition following their experimental fires. Rather, Davies et al. inferred these conclusions based off their observed fire behavior metrics of maximum temperature and a term described as the “heat load”. However, neither metric is appropriate for elucidating the heat flux impacts on plants. This lack of post-fire data, several methodological flaws, and the use of inadequate metrics describing heat cast doubts on the authors’ ability to support their stated conclusions. This article is a commentary highlights the scientific shortcomings in a forthcoming paper by Davies et al. in the International Journal of Wildland Fire. The study has methodological flaw

Native plant propagation and habitat restoration at Hakalau Forest National Wildlie Refuge, Hawaii

Treesearch

Baron Horiuchi; Jack Jeffrey

2002-01-01

Hakalau Forest NWR was established in 1985 under the authority of the Endangered Species Act to preserve and protect five species of endangered forest birds and their rain forest habitat. While most of the 32,730 acre refuge is closed canopy forest, over one hundred years of cattle grazing, logging and burning have convened about 5,000 acres (2,023 ha) of upper...

Using American elm in mixed-species plantings to restore above- and below-ground function to degraded riparian buffers

Treesearch

C.C. Pinchot; D.J. Lodge; R. Minocha; T.W. Noon; V. D’Amico; C. Flower; K.M. Knight; J. Slavicek

2017-01-01

We recently established a study to evaluate the effects of several riparian restoration treatments on degraded streambanks located on the Finger Lakes National Forest (FLNF) in western New York. A legacy of cattle grazing has led to soil compaction, invasion by non-native invasive plant species (NNIP), as well as heavy nitrogen loading and increased bacterial levels in...

Guidelines for managing lesser prairie-chicken populations and their habitats

USGS Publications Warehouse

Hagen, C.A.; Jamison, B.E.; Giesen, K.M.; Riley, T.Z.

2004-01-01

Lesser prairie-chicken (Tympanuchus pallidicinctus) populations have declined by >90% since the 1800s. These declines have concerned both biologists and private conservation groups and led to a petition to list the lesser prairie-chicken as threatened under the Endangered Species Act. Most of the land in the current range of the lesser prairie-chicken is privately owned, and declines have been primarily attributed to anthropogenic factors. Conversion of native rangeland to cropland and excessive grazing have been implicated as leading causes in the species' decline. Periodic drought probably has exacerbated these problems. Little research on habitat requirements was conducted prior to 1970. Despite recent advances in the knowledge of lesser prairie-chicken ecology, no comprehensive guidelines for management of the species have been published. In these guidelines, we provide a synopsis of our current knowledge of lesser prairie-chicken habitat requirements and suggest management strategies to monitor, maintain, and enhance lesser prairie-chicken populations.

Impacts of cattle grazing on spatio-temporal variability of soil moisture and above-ground live plant biomass in mixed grasslands

NASA Astrophysics Data System (ADS)

Virk, Ravinder

Areas with relatively high spatial heterogeneity generally have more biodiversity than spatially homogeneous areas due to increased potential habitat. Management practices such as controlled grazing also affect the biodiversity in grasslands, but the nature of this impact is not well understood. Therefore this thesis studies the impacts of variation in grazing on soil moisture and biomass heterogeneity. These are not only important in terms of management of protected grasslands, but also for designing an effective grazing system from a livestock management point of view. This research is a part of the cattle grazing experiment underway in Grasslands National Park (GNP) of Canada since 2006, as part of the adaptive management process for restoring ecological integrity of the northern mixed-grass prairie region. An experimental approach using field measurements and remote sensing (Landsat) was combined with modelling (CENTURY) to examine and predict the impacts of grazing intensity on the spatial heterogeneity and patterns of above-ground live plant biomass (ALB) in experimental pastures in a mixed grassland ecosystem. The field-based research quantified the temporal patterns and spatial variability in both soil moisture (SM) and ALB, and the influence of local intra-seasonal weather variability and slope location on the spatio-temporal variability of SM and ALB at field plot scales. Significant impacts of intra-seasonal weather variability, slope position and grazing pressure on SM and ALB across a range of scales (plot and local (within pasture)) were found. Grazing intensity significantly affected the ALB even after controlling for the effect of slope position. Satellite-based analysis extended the scale of interest to full pastures and the surrounding region to assess the effects of grazing intensity on the spatio-temporal pattern of ALB in mixed grasslands. Overall, low to moderate grazing intensity showed increase in ALB heterogeneity whereas no change in ALB heterogeneity over time was observed for heavy grazing intensity. All grazing intensities showed decrease in spatial range (patch size) over time indicating that grazing is a patchy process. The study demonstrates that cattle grazing with variable intensity can maintain and change the spatial patterns of vegetation in the studied region. Using a modelling approach, the relative degrees to which grazing intensity and soil properties affect grassland productivity and carbon dynamics at longer time-periods were investigated. Both grass productivity and carbon dynamics are sensitive to variability in soil texture and grazing intensity. Moderate grazing is predicted to be the best option in terms of maintaining sufficient heterogeneity to support species diversity, as well as for carbon management in the mixed grassland ecosystem.

A decision support tool for adaptive management of native prairie ecosystems

USGS Publications Warehouse

Hunt, Victoria M.; Jacobi, Sarah; Gannon, Jill J.; Zorn, Jennifer E.; Moore, Clinton; Lonsdorf, Eric V.

2016-01-01

The Native Prairie Adaptive Management initiative is a decision support framework that provides cooperators with management-action recommendations to help them conserve native species and suppress invasive species on prairie lands. We developed a Web-based decision support tool (DST) for the U.S. Fish and Wildlife Service and the U.S. Geological Survey initiative. The DST facilitates cross-organizational data sharing, performs analyses to improve conservation delivery, and requires no technical expertise to operate. Each year since 2012, the DST has used monitoring data to update ecological knowledge that it translates into situation-specific management-action recommendations (e.g., controlled burn or prescribed graze). The DST provides annual recommendations for more than 10,000 acres on 20 refuge complexes in four U.S. states. We describe how the DST promotes the long-term implementation of the program for which it was designed and may facilitate decision support and improve ecological outcomes of other conservation efforts.

Transitions and coexistence along a grazing gradient in the Eurasian steppe

NASA Astrophysics Data System (ADS)

Ren, Haiyan; Taube, Friedelm; Zhang, Yingjun; Bai, Yongfei; Hu, Shuijin

2017-04-01

Ecological resilience theory has often been applied to explain species coexistence and range condition assessment of various community states and to explicate the dynamics of ecosystems. Grazing is a primary disturbance that can alter rangeland resilience by causing hard-to-reverse transitions in grasslands. Yet, how grazing affects the coexistence of plant functional group (PFG) and transition remains unclear. We conducted a six-year grazing experiment in a typical steppe of Inner Mongolia, using seven grazing intensities (0, 1.5, 3.0, 4.5, 6.0, 7.5 and 9.0 sheep/ hectare) and two grazing systems (i.e. a continuous annual grazing as in the traditional grazing system, and a mixed grazing system combining grazing and haymaking), to examine grazing effects on plant functional group shifts and species coexistence in the semi-arid grassland system. Our results indicate that the relative richness of dominant bunchgrasses and forbs had a compensatory coexistence at all grazing intensities, and the richness of rhizomatous grasses fluctuated but was persistent. The relative productivity of dominant bunchgrasses and rhizomatous grasses had compensatory interactions with grazing intensity and grazing system. Dominant bunchgrasses and rhizomatous grasses resist grazing effects by using their dominant species functional traits: high specific leaf area and low leaf nitrogen content. Our results suggest that: 1. Stabilizing mechanisms beyond grazing management are more important in determining plant functional group coexistence and ecological resilience. 2. Plant functional group composition is more important in influencing ecosystem functioning than diversity. 3. Ecosystem resilience at a given level is related to the biomass of dominant PFG, which is determined by a balanced shift between dominant species biomass. The relatively even ecosystem resilience along the grazing gradient is attributed to the compensatory interactions of dominant species in their biomass variations. Community stability may rely on constantly regulating internal PFGs composition to maintain functional stability in grassland ecosystems. In the semi-arid grassland system, environmental factors mediate grazing effects on PFG transition, leading to homogeneous grassland dominated by bunchgrass.

Functional trait responses to grazing are mediated by soil moisture and plant functional group identity

PubMed Central

Zheng, Shuxia; Li, Wenhuai; Lan, Zhichun; Ren, Haiyan; Wang, Kaibo

2015-01-01

Abundant evidence has shown that grazing alters plant functional traits, community structure and ecosystem functioning of grasslands. Few studies, however, have tested how plant responses to grazing are mediated by resource availability and plant functional group identity. We examined the effects of grazing on functional traits across a broad range of species along a soil moisture gradient in Inner Mongolia grassland. Our results showed that trait syndromes of plant size (individual biomass) and shoot growth (leaf N content and leaf density) distinguished plant species responses to grazing. The effects of grazing on functional traits were mediated by soil moisture and dependent on functional group identity. For most species, grazing decreased plant height but increased leaf N and specific leaf area (SLA) along the moisture gradient. Grazing enhanced the community-weighted attributes (leaf NCWM and SLACWM), which were triggered mainly by the positive trait responses of annuals and biennials and perennial grasses, and increased relative abundance of perennial forbs. Our results suggest that grazing-induced species turnover and increased intraspecific trait variability are two drivers for the observed changes in community weighted attributes. The dominant perennial bunchgrasses exhibited mixed tolerance–resistance strategies to grazing and mixed acquisitive–conservative strategies in resource utilization. PMID:26655858

Functional trait responses to grazing are mediated by soil moisture and plant functional group identity.

PubMed

Zheng, Shuxia; Li, Wenhuai; Lan, Zhichun; Ren, Haiyan; Wang, Kaibo

2015-12-11

Abundant evidence has shown that grazing alters plant functional traits, community structure and ecosystem functioning of grasslands. Few studies, however, have tested how plant responses to grazing are mediated by resource availability and plant functional group identity. We examined the effects of grazing on functional traits across a broad range of species along a soil moisture gradient in Inner Mongolia grassland. Our results showed that trait syndromes of plant size (individual biomass) and shoot growth (leaf N content and leaf density) distinguished plant species responses to grazing. The effects of grazing on functional traits were mediated by soil moisture and dependent on functional group identity. For most species, grazing decreased plant height but increased leaf N and specific leaf area (SLA) along the moisture gradient. Grazing enhanced the community-weighted attributes (leaf NCWM and SLACWM), which were triggered mainly by the positive trait responses of annuals and biennials and perennial grasses, and increased relative abundance of perennial forbs. Our results suggest that grazing-induced species turnover and increased intraspecific trait variability are two drivers for the observed changes in community weighted attributes. The dominant perennial bunchgrasses exhibited mixed tolerance-resistance strategies to grazing and mixed acquisitive-conservative strategies in resource utilization.

Land use change and ecosystem service provision in Pampas and Campos grasslands of southern South America

NASA Astrophysics Data System (ADS)

Modernel, P.; Rossing, W. A. H.; Corbeels, M.; Dogliotti, S.; Picasso, V.; Tittonell, P.

2016-11-01

New livestock production models need to simultaneously meet the increasing global demand for meat and preserve biodiversity and ecosystem services. Since the 16th century beef cattle has been produced on the Pampas and Campos native grasslands in southern South America, with only small amounts of external inputs. We synthesised 242 references from peer-reviewed and grey literature published between 1945 and mid-2015 and analysed secondary data to examine the evidence on the ecosystem services provided by this grassland biodiversity hotspot and the way they are affected by land use changes and their drivers. The analysis followed the requirements of systematic review from the PRISMA statement (Moher et al 2009 Acad. Clin. Ann. Intern. Med. 151 264-9). The Pampas and Campos provide feed for 43 million heads of cattle and 14 million sheep. The biome is habitat of 4000 native plant species, 300 species of birds, 29 species of mammals, 49 species of reptiles and 35 species of amphibians. The soils of the region stock 5% of the soil organic carbon of Latin America on 3% of its area. Driven by high prices of soybean, the soybean area increased by 210% between 2000 and 2010, at the expense of 2 million ha (5%) of native grassland, mostly in the Pampas. Intensification of livestock production was apparent in two spatially distinct forms. In subregions where cropping increased, intensification of livestock production was reflected in an increased use of grains for feed as part of feedlots. In subregions dominated by native grasslands, stocking rates increased. The review showed that land use change and grazing regimes with low forage allowances were predominantly associated with negative effects on ecosystem service provision by reducing soil organic carbon stocks and the diversity of plants, birds and mammals, and by increasing soil erosion. We found little quantitative information on changes in the ecosystem services water provision, nutrient cycling and erosion control. We discuss how changing grazing regimes to higher forage allowance can contribute to greater meat production and enhancing ecosystem services from native grasslands. This would require working with farmers on changing their management strategies and creating enabling economic conditions.

Correlates of Recent Declines of Rodents in Northern and Southern Australia: Habitat Structure Is Critical

PubMed Central

Lawes, Michael J.; Fisher, Diana O.; Johnson, Chris N.; Blomberg, Simon P.; Frank, Anke S. K.; Fritz, Susanne A.; McCallum, Hamish; VanDerWal, Jeremy; Abbott, Brett N.; Legge, Sarah; Letnic, Mike; Thomas, Colette R.; Thurgate, Nikki; Fisher, Alaric; Gordon, Iain J.; Kutt, Alex

2015-01-01

Australia has experienced dramatic declines and extinctions of its native rodent species over the last 200 years, particularly in southern Australia. In the tropical savanna of northern Australia significant declines have occurred only in recent decades. The later onset of these declines suggests that the causes may differ from earlier declines in the south. We examine potential regional effects (northern versus southern Australia) on biological and ecological correlates of range decline in Australian rodents. We demonstrate that rodent declines have been greater in the south than in the tropical north, are strongly influenced by phylogeny, and are consistently greater for species inhabiting relatively open or sparsely vegetated habitat. Unlike in marsupials, where some species have much larger body size than rodents, body mass was not an important predictor of decline in rodents. All Australian rodent species are within the prey-size range of cats (throughout the continent) and red foxes (in the south). Contrary to the hypothesis that mammal declines are related directly to ecosystem productivity (annual rainfall), our results are consistent with the hypothesis that disturbances such as fire and grazing, which occur in non-rainforest habitats and remove cover used by rodents for shelter, nesting and foraging, increase predation risk. We agree with calls to introduce conservation management that limits the size and intensity of fires, increases fire patchiness and reduces grazing impacts at ecological scales appropriate for rodents. Controlling feral predators, even creating predator-free reserves in relatively sparsely-vegetated habitats, is urgently required to ensure the survival of rodent species, particularly in northern Australia where declines are not yet as severe as those in the south. PMID:26111037

Correlates of Recent Declines of Rodents in Northern and Southern Australia: Habitat Structure Is Critical.

PubMed

Lawes, Michael J; Fisher, Diana O; Johnson, Chris N; Blomberg, Simon P; Frank, Anke S K; Fritz, Susanne A; McCallum, Hamish; VanDerWal, Jeremy; Abbott, Brett N; Legge, Sarah; Letnic, Mike; Thomas, Colette R; Thurgate, Nikki; Fisher, Alaric; Gordon, Iain J; Kutt, Alex

2015-01-01

Australia has experienced dramatic declines and extinctions of its native rodent species over the last 200 years, particularly in southern Australia. In the tropical savanna of northern Australia significant declines have occurred only in recent decades. The later onset of these declines suggests that the causes may differ from earlier declines in the south. We examine potential regional effects (northern versus southern Australia) on biological and ecological correlates of range decline in Australian rodents. We demonstrate that rodent declines have been greater in the south than in the tropical north, are strongly influenced by phylogeny, and are consistently greater for species inhabiting relatively open or sparsely vegetated habitat. Unlike in marsupials, where some species have much larger body size than rodents, body mass was not an important predictor of decline in rodents. All Australian rodent species are within the prey-size range of cats (throughout the continent) and red foxes (in the south). Contrary to the hypothesis that mammal declines are related directly to ecosystem productivity (annual rainfall), our results are consistent with the hypothesis that disturbances such as fire and grazing, which occur in non-rainforest habitats and remove cover used by rodents for shelter, nesting and foraging, increase predation risk. We agree with calls to introduce conservation management that limits the size and intensity of fires, increases fire patchiness and reduces grazing impacts at ecological scales appropriate for rodents. Controlling feral predators, even creating predator-free reserves in relatively sparsely-vegetated habitats, is urgently required to ensure the survival of rodent species, particularly in northern Australia where declines are not yet as severe as those in the south.

Fire and grazing impacts on plant diversity and alien plant invasions in the southern Sierra Nevada

USGS Publications Warehouse

Keeley, Jon E.; Lubin, Daniel; Fotheringham, C.J.

2003-01-01

Patterns of native and alien plant diversity in response to disturbance were examined along an elevational gradient in blue oak savanna, chaparral, and coniferous forests. Total species richness, alien species richness, and alien cover declined with elevation, at scales from 1 to 1000 m2. We found no support for the hypothesis that community diversity inhibits alien invasion. At the 1-m2 point scale, where we would expect competitive interactions between the largely herbaceous flora to be most intense, alien species richness as well as alien cover increased with increasing native species richness in all communities. This suggests that aliens are limited not by the number of native competitors, but by resources that affect establishment of both natives and aliens.Blue oak savannas were heavily dominated by alien species and consistently had more alien than native species at the 1-m2 scale. All of these aliens are annuals, and it is widely thought that they have displaced native bunchgrasses. If true, this means that aliens have greatly increased species richness. Alternatively, there is a rich regional flora of native annual forbs that could have dominated these grasslands prior to displacement by alien grasses. On our sites, livestock grazing increased the number of alien species and alien cover only slightly over that of sites free of livestock grazing for more than a century, indicating some level of permanency to this invasion.In chaparral, both diversity and aliens increased markedly several years after fire. Invasive species are rare in undisturbed shrublands, and alien propagules fail to survive the natural crown fires in these ecosystems. Thus, aliens necessarily must colonize after fire and, as a consequence, time since fire is an important determinant of invasive presence. Blue oak savannas are an important propagule source for alien species because they maintain permanent populations of all alien species encountered in postfire chaparral, and because the vegetation mosaic in this region places them in proximity to chaparral. The speed at which alien propagules reach a burned site and the speed at which the shrublands return to their former closed-canopy condition determine alien invasion. Frequent burning of this vegetation alters the balance in favor of alien invasion.In the higher-elevation coniferous forests, species diversity was a function of fire severity and time since fire. High-intensity fires create gaps that decrease canopy coverage and increase light levels and nutrients for an ephemeral successional flora. Few species have persistent seed banks, so the time since fire is an important determinant of colonization success. There was a highly significant interaction between fire severity and time since fire for understory cover, species richness, and alien richness and cover. Understory was sparse in the first year after fire, particularly in low-severity burns, and increased substantially several years after fire, particularly on high-severity burns. Both fire severity and time since fire affected alien species richness and dominance. Coniferous forests had about one-third as many alien species as the foothill oak savannas, and fewer than half of the species were shared between these communities. Unburned coniferous forests were largely free of alien species, whereas some burned sites had a significant alien presence, which presents a challenge for fire restoration of these forests.

Waterfowl production on the Woodworth Station in south-central North Dakota, 1965-1981

USGS Publications Warehouse

Higgins, K.F.; Kirsch, L.M.; Klett, A.T.; Miller, H.W.

1992-01-01

During 17 years of study at the Woodworth, North Dakota study area, the percent of 548 wetland basin with water during 1-15 May ranged from 8 to 87 and averaged 56; waterfowl pair densities varied from 19 to 56/km2 and averaged 40/km2. Pond occupancy by duck pairs averaged 37% during mid-May counts and 48% for late May and early June counts. A positive linear relation occurred between the estimated number of duck pairs and the percent of basins with water during 1-15 May.There were 3,339 duck nests found in grassland habitats from 1966 through 1981. Approximately 66% (85% Mayfield) of these were depredated or abandoned. Mammals caused 88% of nest failures. Half or more of the eventually successful clutches were unhatched by 10 July in 9 of 16 years. Haying would have disturbed or destroyed an average of 43%, 33%, 22%, 15%, and 9% of the duck nests if initiated on 10 July, 15 July, 20 July, 25 July, and 1 August, respectively.The total average size of completed clutch for all species was 29% smaller at the end of the nesting season than at the beginning, underscoring the importance of protecting early clutches.Production averaged 30 broods per 100 pairs of ducks and ranged from 15 to 61 broods per 100 pairs. Brood densities ranged from 10 to 63/km2 and averaged 12/km2. Mean brood size averaged 6.4 for all species. July broods averaged 7.2 ducklings and August broods 5.7 ducklings. Duckling loss averaged 2.6 per brood and 85% (2.2 ducklings) of this loss was estimated to occur during the first 14 days after hatch.Wetlands of all sizes and classes were important at some time to one species of duck or another. With the exception of some diving ducks, all species used a complex of sizes and classes of wetlands for space, food, and shelter necessary for nesting and brooding. Pair counts during 20 May-7 June were most indicative of the breeding population. A combination of two brood counts resulted in the best estimate of annual production. An average of only 50% of the total duck broods per year was counted during the 1-15 July surveys, which approximated the average time of the Service's July aerial surveys. During this study the area produced an average of 1 duck per 4 ha of upland and had a nest density of approximately 1 nest per 14 ha. Nest success rates averaged 35.1% (16.3% Mayfield). Predation was significantly reduced by good vegetative cover at nest sites. Seeded grasslands (dense nesting cover) yielded better production than native prairie or croplands. Seeded grasslands also produced 3 times more ducklings per unit area than adjacent native prairie and more than 14 times as many as adjacent, annually tilled croplands.Ducks generally showed higher nest densities and better nesting success when using growing grain crops than when nesting in standing or mulched stubble fields. Among native mixed-grass prairie and seeded grassland, production was enhanced by leaving fields idle or by treating them with periodic burning. Duck production was generally lowered by grazing field of native prairie but duck production on grazing lands was higher than in annually tilled croplands.

Edge Effects along a Seagrass Margin Result in an Increased Grazing Risk on Posidonia australis Transplants.

PubMed

Statton, John; Gustin-Craig, Samuel; Dixon, Kingsley W; Kendrick, Gary A

2015-01-01

A key issue in habitat restoration are the changes in ecological processes that occur when fragments of habitat are lost, resulting in the persistence of habitat-degraded margins. Margins often create or enhance opportunities for negative plant-herbivore interactions, preventing natural or assisted re-establishment of native vegetation into the degraded area. However, at some distance from the habitat margin these negative interactions may relax. Here, we posit that the intensity of species interactions in a fragmented Posidonia australis seagrass meadow may be spatially dependent on proximity to the seagrass habitat edge, whereby the risk of grazing is high and the probability of survival of seagrass transplants is low. To test this, transplants were planted 2 m within the meadow, on the meadow edge at 0m, and at 2m, 10m, 30m, 50m and 100m distance from the edge of the seagrass meadow into the unvegetated sand sheet. There was an enhanced grazing risk 0-10m from the edge, but decreased sharply with increasing distances (>30m). Yet, the risk of grazing was minimal inside the seagrass meadow, indicating that grazers may use the seagrass meadow for refuge but are not actively grazing within it. The relationship between short-term herbivory risk and long-term survival was not straightforward, suggesting that other environmental filters are also affecting survival of P. australis transplants within the study area. We found that daily probability of herbivory was predictable and operating over a small spatial scale at the edge of a large, intact seagrass meadow. These findings highlight the risk from herbivory can be high, and a potential contributing factor to seagrass establishment in restoration programs.

Edge Effects along a Seagrass Margin Result in an Increased Grazing Risk on Posidonia australis Transplants

PubMed Central

Statton, John; Gustin-Craig, Samuel; Dixon, Kingsley W.; Kendrick, Gary A.

2015-01-01

A key issue in habitat restoration are the changes in ecological processes that occur when fragments of habitat are lost, resulting in the persistence of habitat-degraded margins. Margins often create or enhance opportunities for negative plant-herbivore interactions, preventing natural or assisted re-establishment of native vegetation into the degraded area. However, at some distance from the habitat margin these negative interactions may relax. Here, we posit that the intensity of species interactions in a fragmented Posidonia australis seagrass meadow may be spatially dependent on proximity to the seagrass habitat edge, whereby the risk of grazing is high and the probability of survival of seagrass transplants is low. To test this, transplants were planted 2 m within the meadow, on the meadow edge at 0m, and at 2m, 10m, 30m, 50m and 100m distance from the edge of the seagrass meadow into the unvegetated sand sheet. There was an enhanced grazing risk 0-10m from the edge, but decreased sharply with increasing distances (>30m). Yet, the risk of grazing was minimal inside the seagrass meadow, indicating that grazers may use the seagrass meadow for refuge but are not actively grazing within it. The relationship between short-term herbivory risk and long-term survival was not straightforward, suggesting that other environmental filters are also affecting survival of P. australis transplants within the study area. We found that daily probability of herbivory was predictable and operating over a small spatial scale at the edge of a large, intact seagrass meadow. These findings highlight the risk from herbivory can be high, and a potential contributing factor to seagrass establishment in restoration programs. PMID:26465926

Successful Strategies for Earth Science Research in Native Communities

NASA Astrophysics Data System (ADS)

Redsteer, M. H.; Anderson, D.; Ben, N.; Bitsuie, R.; Blackhorse, A.; Breit, G.; Clifford, A.; Salabye, J.; Semken, S.; Weaver, K.; Yazzie, N.

2004-12-01

A small U.S. Geological Survey pilot project utilizes strategies that are successful at involving the Native community in earth science research. This work has ignited the interest of Native students in interdisciplinary geoscience studies, and gained the recognition of tribal community leaders from the conterminous United States, Alaska, and Canada. This study seeks to examine land use, climatic variability, and their related impacts on land-surface conditions in the ecologically sensitive Tsezhin Bii' region of the Navajo Nation. Work conducted by predominantly Native American researchers, includes studies of bedrock geology, surficial processes, soil and water quality, and plant ecology, as well as the history of human habitation. Community involvement that began during the proposal process, has helped to guide research, and has provided tribal members with information that they can use for land use planning and natural resource management. Work by Navajo tribal members who have become involved in research as it has progressed, includes K-12 science curriculum development, community outreach and education on environmental and geologic hazards, drought mitigation, grazing management, and impacts of climate change and land use on medicinal plants.

Optical Interactions at Randomly Rough Surfaces

DTIC Science & Technology

2003-03-10

frequency range. The design of a random surface that acts as a Lambertian diffuser, especially in the infrared region of the optical spectrum, is...FTIR grazing angle microscopy. Recently, an experimental study was performed of the far-field scattering at small grazing angles, especially the enhanced...a specular component in the scattered light, in this frequency range. The design of a random surface that acts as a Lambertian diffuser, especially in

The influence of cattle grazing and grass seeding on coniferous regeneration after shelterwood cutting in eastern Oregon.

Treesearch

K.W. Seidel; J. Michael Geist; Gerald S. Strickler

1990-01-01

Natural regeneration was abundant, regardless of grazing and grass seeding treatments,after shelterwood cutting to three overstory densities (27, 73, and 119 square feet of basal area per acre) in mixed conifer stands in the Starkey Experimental Forest and Range in eastern Oregon. After 6 years, the number of tree seedlings ranged from about 3,800 per acre on the low-...

FORAGES AND PASTURES SYMPOSIUM: Improving efficiency of production in pasture- and range-based beef and dairy systems.

PubMed

Mulliniks, J T; Rius, A G; Edwards, M A; Edwards, S R; Hobbs, J D; Nave, R L G

2015-06-01

Despite overall increased production in the last century, it is critical that grazing production systems focus on improving beef and dairy efficiency to meet current and future global food demands. For livestock producers, production efficiency is essential to maintain long-term profitability and sustainability. This continued viability of production systems using pasture- and range-based grazing systems requires more rapid adoption of innovative management practices and selection tools that increase profitability by optimizing grazing management and increasing reproductive performance. Understanding the genetic variation in cow herds will provide the ability to select cows that require less energy for maintenance, which can potentially reduce total energy utilization or energy required for production, consequently improving production efficiency and profitability. In the United States, pasture- and range-based grazing systems vary tremendously across various unique environments that differ in climate, topography, and forage production. This variation in environmental conditions contributes to the challenges of developing or targeting specific genetic components and grazing systems that lead to increased production efficiency. However, across these various environments and grazing management systems, grazable forage remains the least expensive nutrient source to maintain productivity of the cow herd. Beef and dairy cattle can capitalize on their ability to utilize these feed resources that are not usable for other production industries. Therefore, lower-cost alternatives to feeding harvested and stored feedstuffs have the opportunity to provide to livestock producers a sustainable and efficient forage production system. However, increasing production efficiency within a given production environment would vary according to genetic potential (i.e., growth and milk potential), how that genetic potential fits the respective production environment, and how the grazing management fits within those genetic parameters. Therefore, matching cow type or genetic potential to the production environment is and will be more important as cost of production increases.

The relative importance of disturbance and exotic-plant abundance in California coastal sage scrub

USGS Publications Warehouse

Fleming, G.M.; Diffendorfer, J.E.; Zedler, P.H.

2009-01-01

Many ecosystems of conservation concern require some level of disturbance to sustain their species composition and ecological function. However, inappropriate disturbance regimes could favor invasion or expansion of exotic species. In southern California coastal sage scrub (CSS) fire is a natural disturbance, but because of human influence, frequencies may now be unnaturally high. Other anthropogenic disturbances such as grazing also occur in reserve areas. Managers charged with imposing or tolerating fire or other disturbance within their reserves are concerned that habitat quality may be degraded by an increasing abundance of exotic plants. We used vegetation monitoring data from Camp Pendleton, California, USA, to assess the correlation between past disturbances (frequent fire, agriculture, or grazing and mechanical disturbances) and current exotic species abundance in CSS. We found that disturbance history was only modestly related to exotic abundance overall, but fire frequency showed the strongest association. We also examined whether cover and richness of various native plant life forms (woody species, perennial herbs, and annual herbs) were more strongly influenced by disturbance history or by exotic-plant abundance. Native plant responses varied among life forms, but woody species and annual herbs were generally more strongly and negatively associated with exotic abundance than with disturbance. Effective CSS conservation will require developing means to curb the negative impacts of exotic plants, which may abound with or without severe or recent disturbance. Additionally, more focus should be given to understory herbs showing sensitivity to invasion. Though understudied, native herbs comprise the greatest portion of plant diversity in CSS and are critical to preservation of the community as a whole. ?? 2009 by the Ecological Society of America.

Effect of Grazing Behavior on Weight Regain Post-Bariatric Surgery: A Systematic Review.

PubMed

Pizato, Nathalia; Botelho, Patrícia B; Gonçalves, Vivian S S; Dutra, Eliane S; de Carvalho, Kênia M B

2017-12-05

Grazing, a type of maladaptive eating behavior, has been associated with poor weight outcomes in bariatric patients. The purpose of this study was to conduct a systematic review of the association between grazing behavior and weight regain post-bariatric surgery. Literature searches, study selection, design of the method, and quality appraisal were carried out by two independent authors. The search strategy was performed until October 2017 in Medline, Embase, Cochrane, Lilacs, Scopus, Web of Science, Google Scholar, ProQuest Dissertation & Theses, and Open Grey. Of a total of 3764 articles, five papers met the inclusion criteria (four original articles and one thesis), comprising 994 subjects, mostly women. The prevalence of grazing behavior ranged from 16.6 to 46.6%, and the highest prevalence of significant weight regain was 47%. The association between grazing and weight regain was observed in four of the five evaluated studies. Our findings support an association between grazing behavior and weight regain after bariatric surgery, regardless of surgery type and contextual concept of grazing. Further studies are needed to confirm the clarity of the real prevalence and interfering factors related to grazing behavior and weight outcomes.

Senior Research Connects Students with a Living Laboratory As Part of an Integrated Crop and Livestock System

NASA Astrophysics Data System (ADS)

Senturklu, Songul; Landblom, Douglas; Brevik, Eric C.

2015-04-01

Soil, water, soil microbes, and solar energy are the main sources that sustain life on this planet. Without them working in concert, neither plants nor animals would survive. Considering the efficiency of animal production targets, soil must be protected and improved. Therefore, through our sustainable integrated crop and livestock research, we are studying animal and soil interactions from the soil to the plate. Integrating beef cattle systems into a diverse cropping system is providing a living laboratory for education beyond the traditional classroom setting. To establish the living learning laboratory at the Dickinson Research Extension Center, a five-crop rotation was established that included adapted cool and warm season grasses and broadleaf crops. The crop rotation is: sunflower > hard red spring wheat > fall seeded winter triticale-hairy vetch (hay)/spring seeded 7-species cover crop > Corn (85-95 day varieties) > field pea-barley intercrop. Sunflower and spring wheat are harvested for cash crop income in the rotation. Livestock integration occurs when yearling steers that had previously grazed perennial pastures until mid-August graze field pea-barley and subsequently unharvested corn. Average grazing days for field pea-barley and unharvested corn is 30 and 70 days, respectively. At the end of the grazing period, the yearling steers average 499-544 kg and are moved to a feedlot and fed an additional 75 days until slaughter. Maximizing grazing days and extending the grazing season through integration with the cropping system reduces custom feeding costs and enhances animal profit. Beef cows do not require high quality feed after their calves have been weaned. Therefore, gestating beef cows are an ideal animal to graze cover crops and crop aftermath (residue) after yearling steer grazing and farming operations have been completed. Extending the grazing season for beef cows by grazing cover crops and residues reduces winter feed cost, which is one of the highest expenses in beef cattle production. Senior research investigating the impact of livestock integration and multi-species cover crop grown within the crop rotation is studying changes in soil attributes resulting from the crop-animal integration by measuring bulk density and in-season soil fertility in the crop rotation. These responses are further contrasted with results from within the crop rotation and responses from perennial native range. Students that become engaged in the research represent a broad cross section of the consuming public and include high school junior and senior students, college undergraduate students that conduct research projects, postdoctoral research scientists engaged in senior level research, agricultural extension educators, and finally, farmer and rancher businessmen. The integrated nature of the research provides a wealth of learning opportunities for these various groups. For the high school students, visits to the living laboratory increase awareness and introduces students to a potential career path in agriculture, natural resource fields, and the many allied vocational fields that support agriculture. When college undergraduate students visit the living laboratory, they seek to address a researchable question or a problem in agriculture, while fulfilling requirements for graduation by conducting a research project. Because postdoctoral students want to be actively engaged in research and advanced learning, they are interested in conducting research in the living laboratory that can be published in peer reviewed journals. Agricultural extension educators, who advise farmers and ranchers, are looking for research results from the living laboratory that can be convey to their constituents. Farmers and ranchers participate in workshop events that give them face-to-face learning opportunities that they can use to effect change in their farm and ranch businesses. Each of these demographic groups are unique in their interest in the interaction between agricultural production and soil science. The authors will describe and discuss how each of these very different research consumers have been assisted during their experience and involvement in the living laboratory.

Using Shrub Clearing, Draining, and Herbivory to Control Bramble Invasion in Mediterranean Dry Grasslands

NASA Astrophysics Data System (ADS)

Masson, Solène; Mesléard, François; Dutoit, Thierry

2015-10-01

For centuries, the dry grassland of the plain of La Crau (south-eastern France) has been subjected to numerous disturbances resulting in the destruction and the fragmentation of this emblematic rangeland ecosystem of the Mediterranean. Today, this ecosystem is facing a new threat from a proliferating native species, the bramble ( Rubus ulmifolius Schott), which preferentially colonizes areas that were formerly cultivated and/or exposed to water infiltration. To identify a strategy for effective control of this colonization, in situ experiments testing disturbance regimes (shrub clearing and/or mixed grazing by sheep and goats) combined with the control of access to water resources (with or without drainage trenches) were undertaken between 2010 and 2013. Only clearing and grazing combined over 3 years led to significant changes in vegetation height and bramble cover as well as modifications in the floristic composition, diversity, similarity, and richness of the plant community. Neither a clearing operation carried out in 2010 alone, nor grazing alone, reduced bramble cover, and neither treatment increased the species richness of the plant community. Similarly, digging drainage trenches had no significant impact either on the plant community or on bramble cover. Our study suggests that only annual mechanical clearing coupled with sheep and goats grazing can significantly reduce bramble cover. This combined restoration treatment needs to be applied for at least 3 consecutive years to induce significant changes and enable this ecosystem to return to the dry grassland succession.

Nest sites of ducks in grazed mixed-grass prairie in North Dakota

USGS Publications Warehouse

Duebbert, H.F.; Lokemoen, J.T.; Sharp, D.E.

1986-01-01

Habitat use and nesting success of seven species of dabbling ducks were evaluated in five vegetative associations within grazed mixed-grass prairie in central North Dakota. During 1976-80, 548 nests were found on 412 ha of grazed prairie for an annual average density of 27 nests/100 ha. Numbers of nests found ranged from 1/100 ha in 1977 (a drought year) to 58/100 ha in 1979 (a very wet year), reflecting the variability that may be expected in a dynamic prairie wetland environment. Nesting success ranged from an average of 23% in the western snowberry (Symphoricarpos occidentalis) association to 34% in the mixed-grass association. Forty-two percent of the mallard (Anas platyrhynchos) nests and 35% of the gadwall (A. strepera) nests were in patches of western snowberry and/or Wood's rose (Rosa woodsii) that made up 2% of the available cover. Numbers of nests of blue-winged teal (A. discors) and northern shoveler (A. clypeata) were highest in cool-season grasses, especially green needlegrass (Stipa viridula) and western wheatgrass (Agropyron smithii). Height/density (HD) of residual cover decreased exponentially with increased grazing pressure. Use of grazed prairie by blue-winged teal was maximized when the HD of residual cover was 0.5 dm or higher, as could be maintained under light grazing. Results of this study indicated that properly grazed mixed-grass prairie can provide adequate nesting habitat for dabbling ducks. We recommend that preservation and sound ecological management be focused on large tracts of mixed-grass prairie with complexes of seasonal and semipermanent wetlands.

A toxic endophyte-infected grass helps reverse degradation and loss of biodiversity of over-grazed grasslands in northwest China.

PubMed

Yao, Xiang; Christensen, Michael J; Bao, Gensheng; Zhang, Chunping; Li, Xiuzhang; Li, Chunjie; Nan, Zhibiao

2015-12-18

Overgrazing of China's grasslands is increasingly causing biodiversity to decline. In degenerated grasslands of northwest China endophyte (Epichloё gansuensis) infected Achnatherum inebrians (drunken horse grass) is becoming widely distributed because of its toxicity to livestock. In this study, we investigated the ecological consequences of endophyte toxicity in this native grass, at three sites in northwest China, by comparing seed production of plant species and arthropod abundance in overgrazed grasslands with and without the presence of A. inebrians. Our findings demonstrate that the presence of endophyte infected A. inebrians reduces the loss of plant and arthropod biodiversity by providing a protected nursery free of animal grazing. Therefore, A. inebrians, typically regarded as an unwanted toxic invader by pastoralists, should be viewed as beneficial for grasslands as its presence maintains plant and arthropod biodiversity, and provides a foundation stone in the reconstruction and restoration of these grassland ecosystems.

Range-wide assessment of livestock grazing across the sagebrush biome

USGS Publications Warehouse

Veblen, Kari E.; Pyke, David A.; Jones, Christopher A.; Casazza, Michael L.; Assal, Timothy J.; Farinha, Melissa A.

2011-01-01

Domestic livestock grazing occurs in virtually all sagebrush habitats and is a prominent disturbance factor. By affecting habitat condition and trend, grazing influences the resources required by, and thus, the distribution and abundance of sagebrush-obligate wildlife species (for example, sage-grouse Centrocercus spp.). Yet, the risks that livestock grazing may pose to these species and their habitats are not always clear. Although livestock grazing intensity and associated habitat condition may be known in many places at the local level, we have not yet been able to answer questions about use, condition, and trend at the landscape scale or at the range-wide scale for wildlife species. A great deal of information about grazing use, management regimes, and ecological condition exists at the local level (for individual livestock management units) under the oversight of organizations such as the Bureau of Land Management (BLM). However, the extent, quality, and types of existing data are unknown, which hinders the compilation, mapping, or analysis of these data. Once compiled, these data may be helpful for drawing conclusions about rangeland status, and we may be able to identify relationships between those data and wildlife habitat at the landscape scale. The overall objective of our study was to perform a range-wide assessment of livestock grazing effects (and the relevant supporting data) in sagebrush ecosystems managed by the BLM. Our assessments and analyses focused primarily on local-level management and data collected at the scale of BLM grazing allotments (that is, individual livestock management units). Specific objectives included the following: 1. Identify and refine existing range-wide datasets to be used for analyses of livestock grazing effects on sagebrush ecosystems. 2. Assess the extent, quality, and types of livestock grazing-related natural resource data collected by BLM range-wide (i.e., across allotments, districts and regions). 3. Compile and synthesize recommendations from federal and university rangeland science experts about how BLM might prioritize collection of different types of livestock grazing-related natural resource data. 4. Investigate whether range-wide datasets (Objective 1) could be used in conjunction with remotely sensed imagery to identify across broad scales (a) allotments potentially not meeting BLM Land Health Standards (LHS) and (b) allotments in which unmet standards might be attributable to livestock grazing. Objective 1: We identified four datasets that potentially could be used for analyses of livestock grazing effects on sagebrush ecosystems. First, we obtained the most current spatial data (typically up to 2007, 2008, or 2009) for all BLM allotments and compiled data into a coarse, topologically enforced dataset that delineated grazing allotment boundaries. Second, we obtained LHS evaluation data (as of 2007) for all allotments across all districts and regions; these data included date of most recent evaluation, BLM determinations of whether region-specific standards were met, and whether BLM deemed livestock to have contributed to any unmet standards. Third, we examined grazing records of three types: Actual Use (permittee-reported), Billed Use (BLM-reported), and Permitted Use (legally authorized). Finally, we explored the possibility of using existing Natural Resources Conservation Service (NRCS) Ecological Site Description (ESD) data to make up-to-date estimates of production and forage availability on BLM allotments. Objective 2: We investigated the availability of BLM livestock grazing-related monitoring data and the status of LHS across 310 randomly selected allotments in 13 BLM field offices. We found that, relative to other data types, the most commonly available monitoring data were Actual Use numbers (permittee-reported livestock numbers and season-of-use), followed by Photo Point, forage Utilization, and finally, Vegetation Trend measurement data. Data availability and frequency of data collection varied across allotments and field offices. Analysis of the BLM's LHS data indicated 67 percent of allotments analyzed were meeting standards. For those not meeting standards, livestock were considered the causal factor in 45 percent of cases (about 15 percent of all allotments). Objective 3: We sought input from 42 university and federal rangeland science experts about how best to prioritize rangeland monitoring activities associated with ascertaining livestock impacts on vegetation resources. When we presented a hypothetical scenario to these scientists and asked them to prioritize monitoring activities, the most common response was to measure ground and vegetation cover, a variable that in many cases (10 of 13 field offices sampled) BLM had already identified as a monitoring priority. Experts identified several other traditional (for example, photo points) and emerging approaches (for example, high-resolution aerial photography) to monitoring. Objective 4: We used spatial allotment data (described in Objective 1) and remotely sensed vegetation data (sagebrush cover, herbaceous vegetation cover, litter and bare soil) to assess differences in allotment LHS status ("Not met" vs. "Met"; if "Not met" - livestock-caused vs. not). We then developed logistic regression models, using vegetation variables to predict LHS status of BLM allotments in sagebrush steppe habitats in Wyoming and portions of Montana and Colorado. In general, we found that more consistent data collection at the local level might improve suitability of data for broad-scale analyses of livestock impacts. As is, data collection methodologies varied across field offices and States, and we did not find any local-level monitoring data (Actual Use, Utilization, Vegetation Trend) that had been collected consistently enough over time or space for range-wide analyses. Moreover, continued and improved emphasis on monitoring also may aid local management decisions, particularly with respect to effects of livestock grazing. Rangeland science experts identified ground cover as a high monitoring priority for assessing range condition and emphasized the importance of tracking livestock numbers and grazing dates. Ultimately, the most effective monitoring program may entail both increased data collection effort and the integration of alternative monitoring approaches (for example, remote sensing or monitoring teams). In the course of our study, we identified three additional datasets that could potentially be used for range-wide analyses: spatial allotment boundary data for all BLM allotments range-wide, LHS evaluations of BLM allotments, and livestock use data (livestock numbers and grazing dates). It may be possible to use these spatial datasets to help prioritize monitoring activities over the extensive land areas managed by BLM. We present an example of how we used spatial allotment boundary data and LHS data to test whether remotely sensed vegetation characteristics could be used to predict which allotments met or did not meet LHS. This approach may be further improved by the results of current efforts by BLM to test whether more intensive (higher resolution) LHS assessments more accurately describe land health status. Standardized data collection in more ecologically meaningful land units may improve our ability to use local-level data for broad-scale analyses.

Sandy River Delta Habitat Restoration Project, Annual Report 2001.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelly, Virginia; Dobson, Robin L.

The Sandy River Delta is located at the confluence of the Sandy and Columbia Rivers, just east of Troutdale, Oregon. It comprises about 1,400 land acres north of Interstate 84, managed by the USDA Forest Service, and associated river banks managed by the Oregon Division of State Lands. Three islands, Gary, Flag and Catham, managed by Metro Greenspaces and the State of Oregon lie to the east, the Columbia River lies to the north and east, and the urbanized Portland metropolitan area lies to the west across the Sandy River. Sandy River Delta was historically a wooded, riparian wetland withmore » components of ponds, sloughs, bottomland woodland, oak woodland, prairie, and low and high elevation floodplain. It has been greatly altered by past agricultural practices and the Columbia River hydropower system. Restoration of historic landscape components is a primary goal for this land. The Forest Service is currently focusing on restoration of riparian forest and wetlands. Restoration of open upland areas (meadow/prairie) would follow substantial completion of the riparian and wetland restoration. The Sandy River Delta is a former pasture infested with reed canary grass, blackberry and thistle. The limited over story is native riparian species such as cottonwood and ash. The shrub and herbaceous layers are almost entirely non-native, invasive species. Native species have a difficult time naturally regenerating in the thick, competing reed canary grass, Himalayan blackberry and thistle. A system of drainage ditches installed by past owners drains water from historic wetlands. The original channel of the Sandy River was diked in the 1930's, and the river diverted into the ''Little Sandy River''. The original Sandy River channel has subsequently filled in and largely become a slough. The FS acquired approximately 1,400 acres Sandy River Delta (SRD) in 1991 from Reynolds Aluminum (via the Trust for Public Lands). The Delta had been grazed for many years but shortly after FS acquisition grazing was terminated while a master plan and Environmental Impact Statement (EIS) were developed for the site. During the following three years, the vegetation changed dramatically as a result of cessation of grazing. The dramatic changes included the explosive increases of reed canary grass monocultures in wet areas and the expansion of Himalayan blackberries throughout the site.« less

36 CFR 222.52 - National Grasslands.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false National Grasslands. 222.52 Section 222.52 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE RANGE MANAGEMENT Grazing Fees § 222.52 National Grasslands. Grazing fees for National Grasslands will be...

36 CFR 222.52 - National Grasslands.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false National Grasslands. 222.52 Section 222.52 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE RANGE MANAGEMENT Grazing Fees § 222.52 National Grasslands. Grazing fees for National Grasslands will be...

25 CFR 700.722 - Grazing associations.

Code of Federal Regulations, 2013 CFR

2013-04-01

... association's constitution and bylaws. (3) The officers other than secretary and treasurer must be grazing permittees on the range unit involved. (4) The association's activities must be governed by a constitution and bylaws acceptable to the Commissioner and signed by him. (5) The association's constitution and...

National-Scale Changes in Soil Profile C and N in New Zealand Pastures are Determined by Land Use

NASA Astrophysics Data System (ADS)

Schipper, L. A.; Parfitt, R.; Ross, C.; Baisden, W. T.; Claydon, J.; Fraser, S.

2010-12-01

Grazed pasture is New Zealand’s predominant agricultural land-use and has been relatively recently developed from forest and native grasslands/shrub communities. From the 1850s onwards, land was cleared and exotic pastures established. Phosphorus fertilizer was increasingly used after 1950 which accelerated N fixation by clover. In the last two decades N fertilizers have been used, and grazing intensity has increased, thus affecting soil C and N. Re-sampling of 31 New Zealand soil profiles under grazed pasture measured surprisingly large losses of C and N over the last 2-3 decades (Schipper et al., 2007 Global Change Biology 13:1138-1144). These profiles were predominantly on the most intensively grazed flat land. We extended this re-sampling to 83 profiles (to 90 cm depth), to investigate whether changes in soil C and N stocks also occurred in less intensively managed pasture. Archived soils samples were analysed for total soil C and N alongside the newly collected samples. Intact cores were collected to determine bulk density through the profile. Over an average of 27 years, soils (0-30 cm) in flat dairy pastures significantly lost 0.73±0.16 Mg C ha-1y-1 and 57±16 kg N ha-1y-1 while we observed no change in soil C or N in flat pasture grazed by “dry stock” (e.g., sheep, beef), or in grazed tussock grasslands. Grazed hill country soils (0-30 cm) gained 0.52±0.18 Mg C ha-1y-1 and 66±18 kg N ha-1y-1. The losses of C and N were strongly correlated and C:N ratio has generally declined suggesting soils are becoming N saturated. Losses and gains also occurred in soil layers below 30 cm demonstrating that organic matter throughout the profile was responding to land use. The losses under dairying may be due to greater grazing pressure, fertilizer inputs and exports of C and N. There is evidence that grazing pressure reduces inputs of C below ground, reduces soil microbial C, and that dairy cow urine can mobilise C and N. Gains in hill country pastures may be due to long-term recovery from erosion and disturbance following land clearance. When changes were extrapolated across New Zealand taking into account the different areas of pastures, gains and losses cancelled one another (Table 1) but none-the-less demonstrate considerable alteration of basic soil properties at national scales, and show the usefulness of resampling sites providing that older samples have been archived.Table 1. Change in total C and total N of grazed land for top 30 cm extrapolated across New Zealand. SEM - standard error of the mean

The Effect of Different Type of Herbivores, Grazing Types and Grazing Intensities on Alpine Basiphillous Vegetation of the Romanian Carpathians

NASA Astrophysics Data System (ADS)

Ballová, Zuzana; Pekárik, Ladislav; Šibík, Jozef

2017-04-01

The major purpose of the present study was to test the hypothesis that there are significant differences in vegetation structure, plant species composition, and soil chemical properties in relation to type of grazing animals, various levels of grazing intensity and grazing type, and if potential differences alter with ecosystem productivity (increase in more productive ecosystems). The study was conducted in three mountain ranges of the Romanian Carpathians with a predominance of alkaline substrates (the Bucegi Mts, the Little Retezat Mts and the Ceahlău Massif). Statistical analyses were performed in R statistical software environment. The effects of grazing animals (cattle, horses and sheep), grazing types (fence, regular, irregular) and grazing intensity (low, medium, high) on the community structure were tested using ordination methods. In the case of soil properties, General Linear Mixed Model was applied. Special statistical approach eliminated the differences between the examined mountains and sites. Type of grazing animal does not significantly influence species cover but it is related to specific species occurrence. According to our results, grazing horses had similar effects as cattle compared to sheep. Grazing in restricted areas (surrounded by fence) and regular unrestricted grazing were more similar if compared to irregular grazing. When comparing the intensity of grazing, high and medium intensity were more similar to each other than to the low intensity grazing. Cattle grazed sites had significantly higher lichens cover, while the sheep patches were covered with increased overall herb layer (forbs, graminoids and low shrubs together). Medium grazing intensity decreased the lichens cover, cover of overall herb layer, and total vegetation cover compared to high and low grazing intensity. Grazing type had important impact on the lichens cover and cover of overall herb layer. The lichens cover appeared to decrease while the cover of overall herb layer increased the most in restricted areas compared to irregularly and regularly grazed sites. When analyzing soil properties, Generalized mixed models revealed reliable results in the differences among categories of grazing types and intensity. These differences were only noticeable in calcium concentration being calcium the most decreased by medium grazing intensity and the most increased by irregular grazing. Grazing had significant effects on individual plant species occurrences and covers. Horses decreased presence of Anthoxanthum odoratum and regular grazing sites as well as fences had significantly higher occurrence of trampling tolerant species Nardus stricta compared to sites with irregular grazing. The type of grazing herbivores influenced covers of Agrostis capillaris, A. rupestris, Campanula rotundifolia, Festuca supina, Luzula multiflora, and Ranunculus pseudomontanus. The grazing types significantly altered covers of Agrostis capillaris, Alchemilla sp. div., Campanula rotundifolia, Festuca supina, Luzula multiflora, Nardus stricta, and Potentilla ternata (Potentilla aurea subsp. chrysocraspeda). The intensity of grazing had important impact on covers of Agrostis rupestris, Alchemilla sp. div., Campanula rotundifolia, Festuca supina, Luzula multiflora, Poa alpina, Potentilla ternata, and Ranunculus pseudomontanus. Key words: alpine meadows; pastures; GLMM; NMDS; (nested) PERMANOVA

A Polarization Technique for Mitigating Low Grazing Angle Radar Sea Clutter

DTIC Science & Technology

2017-03-03

alarm mitigation, low grazing angles, polarimetry , radar, sea clutter. I. INTRODUCTION Sea clutter poses unique challenges for maritime radars looking...radar polarimetry offers a practical means of robustly mitigating LGA sea clutter across a range of radar and environmental parameters, we stood up a

Challenges to Predicting Productivity of Grazing Ruminants. Where to now?

USDA-ARS?s Scientific Manuscript database

The Fourth Grazing Livestock Nutrition Conference was convened at Estes Park July 9 and 10.There were over 28 poster presentations and 12 conference papers presented. The papers were organized in 6 topical sessions ranging from microbiology to supplementation. The first session covered the potential...

Consumption of Low Larkspur (Delphinium nuttallianum) by Grazing Sheep

USDA-ARS?s Scientific Manuscript database

Low larkspur (Delphinium nuttallianum Pritz.) poisoning causes serious economic loss to livestock producers that graze cattle on foothill and mountain ranges in western North America. In general, all Delphinium spp. are five times less toxic to sheep than to cattle. Because sheep are less suscepti...

Physiological responses to variations in grazing and light conditions in native and invasive fucoids.

PubMed

Olabarria, Celia; Arenas, Francisco; Fernández, Ángela; Troncoso, Jesús S; Martínez, Brezo

2018-08-01

Poor physiological acclimatization to climate change has led to shifts in the distributional ranges of various species and to biodiversity loss. However, evidence also suggests the relevance of non-climatic physical factors, such as light, and biotic factors, which may act in interactive or additive way. We used a mechanistic approach to evaluate the ecophysiological responses of four seaweed species (three dominant intertidal fucoids, Fucus serratus, Ascophyllum nodosum, Bifurcaria bifurcata, and the invasive Sargassum muticum) to different conditions of grazing, light irradiance and ultraviolet (UV) radiation. We performed a large-scale mesocosm experiment with a total of 800 individual thalli of macroalgae. The factorial experimental design included major algal traits, photoacclimation, nutrient stoichiometry and chemical defence as response variables. Few significant effects of the factors acting alone or in combination were observed, suggesting a good capacity for acclimatization in all four species. The significant effects were generally additive and there were no potentially deleterious synergistic effects between factors. Fucus serratus, a species currently undergoing a drastic contraction of its southern distribution limit in Europe, was the most strongly affected species, showing overall lower photosynthetic efficiency than the other species. The growth rate of F. serratus decreased when UV radiation was filtered out, but only in the presence of grazers. Moreover, more individuals of this species tended to reach maturity in the absence of grazers, and the nitrogen content of tissues decreased under full-spectrum light. Only the phlorotannin content of tissues of B. bifurcata and of exudates of A. nodosum, both slow-growing species, were positively affected by respectively removal of UVB radiation and the presence of grazers. The findings for S. muticum, a well-established invasive seaweed across European coasts, suggested similar physiological response of this fast-growing species to different levels of grazing activity and light quality/intensity. As expected, this species grew faster than the other species. Bifurcaria bifurcata and A. nodosum only showed minor effects of light quality and grazing on phlorotannins content, which suggests good resistance of these two long-lived species to the experimental conditions. Mechanistic approaches that are designed to analyse interactive effects of physical and biotic factors provide an understanding of physiological responses of species and help to improve the confidence of predictive distribution models. Copyright © 2018 Elsevier Ltd. All rights reserved.

Forage kochia (Kochia Prostrata) increases nutritional value, carrying capacity, and livestock performance on semiarid rangelands

USDA-ARS?s Scientific Manuscript database

Extending the grazing season into the fall and winter increases the sustainability of livestock production by reducing winter feed costs. However, without exception, stockpiled range grasses do not meet nutritional requirements for ruminant livestock. This study compared fall/winter grazing of tra...

Grazing and Land Management Strategies for Hardwood Rangelands

Treesearch

Melvin R. George

1991-01-01

Annual rangelands produce 84 percent of California's range forage which are used all year by sedentary ranching operations and seasonally by migratory operations. Environmental policy, energy and water costs may reduce traditional summer forage sources, resulting in increased grazing pressure on hardwood and annual rangelands. However, the landowner's...

Seasonal and interannual variability in surface energy partitioning and vegetation cover with grazing at shortgrass steppe

USDA-ARS?s Scientific Manuscript database

We evaluated shortgrass steppe energy budgets based on the Bowen Ratio Energy Balance method for three different grazing intensity treatments at the Central Plains Experimental Range Long-Term Ecological Research (CPER-LTER) site. We tested the correlations between aboveground biomass and surface en...

Food sources of dominant macrozoobenthos between native and non-native mangrove forests: A comparative study

NASA Astrophysics Data System (ADS)

Chen, Luzhen; Yan, Ting; Xiong, Yiyi; Zhang, Yihui; Lin, Guanghui

2017-03-01

The macrozoobenthos is an important link of the food web in coastal wetlands. Diet-habitat relationships may significantly depend on qualitative differences and seasonal availability of food sources. Increasing interest has been shown in food web structure altered by non-native plants. In particular, however, a non-native mangrove species from Bangladesh, Sonneratia apetala, has been widely planted in China, but little is known about its possible impact on food sources of macrozoobenthos living in these non-native mangrove forests. Therefore, in this study, we used fatty acid analysis to compare the food sources of one littorinid snail and two grapsid crab species between two native mangrove forests and one non-native S. apetala plantation in the Zhanjiang Mangrove National Nature Reserve of China. We found that the sediment of all three forests had high diatom and bacteria signals, but low mangrove leaf signals, while the opposite patterns were detected in the three macrozoobenthos. Specifically, the gastropod Littoraria melanostoma relied mainly on mangrove leaves and brown algae as food sources, with significant differences among the three mangrove forests, and showed significant seasonal variation in its diet. The grapsidae species (Perisesarma bidens and Parasesarma plicatum) mainly grazed on mangrove litter, brown and green algae, and occasionally consumed diatoms and bacteria, also showing significant seasonal variation in their diet. Overall, Principle Components Analysis (PCA) of the fatty acid profiles showed a significant overlapping in food sources among the macrozoobenthos living in the non-native and native mangrove forests, but significant seasonal variations in their food sources. This suggests that the planting of non-native S. apetala near original mangrove forests has had little effect on the feeding behavior of macrozoobenthos some 10 years after planting.

In situ grazing experiments apply new technology to gain insights into deep-sea microbial food webs

NASA Astrophysics Data System (ADS)

Pachiadaki, Maria G.; Taylor, Craig; Oikonomou, Andreas; Yakimov, Michail M.; Stoeck, Thorsten; Edgcomb, Virginia

2016-07-01

Predation by grazing protists in aquatic habitats can influence prokaryotic community structure and provides a source of new, labile organic matter. Due to methodological difficulties associated with studies of deep-sea (below photic zone) microbiota, trophic interactions between eukaryotes and prokaryotes in mesopelagic and bathypelagic realms are largely obscured. Further complicating matters, examinations of trophic interactions using water samples that have been exposed to upwards of hundreds of atmospheres of pressure change prior to initiating experiments can potentially introduce significant artifacts. Here we present results of the first study of protistan grazing in water layers ranging from the euphotic zone to the bathypelagic, utilizing the Microbial Sampler-Submersible Incubation Device (MS-SID) that makes possible in situ studies of microbial activities. Protistan grazing in the mesopelagic and bathypelagic realm of the East Mediterranean Sea was quantified using fluorescently labeled prokaryotes (FLP) prepared from the naturally-occurring prokaryotic assemblages. These studies reveal daily prokaryotic removal due to grazing ranging from 31.3±5.9% at 40 m depth to 0.5±0.3% at 950 m. At 3540 m depth, where a chemocline habitat exists with abundant and active prokaryotes above Urania basin, the daily consumption of prokaryotes by protists was 19.9±6.6% of the in situ abundance.

Holocene vegetation and historic grazing impacts at Capitol Reef National Park reconstructed using packrat middens

USGS Publications Warehouse

Cole, K.L.; Henderson, N.; Shafer, D.S.

1997-01-01

Mid- to late-Holocene vegetation change from a remote high-desert site was reconstructed using plant macrofossils and pollen from 9 packrat middens ranging from 0 to 5400 yr in age. Presettlement middens consistently contained abundant macrofossils of plant species palatable to large herbivores that are now absent or reduced, such as winterfat (Ceratoides lanatd) and ricegrass (Stipa hymenoides). Macrofossils and pollen of pinyon pine (Pinus edulis), sagebrush (Artemisia spp.), and roundleaf buffaloberry (Shepherdia rotundifolia) were also recently reduced to their lowest levels for the 5400-yr record. Conversely, species typical of overgrazed range, such as snakeweed (Gutierrezia sarothrae), viscid rabbitbrush (Chrysothamnus visidiflorus), and Russian thistle (Salsola sp.), were not recorded prior to the historic introduction of grazing animals. Pollen of Utah juniper (Juniperus osteosperma) also increased during the last 200 yr. These records demonstrate that the most severe vegetation changes of the last 5400 yr occurred during the past 200 yr. The nature and timing of these changes suggest that they were primarily caused by 19th-century open-land sheep and cattle ranching. The reduction of pinyon and sagebrush concurrent with other grazing impacts suggests that effects of cattle grazing at modern stocking levels may be a poor analog for the effects of intense sheep grazing during drought.

Short-term nutritional treatments grazing legumes or feeding concentrates increase prolificacy in Corriedale ewes.

PubMed

Viñoles, C; Meikle, A; Martin, G B

2009-07-01

We tested whether short periods of increased nutrition will improve ovulation rate and prolificacy, irrespective of the method used to synchronise the cycles of the ewes. In Experiment 1, we used 138 Corriedale ewes to evaluate two factors: synchronization treatment (sponges versus a single injection of prostaglandin) and type of pasture (native versus improved with Lotus corniculatus). Ewes were mated at the end of the grazing period and prolificacy was evaluated at lambing. Grazing Lotus corniculatus for 12 days tended to increase the number of twin lambs born (P=0.09). The percentage of ewes showing oestrus during a 9-day period was similar among synchronization treatments. Animals in Experiments 2 (n=282) and 3 (n=288) were allocated to a control group or a group fed a supplement of corn grain and soybean meal for 7 days. Ewes received 2 prostaglandin injections and the supplement was fed from Days 11 to 17 after the second prostaglandin. Ovulation rate was measured in 65 (Experiment 2) and 61 (Experiment 3) ewes that were confirmed to have consumed the supplement and showed oestrus in a 4-day period. The supplement increased ovulation rate by 14% in both experiments (P<0.05). We conclude that Corriedale ewes can respond with increases in prolificacy to a 12-day period grazing Lotus corniculatus and in ovulation rate to 7 days feeding with a supplement rich in energy and protein. Moreover, in these studies, prostaglandin was as effective as sponges for synchronising oestrus, an important factor in future decisions about hormonal management of fertility.

A systematic review of wild burro grazing effects on Mojave Desert vegetation, USA.

PubMed

Abella, Scott R

2008-06-01

Wild burros (Equus asinus), protected by the 1971 Wild Free-Roaming Horse and Burro Act on some federal lands but exotic animals many ecologists and resource mangers view as damaging to native ecosystems, represent one of the most contentious environmental management problems in American Southwest arid lands. This review synthesizes the scattered literature about burro effects on plant communities of the Mojave Desert, a center of burro management contentions. I classified 24 documents meeting selection criteria for this review into five categories of research: (i) diet analyses directly determining which plant species burros consume, (ii) utilization studies of individual species, (iii) control-impact comparisons, (iv) exclosure studies, and (v) forage analyses examining chemical characteristics of forage plants. Ten diet studies recorded 175 total species that burros consumed. However, these studies and two exclosure studies suggested that burros preferentially eat graminoid and forb groups over shrubs. One study in Death Valley National Park, for example, found that Achnatherum hymenoides (Indian ricegrass) was 11 times more abundant in burro diets than expected based on its availability. Utilization studies revealed that burros also exhibit preferences within the shrub group. Eighty-three percent of reviewed documents were produced in a 12-year period, from 1972 to 1983, with the most recent document produced in 1988. Because burros remain abundant on many federal lands and grazing may interact with other management concerns (e.g., desert wildfires fueled by exotic grasses), rejuvenating grazing research to better understand both past and present burro effects could help guide revegetation and grazing management scenarios.

A Systematic Review of Wild Burro Grazing Effects on Mojave Desert Vegetation, USA

NASA Astrophysics Data System (ADS)

Abella, Scott R.

2008-06-01

Wild burros ( Equus asinus), protected by the 1971 Wild Free-Roaming Horse and Burro Act on some federal lands but exotic animals many ecologists and resource mangers view as damaging to native ecosystems, represent one of the most contentious environmental management problems in American Southwest arid lands. This review synthesizes the scattered literature about burro effects on plant communities of the Mojave Desert, a center of burro management contentions. I classified 24 documents meeting selection criteria for this review into five categories of research: (i) diet analyses directly determining which plant species burros consume, (ii) utilization studies of individual species, (iii) control-impact comparisons, (iv) exclosure studies, and (v) forage analyses examining chemical characteristics of forage plants. Ten diet studies recorded 175 total species that burros consumed. However, these studies and two exclosure studies suggested that burros preferentially eat graminoid and forb groups over shrubs. One study in Death Valley National Park, for example, found that Achnatherum hymenoides (Indian ricegrass) was 11 times more abundant in burro diets than expected based on its availability. Utilization studies revealed that burros also exhibit preferences within the shrub group. Eighty-three percent of reviewed documents were produced in a 12-year period, from 1972 to 1983, with the most recent document produced in 1988. Because burros remain abundant on many federal lands and grazing may interact with other management concerns (e.g., desert wildfires fueled by exotic grasses), rejuvenating grazing research to better understand both past and present burro effects could help guide revegetation and grazing management scenarios.

Ecology of grazing lawns in Africa.

PubMed

Hempson, Gareth P; Archibald, Sally; Bond, William J; Ellis, Roger P; Grant, Cornelia C; Kruger, Fred J; Kruger, Laurence M; Moxley, Courtney; Owen-Smith, Norman; Peel, Mike J S; Smit, Izak P J; Vickers, Karen J

2015-08-01

Grazing lawns are a distinct grassland community type, characterised by short-stature and with their persistence and spread promoted by grazing. In Africa, they reveal a long co-evolutionary history of grasses and large mammal grazers. The attractiveness to grazers of a low-biomass sward lies in the relatively high quality of forage, largely due to the low proportion of stem material in the sward; this encourages repeat grazing that concomitantly suppresses tall-grass growth forms that would otherwise outcompete lawn species for light. Regular grazing that prevents shading and maintains sward quality is thus the cornerstone of grazing lawn dynamics. The strong interplay between abiotic conditions and disturbance factors, which are central to grazing lawn existence, can also cause these systems to be highly dynamic. Here we identify differences in growth form among grazing lawn grass species, and assess how compositional differences among lawn types, as well as environmental variables, influence their maintenance requirements (i.e. grazing frequency) and vulnerability to degradation. We also make a clear distinction between the processes of lawn establishment and lawn maintenance. Rainfall, soil nutrient status, grazer community composition and fire regime have strong and interactive influences on both processes. However, factors that concentrate grazing pressure (e.g. nutrient hotspots and sodic sites) have more bearing on where lawns establish. Similarly, we discuss the relevance of enhanced rates of nitrogen cycling and of sodium levels to lawn maintenance. Grazer community composition and density has considerable significance to grazing lawn dynamics; not all grazers are adapted to foraging on short-grass swards, and differences in body size and relative mouth dimensions determine which species are able to convert tall-grass swards into grazing lawns under different conditions. Hence, we evaluate the roles of different grazers in lawn dynamics, as well as the benefits that grazer populations derive from having access to grazing lawns. The effects of grazing lawns can extend well beyond their borders, due to their influence on grazer densities, behaviour and movements as well as fire spread, intensity and frequency. Variation in the area and proportion of a landscape that is grazing lawn can thus have a profound impact on system dynamics. We provide a conceptual model that summarises grazing lawn dynamics, and identify a rainfall range where we predict grazing lawns to be most prevalent. We also examine the biodiversity associated with grazing lawn systems, and consider their functional contribution to the conservation of this biodiversity. Finally, we assess the utility of grazing lawns as a resource in a rangeland context. © 2014 The Authors. Biological Reviews © 2014 Cambridge Philosophical Society.

Characteristics of Columbia spotted frog (Rana luteiventris) oviposition sites in northeastern Oregon, USA

USGS Publications Warehouse

Pearl, Christopher A.; Adams, Michael J.; Wente, Wendy

2007-01-01

Several western ranid frogs possess a unique strategy of breeding communally over a short temporal window and reusing oviposition sites between years. However, little is published on the characteristics of oviposition sites selected by these explosive breeders. The Columbia spotted frog (Rana luteiventris) is native to northwestern North America and is of conservation concern in the southern portions of its range. As part of a study examining relationships between livestock grazing and R. luteiventris habitat, we assessed characteristics of the species' oviposition sites in 25 fishless ponds in northeastern Oregon. Oviposition sites were generally in shallow water (<25 cm) close to shore and tended to be in the northeastern portion of ponds. Oviposition sites were found more frequently over heavily vegetated substrates and in areas of less substrate slope and shade than random points in littoral zones. We did not quantify temperature differences within ponds, but the patterns we documented are consistent with preferential use of warmer microhabitats for oviposition.

43 CFR 4300.90 - What is a trespass?

Code of Federal Regulations, 2012 CFR

2012-10-01

... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false What is a trespass? 4300.90 Section 4300..., DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION; ALASKA; REINDEER; GENERAL Trespass § 4300.90 What is a trespass? (a) A trespass is any use of Federal land for reindeer grazing purposes...

25 CFR 167.13 - Trespass.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 25 Indians 1 2014-04-01 2014-04-01 false Trespass. 167.13 Section 167.13 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.13 Trespass. The owner of any livestock grazing in trespass in Navajo Tribal ranges shall be subject to action by the Navajo...

25 CFR 167.13 - Trespass.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 25 Indians 1 2012-04-01 2011-04-01 true Trespass. 167.13 Section 167.13 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.13 Trespass. The owner of any livestock grazing in trespass in Navajo Tribal ranges shall be subject to action by the Navajo...

43 CFR 4300.90 - What is a trespass?

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false What is a trespass? 4300.90 Section 4300..., DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION; ALASKA; REINDEER; GENERAL Trespass § 4300.90 What is a trespass? (a) A trespass is any use of Federal land for reindeer grazing purposes...

25 CFR 167.13 - Trespass.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 25 Indians 1 2011-04-01 2011-04-01 false Trespass. 167.13 Section 167.13 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.13 Trespass. The owner of any livestock grazing in trespass in Navajo Tribal ranges shall be subject to action by the Navajo...

25 CFR 167.13 - Trespass.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 25 Indians 1 2013-04-01 2013-04-01 false Trespass. 167.13 Section 167.13 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.13 Trespass. The owner of any livestock grazing in trespass in Navajo Tribal ranges shall be subject to action by the Navajo...

43 CFR 4300.90 - What is a trespass?

Code of Federal Regulations, 2013 CFR

2013-10-01

... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false What is a trespass? 4300.90 Section 4300..., DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION; ALASKA; REINDEER; GENERAL Trespass § 4300.90 What is a trespass? (a) A trespass is any use of Federal land for reindeer grazing purposes...

25 CFR 167.13 - Trespass.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 1 2010-04-01 2010-04-01 false Trespass. 167.13 Section 167.13 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.13 Trespass. The owner of any livestock grazing in trespass in Navajo Tribal ranges shall be subject to action by the Navajo...

43 CFR 4300.90 - What is a trespass?

Code of Federal Regulations, 2014 CFR

2014-10-01

... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false What is a trespass? 4300.90 Section 4300..., DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION; ALASKA; REINDEER; GENERAL Trespass § 4300.90 What is a trespass? (a) A trespass is any use of Federal land for reindeer grazing purposes...

43 CFR 4120.3-4 - Standards, design and stipulations.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Standards, design and stipulations. 4120.3-4 Section 4120.3-4 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Grazing Management § 4120.3-4...

Amazing Grazing.

ERIC Educational Resources Information Center

Peterson, Cris

Countless acres of grasslands stretch across the American West. Centuries ago, bison roamed the range freely and lived off the grass. By the 19th century, herds of cattle grazed the same land. Over time, much of the original grassland was either plowed and planted or trampled to dust, causing the topsoil to dry up and blow away. Today many…

Effects of past logging and grazing on understory plant communities in a montane Colorado forest

USGS Publications Warehouse

Fornwalt, P.J.; Kaufmann, M.R.; Huckaby, L.S.; Stohlgren, T.J.

2009-01-01

Throughout Pinus ponderosa-Pseudotsuga menziesii forests of the southern Colorado Front Range, USA, intense logging and domestic grazing began at the time of Euro-American settlement in the late 1800s and continued until the early 1900s. We investigated the long-term impacts of these settlement-era activities on understory plant communities by comparing understory composition at a historically logged and grazed site to that of an environmentally similar site which was protected from past use. We found that species richness and cover within functional groups rarely differed between sites in either upland or riparian areas. Multivariate analyses revealed little difference in species composition between sites on uplands, though compositional differences were apparent in riparian zones. Our findings suggest that settlement-era logging and grazing have had only minor long-term impacts on understories of upland Front Range P. ponderosa-P. menziesii forests, though they have had a greater long-term influence on riparian understories, where these activities were likely the most intense. ?? 2008 Springer Science+Business Media B.V.

Ruminal motility of stocker cattle grazed on winter wheat pasture.

PubMed

Horn, G W; Frost, D F

1982-10-01

A 2-yr study was conducted to determine whether bloat of stocker cattle grazing winter wheat pasture is a primary bloat or a secondary bloat as a result of reduced ruminal motility. Amplitude (mm Hg) and frequency of ruminal contractions (contractions/min) of steers were measured before and after the steers were placed on wheat pasture, and at about weekly intervals during the pasture grazing periods. Implantable pressure transducers and water-filled balloon cannulas were used to measure ruminal motility. During the first year, amplitude of contractions increased (P less than .005) during grazing of wheat pasture (i.e., 20.5 vs 6.7 and 21.6 vs 12.9, respectively, for steers with implanted pressure transducers and water-filled balloon cannulas). Frequency of ruminal contractions of steers on wheat pasture was not decreased (P greater than .05). In the second year, amplitudes of ruminal contractions of steers on wheat pasture ranged from 11.0 to 33.5, and were either similar or greater (P less than .05) than the mean for the pre- and post-wheat pasture period (16.5). Frequencies of ruminal contractions that ranged from 1.66 to 1.80 were observed on four dates during the pasture grazing period, and were decreased (P less than .05) as compared with the mean for the pre- and post-wheat pasture period (2.43). However, the reduced frequencies were not accompanied by reduced (P greater than .05) amplitude x frequency of contractions. The data indicate that ruminal motility is not decreased in stocker cattle grazing winter wheat pasture.

Fire, grazing history, lichen abundance, and winter distribution of caribou in Alaska's taiga

USGS Publications Warehouse

Collins, William B.; Dale, Bruce W.; Adams, Layne G.; McElwain, Darien E.; Joly, Kyle

2011-01-01

In the early 1990s the Nelchina Caribou (Rangifer tarandus) Herd (NCH) began a dramatic shift to its current winter range, migrating at least an additional 100 km beyond its historic range. We evaluated the impacts of fire and grazing history on lichen abundance and subsequent use and distribution by the NCH. Historic (prior to 1990) and current (2002) winter ranges of the NCH had similar vascular vegetation, lichen cover (P = 0.491), and fire histories (P = 0.535), but the former range had significantly less forage lichen biomass as a result of grazing by caribou. Biomass of forage lichens was twice as great overall (P = 0.031) and 4 times greater in caribou selected sites on the current range than in the historic range, greatly increasing availability to caribou. Caribou on the current range selected for stands with >20% lichen cover (P < 0.001), greater than 1,250 kg/ha (P < 0.001) forage lichen biomass and stands older than 80 yr postfire (P < 0.001). After fires, forage lichen cover and biomass seldom recovered sufficiently to attract caribou grazing until after ≥60 yr, and, as a group, primary forage lichen species did not reach maximum abundance until 180 yr postfire. Recovery following overgrazing can occur much more quickly because lichen cover, albeit mostly fragments, and organic substrates remain present. Our results provide benchmarks for wildlife managers assessing condition of caribou winter range and predicting effects of fires on lichen abundance and caribou distribution. Of our measurements of cover and biomass by species, densities and heights of trees, elevation, slope and aspect, only percentage cover by Cladonia amaurocraea, Cladina rangiferina, Flavocetraria cuculata, and lowbush cranberry (Vaccinium vitis‐idaea) were necessary for predicting caribou use of winter range.

Measurement and mitigation of methane emissions from beef cattle in tropical grazing systems: a perspective from Australia and Brazil.

PubMed

Berndt, A; Tomkins, N W

2013-06-01

The growing global demand for food of animal origin will be the incentive for countries such as Australia and Brazil to increase their beef production and international exports. This increased supply of beef is expected to occur primarily through on-farm productivity increases. The strategies for reducing resultant greenhouse gas (GHG) emissions should be evaluated in the context of the production system and should encompass a broader analysis, which would include the emissions of methane (CH4) and nitrous oxide (N2O) and carbon sequestration. This paper provides an insight into CH4 measurement techniques applicable to grazing environments and proposed mitigation strategies, with relevance to the production systems that are predominant in grazing systems of Australia and Brazil. Research and technology investment in both Australia and Brazil is aimed at developing measurement techniques and increasing the efficiency of cattle production by improving herd genetics, utilization of the seasonal feed-base and reducing the proportion of metabolizable energy lost as CH4. Concerted efforts in these areas can be expected to reduce the number of unproductive animals, reduce age at slaughter and inevitably reduce emission intensity (EI) from beef production systems. Improving efficiency of livestock production systems in tropical grazing systems for Australia and Brazil will be based on cultivated and existing native pastures and the use of additives and by-products from other agricultural sectors. This approach spares grain-based feed reserves typically used for human consumption, but potentially incurs a heavier EI than current intensive feeding systems. The determination of GHG emissions and the value of mitigation outcomes for entire beef production systems in the extensive grazing systems is complex and require a multidisciplinary approach. It is fortunate that governments in both Australia and Brazil are supporting ongoing research activities. Nevertheless, to achieve an outcome that feeds a growing population while reducing emissions on a global scale continues to be a monumental challenge for ruminant nutritionists.

Soil-occupancy effects of invasive and native grassland plant species on composition and diversity of mycorrhizal associations

USGS Publications Warehouse

Jordan, Nicholas R.; Aldrich-Wolfe, Laura; Huerd, Sheri C.; Larson, Diane L.; Muehlbauer, Gary

2012-01-01

Diversified grasslands that contain native plant species can produce biofuels, support sustainable grazing systems, and produce other ecosystem services. However, ecosystem service production can be disrupted by invasion of exotic perennial plants, and these plants can have soil-microbial “legacies” that may interfere with establishment and maintenance of diversified grasslands even after effective management of the invasive species. The nature of such legacies is not well understood, but may involve suppression of mutualisms between native species and soil microbes. In this study, we tested the hypotheses that legacy effects of invasive species change colonization rates, diversity, and composition of arbuscular-mycorrhizal fungi (AMF) associated with seedlings of co-occurring invasive and native grassland species. In a glasshouse, experimental soils were conditioned by cultivating three invasive grassland perennials, three native grassland perennials, and a native perennial mixture. Each was grown separately through three cycles of growth, after which we used T-RFLP analysis to characterize AMF associations of seedlings of six native perennial and six invasive perennial species grown in these soils. Legacy effects of soil conditioning by invasive species did not affect AMF richness in seedling roots, but did affect AMF colonization rates and the taxonomic composition of mycorrhizal associations in seedling roots. Moreover, native species were more heavily colonized by AMF and roots of native species had greater AMF richness (number of AMF operational taxonomic units per seedling) than did invasive species. The invasive species used to condition soil in this experiment have been shown to have legacy effects on biomass of native seedlings, reducing their growth in this and a previous similar experiment. Therefore, our results suggest that successful plant invaders can have legacies that affect soil-microbial associations of native plants and that these effects can inhibit growth of native plant species in invaded communities.

Land uses, fire, and invasion: Exotic annual Bromus and human dimensions

USGS Publications Warehouse

Pyke, David A.; Chambers, Jeanne C.; Beck, Jeffrey L.; Brooks, Matthew L.; Mealor, Brian A.

2016-01-01

Human land uses are the primary cause of the introduction and spread of exotic annual Bromusspecies. Initial introductions were likely linked to contaminated seeds used by homesteading farmers in the late 1880s and early 1900s. Transportation routes aided their spread. Unrestricted livestock grazing from the 1800s through the mid-1900s reduced native plant competitors leaving large areas vulnerable to Bromus dominance. Ecosystems with cooler and moister soils tend to have greater potential to recover from disturbances (resilience) and to be more resistant to Bromusinvasion and dominance. Warmer and drier ecosystems are less resistant to Bromus and are threatened by altered fire regimes which can lead to Bromus dominance, impacts to wildlife, and alternative stable states. Native Americans used fire for manipulating plant communities and may have contributed to the early dominance of Bromus in portions of California. Fire as a tool is now limited to site preparation for revegetation in most ecosystems where Bromus is a significant problem. Once Bromus dominates, breaking annual grass/fire cycles requires restoring fire-tolerant perennial grasses and forbs, which can compete with Bromus and resist its dominance. Current weed management policies often lack regulations to prevent further expansion of Bromus. Research is needed on how and where livestock grazing might help increase perennial grass and forb cover and density to create ecosystems that are more resistant to Bromus. Also, studies are needed to ascertain the role, if any, of oil and gas development in contributing to the spread of Bromus.

Light as a regulator of structural and chemical leaf defenses against insects in two Prunus species

NASA Astrophysics Data System (ADS)

Mąderek, Ewa; Zadworny, Marcin; Mucha, Joanna; Karolewski, Piotr

2017-11-01

Light is a key factor influencing competition between species, and the mechanisms by which trees overcome insect outbreaks can be associated with alternation of the leaves structure, which then prevent or promotes their susceptibility to herbivores. It was predicted that leaf tissue anatomy would likely be different in sun and shade leaves, with a gradual decline of leaves resistance coupled with reduction of accessible light. We quantified anatomical patterns and the distribution of defence compounds (phenols, total tannins, catechol tannins) within heavily grazed leaves of Prunus padus, native in Europe and Prunus serotina, an invasive to Central Europe. Both species were strongly attacked by folivorous insects when shrubs grew in the shade. In the sun, however only P. padus leaves were grazed, but P. serotina leaves were almost unaffected. We identified that anatomical characteristics are not linked to different P. padus and P. serotina leaf vulnerability to insects. Furthermore, the staining of defence compounds of P. serotina leaves grown in full sun revealed that the palisade mesophyll cells had a higher content of phenolic compounds and catechol tannins. Thus, our results indicate that a specific distribution of defence compounds, but not the anatomical relationships between palisade and spongy mesophyll, may be beneficial for P. serotina growth outside its natural range. The identified pattern of defence compounds distribution is linked to a lower susceptibility of P. serotina leaves to herbivores, and is associated with its invasiveness. This likely reflects that P. serotina is a stronger competitor than P. padus, especially at high sunlit sites i.e. gaps in the forest.

Assessing the impacts of livestock production on biodiversity in rangeland ecosystems.

PubMed

Alkemade, Rob; Reid, Robin S; van den Berg, Maurits; de Leeuw, Jan; Jeuken, Michel

2013-12-24

Biodiversity in rangelands is decreasing, due to intense utilization for livestock production and conversion of rangeland into cropland; yet the outlook of rangeland biodiversity has not been considered in view of future global demand for food. Here we assess the impact of future livestock production on the global rangelands area and their biodiversity. First we formalized existing knowledge about livestock grazing impacts on biodiversity, expressed in mean species abundance (MSA) of the original rangeland native species assemblages, through metaanalysis of peer-reviewed literature. MSA values, ranging from 1 in natural rangelands to 0.3 in man-made grasslands, were entered in the IMAGE-GLOBIO model. This model was used to assess the impact of change in food demand and livestock production on future rangeland biodiversity. The model revealed remarkable regional variation in impact on rangeland area and MSA between two agricultural production scenarios. The area of used rangelands slightly increases globally between 2000 and 2050 in the baseline scenario and reduces under a scenario of enhanced uptake of resource-efficient production technologies increasing production [high levels of agricultural knowledge, science, and technology (high-AKST)], particularly in Africa. Both scenarios suggest a global decrease in MSA for rangelands until 2050. The contribution of livestock grazing to MSA loss is, however, expected to diminish after 2030, in particular in Africa under the high-AKST scenario. Policies fostering agricultural intensification can reduce the overall pressure on rangeland biodiversity, but additional measures, addressing factors such as climate change and infrastructural development, are necessary to totally halt biodiversity loss.

Assessing the impacts of livestock production on biodiversity in rangeland ecosystems

PubMed Central

Alkemade, Rob; Reid, Robin S.; van den Berg, Maurits; de Leeuw, Jan; Jeuken, Michel

2013-01-01

Biodiversity in rangelands is decreasing, due to intense utilization for livestock production and conversion of rangeland into cropland; yet the outlook of rangeland biodiversity has not been considered in view of future global demand for food. Here we assess the impact of future livestock production on the global rangelands area and their biodiversity. First we formalized existing knowledge about livestock grazing impacts on biodiversity, expressed in mean species abundance (MSA) of the original rangeland native species assemblages, through metaanalysis of peer-reviewed literature. MSA values, ranging from 1 in natural rangelands to 0.3 in man-made grasslands, were entered in the IMAGE-GLOBIO model. This model was used to assess the impact of change in food demand and livestock production on future rangeland biodiversity. The model revealed remarkable regional variation in impact on rangeland area and MSA between two agricultural production scenarios. The area of used rangelands slightly increases globally between 2000 and 2050 in the baseline scenario and reduces under a scenario of enhanced uptake of resource-efficient production technologies increasing production [high levels of agricultural knowledge, science, and technology (high-AKST)], particularly in Africa. Both scenarios suggest a global decrease in MSA for rangelands until 2050. The contribution of livestock grazing to MSA loss is, however, expected to diminish after 2030, in particular in Africa under the high-AKST scenario. Policies fostering agricultural intensification can reduce the overall pressure on rangeland biodiversity, but additional measures, addressing factors such as climate change and infrastructural development, are necessary to totally halt biodiversity loss. PMID:22308313

25 CFR 700.715 - Assignment, modification, and cancellation of grazing permits.

Code of Federal Regulations, 2011 CFR

2011-04-01

... permit and may be transferred with the term permit if the transferee signs the range unit management plan... not be transferred and shall be null and void if the term permit transferee does not sign the... § 700.711. (d) Grazing permits must be transferred in whole to a single transferee—the transferor...

25 CFR 700.715 - Assignment, modification, and cancellation of grazing permits.

Code of Federal Regulations, 2010 CFR

2010-04-01

... permit and may be transferred with the term permit if the transferee signs the range unit management plan... not be transferred and shall be null and void if the term permit transferee does not sign the... § 700.711. (d) Grazing permits must be transferred in whole to a single transferee—the transferor...

Effects of past logging and grazing on understory plant communities in a montane Colorado forest

Treesearch

Paula J. Fornwalt; Merrill R. Kaufmann; Laurie S. Huckaby

2009-01-01

Throughout Pinus ponderosa-Pseudotsuga menziesii forests of the southern Colorado Front Range, USA, intense logging and domestic grazing began at the time of Euro-American settlement in the late 1800s and continued until the early 1900s. We investigated the long-term impacts of these settlement-era activities on understory plant...

Range management on the National Forests

Treesearch

James T. Jardine; Mark Anderson

1919-01-01

In the administration of the National Forests the aim is to convey to the greatest possible number the full benefit of all the resources which the Forests contain and at the same time to perpetuate these resources by regulating their use. Accordingly, grazing on the National Forests is regulated with the object of using the grazing resources to the fullest extent...

Streambank Erosion from Grazed Pastures, Grass Filters and Forest Buffers Over a Six-Year Period

USDA-ARS?s Scientific Manuscript database

In agricultural landscapes, streambank erosion, as a source of non-point water pollution, is one of the major contributors to stream habitat degradation. Streambank erosion rates from riparian forest buffers, grass filters and grazed pastures (stocking rates ranged from 0.23 to 1.15 cow-days ha-1 m-...

25 CFR 161.203 - Are range management plans required?

Code of Federal Regulations, 2010 CFR

2010-04-01

...: (a) Consult with the Navajo Nation in planning conservation practices, including grazing control and range restoration activities for the Navajo Partitioned Lands. (b) Develop range management plans with...

A toxic endophyte-infected grass helps reverse degradation and loss of biodiversity of over-grazed grasslands in northwest China

PubMed Central

Yao, Xiang; Christensen, Michael J.; Bao, Gensheng; Zhang, Chunping; Li, Xiuzhang; Li, Chunjie; Nan, Zhibiao

2015-01-01

Overgrazing of China’s grasslands is increasingly causing biodiversity to decline. In degenerated grasslands of northwest China endophyte (Epichloё gansuensis) infected Achnatherum inebrians (drunken horse grass) is becoming widely distributed because of its toxicity to livestock. In this study, we investigated the ecological consequences of endophyte toxicity in this native grass, at three sites in northwest China, by comparing seed production of plant species and arthropod abundance in overgrazed grasslands with and without the presence of A. inebrians. Our findings demonstrate that the presence of endophyte infected A. inebrians reduces the loss of plant and arthropod biodiversity by providing a protected nursery free of animal grazing. Therefore, A. inebrians, typically regarded as an unwanted toxic invader by pastoralists, should be viewed as beneficial for grasslands as its presence maintains plant and arthropod biodiversity, and provides a foundation stone in the reconstruction and restoration of these grassland ecosystems. PMID:26679518

Habitat Evaluation Procedures (HEP) Report; Iskuulpa Wildlife Mitigation and Watershed Project, Technical Report 1998-2003.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quaempts, Eric

U.S. Fish and Wildlife Service (USFWS) Habitat Evaluation Procedures (HEP) were used to determine the number of habitat units credited to evaluate lands acquired and leased in Eskuulpa Watershed, a Confederated Tribes of the Umatilla Indian Reservation watershed and wildlife mitigation project. The project is designed to partially credit habitat losses incurred by BPA for the construction of the John Day and McNary hydroelectric facilities on the Columbia River. Upland and riparian forest, upland and riparian shrub, and grasslands cover types were included in the evaluation. Indicator species included downy woodpecker (Picuides puhescens), black-capped chickadee (Pams atricopillus), blue grouse (Beadragapusmore » obscurus), great blue heron (Ardea herodias), yellow warbler (Dendroica petschia), mink (Mustela vison), and Western meadowlark (Sturnello neglects). Habitat surveys were conducted in 1998 and 1999 in accordance with published HEP protocols and included 55,500 feet of transects, 678 m2 plots, and 243 one-tenth-acre plots. Between 123.9 and f 0,794.4 acres were evaluated for each indicator species. Derived habitat suitability indices were multiplied by corresponding cover-type acreages to determine the number of habitat units for each species. The total habitat units credited to BPA for the Iskuulpa Watershed Project and its seven indicator species is 4,567.8 habitat units. Factors limiting habitat suitability are related to the direct, indirect, and cumulative effects of past livestock grazing, road construction, and timber harvest, which have simplified the structure, composition, and diversity of native plant communities. Alternatives for protecting and improving habitat suitability include exclusion of livestock grazing or implementation of restoration grazing schemes, road de-commissioning, reforestation, large woody debris additions to floodplains, control of competing and unwanted vegetation, reestablishing displaced or reduced native vegetation species, and the allowance of normative processes such as fire occurrence. Implementation of these alternatives could generate an estimated minimum of 393 enhancement credits in 10 years. Longer-term benefits of protection and enhancement activities include increases in native species diversity and structural complexity in all cover types. While such benefits are not readily recognized by HEP models and reflected in the number of habitat units generated, they also provide dual benefits for fisheries resources. Implementation of the alternatives will require long-term commitments from managers to increase probabilities of success and meet the goals and objectives of the Northwest Power Planning Council's Fish and Wildlife Mitigation Program.« less

Radionuclide transport from soil to air, native vegetation, kangaroo rats and grazing cattle on the Nevada test site.

PubMed

Gilbert, R O; Shinn, J H; Essington, E H; Tamura, T; Romney, E M; Moor, K S; O'Farrell, T P

1988-12-01

Between 1970 and 1986 the Nevada Applied Ecology Group (NAEG), U.S. Department of Energy, conducted environmental radionuclide studies at weapons-testing sites on or adjacent to the Nevada Test Site. In this paper, NAEG studies conducted at two nuclear (fission) sites (NS201, NS219) and two nonnuclear (nonfission) sites (Area 13 [Project 57] and Clean Slate 2) are reviewed, synthesized and compared regarding (1) soil particle-size distribution and physical-chemical characteristics of 239 + 240Pu-bearing radioactive particles, (2) 239 + 240Pu resuspension rates and (3) transuranic and fission-product radionuclide transfers from soil to native vegetation, kangaroo rats and grazing cattle. The data indicate that transuranic radionuclides were transferred more readily on the average from soil to air, the external surfaces of native vegetation and to tissues of kangaroo rats at Area 13 than at NS201 or NS219. The 239 + 240Pu resuspension factor for undisturbed soil at Area 13 was three to four orders-of-magnitude larger than at NS201 and NS219, the geometric mean (GM) vegetation-over-soil 239 + 240Pu concentration ratio was from ten to 100 times larger than at NS201, and the GM GI-over-soil, carcass-over-soil and pelt-over-soil 239 + 240Pu ratios for kangaroo rats were about ten times larger than at NS201. These results are consistent with the finding that Area 13, compared with NS201 or NS219, has a higher percentage of radioactivity associated with smaller soil particles and a larger percentage of resuspendable and respirable soil. However, the resuspension factor increased by a factor of 27 at NS201 when the surface soil was disturbed, and by a factor of 12 at NS219 following a wildfire. The average (GM) concentration of 239 + 240Pu for the GI (and contents) of Area 13 kangaroo rats and for the rumen contents of beef cattle that grazed Area 13 were very similar (400 vs. 440 Bq kg-1 dry wt, respectively) although the variability between individuals was very large. The GM carcass-over-GI 239 + 240Pu concentration ratio for kangaroo rats at Area 13, Clean Slate 2, and NS201 were similar in value (approximately 2 X 10(-2)), as were the GM GI-over-vegetation concentration ratios (approximately 2 X 10(0)) (no statistical differences).(ABSTRACT TRUNCATED AT 400 WORDS)

Impact of Non-Native Birds on Native Ecosystems: A Global Analysis.

PubMed

Martin-Albarracin, Valeria L; Amico, Guillermo C; Simberloff, Daniel; Nuñez, Martin A

2015-01-01

Introduction and naturalization of non-native species is one of the most important threats to global biodiversity. Birds have been widely introduced worldwide, but their impacts on populations, communities, and ecosystems have not received as much attention as those of other groups. This work is a global synthesis of the impact of nonnative birds on native ecosystems to determine (1) what groups, impacts, and locations have been best studied; (2) which taxonomic groups and which impacts have greatest effects on ecosystems, (3) how important are bird impacts at the community and ecosystem levels, and (4) what are the known benefits of nonnative birds to natural ecosystems. We conducted an extensive literature search that yielded 148 articles covering 39 species belonging to 18 families -18% of all known naturalized species. Studies were classified according to where they were conducted: Africa, Asia, Australasia, Europe, North America, South America, Islands of the Indian, of the Pacific, and of the Atlantic Ocean. Seven types of impact on native ecosystems were evaluated: competition, disease transmission, chemical, physical, or structural impact on ecosystem, grazing/ herbivory/ browsing, hybridization, predation, and interaction with other non-native species. Hybridization and disease transmission were the most important impacts, affecting the population and community levels. Ecosystem-level impacts, such as structural and chemical impacts were detected. Seven species were found to have positive impacts aside from negative ones. We provide suggestions for future studies focused on mechanisms of impact, regions, and understudied taxonomic groups.

Explaining variability in first grazing season heifer growth combining individually measured parasitological and clinical indicators with exposure to gastrointestinal nematode infection based on grazing management practice.

PubMed

Merlin, Aurélie; Chauvin, Alain; Madouasse, Aurélien; Froger, Sébastien; Bareille, Nathalie; Chartier, Christophe

2016-07-30

The objective of our study was to explain the variability of average daily weight gain (ADWG) due to gastrointestinal nematode (GIN) infection for 291 non treated first grazing season (FGS) heifers, from 12 independent groups in the western part of France, by combining parasitological and clinical indicators at individual level and grazing management indicators at group level. Parasitological indicators were faecal egg count (FEC), anti Ostertagia ostertagi antibody level (Ostertagia ODR), and pepsinogen level. Clinical indicators were diarrhea score (DISCO) and breech soiling score (BSS). At group level, grazing management practice (GMP), based on three variables (supplementation, month of turnout, grazing season duration), was clustered into three categories reflecting low, medium or high exposure (EXP) to GIN. Depending on the groups, turnout was from mid-March to early July and housing was from mid-October to late November, with a FGS duration ranging from 4 to 8.4 months. At turnout, the mean age of heifers was 8 months (range: 6-16 months) and they weighed between 175 and 268kg. In each GMP category, FEC significantly decreased between the mid-season and the housing, while Ostertagia ODR and pepsinogen level increased gradually throughout the grazing season. In contrast, clinical indicators did not show any seasonal variation. In a multivariate linear model, 22% of the ADWG variability was significantly explained by two individual indicators (Ostertagia ODR: 12.6%, DISCO: 4.8%) and by the group indicator (GMP category: 4.8%). ADWG losses due to GIN exposure (Ostertagia ODR) were estimated up to 39kg per heifer for the overall grazing season. For groups within the low EXP category the difference between animals with low (<697g/day) or high (>697g/day) ADWG was explained by the clinical indicator DISCO. In contrast, for groups within the medium and high EXP categories this difference was explained by a parasitological indicator (Ostertagia ODR). This study highlighted the value of combining both grazing management (group level) and parasitological (individual level) indicators to assess the impact of GIN on ADWG of FGS heifers. As a result, this combination might allow a better discrimination of animals or groups that may be in need of treatment in a targeting selective treatment approach. Copyright © 2016 Elsevier B.V. All rights reserved.

Low quality roughages for steers grazing wheat pasture. I. Effect on weight gains and bloat.

PubMed

Mader, T L; Horn, G W; Phillips, W A; McNew, R W

1983-05-01

The effect of feeding low quality roughages (LQR) on live and carcass weight gains and the incidence and severity of bloat of stocker cattle grazed on wheat pasture was evaluated in a 3 yr study. One hundred eighty-five steer calves (172 kg mean initial weight) grazed clean-tilled wheat pasture and were either fed no LQR or had ad libitum access to wheat straw (WS) or sorghum-Sudan hay (SS). Grazing periods were (I) fall grazing, (II) winter grazing, (III) period of lush spring growth of wheat forage and (IV) period of advancing forage maturity and declining quality. Mean dry matter (DM), crude protein and acid detergent fiber (ADF) content (percentage of DM) of wheat forage averaged across years ranged, respectively, from 23.8 to 33.0, 19.8 to 26.4 and 21.5 to 27.7. Mean daily consumption (kg DM/head) of WS and SS by steers ranged from .076 to .100 and .199 to .248, respectively. Live and carcass weight gains of steers during Periods I through III (i.e., the usual wheat pasture grazing period) were not influenced (P greater than .05) by treatments. Carcass weight gains were about 74% of live weight gains. Bloat was observed only during the last 2 wk of Period III of the first year. The incidence (steer days of bloat) and severity (bloat score) of control, WS- and SS-fed steers were 9.5 and 1.2, .5 and .5 and 2.0 and 1.0, and were not different (P greater than .05) among treatments. Intake of WS and SS [g/body weight (BW).75kg] during Periods I to III was, respectively, only about 5 and 12% of roughage intakes (i.e., 37.5 g/BW.75kg) reported in the literature to "effectively control" or aid the prevention of bloat. It seems unlikely that LQR consumed to amounts similar to those of this study would control bloat of stocker cattle on wheat pasture.

δ13C values of soil organic matter in semiarid grassland with mesquite (Prosopis) encroachment in southeastern Arizona

USGS Publications Warehouse

Biggs, Thomas H.; Quade, Jay; Webb, Robert H.

2002-01-01

Over the past century, C3 woody plants and trees have increased in abundance in many semiarid ecosystems, displacing native C4 grasses. Livestock grazing, climatic fluctuations, and fire suppression are several reasons proposed for this shift. Soil carbon isotopic signatures are an ideal technique to evaluate carbon turnover rates in such ecosystems. On the gunnery ranges of Fort Huachuca in southeastern Arizona, study sites were established on homogeneous granitic alluvium to investigate the effects of fire frequency on δ13C values in surface soil organic matter (SOM). These ranges have had no livestock grazing for 50 years and a well-documented history of fires. Prosopis velutina Woot. (mesquite) trees have altered SOM δ13C pools by the concentration of plant nutrients and the addition of isotopically light litter. These soil carbon changes do not extend beyond canopy margins. Elevated total organic carbon (TOC), plant nutrient (N and P) concentrations, and depleted SOM δ13C values are associated with C3Prosopis on an unburned plot, which enables recognition of former Prosopis-occupied sites on plots with recent fire histories. Elevated nutrient concentrations associated with former Prosopis are retained in SOM for many decades. Surface SOM δ13C values indicate the estimated minimum turnover time of C4-derived carbon beneath large mature Prosopis is about 100–300 years. In contrast, complete turnover of original C3 carbon to C4 carbon under grasslands is estimated to take a minimum of 150–500 years. Our study confirms that C4 grass cover has declined over the past 100 years, although isolated C3 trees or shrubs were not uncommon on the historic C4-dominated grasslands. We find evidence in surface soil layers for a modern C3 plant expansion reflected in the substantial shift of SOM δ13C values from C4 grasses to C3 shrublands.

Assessing the production and economic benefits from preventing cows grazing on wet soils in New Zealand.

PubMed

Laurenson, Seth; Houlbrooke, David J; Beukes, Pierre C

2016-10-01

Intensive grazing by cattle on wet pasture can have a negative effect on soil physical quality and future pasture production. On a North Otago dairy farm in New Zealand, experimental plots were monitored for four years to assess whether preventing cow grazing of wet pastures during the milking season would improve soil structure and pasture production compared with unrestricted access to pastures. The DairyNZ Whole Farm Model was used to scale up results to a farm system level and ascertain the cost benefit of deferred grazing management. Soils under deferred grazing management had significantly higher total porosity, yet no significant improvement in macroporosity (values ranging between 0.112 and 0.146 m(3)  m(-3) ). Annual pasture production did not differ between the control and deferred grazing treatments, averaging 17.0 ± 3.8 and 17.9 ± 4.1 t DM ha(-1) year(-1) respectively (P > 0.05). Furthermore, whole farm modelling indicated that farm operating profit was reduced by NZ$1683 ha(-1) year(-1) (four-year average) under deferred grazing management. Deferring dairy cow grazing from wet Pallic soils in North Otago was effective in improving soil structure (measured as total soil porosity), yet did not lead to a significant increase in pasture production. Whole farm modelling indicated no economic benefit of removing cows from wet soils during the milking season. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Biotic Interactivity between Grazers and Plants: Relationships Contributing to Atmospheric Boundary Layer Dynamics.

NASA Astrophysics Data System (ADS)

Dyer, M. I.; Turner, C. L.; Seastedt, T. R.

1998-04-01

During 1987 and 1988 First ISLSCP (International Satellite Land Surface Climatology Project) Field Experiment (FIFE) studies conducted in the tallgrass prairie of central Kansas, variations in ungulate grazing intensity produced a patchy spatial and temporal distribution of remaining vegetation. Equally variable plant regrowth patterns contributed further to a broad array of total primary production that resulted in a pronounced mosaic of grazing impacts. This regrowth potential, derived from a relative growth rate (RGR) equation comparing ungrazed and grazed plants, determines much of the ecosystem dynamics within and among the grazed pastures and between years. Rates of change in new plant growth (RGRg) ranged from 100% to +40%; however, 78% of the time in 1987 and 71% in 1988, productivity increased as a function of grazing intensity. Since plant growth potential in ungrazed (RGRug) and grazed systems (RGRg) have inherently different attributes, interactions with the abiotic environment may develop many uncertainties. Thus, changes in growth rates in grazed areas compared to ungrazed areas (RGRg) may impose major controls over system productivity and associated biological processes currently not accounted for in ecosystem models.Because FIFE microsite atmospheric boundary layer (ABL) studies did not directly incorporate grazing intensity into their design, Type I and Type II statistical errors may introduce significant uncertainties for understanding cause and effect in surface flux dynamics. As a consequence these uncertainties compromise the ability to extrapolate microsite ABL biophysical findings to other spatial and temporal scales.

Effect of stocking rate and supplementation on performance of dairy cows grazing native grassland in small-scale systems in the highlands of central Mexico.

PubMed

Sainz-Sánchez, Pedro Alan; López-González, Felipe; Estrada-Flores, Julieta Gertrudis; Martínez-García, Carlos Galdino; Arriaga-Jordán, Carlos Manuel

2017-01-01

The use and management of native grassland for dairy production during the rainy season was studied on two small-scale dairy farms in the highlands of central Mexico. Two stocking rates (2 and 4 cows/ha) and two levels of supplementation with commercial concentrate (4 and 6 kg/cow/day) under grazing were given to 12 milking Holstein cows in a 4 × 4 Latin square design replicated three times in a factorial arrangement. Net herbage accumulation (NHA), sward height, chemical composition, and in vitro digestibility of organic matter were recorded for the grassland, as well as vegetation cover and herbage mass 12 weeks post experiment. Animal performance variables were milk yield and composition, live weight, and body condition score. A partial budget analysis of feeding costs, returns, and margins was calculated. There were no differences between periods for NHA and herbage height and between plots for chemical composition (P > 0.05). However, there were highly significant differences among periods (P < 0.01) for organic matter, neutral detergent fibre (NDF), acid detergent fibre, in vitro organic matter digestibility (IVOMD), and estimated metabolisable energy (eME), with highly significant plot × period interactions (P < 0.01) for NDF, IVOMD, and eME. There were no statistical differences (P > 0.05) between treatments for milk yield, chemical composition of milk, live weight, or body condition score. Post-experimental vegetation cover was 72 % for both stocking rates, indicating there was no degradation of the grassland. Lower feeding costs were for the low supplementation treatments. It is concluded that a high stocking rate in studied native grasslands of 4 cows/ha with moderate concentrate supplementation supports a mean milk yield of 11.9 kg/cow/day during the rainy season without deleterious effects on the grassland.

Radionuclide transport from soil to air, native vegetation, kangaroo rats and grazing cattle on the Nevada test site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gilbert, R.O.; Shinn, J.H.; Essington, E.H.

Between 1970 and 1986 the Nevada Applied Ecology Group (NAEG), U.S. Department of Energy, conducted environmental radionuclide studies at weapons-testing sites on or adjacent to the Nevada Test Site. In this paper, NAEG studies conducted at two nuclear (fission) sites (NS201, NS219) and two nonnuclear (nonfission) sites (Area 13 (Project 57) and Clean Slate 2) are reviewed, synthesized and compared regarding (1) soil particle-size distribution and physical-chemical characteristics of 239 + 240Pu-bearing radioactive particles, (2) 239 + 240Pu resuspension rates and (3) transuranic and fission-product radionuclide transfers from soil to native vegetation, kangaroo rats and grazing cattle. The data indicatemore » that transuranic radionuclides were transferred more readily on the average from soil to air, the external surfaces of native vegetation and to tissues of kangaroo rats at Area 13 than at NS201 or NS219. The 239 + 240Pu resuspension factor for undisturbed soil at Area 13 was three to four orders-of-magnitude larger than at NS201 and NS219, the geometric mean (GM) vegetation-over-soil 239 + 240Pu concentration ratio was from ten to 100 times larger than at NS201, and the GM GI-over-soil, carcass-over-soil and pelt-over-soil 239 + 240Pu ratios for kangaroo rats were about ten times larger than at NS201. These results are consistent with the finding that Area 13, compared with NS201 or NS219, has a higher percentage of radioactivity associated with smaller soil particles and a larger percentage of resuspendable and respirable soil. However, the resuspension factor increased by a factor of 27 at NS201 when the surface soil was disturbed, and by a factor of 12 at NS219 following a wildfire.« less

Liver functional genomics in beef cows on grazing systems: novel genes and pathways revealed.

PubMed

Laporta, Jimena; Rosa, Guilherme J M; Naya, Hugo; Carriquiry, Mariana

2014-02-15

The adaptation of the liver to periods of negative energy balance is largely unknown in beef cattle on grazing systems. We evaluated liver transcriptome throughout gestation and early lactation of purebred and crossbred beef cows [Angus, Hereford, and their F1 crossbreeds (CR)], grazing high or low herbage allowances (HA) of native grasslands (4 and 2.5 kg dry matter/kg body wt annual mean; n = 16) using an Agilent 4 × 44k bovine array. A total of 4,661 transcripts were affected by days [272 ≥ 2.5-fold difference, false discovery rate (FDR) ≤ 0.10] and 47 pathways were altered during winter gestation (-165 to -15 days relative to calving), when cows experienced decreased body condition score, decreased insulin, and increased nonesterified fatty acid concentrations. Gluconeogenesis and fatty acid oxidation pathways were upregulated, while cell growth, DNA replication, and transcription pathways were downregulated (FDR ≤ 0.25). We observed only small changes in the liver transcriptome during early lactation (+15 to +60 days). A total of 225 genes were differentially expressed (47 ≥ 2-fold difference, FDR ≤ 0.10) between HA. The majority of those were related to glucose and pyruvate metabolism and were upregulated in high HA, reflecting their better metabolic status. Two genes were upregulated in CR cows, but 148 transcripts (74 ≥ 2-fold change difference, FDR ≤ 0.10) were affected by the HA and cow genotype interaction. The transcriptional changes observed indicated a complex and previously unrecognized, hepatic adaptive program of grazing beef cows in different nutritional environments. Novel target candidate genes, metabolic pathways, and regulatory mechanisms were reported.

Sediment dynamics and sources in a grazed hardwood rangeland watershed

Treesearch

Melvin R. George; Neil K. McDougald; Kenneth W. Tate; Royce Larsen

2002-01-01

From 1994 to 1998 we documented sediment transport dynamics and sources in a 137 ha grazed hardwood rangeland watershed on granitic soils at the San Joaquin Experimental Range in Madera County. Sediment transport for this watershed was determined by measuring total suspended solids, bedload and flow at an H-flume installed in 1994. Sediment movement as bedload is the...

Public resource pricing: an analysis of range policy.

Treesearch

Thomas M. Quigley; R. Garth Taylor; R. McGreggor Cawley

1988-01-01

Pricing represents an important step in the allocation of scarce resources. Markets, which set the price policy, are not restricted by a simple buyer-seller relation. The Federal grazing-fee policy is at the forefront of controversy surrounding the pricing of all uses of public lands. The pricing process of grazing fees has been cyclical. With few exceptions, the cycle...

Response of a depleted sagebrush steppe riparian system to grazing control and woody plantings

Treesearch

Warren P. Clary; Nancy L. Shaw; Jonathan G. Dudley; Victoria A. Saab; John W. Kinney; Lynda C. Smithman

1996-01-01

To find out if a depleted riparian system in the sagebrush steppe of eastern Oregon would respond quickly to improved management, five management treatments were applied for 7 years, ranging from ungrazed to heavily grazed treatments, including in some cases, planting of woody species. While the results varied, all treatments were too limited to significantly restore...

Grazing and Burning Impacts on Deer Diets on Lousiana Pine-Bluestem Range

Treesearch

Ronald E. Thill; Alton Martin; Hershel F. Morris; E. Donice McCune

1987-01-01

Diets of 3-5 tame white-tailed deer (Odocoileus virginianus) on adjacent ungrazed and continuously grazed (35% herbage removal by late CM) forested pastures were compared for forage-class use, botanical similarities, foraging selectivity and efficiency, and diet quality. Both pastures were divided into 3 burning subunits and burned in late February on a 3-year...

Deer and Cattle Diets on Heavily Grazed Pine-Bluestem Range

Treesearch

Ronald E. Thill; Alton Martin

1989-01-01

We studied dietary overlap between captive white-tailed deer (n = 3) (Odocoileus virginianus) and cattle (n = 4) for 3 years on 2 rotationally burned, 54-ha longleaf pine (Pinus palustris)-bluestem (Andropogon spp.) pastures in central Louisiana. A third of each pasture was burned each year in late February. One pasture was grazed heavily (61-77% herbage use) yearlong...

Biological Agents Influencing Physical Process in a Stream: A Case Study in Response to Human-Induced Alteration

NASA Astrophysics Data System (ADS)

Sondossi, H. A.; Bienz, C.

2013-12-01

We present a case study of the Upper Williamson River, a major tributary to Upper Klamath Lake (UKL), to demonstrate illustrate the importance of biophysical interactions. The Klamath River is called 'the upside-down river' by some, due to its peculiar longitudinal profile--low-gradient at the headwaters east of the Cascade Range and steeper close to the mouth as it crosses the Cascades. The Upper Williamson River, as with other tributaries of UKL, flows through highly erodible volcanic ash (pumice) deposits of the Mazama eruption ~7,000 years ago, which created Crater Lake. There is little or no gravel in the broad, shallow alluvial valley of the River. We make the case that in this particular setting, the role of biological agents (e.g., riparian vegetation) is even more prominent than in settings with normal silica-derived sediment. Therefore, typical agricultural practices (removal of woody riparian vegetation, livestock grazing and trampling, etc.) cause rapid and severe channel response and therefore habitat degradation. However, when appropriately restored the recovery is also rapid and drastic. This spring-fed stream with few tributaries in the study area conveys relatively stable discharge, and has good water quality particularly in the upper reaches. It historically supported a population of native redband trout (Oncorhynchus mykiss gairdnerii), and the candidate species (for listing under the Endangered Species Act) Oregon spotted frog (Rana pretiosa) and countless other avian species. In the late 20th Century, after decades of heavy grazing and active removal of willows from the floodplain, the River banks were nearly bare and unstable. The channel was wide, shallow, and smooth. Consequently, poor water quality, particularly high temperature rendered the stream extremely poor habitat. With controlled grazing, re-establishment of willow galleries, and addition of large woody debris (LWD) the channel has recovered to a narrower, deeper cross-section, with ample depth variability. Water quality has improved to the point that it supports a healthy and expanding population of redband trout alongside introduced eastern brook trout (Salvelinus fontinalis). There have been no sightings of Oregon spotted frog yet, but the habitat is deemed suitable.

Grazing Potential of Louisiana Pine Forest-Ranges

Treesearch

Herbert S. Sternitzke

1975-01-01

Louisiana's 5 million acres of pine forest-range have an estimated forage potential for 135,776 yearlong cow-calf units. Two-thirds of the units can be sustained on loblolly-shortleaf pine ranges; the rest, on longleaf-slash pine ranges.

Salp distribution and grazing in a saline intrusion off NW Spain

NASA Astrophysics Data System (ADS)

Huskin, Iñaki; Elices, Ma. José; Anadón, Ricardo

2003-07-01

Salp distribution and grazing were studied along three transects (19 stations) and a Lagrangian phase (7 stations) off Galician coast (NW Spain) in November 1999 during GIGOVI 99 cruise. A poleward saline intrusion was detected at the shelf-break, reaching salinity values above 35.90 u.p.s. at 100-m depth. The salp community was dominated by Salpa fusiformis, although Cyclosalpa bakeri, Thalia democratica and Iasis zonaria were also found in the study area. Total salp abundance ranged from 4 to 4500 ind m -2, representing biomass values between 0.2 and 2750 mg C m -2. Maximum densities were located in the frontal area separating the saline body from coastal waters. S. fusiformis pigment ingestion was estimated using the gut fluorescence method. Gut contents were linearly related to salp body size. Total pigment ingestion ranged from 0.001 to 15 mg Chl- a m -2 d -1, with maximum values at the coastal edge of the saline body. Estimated ingestion translates into an average daily grazing impact of 7% of chlorophyll standing stock, ranging from <1% to 77%.

Elk-effects vegetation monitoring program for Tomales Point Elk Range, Point Reyes National Seashore, California

USGS Publications Warehouse

McEachern, Kathryn; Semenoff-Irving, Marcia; van der Leeden, Pamela

2000-01-01

The monitoring program for elk effects on Tomales Point vegetation is designed to provide information on how tule elk grazing affects plant communities and rare species. The basic objective of the program is to show whether the elk are driving the vegetation into an unacceptable state by their grazing. The expectation is that as elk numbers increase, grazing pressure will increase too, resulting in unacceptable levels of any or all of the following: low vegetation ground cover, poor nutritional quality for the elk, undesirable increases in weedy species, unacceptable loss of native plant biodiversity, population declines in rare plants, population declines in plants used for food and nectar by the endangered silverspot butterfly, and increased erosion.The monitoring program has 3 basic components designed to provide complementary information on different aspects of the elk-vegetation system. Long-term plant community monitoring along permanent transects will show how plant species composition and cover are changing since cattle removal in 1979, and it will show whether any of he undesirable traits listed above are developing in the vegetation. However, monitoring these transects alone will not tell us what the effects of continued grazing by elk are apart from changes the vegetation would be undergoing anyway. In order to tease apart the elk effects from change that is happening because of cattle removal, elk exclosures are needed. By sampling inside and outside exclosures, we will be able to see how elk are modifying the rates and directions of change in the vegetation that would be happening in their absence. In a sense, the exclosures serve as a “check” on elk effects. They will allow us to interpret how much of the change is due to elk and how much can be attributed to other processes such as natural succession or weather patterns. This information will allow us to analyze whether changing elk management will have a desirable effect on the vegetation. Finally, periodic mapping and counting of plants in rare plant populations will show whether plant population ranges are expanding and populations are stable or growing. If not, then management actions can be taken to improve habitat conditions for the plants.A general summary of the rationale and sample design for each of the 3 components of the elk-effects monitoring program follows. Field sampling for the entire program should require about 15 weeks for a 2 to 3- person team, and data processing, analysis, and report writing should require about 9 weeks. Time and labor estimates for this program are given in Table A-1. In addition to elk-effects monitoring, Point Reyes staff periodically monitor fire transects and residual dry matter plots on Tomales Point. They are not included as part of the elk-effects monitoring program and they are described elsewhere. Protocols for fire and residual dry matter sampling are not included in the time estimate for the elk- effects monitoring program.

Managing broiler litter application rate and grazing to decrease watershed runoff losses.

PubMed

Sistani, K R; Brink, G E; Oldham, J L

2008-01-01

Pasture management and broiler litter application rate are critical factors influencing the magnitude of nutrients being transported by runoff from fields. We investigated the impact of pasture management and broiler litter application rate on nutrient runoff from bermudagrass (Cynodon dactylon) pastures. The experiment was conducted on a Ruston fine sandy loam with a factorial arrangement on 21 large paddocks. Runoff water was collected from natural rainfall events from 2001 to 2003. Runoff water and soil samples were analyzed for nutrients and sediments. Runoff was generally greater (29%) from grazed than hayed pastures regardless of the litter application rate. There was greater inorganic N in the runoff from grazed paddocks when litter rate was based on N rather than P. The mean total P loss per runoff event for all treatments ranged from 7 to 45 g ha(-1) and the grazed treatment with litter applied on N basis had the greatest total P loss. Total dissolved P was the dominant P fraction in the runoff, ranging from 85% to 93% of the total P. The soluble reactive P was greater for treatments with litter applied on N basis regardless of pasture management. Runoff total sediments were greater for N-based litter application compared to those which received litter on P basis. Our results indicate that litter may be applied on N basis if the pasture is hayed and the soil P is low. In contrast, litter rates should be based on a P-basis if pasture is grazed.

The relative roles of climate and land use in the degradation of a terrestrial ecosystem: a case study from Kjarardalur, West Iceland

NASA Astrophysics Data System (ADS)

Erlendsson, Egill; Gísladóttir, Guðrún

2016-04-01

Around AD 870 the virgin environment of Iceland became populated by humans and mammal land herbivores. Since then, the island has lost nearly all of its native birch woodland, resulting in dramatic degradation of landscapes and ecosystems, attributed mainly to over-exploitation of woodlands and late-medieval climate deterioration. As part of policy making in agriculture, a heated debate is ongoing over limitations to sheep grazing in pastures suffering from long-term degradation. In this context the history of climate and land use is of great importance. Those who consider grazing a minimal attribute to land degradation argue that the harsh climate conditions of the little ice age are the primary mechanism behind the current degraded landscape. Others err on the side of caution and propose a careful approach to grazing. This study forms a contribution to the historical context of the impact of grazing upon the Icelandic terrestrial ecosystem. Using the analyses of pollen and spores from coprophilous fungi as principal methods, we present data about historical environmental change from within two different land holdings in Kjarardalur Valley, West Iceland. One dataset comes from within a landholding governed by the chieftain farm Reykholt, the other comes from within the land of the indipendent farm, Norðtunga. In the past the valley was used primarily as a pasture, associated with shielings (organised seasonal grazing). Pollen data from the pasture in Kjarardalur Valley, West Iceland, demonstrate a rapid loss of birch (Betula pubescens) woodland from grazing areas owned by the major farm and institution, Reykholt. The suppressive nature of grazing is demonstrated by the expansion of woodland as soon when animal stocks are reduced, probably as a consequence of the bubonic plague after AD 1402. Resumed exploitation of resources eventually depleted all birch woodland from the Reykholt landholding and precipitated soil erosion. The trajectory of environmental change in the adjacent woodland belonging to the independent farm, Norðtunga is quite different. There woodland and landscape stability recovered from an initial period of decline and survived throughout the 11 centuries of land use and unfavourable climate during the little ice age. After c. AD 1700 a significant rise in livestock numbers, particularly sheep, caused a decline in the remaining woodland at both sites. In the case of the Reykholt land holding this led to the final depletion of birch woodland. The research shows that careful land management, perhaps resulting from secular ownership of land, could have minimised the deterioration of terrestrial ecosystems.

Nitrogen rate and application timing affect the yield and risk associated with stockpiling tall fescue for winter grazing

USDA-ARS?s Scientific Manuscript database

Stockpiled tall fescue can provide economical winter feed for grazing livestock in the mid-Atlantic of the United States. The objective of this study was to evaluate the effect of N rate and application timing on the yield of stockpiled tall fescue. Four N rates ranging from 0 to 120 lb N/acre wer...

Artificial Water Point for Livestock Influences Spatial Ecology of a Native Lizard Species

PubMed Central

Leu, Stephan T.; Bull, C. Michael

2016-01-01

Pastoralism is a major agricultural activity in drier environments, and can directly and indirectly impact native species in those areas. We investigated how the supply of an artificial watering point to support grazing livestock affected movement and activity patterns of the Australian sleepy lizard (Tiliqua rugosa) during a drought year. We observed 23 adult lizards; six had access to a dam, whereas 17 lizards did not. Lizards with access to the dam had larger home ranges, were substantially active on more days (days with >100 steps), and moved more steps per day compared to lizards that did not have access to the dam, both during the early and late period of our observation. Furthermore, while the two groups of lizards had similar body condition early in the season, they differed later in the season. Lizards with dam access retained, whereas lizards without access lost body condition. Local heterogeneity in access to an artificial water resource resulted in spatially dependent behavioural variation among sleepy lizard individuals. This suggests that sleepy lizards have flexible responses to changing climatic conditions, depending on the availability of water. Furthermore, while reducing activity appears a suitable short term strategy, if harsh conditions persist, then access to dams could be of substantial benefit and could support sustained lizard activity and movement and allow maintenance of body condition. Hence, artificial watering points, such as the dams constructed by pastoralists, may provide local higher quality refugia for sleepy lizards and other species during drought conditions. PMID:26800274

The role of plant-soil feedbacks in driving native-species recovery.

PubMed

Yelenik, Stephanie G; Levine, Jonathan M

2011-01-01

The impacts of exotic plants on soil nutrient cycling are often hypothesized to reinforce their dominance, but this mechanism is rarely tested, especially in relation to other ecological factors. In this manuscript we evaluate the influence of biogeochemically mediated plant-soil feedbacks on native shrub recovery in an invaded island ecosystem. The introduction of exotic grasses and grazing to Santa Cruz Island, California, USA, converted native shrublands (dominated by Artemisia californica and Eriogonum arborescens) into exotic-dominated grasslands (dominated by Avena barbata) over a century ago, altering nutrient-cycling regimes. To test the hypothesis that exotic grass impacts on soils alter reestablishment of native plants, we implemented a field-based soil transplant experiment in three years that varied widely in rainfall. Our results showed that growth of Avena and Artemisia seedlings was greater on soils influenced by their heterospecific competitor. Theory suggests that the resulting plant-soil feedback should facilitate the recovery of Artemisia in grasslands, although four years of monitoring showed no such recovery, despite ample seed rain. By contrast, we found that species effects on soils lead to weak to negligible feedbacks for Eriogonum arborescens, yet this shrub readily colonized the grasslands. Thus, plant-soil feedbacks quantified under natural climate and competitive conditions did not match native-plant recovery patterns. We also found that feedbacks changed with climate and competition regimes, and that these latter factors generally had stronger effects on seedling growth than species effects on soils. We conclude that even when plant-soil feedbacks influence the balance between native and exotic species, their influence may be small relative to other ecological processes.

43 CFR 4140.1 - Acts prohibited on public lands.

Code of Federal Regulations, 2013 CFR

2013-10-01

... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA... terms, conditions, and stipulations of cooperative range improvement agreements or range improvement permits; (5) Refusing to install, maintain, modify, or remove range improvements when so directed by the...

43 CFR 4140.1 - Acts prohibited on public lands.

Code of Federal Regulations, 2014 CFR

2014-10-01

... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA... terms, conditions, and stipulations of cooperative range improvement agreements or range improvement permits; (5) Refusing to install, maintain, modify, or remove range improvements when so directed by the...

43 CFR 4140.1 - Acts prohibited on public lands.

Code of Federal Regulations, 2012 CFR

2012-10-01

... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA... terms, conditions, and stipulations of cooperative range improvement agreements or range improvement permits; (5) Refusing to install, maintain, modify, or remove range improvements when so directed by the...

[Effects of grazing disturbance on soil active organic carbon in mountain forest-arid valley ecotone in the upper reaches of Minjiang River].

PubMed

Liu, Shan-Shan; Zhang, Xing-Hua; Gong, Yuan-Bo; Li, Yuan; Wang, Yan; Yin, Yan-Jie; Ma, Jin-Song; Guo, Ting

2014-02-01

Effects of grazing disturbance on the soil carbon contents and active components in the four vegetations, i.e., artificial Robinia pseudoacacia plantation, artificial poplar plantation, Berberis aggregate shrubland and grassland, were studied in the mountain forest-arid valley ecotone in the upper Minjiang River. Soil organic carbon and active component contents in 0-10 cm soil layer were greater than in 10-20 cm soil layer at each level of grazing disturbance. With increasing the grazing intensity, the total organic carbon (TOC), light fraction organic carbon (LFOC), particulate organic carbon (POC) and easily oxidized carbon (LOC) contents in 0-10 cm soil layer decreased gradually in the artificial R. pseudoacacia plantation. The LFOC content decreased, the POC content increased, and the TOC and LOC contents decreased initially and then increased with increasing the grazing intensity in the artificial poplar plantation. The POC content decreased, and the TOC, LFOC and LOC contents decreased initially and then increased with increasing the grazing intensity in the B. aggregate shrubland. The POC and TOC contents decreased, and the LFOC and LOC contents decreased initially and then increased with increasing the grazing intensity in the grassland. The decreasing ranges of LOC, LFOC and POC contents were 0.1-7.9 times more than that of TOC content. There were significant positive relationships between TOC and LOC, LFOC and POC, suggesting that the active organic carbon components could reflect the change of soil total carbon content.

Effect of surface roughness and subsurface damage on grazing-incidence x-ray scattering and specular reflectance.

PubMed

Lodha, G S; Yamashita, K; Kunieda, H; Tawara, Y; Yu, J; Namba, Y; Bennett, J M

1998-08-01

Grazing-incidence specular reflectance and near-specular scattering were measured at Al-K(alpha) (1.486-keV, 8.34-?) radiation on uncoated dielectric substrates whose surface topography had been measured with a scanning probe microscope and a mechanical profiler. Grazing-incidence specular reflectance was also measured on selected substrates at the Cu-K(alpha) (8.047-keV, 1.54-?) wavelength. Substrates included superpolished and conventionally polished fused silica; SiO(2) wafers; superpolished and precision-ground Zerodur; conventionally polished, float-polished, and precision-ground BK-7 glass; and superpolished and precision-ground silicon carbide. Roughnesses derived from x-ray specular reflectance and scattering measurements were in good agreement with topographic roughness values measured with a scanning probe microscope (atomic force microscope) and a mechanical profiler that included similar ranges of surface spatial wavelengths. The specular reflectance was also found to be sensitive to the density of polished surface layers and subsurface damage down to the penetration depth of the x rays. Density gradients and subsurface damage were found in the superpolished fused-silica and precision-ground Zerodur samples. These results suggest that one can nondestructively evaluate subsurface damage in transparent materials using grazing-incidence x-ray specular reflectance in the 1.5-8-keV range.

36 CFR 222.9 - Range improvements.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., Forest Service, is authorized to install and maintain structural and nonstructural range improvements... provisions of which become a part of the grazing permit(s). (2) Title to permanent structural range improvements shall rest in the United States. (3) Title to temporary structural range improvements may be...

Investigating the Effect of Livestock Grazing and Associated Plant Community Shifts on Carbon and Nutrient Cycling in Alberta, Canada

NASA Astrophysics Data System (ADS)

Hewins, D. B.; Chuan, S.; Stolnikova, E.; Bork, E. W.; Carlyle, C. N.; Chang, S. X.

2015-12-01

Grassland ecosystems are ubiquitous across the globe covering an estimated 40 % of Earth's terrestrial landmass. These ecosystems are widely valued for providing forage for domestic livestock and a suite of important ecosystem goods and services including carbon (C) storage. Despite storing more than 30 % of soil C globally, the effect of both livestock grazing and the associated change in plant community structure in response to grazing on C and nutrient cycling remains uncertain. To gain a quantitative understanding of the direct and indirect effects of livestock grazing on C and nutrient cycling, we established study sites at 15 existing site localities with paired long-term grazing (ca. 30 y) and non-grazed treatments (totaling 30 unique plant communities). Our sites were distributed widely across Alberta in three distinct grassland bioclimatic zones allowing us to make comparisons across the broad range of climate variability typical of western Canadian grasslands. In each plant community we decomposed 5 common plant species that are known to increase or decrease in response to grazing pressure, a unique plant community sample, and a cellulose paper control. We measured mass loss, initial lignin, C and N concentrations at 0, 1, 3, 6 and 12 months of field incubation. In addition we assayed hydrolytic and oxidative extracellular enzymes associated with for C (n= 5 hydrolytic; phenoloxidase and peroxidase) and nutrients (i.e. N and P; n=1 ea.) cycling from each litter sample at each collection. Our results suggest that by changing the plant community structure, grazing can affect rates of decomposition and associated biogeochemical cycling by changing plant species and associated litter inputs. Moreover, measures of microbial function are controlled by site-specific conditions (e.g. temperature and precipitation), litter chemistry over the course of our incubation.

Developing management guidelines that balance cattle and timber production with ecological interests in the Black Hills of South Dakota

NASA Astrophysics Data System (ADS)

Chowanski, Kurt M.

Forested lands contribute to the United States (US) economy by providing livestock and timber production. Livestock grazing of forested lands has been widespread throughout the western US since the settlement era, and currently occurs on 51.4 million hectares (ha) representing 16% of all US grazing land and 22% of all US forested land (Nickerson et al. 2011). While livestock grazing and timber harvest are occurring on a substantial amount of forested land, relationships between management practices, tree stocking, timber production, forage production, livestock grazing, wildlife, aesthetics, and ecological integrity are not well documented. Whether considering timber or cattle, finding a balance between production and resource conservation is a fundamental challenge to agricultural producers, and is often a tradeoff between short term gains and long term sustainability. This dissertation aims to identify livestock and timber management practices that optimize production and are ecologically conservative. Specifically, I focused on three objectives. First, I reviewed the published literature and summarized what is known about best-practices for concurrent management of livestock and timber production in pine forests in the US. I found most studies came from the southeastern and western US where timber and livestock production on the same land unit are common. The relationship between pine cover and forage seemed fairly consistent across the US, and production was optimized when cattle grazed open canopy forests with basal areas between 5 and 14 m2 ha-1 (15-35% tree canopy cover). Second, I developed forest cover maps to estimate forage production in the Black Hills, South Dakota (SD) for the period from 1999 to 2015. I developed a regression model based on Landsat and Ikonos satellite imagery and was able to detect large changes in forest cover over time. I then used these maps in combination with maps of soil type and Palmer Drought Severity Index (PDSI) to update forage production estimates for the region. These changes in forest cover have large implications for forage production in the Black Hills. Over the 15 year period, mean tree cover decreased in 181 pastures in the Mystic Ranger District by 17.6 +/- 0.6%, and there was a corresponding 15.5 +/- 0.6% increase in mean forage production. Third, I conducted a 2 -year field experiment in the Black Hills, SD to study the relationships between management practices such as livestock stocking rates, grazing pressure, and timber harvest history, and aspects of resource condition such as tree regeneration, forage production, and plant community composition. From 2014-2015, I visited 44 pastures across a spectrum of management practices and measured seedling regeneration (590 plots), plant species richness (393 plots), primary production (246 plots), and visual obstruction (120 transects). I found that cattle grazing did not affect ponderosa pine regeneration. Grazing did affect plant diversity, and I found the highest plant diversity in areas of moderate grazing pressure. This work suggests that moderate stocking rates should have no effect on the timber industry but could positively affect native plant diversity. In the conclusion, I summarize what I learned from the literature review, mapping exercise, and field study and provide some management recommendations based on this work. Overall, I found that updated forage production estimates based on satellite imagery, and using grazing pressure index (GPI) to identify optimal stocking rates are tools that can facilitate management of livestock and timber production in the Black Hills, SD.

Impact of protists on a hydrocarbon-degrading bacterial community from deep-sea Gulf of Mexico sediments: A microcosm study

NASA Astrophysics Data System (ADS)

Beaudoin, David J.; Carmichael, Catherine A.; Nelson, Robert K.; Reddy, Christopher M.; Teske, Andreas P.; Edgcomb, Virginia P.

2016-07-01

In spite of significant advancements towards understanding the dynamics of petroleum hydrocarbon degrading microbial consortia, the impacts (direct or indirect via grazing activities) of bacterivorous protists remain largely unknown. Microcosm experiments were used to examine whether protistan grazing affects the petroleum hydrocarbon degradation capacity of a deep-sea sediment microbial community from an active Gulf of Mexico cold seep. Differences in n-alkane content between native sediment microcosms and those treated with inhibitors of eukaryotes were assessed by comprehensive two-dimensional gas chromatography following 30-90 day incubations and analysis of shifts in microbial community composition using small subunit ribosomal RNA gene clone libraries. More biodegradation was observed in microcosms supplemented with eukaryotic inhibitors. SSU rRNA gene clone libraries from oil-amended treatments revealed an increase in the number of proteobacterial clones (particularly γ-proteobacteria) after spiking sediments with diesel oil. Bacterial community composition shifted, and degradation rates increased, in treatments where protists were inhibited, suggesting protists affect the hydrocarbon degrading capacity of microbial communities in sediments collected at this Gulf of Mexico site.

Western rangelands: overgrazed and undermanaged

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheridan, D.

1981-05-01

Overgrazing and poor management of the western arid lands causes desertification as the levels of water tables and surface waters drop, top soil and surface waters become more saline, soil erodes, and native vegetation disappears. This process had led to severe desertification in an estimated 1.1 million square miles and very severe desertification on 10,500 square miles in the US. The three areas in the very severe category occur in the Navajo Indian reservation in Arizona and New Mexico and on either side of El Paso, Texas. All were subjected to overgrazing. Government policies have only recently tried to bringmore » public land grazing in line with the land's carrying capacity by focusing on long-term productivity. The Public Rangelands Improvement Act of 1978 authorizes better management and multiple use of public lands, but the Bureau of Land Management has not established an effective monitoring system to ensure its implementation or to overcome political constraints against reducing livestock. Ranchers disagree with the assessments made by scientists and support vegetation modification instead of grazing allotments. 58 references, 7 figures. (DCK)« less

Hydrology and Geomorphology of Tallgrass Prairie Intermittent Headwater Streams

NASA Astrophysics Data System (ADS)

Daniels, M. D.; Grudzinski, B.

2011-12-01

The arid to semi-arid Great Plains region of the United States covers more than 1 million km2, yet virtually nothing is known about the geomorphology of its intermittent headwater streams. These streams and the perennial rivers they feed support a unique and increasingly endangered assemblage of endemic fish species. While human impacts in the region are not at first glace significant, the reality is that the Great Plains are an intensively managed landscape, with pervasive cattle grazing, channelization, and groundwater over-pumping affecting these systems. These stresses will only increase with potential climate and related land use changes. Few natural remnants of native grassland remain today, limiting opportunities to study the natural dynamics of these systems in contrast to the anthropogenically modified systems. This paper presents a review of the existing geomorphological and hydrological knowledge of Great Plains headwater streams and presents the initial analysis of an 18 year intermittent headwater stream record from the tallgrass Konza Prairie LTER, Kansas. Results suggest that fire frequency and grazing and the resultant riparian vegetation composition strongly influence stream flow dynamics as well as stream geomorphology.

Structure of n-alkyltrichlorosilane mono layers on Si(100)/SiO 2

DOE PAGES

H. -G. Steinruck; Ocko, B.; Will, J.; ...

2015-10-05

The structure of n-alkyltrichlorosilane self-assembled monolayers (SAMs) of alkyl chain lengths n = 12, 14, 18, and 22 formed on the amorphous native oxide of silicon (100) has been investigated via angstrom-resolution surface X-ray scattering techniques, with particular focus on the proliferation of lateral order along the molecules’ long axis. Grazing incidence diffraction shows that the monolayer is composed of hexagonally packed crystalline-like domains for n = 14, 18, and 22 with a lateral size of about 60 Å. However, Bragg rod analysis shows that ~12 of the CH 2 units are not included in the crystalline-like domains. We assignmore » this, and the limited lateral crystallites’ size, to strain induced by the size mismatch between the optimal chain–chain and headgroup–headgroup spacings. Lastly, analysis of X-ray reflectivity profiles for n = 12, 14, and 22 shows that the density profile used to successfully model n = 18 provides an excellent fit where the analysis-derived parameters provide complementary structural information to the grazing incidence results.« less

Live weight, carcass ultrasound images, and visual scores in Angus cattle under feeding regimes in Brazil.

PubMed

Pinto, Luís Fernando Batista; Tarouco, Jaime Urdapilleta; Pedrosa, Victor Breno; de Farias Jucá, Adriana; Leão, André Gustavo; Moita, Antonia Kécya França

2013-08-01

This study aimed to evaluate visual precocity, muscling, conformation, skeletal, and breed scores; live weights at birth, at 205, and at 550 days of age; and, besides, rib eye area and fat thickness between the 12th and 13th ribs obtained by ultrasound. Those traits were evaluated in 1,645 Angus cattle kept in five feeding conditions as follows: supplemented or non-supplemented, grazing native pasture or grazing cultivated pasture, and feedlot. Descriptive statistics, Pearson's correlations, and principal component analysis were carried out. Gender and feeding conditions were fixed effects, while animal's age and mother's weight at weaning were the covariates analyzed. Gender and feeding conditions were very significant for the studied traits, but visual scores were not influenced by gender. Animal's age and mother's weight at weaning influenced many traits and must be appropriately adjusted in the statistical models. An important correlation between visual scores, live weights, and carcass traits obtained by ultrasound was found, which can be analyzed by univariate procedure. However, the multivariate approach revealed some information that cannot be neglected in order to ensure a more detailed assessment.

AmeriFlux US-ARb ARM Southern Great Plains burn site- Lamont

DOE Data Explorer

Torn, Margaret [Lawrence Berkeley National Laboratory

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site US-ARb ARM Southern Great Plains burn site- Lamont. Site Description - The ARM SGP Burn site is located in the native tallgrass prairies of the USDA Grazinglands Research Laboratory near El Reno, OK. One of two adjacent 35 ha plots, the US-ARb plot was burned on 2005/03/08. The second plot, US-ARc, was left unburned as the control for experimental purposes. Aside from 2005, the region evaded burning activities for at least 15 years. Current disturbances consist of only light grazing activities.

Biotic soil crusts in relation to topography, cheatgrass, and fire in the Columbia Basin, Washington

USGS Publications Warehouse

Ponzetti, Jeanne; McCune, B.; Pyke, David A.

2007-01-01

We studied lichen and bryophyte soil crust communities in a large public grazing allotment within a sagebrush steppe ecosystem in which the biotic soil crusts are largely intact. The allotment had been rested from grazing for 12 years, but experienced an extensive series of wildfires. In the 350, 4 ?? 0.5 m plots, stratified by topographic position, we found 60 species or species groups that can be distinguished in the field with a hand lens, averaging 11.5 species groups per plot. Lichen and bryophyte soil crust communities differed among topographic positions. Draws were the most disturbed, apparently from water erosion in a narrow channel and mass wasting from the steepened sides. Presumably because of this disturbance, draws had the lowest average species richness of all the topographic strata we examined. Biotic crust species richness and cover were inversely related to cover of the invasive annual, cheatgrass (Bromus tectorum), and positively related to cover of native bunchgrasses. Integrity of the biotic crust was more strongly related to cheatgrass than to fire. In general, we observed good recovery of crusts following fire, but only in those areas dominated by perennial bunchgrasses. We interpret the resilience of the biotic crust, in this case, to the low abundance of cheatgrass, low amounts of soil disturbance and high moss cover. These fires have not resulted in an explosion of the cheatgrass population, perhaps because of the historically low levels of livestock grazing.

Performance of the herb Verbascum thapsus along environmental gradients in its native and non-native ranges

Treesearch

Tim Seipel; Jake M. Alexander; Curtis C. Daehler; Lisa J. Rew; Peter J. Edwards; Pervaiz A. Dar; Keith McDougall; Bridgett Naylor; Catherine Parks; Fredric W. Pollnac; Zafar A. Reshi; Mel Schroder; Christoph Kueffer; Peter Pearman

2014-01-01

Aim We evaluated whether the performance of individuals and populations of the invasive plant Verbascum thapsus differs between its native and non-native ranges, across climate gradients, and in response to its position in a global- scaled niche model.Location India (Kashmir) and Switzerland (native range) and Australia and USA (Hawaii,...

Germination responses of an invasive species in native and non-native ranges

Treesearch

Jose L. Hierro; Ozkan Eren; Liana Khetsuriani; Alecu Diaconu; Katalin Torok; Daniel Montesinos; Krikor Andonian; David Kikodze; Levan Janoian; Diego Villarreal; Maria Estanga-Mollica; Ragan M. Callaway

2009-01-01

Studying germination in the native and non-native range of a species can provide unique insights into processes of range expansion and adaptation; however, traits related to germination have rarely been compared between native and nonnative populations. In a series of common garden experiments, we explored whether differences in the seasonality of precipitation,...

Final Environmental Assessment for the Semiannual Joint Integrated Fires Exercises at Avon Park Air Force Range, Florida

DTIC Science & Technology

2006-04-01

spring that would have the potential to create wildfires. 3.11 Grazing Management : All alternatives would have minimal impact to grazing...3.12 Invasive Plant Management : All alternatives would have minimal impact to management . 3.13 Timber Management : All alternatives would have...food and fuel within the local communities. 3.18 Coastal Zone Management : The alternatives would be consistent with the Florida Coastal Zone

Doing More with Less? Toward Increasing the Resolution of Protistan Grazing-rate Measurements.

NASA Astrophysics Data System (ADS)

Morison, F.; Menden-Deuer, S.

2016-02-01

The dilution method is the standard protocol to quantify phytoplankton grazing-mortality rates and has been key in developing an understanding of protistan grazing impact on ocean primary production. Although the method's extensive use has facilitated the acquisition of a global dataset, its laborious application hinders the sampling resolution needed to fill knowledge gaps remaining at the geographical, seasonal, and vertical scales, and of the effects of climate-related factors influencing grazing magnitude. Here we present a rigorous assessment of an abbreviated method known as the 2-point. We analyzed unpublished results from 77 dilution experiments performed using a series of up to 5 dilutions under a wide range of chlorophyll concentrations and temperatures. We quantified the difference between estimates of both phytoplankton growth and grazing-mortality obtained based on the full dilution series and those obtained when the number of dilutions was reduced to 2. We considered the effect of non-linearity and chlorophyll concentration, and generated quantified estimates of trade-offs when choosing the fraction of seawater in the diluted treatment. Ultimately, we provide an assessment of the reliability of the 2-point method and recommendations on how to apply it.

Effect of field pea-based creep feed on intake, digestibility, ruminal fermentation, and performance by nursing calves grazing native range in western North Dakota.

PubMed

Gelvin, A A; Lardy, G P; Soto-Navarro, S A; Landblom, D G; Caton, J S

2004-12-01

Two experiments evaluated digestive and performance effects of field pea-based creep feed in nursing calf diets. In Exp.1, eight nursing steer calves (145 +/- 27 kg initial BW) with ruminal cannulas were used to evaluate effects of supplementation and advancing season on dietary composition, intake, digestion, and ruminal fermentation characteristics. Treatments were unsupplemented control (CON) and field pea-based creep (SUP; 19.1% CP, DM basis) fed at 0.45% BW (DM basis) daily. Calves grazed native range with their dams from early July through early November. Periods were 24 d long and occurred in July (JUL), August (AUG), September (SEP), and October (OCT). Experiment 2 used 80 crossbred nursing calves, 48 calves in yr 1 and 32 calves in yr 2 (yr 1 = 144 +/- 24 kg; yr 2 = 121 +/- 20 kg initial BW), to evaluate effects of field pea-based creep on calf performance. Treatments included unsupplemented control (CON); field pea-based creep feeds containing either 8% (LS); or 16% (HS) salt; and soybean meal/field pea-based creep containing (as-fed basis) 16% salt (HIPRO). Masticate samples from SUP calves in Exp.1 had greater CP (P = 0.05) than those from CON calves. Forage CP and ADIN decreased linearly with advancing season (P = 0.01 and 0.03, respectively). In vitro OM digestibility of diet masticate decreased from JUL to OCT (P < 0.01; 58.5 to 41.3%). Forage intake did not differ (P = 0.33) between treatments but increased linearly with advancing season (1.67, 1.90, 3.12, 3.38 kg/d for JUL, AUG, SEP, and OCT, respectively; P < 0.01). Milk intake (percentage of BW) did not differ (P = 0.56) between CON and SUP calves but decreased linearly (P < 0.01) with advancing season. Supplemented calves had greater (P = 0.03) total intake (g/kg of BW; forage + milk + creep) compared with CON calves. Treatment did not affect (P < 0.30) rate of in situ disappearance of forage or creep. Forage DM, CP, and creep DM disappearance rate decreased linearly (P < or = 0.02) with advancing season. Supplementation decreased (P = 0.05) ruminal pH, whereas ruminal ammonia and VFA concentrations were greater (P < or = 0.02) in SUP calves. In Exp. 2, creep-fed calves had greater ADG and final BW than CON calves (P < 0.01). Calves offered HS tended (P = 0.07) to have increased gain efficiency above CON than LS calves. Field peas can be used as an ingredient in creep feed to increase calf weight gain without negatively affecting ruminal fermentation and digestion.

43 CFR 4120.3-8 - Range improvement fund.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., improvement and protection, fish and wildlife habitat improvement or protection, soil and water resource... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Range improvement fund. 4120.3-8 Section... Grazing Management § 4120.3-8 Range improvement fund. (a) In addition to range developments accomplished...

25 CFR 700.721 - Range management plans.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 2 2010-04-01 2010-04-01 false Range management plans. 700.721 Section 700.721 Indians... Lands Grazing § 700.721 Range management plans. The Commissioner (or his designee) and the permittees of each range unit will meet as a group and develop a Range Management Plan for the common use of the...

Indicators of grazing impact in Inner Mongolian steppe ecosystems

NASA Astrophysics Data System (ADS)

Blank, B.; Breuer, L.; Butterbach-Bahl, K.; Frede, H.-G.

2009-04-01

The DFG research group 536 MAGIM (Matter fluxes in grasslands of Inner Mongolia as influenced by stocking rate) investigates the influence of grazing intensity on matter and water cycles in grazed steppe ecosystems of Inner Mongolia. This Sino-German co-operation applies an interdisciplinary approach to investigate major ecosystem functions and how they are affected by grazing and overgrazing. Within the research group an indicator system is developed to systemize the feedback of ecosystem parameters to the influence of grazing and to analyse, which parameter or parameter group reacts most sensitively. Parameters were measured at up to five different grazing intensities (from ungrazed to heavy grazed) and are related to four thematic indicator groups (plant productivity, atmosphere, pedosphere, hydrosphere). The parameters were scaled to allow assessing the influence of grazing intensity between different sets of parameters. For this the average value of a parameter at the lowest grazing intensity (ungrazed) was set 100%, so that the values at the other intensities could be scaled scaled adequately. Then the difference between highest and lowest grazing intensity was determined. According to this difference the influence of grazing was characterized as weak (< 20% difference), medium (20-40%), strong (40-60%) and very strong (> 60%). Impact of grazing on the parameters will be marked as weak (w), medium (m), strong (s) and very strong (vs) in the text. The group plant productivity includes the vegetation parameters aboveground biomass and belowground biomass. Belowground biomass (s) was significantly different between grazing treatments with the highest value at the ungrazed site (399.00 g m-2 a-1) and the lowest at the heavy grazed site (208.00 g m-2 a-1). Aboveground biomass (m) ranged between 91.33-131.67 g m-2 a-1 and differed significantly between the ungrazed and the heavy grazed site, again with higher values at the ungrazed site (Gao et al. 2008). The group atmosphere consists of micrometeorological parameters, dust flux and deposition as measure of erosive processes and trace gas fluxes. Available energy and soil temperature were always significantly different between two simultaneously measured grazing intensities. Available energy was higher at the ungrazed site in all years measured (mean difference of about 19 W m-2). Soil temperature was lower at the ungrazed site (Ketzer et al. 2008). Dust deposition is important for the C and N balance in semi-arid grasslands and was investigated during the dust storm period from March to May. The largest matter deposition of C (vs) and N (vs) was measured at the ungrazed site with 328.7 (mg Corg m-2 d-1) and 30.30 (mg Nt m-2 d-1) on average. Heavy grazing resulted in average organic carbon and nitrogen deposition of 106.67 (mg Corg m-2 d-1) and 9.8 (mg N m-2 d-1) in average (Hoffmann et al. 2008). Wind driven soil deposition and erosion were influenced heavily by grazing. The critical vegetation cover is about 20-30%, at which net soil losses occur. No significant differences in N trace gas fluxes were found between plots. Mean values of N2O fluxes (s) varied between 0.39 and 1.60 μg N2O-N m-2 h-1 (Holst et al. 2007). During all measuring periods, significantly lower mean soil CH4 uptake at moderate grazing (28 mg C m-2 h-1) as compared to ungrazed (56 μg C m-2 h-1) was found (Liu et al. 2007). The pedosphere indicator group includes soil chemical, soil physical and microbiological parameters. Organic carbon (s) and total N (s) concentrations decreased significantly with increasing grazing intensity. No effect of grazing on pH (w) or soil C/N ratio (w) was detected. Bulk density (m) significantly increased with increasing grazing intensity, from 0.94 g cm-3 at the ungrazed site to 1.28 g cm-3 at the heavily grazed site (Steffens et al. 2008). Also shear strength (m) increased with increasing grazing intensity (Zhao et al. 2007). Gross rates of N mineralization (vs) and nitrification (vs) determined at in situ soil moisture and soil temperature conditions were in a range of 0.5-4.1 mg N kg-1 soil dry weight day)1. In 2005, gross N turnover rates were significantly higher at the ungrazed plots than at the moderately and overgrazed plots (Holst et al. 2007). In the hydrosphere group soil water content (w) was the highest at the ungrazed site and lowest at the heavy grazed site. Compared with moderately grazed treatments, soil water content was little higher in ungrazed treatments after long dryness but lower under wet conditions. Water drop penetration time (s) was higher in the ungrazed plots showing a slight to strong water repellency than in the grazed plots (Zhao et al. 2007). References Gao, Y., Giese, M., Lin, S., Sattelmacher, B., Zhao, Y. and Brueck, H. Belowground net primary productivity and biomass allocation of a grassland in Inner Mongolia is affected by grazing intensity. 2008. Plant and Soil DOI 10.1007/s11104-008-9579-3. Hoffmann, C., Funk, R., Li, Y. and Sommer, M. Effect of grazing on wind driven carbon and nitrogen ratios in the grasslands of Inner Mongolia. 2008. Catena 75: 182-190. Holst, J., Liu, C., Brueggemann, N., Butterbach-Bahl, K., Zheng, X., Wang, Y., Han, S., Yao, Z., Yue, J. and Han, X. Microbial N Turnover and N-Oxide (N2O/NO/NO2) Fluxes in Semi-arid Grassland of Inner Mongolia as influenced by grazing intensity. 2007. Ecosystems. Ketzer, B., Bernhofer, Ch. and Liu, H. Sensitivity of micrometeorological measurements to detect surface characteristics of grasslands in Inner Mongolia. 2008. Int. J. Biometeorol. Liu, C., Holst, J., Brueggemann, N., Butterbach-Bahl, K., Yao, Z., Yue, J., Han, S., Han, X., Kruemmelbein, J., Horn, R. and Zheng, X. Winter-grazing reduces methane uptake by soils of a typical semi-arid steppe in Inner Mongolia, China. 2007. Journal of Atmospheric Environment doi:10.1016/j.atmosenv.2007.03.017. Steffens, M., Koelbl, A., Totsche, K. U. and Koegel-Knabner, I. Grazing effects on soil chemical and physical properties in a semiarid steppe of Inner Mongolia (P.R. China). 2008. Geoderma 143: 63-72. Zhao, Y., Peth, S., Kruemmelbein, J., Horn, R., Wang, Z., Steffens, M., Hoffmann, C. and Peng, X. Spatial variability of soil properties affected by grazing intensity in Inner Mongolia grassland. 2007. Ecological Modelling 205: 241-254.

Absence of a weight gain response to Vitamin B12 supplementation in weaned dairy heifers grazing pastures of marginal cobalt content.

PubMed

Clark, R G; Ellison, R S; Mortleman, L; Kirk, J A; Henderson, H V

1999-08-01

To obtain information on serum and liver vitamin B12 and urinary methylmalonic acid concentrations as diagnostic tests to predict a weight gain response to supplementation with vitamin B12 in young dairy cattle when grazing pasture of low cobalt content. Methodology. Forty dairy cattle (12 Friesian, 14 Friesian x Jersey and 14 Jersey) were allocated to two equal sized groups, treated and untreated, based on liveweight. At monthly intervals for 14 months, all animals were weighed, their serum and urine sampled, their liver biopsied and the pasture sampled from the paddocks they were grazing and going to graze. Serum and liver were assayed for vitamin B12 concentrations. For the first 5 months of the trial, urine was assayed for methylmalonic acid concentrations. Both washed and unwashed pasture samples were assayed for cobalt concentrations. No weight gain response occurred vitamin B12 supplementation in young growing cattle grazing pasture with a cobalt concentration of 0.04-0.06 mg/kg DM. For 5 months of the trial, liver vitamin B12 concentrations from untreated calves were in the range 75-220 nmol/kg and serum vitamin B12 concentrations were as low as 72 pmol/1. There was no associated growth response to supplementation. Further trials involving young cattle grazing pastures with cobalt concentrations less than 0.04 mg/kg DM are required to reliably determine liver and serum vitamin B12 concentrations at which growth responses to vitamin B12 or cobalt supplementation are likely under New Zealand pastoral grazing conditions.

Microzooplankton grazing and phytoplankton growth in marine mesocosms with increased CO2 levels

NASA Astrophysics Data System (ADS)

Suffrian, K.; Simonelli, P.; Nejstgaard, J. C.; Putzeys, S.; Carotenuto, Y.; Antia, A. N.

2008-01-01

Microzooplankton grazing and algae growth responses to increasing pCO2 levels (350, 700 and 1050 μatm) were investigated in nitrate and phosphate fertilized mesocosms during the PeECE III experiment 2005. Grazing and growth rates were estimated by the dilution technique combined with taxon specific HPLC pigment analysis. Phytoplankton and microzooplankton composition were determined by light microscopy. Despite a range up to 3 times the present CO2 levels, there were no clear differences in any measured parameter between the different CO2 treatments. Thus, during the first 9 days of the experiment the algae community standing stock (SS), measured as chlorophyll a (Chl a), showed the highest instantaneous grow rates (0.02-0.99 d-1) and increased from ca 2-3 to 6-12 μg l-1, in all mesocosms. Afterwards the phytoplankton SS decreased in all mesocosms until the end of the experiment. The microzooplankton SS, that was mainly dinoflagellates and ciliates varied between 23 and 130 μg C l-1, peaking on day 13-15, apparently responding to the phytoplankton development. Instantaneous Chl a growth rates were generally higher than the grazing rates, indicating only a limited overall effect of microzooplankton grazing on the most dominant phytoplankton. Diatoms and prymnesiophytes were significantly grazed (14-43% of the SS d-1) only in the pre-bloom phase when they were in low numbers and in the post-bloom phase when they were already limited by low nutrients and/or virus lysis. The cyanobacteria populations appeared more effected by microzooplankton grazing, generally removing 20-65% of the SS d-1.

Shade treatment affects structure and recovery of invasive C4 African grass Echinochloa pyramidalis.

PubMed

López Rosas, Hugo; Moreno-Casasola, Patricia; Espejel González, Verónica E

2015-03-01

Echinochloa pyramidalis (Lam.) Hitchc. & Chase is an African grass with C4 photosynthesis, high biomass production, and high vegetative propagation that is tolerant to grazing and able to grow in flooded and dry conditions. Thus, it is highly invasive in tropical freshwater marshes where it is intentionally planted by ranchers to increase cattle production. This invasion is reducing plant biodiversity by increasing the invader's aerial coverage, changing wetland hydrology and causing soil physicochemical changes such as vertical accretion. Reducing the dominance of this species and increasing the density of native wetland species is a difficult, expensive, and time-consuming process. We applied a series of disturbance treatments aimed at eliminating E. pyramidalis and recovering the native vegetation of a partially invaded freshwater marsh. Treatments included physical (cutting, soil disking, transplanting individuals of the key native species Sagittaria lancifolia subsp. media (Micheli) Bogin, and/or reducing light with shade mesh) and/or chemical (spraying Round-Up™ herbicide) disturbances. At the end of the experiment, four of the five treatments used were effective in increasing the cover and biomass of native species and reducing that of E. pyramidalis. The combination of these treatments should be used to generate a proposal for the restoration of tropical wetlands invaded by non-native grasses. A promising treatment is using soil disked to soften the soil and destroy belowground structures such as roots and rhizomes. This treatment would be more promising if combined with the use of shade cloth. If it is desirable not to impact the soil or if there is not enough budget to make an effort to include active restoration disking soil, the use of shade cloth will suffice, although the recovery of native vegetation will be slower.

Shade treatment affects structure and recovery of invasive C4 African grass Echinochloa pyramidalis

PubMed Central

López Rosas, Hugo; Moreno-Casasola, Patricia; Espejel González, Verónica E

2015-01-01

Echinochloa pyramidalis (Lam.) Hitchc. & Chase is an African grass with C4 photosynthesis, high biomass production, and high vegetative propagation that is tolerant to grazing and able to grow in flooded and dry conditions. Thus, it is highly invasive in tropical freshwater marshes where it is intentionally planted by ranchers to increase cattle production. This invasion is reducing plant biodiversity by increasing the invader's aerial coverage, changing wetland hydrology and causing soil physicochemical changes such as vertical accretion. Reducing the dominance of this species and increasing the density of native wetland species is a difficult, expensive, and time-consuming process. We applied a series of disturbance treatments aimed at eliminating E. pyramidalis and recovering the native vegetation of a partially invaded freshwater marsh. Treatments included physical (cutting, soil disking, transplanting individuals of the key native species Sagittaria lancifolia subsp. media (Micheli) Bogin, and/or reducing light with shade mesh) and/or chemical (spraying Round-Up™ herbicide) disturbances. At the end of the experiment, four of the five treatments used were effective in increasing the cover and biomass of native species and reducing that of E. pyramidalis. The combination of these treatments should be used to generate a proposal for the restoration of tropical wetlands invaded by non-native grasses. A promising treatment is using soil disked to soften the soil and destroy belowground structures such as roots and rhizomes. This treatment would be more promising if combined with the use of shade cloth. If it is desirable not to impact the soil or if there is not enough budget to make an effort to include active restoration disking soil, the use of shade cloth will suffice, although the recovery of native vegetation will be slower. PMID:25859337

Environmental Assessment: Black-Tailed Prairie Dog Management Cannon Air Force Base and Melrose Air Force Range, New Mexico

DTIC Science & Technology

2005-12-01

requirements are met by metabolizing grazed vegetation. Prairie dogs dig burrows to an average depth of 2-3 meters with some tunnels interconnecting with...the potential to impact non- target species such as mice, kangaroo rats, and some songbirds. Establishing control zones at CAFB and MAFR could not be...Gutierrezia sarothrae), and Russian thistle (Salsola iberica). Water requirements are met by metabolizing grazed vegetation. Prairie dogs dig burrows

Soil intake of lactating dairy cows in intensive strip grazing systems.

PubMed

Jurjanz, S; Feidt, C; Pérez-Prieto, L A; Ribeiro Filho, H M N; Rychen, G; Delagarde, R

2012-08-01

Involuntary soil intake by cows on pasture can be a potential route of entry for pollutants into the food chain. Therefore, it appears necessary to know and quantify factors affecting soil intake in order to ensure the food safety in outside rearing systems. Thus, soil intake was determined in two Latin square trials with 24 and 12 lactating dairy cows. In Trial 1, the effect of pasture allowance (20 v. 35 kg dry matter (DM) above ground level/cow daily) was studied for two sward types (pure perennial ryegrass v. mixed perennial ryegrass-white clover) in spring. In Trial 2, the effect of pasture allowance (40 v. 65 kg DM above ground level/cow daily) was studied at two supplementation levels (0 or 8 kg DM of a maize silage-based supplement) in autumn. Soil intake was determined by the method based on acid-insoluble ash used as an internal marker. The daily dry soil intake ranged, between treatments, from 0.17 to 0.83 kg per cow in Trial 1 and from 0.15 to 0.85 kg per cow in Trial 2, reaching up to 1.3 kg during some periods. In both trials, soil intake increased with decreasing pasture allowance, by 0.46 and 0.15 kg in Trials 1 and 2, respectively. In Trial 1, this pasture allowance effect was greater on mixed swards than on pure ryegrass swards (0.66 v. 0.26 kg reduction of daily soil intake between medium and low pasture allowance, respectively). In Trial 2, the pasture allowance effect was similar at both supplementation levels. In Trial 2, supplemented cows ate much less soil than unsupplemented cows (0.20 v. 0.75 kg/day, respectively). Differences in soil intake between trials and treatments can be related to grazing conditions, particularly pre-grazing and post-grazing sward height, determining at least in part the time spent grazing close to the ground. A post-grazing sward height lower than 50 mm can be considered as a critical threshold. Finally, a dietary supplement and a low grazing pressure, that is, high pasture allowance increasing post-grazing sward height, would efficiently limit the risk for high level of soil intake, especially when grazing conditions are difficult. Pre-grazing and post-grazing sward heights, as well as faecal crude ash concentration appear to be simple and practical tools for evaluating the risk for critical soil intake in grazing dairy cows.

A review of Ruffe (Gymnocephalus cernuus) life history in its ...

EPA Pesticide Factsheets

Ruffe (Gymnocephalus cernuus) have caused and have the potential to cause great ecological damage as invasive species in North America, parts of the European Union, Scandinavian countries, and the United Kingdom. The objectives of this review are to define the Ruffe's native and non-native range, examine the life history requirements of Ruffe, explore the Ruffe life cycle, and differentiate between the life stages. We compare Ruffe in their native range to Ruffe in their non-native range to determine if there are any differences in habitat, size, age, genotype, or migratory patterns in the winter. Literature from both the native and non-native ranges of Ruffe, with a particular emphasis on rare translated literature, is used. Ruffe have variability and plasticity in their chemical, physical, biological, and habitat requirements in their native and non-native ranges. Adult Ruffe have a suite of characteristics that make them adaptable to novel environments, including age and size at maturity, maximum age and length (and/ or weight), reproduction type, genotype, feeding habits, seasonal movements, and spawning movements. There is variability among these characteristics seen between the Ruffe's native, non-native North American, and European non-native populations. Based on the Ruffe's variable life history strategies and their recent range expansion, all of the Great Lakes and many other regions in the U.K., Europe, and Scandinavian countries could be vulnerable t

43 CFR 9269.3-4 - Range management.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Range management. 9269.3-4 Section 9269.3-4 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT... Range management. (a) Grazing administration—exclusive of Alaska—(1) Unlawful enclosures or occupancy...

43 CFR 9269.3-4 - Range management.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Range management. 9269.3-4 Section 9269.3-4 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT... Range management. (a) Grazing administration—exclusive of Alaska—(1) Unlawful enclosures or occupancy...

43 CFR 9269.3-4 - Range management.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Range management. 9269.3-4 Section 9269.3-4 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT... Range management. (a) Grazing administration—exclusive of Alaska—(1) Unlawful enclosures or occupancy...

43 CFR 9269.3-4 - Range management.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Range management. 9269.3-4 Section 9269.3-4 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT... Range management. (a) Grazing administration—exclusive of Alaska—(1) Unlawful enclosures or occupancy...

Assessment of range planting as a conservation practice [Chapter 4

Treesearch

Stuart P. Hardegree; Thomas A. Jones; Bruce A. Roundy; Nancy L. Shaw; Thomas A. Monaco

2011-01-01

The Range Planting Conservation Practice Standard is used to inform development of Natural Resource Conservation Service (NRCS) management recommendations for improving vegetation composition and productivity of grazed plant communities. Range planting recommendations are generally implemented within an integrated conservation management system in conjunction with...

Sympatric cattle grazing and desert bighorn sheep foraging

USGS Publications Warehouse

Garrison, Kyle R.; Cain, James W.; Rominger, Eric M.; Goldstein, Elise J.

2015-01-01

Foraging behavior affects animal fitness and is largely dictated by the resources available to an animal. Understanding factors that affect forage resources is important for conservation and management of wildlife. Cattle sympatry is proposed to limit desert bighorn population performance, but few studies have quantified the effect of cattle foraging on bighorn forage resources or foraging behavior by desert bighorn. We estimated forage biomass for desert bighorn sheep in 2 mountain ranges: the cattle-grazed Caballo Mountains and the ungrazed San Andres Mountains, New Mexico. We recorded foraging bout efficiency of adult females by recording feeding time/step while foraging, and activity budgets of 3 age-sex classes (i.e., adult males, adult females, yearlings). We also estimated forage biomass at sites where bighorn were observed foraging. We expected lower forage biomass in the cattle-grazed Caballo range than in the ungrazed San Andres range and lower biomass at cattle-accessible versus inaccessible areas within the Caballo range. We predicted bighorn would be less efficient foragers in the Caballo range. Groundcover forage biomass was low in both ranges throughout the study (Jun 2012–Nov 2013). Browse biomass, however, was 4.7 times lower in the Caballo range versus the San Andres range. Bighorn in the Caballo range exhibited greater overall daily travel time, presumably to locate areas of higher forage abundance. By selecting areas with greater forage abundance, adult females in the Caballo range exhibited foraging bout efficiency similar to their San Andres counterparts but lower overall daily browsing time. We did not find a significant reduction in forage biomass at cattle-accessible areas in the Caballo range. Only the most rugged areas in the Caballo range had abundant forage, potentially a result of intensive historical livestock use in less rugged areas. Forage conditions in the Caballo range apparently force bighorn to increase foraging effort by feeding only in areas where adequate forage remains.

25 CFR 168.4 - Establishment of range units.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 1 2010-04-01 2010-04-01 false Establishment of range units. 168.4 Section 168.4 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.4 Establishment of range units. The Area Director will use Soil and Range...

RANGE RAM: a long-term planning method for managing grazing lands

Treesearch

Henricus C. Jansen

1976-01-01

Range RAM (Resource Allocation Method) is a computerized planning method designed to assist range managers in developing and selecting alternatives in spatial and temporal allocation of resources. The technique is applicable at the frest or district management levels, or their equivalents. Range RAM can help formulate plans that maximize the production of range outputs...

Effects of native forest restoration on soil hydraulic properties, Auwahi, Maui, Hawaiian Islands

USGS Publications Warehouse

Perkins, Kimberlie S.; Nimmo, John R.; Medeiros, Arthur C.

2012-01-01

Over historic time Hawai'i's dryland forests have been largely replaced by grasslands for grazing livestock. On-going efforts have been undertaken to restore dryland forests to bring back native species and reduce erosion. The reestablishment of native ecosystems on land severely degraded by long-term alternative use requires reversal of the impacts of erosion, organic-matter loss, and soil structural damage on soil hydraulic properties. This issue is perhaps especially critical in dryland forests where the soil must facilitate native plants' optimal use of limited water. These reforestation efforts depend on restoring soil ecological function, including soil hydraulic properties. We hypothesized that reforestation can measurably change soil hydraulic properties over restoration timescales. At a site on the island of Maui (Hawai'i, USA), we measured infiltration capacity, hydrophobicity, and abundance of preferential flow channels in a deforested grassland and in an adjacent area where active reforestation has been going on for fourteen years. Compared to the nearby deforested rangeland, mean field-saturated hydraulic conductivity in the newly restored forest measured by 55 infiltrometer tests was greater by a factor of 2.0. Hydrophobicity on an 8-point scale increased from average category 6.0 to 6.9. A 4-point empirical categorization of preferentiality in subsurface wetting patterns increased from an average 1.3 in grasslands to 2.6 in the restored forest. All of these changes act to distribute infiltrated water faster and deeper, as appropriate for native plant needs. This study indicates that vegetation restoration can lead to ecohydrologically important changes in soil hydraulic properties over decadal time scales.

Synergies between climate anomalies and hydrological modifications facilitate estuarine biotic invasions.

PubMed

Winder, Monika; Jassby, Alan D; Mac Nally, Ralph

2011-08-01

Environmental perturbation, climate change and international commerce are important drivers for biological invasions. Climate anomalies can further increase levels of habitat disturbance and act synergistically to elevate invasion risk. Herein, we use a historical data set from the upper San Francisco Estuary to provide the first empirical evidence for facilitation of invasions by climate extremes. Invasive zooplankton species did not become established in this estuary until the 1970s when increasing propagule pressure from Asia coincided with extended drought periods. Hydrological management exacerbated the effects of post-1960 droughts and reduced freshwater inflow even further, increasing drought severity and allowing unusually extreme salinity intrusions. Native zooplankton experienced unprecedented conditions of high salinity and intensified benthic grazing, and life history attributes of invasive zooplankton were advantageous enough during droughts to outcompete native species and colonise the system. Extreme climatic events can therefore act synergistically with environmental perturbation to facilitate the establishment of invasive species. © 2011 Blackwell Publishing Ltd/CNRS.

Nickel, Cobalt, Chromium and Copper in agricultural and grazing land soils of Europe

NASA Astrophysics Data System (ADS)

Albanese, Stefano; Sadeghi, Martiya; De Vivo, Benedetto; Lima, Annamaria; Cicchella, Domenico; Dinelli, Enrico

2014-05-01

In the framework of the GEMAS (Geochemical Mapping of Agricultural and Grazing Land Soils) project, concentrations of Ni, Co, Cu and Cr were determined for the whole available dataset (2218 samples of agricultural soil and 2127 samples of grazing land soil) covering a total area of 5.6 million sq km all over Europe. The distribution pattern of Ni in the European soils (both agricultural and grazing land soils) shows the highest concentrations in correspondence with the Mediterranean area (especially in Greece, the Balcan Peninsula and NW Italy) with average values generally ranging between 40 mg/kg and 140 mg/kg and anomalous areas characterized by peaks higher than 2400 mg/kg. Concentrations between 10 mg/kg and 40 mg/kg characterize Continental Europe north of Alps and, partly, the Scandinavian countries. Lower concentrations (< 10 mg/kg) occurs near the Trans-European Suture Zone, one of the main tectonic borders in Europe, and they are limited on the south by the maximum extent limit of the last glaciation. Cobalt and Cr show distribution patterns similar to Ni in both agricultural and grazing land soils. The maximum concentration peaks of Cobalt and Cr rise up to respectively 126 mg/kg and 696 mg/kg in agricultural soils and up to 255 mg/kg and 577 mg/kg in grazing land soils. Copper distribution in the soils collected across Europe, although has a general correspondence with the patterns of Ni, Co, Cr, shows some peculiarities. Specifically, Cu is characterized by high concentration values (up to 395 mg/kg in agricultural soils and 373 mg/kg in Grazing land soils) also in correspondence with the Roman Comagmatic Province and the south western coast of France characterized by a wide spread of vineyards.

Microzooplankton grazing and phytoplankton growth in marine mesocosms with increased CO2 levels

NASA Astrophysics Data System (ADS)

Suffrian, K.; Simonelli, P.; Nejstgaard, J. C.; Putzeys, S.; Carotenuto, Y.; Antia, A. N.

2008-08-01

Microzooplankton grazing and algae growth responses to increasing pCO2 levels (350, 700 and 1050 μatm) were investigated in nitrate and phosphate fertilized mesocosms during the PeECE III experiment 2005. Grazing and growth rates were estimated by the dilution technique combined with taxon specific HPLC pigment analysis. Microzooplankton composition was determined by light microscopy. Despite a range of up to 3 times the present CO2 levels, there were no clear differences in any measured parameter between the different CO2 treatments. During days 3 9 of the experiment the algae community standing stock, measured as chlorophyll a (Chl-a), showed the highest instantaneous grow rates (k=0.37 0.99 d-1) and increased from ca. 2 3 to 6 12 μg l-1, in all mesocosms. Afterwards the phytoplankton standing stock decreased in all mesocosms until the end of the experiment. The microzooplankton standing stock, that was mainly constituted by dinoflagellates and ciliates, varied between 23 and 130 μg C l-1 (corresponding to 1.9 and 10.8 μmol C l-1), peaking on day 13 15, apparently responding to the phytoplankton development. Instantaneous Chl-a growth rates were generally higher than the grazing rates, indicating only a limited overall effect of microzooplankton grazing on the most dominant phytoplankton. Diatoms and prymnesiophytes were significantly grazed (12 43% of the standing stock d-1) only in the pre-bloom phase when they were in low numbers, and in the post-bloom phase when they were already affected by low nutrients and/or viral lysis. The cyanobacteria populations appeared more affected by microzooplankton grazing which generally removed 20 65% of the standing stock per day.

Protistan Grazing Analysis by Flow Cytometry Using Prey Labeled by In Vivo Expression of Fluorescent Proteins

PubMed Central

Fu, Yutao; O'Kelly, Charles; Sieracki, Michael; Distel, Daniel L.

2003-01-01

Selective grazing by protists can profoundly influence bacterial community structure, and yet direct, quantitative observation of grazing selectivity has been difficult to achieve. In this investigation, flow cytometry was used to study grazing by the marine heterotrophic flagellate Paraphysomonas imperforata on live bacterial cells genetically modified to express the fluorescent protein markers green fluorescent protein (GFP) and red fluorescent protein (RFP). Broad-host-range plasmids were constructed that express fluorescent proteins in three bacterial prey species, Escherichia coli, Enterobacter aerogenes, and Pseudomonas putida. Micromonas pusilla, an alga with red autofluorescence, was also used as prey. Predator-prey interactions were quantified by using a FACScan flow cytometer and analyzed by using a Perl program described here. Grazing preference of P. imperforata was influenced by prey type, size, and condition. In competitive feeding trials, P. imperforata consumed algal prey at significantly lower rates than FP (fluorescent protein)-labeled bacteria of similar or different size. Within-species size selection was also observed, but only for P. putida, the largest prey species examined; smaller cells of P. putida were grazed preferentially. No significant difference in clearance rate was observed between GFP- and RFP-labeled strains of the same prey species or between wild-type and GFP-labeled strains. In contrast, the common chemical staining method, 5-(4,6-dichloro-triazin-2-yl)-amino fluorescein hydrochloride, depressed clearance rates for bacterial prey compared to unlabeled or RFP-labeled cells. PMID:14602649

Forest-range resources of Southwest Louisiana

Treesearch

Herbert S. Sternitzke; Henry A. Pearson

1975-01-01

Findings of the first forest-range inventory of southwest Louisiana conducted as part of the nationwide Forest Survey are described and evaluated. Measurements indicate that the grazing potential of the region's forest ranges is not being fully used. Little competition with wildlife populations and timber stands is indicated at existing levels of understory...

Disturbance impacts on understory plant communities of the Colorado Front Range

Treesearch

Paula J. Fornwalt

2009-01-01

Pinus ponderosa - Pseudotsuga menziesii (ponderosa pine - Douglas-fir) forests of the Colorado Front Range have experienced a range of disturbances since they were settled by European-Americans approximately 150 years ago, including settlement-era logging and domestic grazing, and more recently, wildfire. In this dissertation, I...

77 FR 70137 - Okanogan-Wenatchee National Forest, Okanogan County, WA; Bannon, Aeneas, Revis, and Tunk Grazing...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-23

... range infrastructure and livestock management to move toward desired conditions for soils, vegetation... levels using a combination of range improvements and adaptive management strategies to meet or move... Forest Plan standards and guidelines. Range improvement proposals include: Removal of approximately 3...

A modified utilization gauge for western range grasses

Treesearch

Earl F. Aldon; Richard E. Francis

1984-01-01

Accurate, low cost measurements of forage utilization by livestock are essential in range management and the evaluation of grazing systems. However, because of difficulty in making these measurements, visual estimates often are substituted for measured values. To help land managers better determine use, range utilization calculating charts (Crafts 1938, NRCAB 1962)...

25 CFR 161.204 - How are carrying capacities and stocking rates established?

Code of Federal Regulations, 2010 CFR

2010-04-01

... be based on forage production, range utilization, the application of land management practices, and range improvements in place to achieve uniformity of grazing under sustained yield management principles... agricultural resource management plan and range unit management plan. (b) BIA, with the concurrence of the...

Grazing effects on soil characteristics and vegetation of grassland in northern China

NASA Astrophysics Data System (ADS)

Wang, Z.; Johnson, D. A.; Rong, Y.; Wang, K.

2016-01-01

Large areas of grassland in the agro-pastoral region of northern China were converted into cropland for grain production, and the remaining grasslands are being overgrazed and seriously degraded. The objective of this study was to evaluate how reductions in grazing intensity affect the soil and vegetation characteristics in grasslands of northern China. Soil heterogeneity and vegetation characteristics were evaluated for ungrazed (UG), moderate grazing (MG), and heavy grazing (HG) sites. Grazing increased diversity, but heavy grazing decreased aboveground biomass and increased the non-grass component. The non-grass proportion of total biomass increased with grazing intensity, which was 8, 16 and 48 % for UG, MG and HG sites, respectively. Species richness at the MG and HG sites was significantly higher than at the UG site (P< 0.05) with 3.6, 5.5 and 5.7 for UG, MG and HG sites, respectively. Strong spatial dependence of the examined soil properties at 10 m scale for all grazed sites was revealed by the ratio of nugget to total variation (0-23 %). Overgrazing homogenized soil characteristics at a 10 m scale. The ranges of spatial autocorrelation for soil organic C (SOC) and total N were both > 120 m at the HG site, which was considerably larger than that at the MG and UG sites with corresponding distances of 17.3 and 20.8 m for the MG site and 8.6 and 15.0 m for the UG site, respectively. The sampling density and sampling space for the HG site could be decreased under this scale sampling interval (10 m). Therefore, MG was recommended as the preferred management alternative for grasslands in northern China because of increased plant diversity without negative consequences related to decreased forage quality, forage quantity and soil heterogeneity for the investigated soil properties in northern China's grasslands.

Mesozooplankton grazing during spring sea-ice conditions in the eastern Bering Sea

NASA Astrophysics Data System (ADS)

Campbell, Robert G.; Ashjian, Carin J.; Sherr, Evelyn B.; Sherr, Barry F.; Lomas, Michael W.; Ross, Celia; Alatalo, Philip; Gelfman, Celia; Keuren, Donna Van

2016-12-01

Mesozooplankton (copepods and euphausiids) grazing rates and prey preferences were determined during a series of three research cruises to the eastern Bering Sea in spring 2008, 2009, and 2010. Chlorophyll was dominated by large cells (>5 μm), especially at bloom locations where they usually comprised greater than 90% of the total chlorophyll biomass. The relative importance of microzooplankton to the prey field biomass decreased with increasing chlorophyll concentration, and was less than 10% of the total prey biomass in ice-edge bloom regions. Overall, microzooplankton was the preferred prey of the mesozooplankton, although phytoplankton/ice algae were the dominant component of the diet because of their much greater biomass, especially during blooms. There were differences between mesozooplankton species in their prey preferences: Metridia pacifica, Pseudocalanus spp. and Calanus spp. had the strongest preference for microzooplankton prey, while euphausiids (Thysanoessa spp.) and Neocalanus flemingeri/plumchrus appeared to feed non-selectively on all prey items. Mesozooplankton exhibited a saturating feeding response to chlorophyll concentration (Holling's type II) that could be modeled by Michaelis-Menten equations. Taxa-specific maximum ingestion rates generally followed allometric theory, with smaller zooplankton having higher feeding rates than larger zooplankton, and ranged from about 4-30% body carbon day-1. Trophic cascades during grazing experiments could result in a substantial underestimate of chlorophyll ingestion rates, especially for those taxa that had a strong preference for microzooplankton. Grazing impacts by mesozooplankton on the integrated chlorophyll biomass and primary production were 2.7±4.4 and 26±48% day-1, respectively. Impacts increased significantly with increasing mesozooplankton biomass, which increased from early to late spring. However, grazing impacts were extremely low in ice-edge bloom regions. Our findings suggest that even when grazing by microzooplankton is included in our grazing impact estimates, about 50% of the primary production in phytoplankton blooms during spring on the eastern Bering Sea shelf is not grazed and is available for direct export to the benthic community.

Unintended consequences of invasive predator control in an Australian forest: overabundant wallabies and vegetation change.

PubMed

Dexter, Nick; Hudson, Matt; James, Stuart; Macgregor, Christopher; Lindenmayer, David B

2013-01-01

Over-abundance of native herbivores is a problem in many forests worldwide. The abundance of native macropod wallabies is extremely high at Booderee National Park (BNP) in south-eastern Australia. This has occurred because of the reduction of exotic predators through an intensive baiting program, coupled with the absence of other predators. The high density of wallabies at BNP may be inhibiting the recruitment of many plant species following fire-induced recruitment events. We experimentally examined the post-fire response of a range of plant species to browsing by wallabies in a forest heavily infested with the invasive species, bitou bush Chrysanthemoides monilifera. We recorded the abundance and size of a range of plant species in 18 unfenced (browsed) and 16 fenced (unbrowsed) plots. We found the abundance and size of bitou bush was suppressed in browsed plots compared to unbrowsed plots. Regenerating seedlings of the canopy or middle storey tree species Eucalyptus pilularis, Acacia implexa, Allocasuarina littoralis, Breynia oblongifolia and Banksia integrifolia were either smaller or fewer in number in grazed plots than treatment plots as were the vines Kennedia rubicunda, Glycine tabacina and Glycine clandestina. In contrast, the understorey fern, Pteridium esculentum increased in abundance in the browsed plots relative to unbrowsed plots probably because of reduced competition with more palatable angiosperms. Twelve months after plots were installed the community structure of the browsed and unbrowsed plots was significantly different (P = 0.023, Global R = 0.091). The relative abundance of C. monilifera and P. esculentum contributed most to the differences. We discuss the possible development of a low diversity bracken fern parkland in Booderee National Park through a trophic cascade, similar to that caused by overabundant deer in the northern hemisphere. We also discuss its implications for broad scale fox control in southern Australian forests.

Impacts of mesquite distribution on seasonal space use of lesser prairie-chickens

USGS Publications Warehouse

Boggie, Matthew A.; Strong, Cody R.; Lusk, Daniel; Carleton, Scott A.; Gould, William R.; Howard, Randy L.; Nichols, Clay T.; Falkowski, Michael J.; Hagen, Christian A.

2017-01-01

Loss of native grasslands by anthropogenic disturbances has reduced availability and connectivity of habitat for many grassland species. A primary threat to contiguous grasslands is the encroachment of woody vegetation, which is spurred by disturbances that take on many forms from energy development, fire suppression, and grazing. These disturbances are exacerbated by natural- and human-driven cycles of changes in climate punctuated by drought and desertification conditions. Encroachment of honey mesquite (Prosopis glandulosa) into the prairies of southeastern New Mexico has potentially limited habitat for numerous grassland species, including lesser prairie-chickens (Tympanuchus pallidicinctus). To determine the magnitude of impacts of distribution of mesquite and how lesser prairie-chickens respond to mesquite presence on the landscape in southeastern New Mexico, we evaluated seasonal space use of lesser prairie-chickens in the breeding and nonbreeding seasons. We derived several remotely sensed spatial metrics to characterize the distribution of mesquite. We then used these data to create population-level resource utilization functions and predict intensity of use of lesser prairie-chickens across our study area. Home ranges were smaller in the breeding season compared with the nonbreeding season; however, habitat use was similar across seasons. During both seasons, lesser prairie-chickens used areas closer to leks and largely avoided areas with mesquite. Relative to the breeding season, during the nonbreeding season habitat use suggested a marginal increase in mesquite within areas of low intensity of use, yet aversion to mesquite was strong in areas of medium to high intensity of use. To our knowledge, our study is the first to demonstrate a negative behavioral response by lesser prairie-chickens to woody encroachment in native grasslands. To mitigate one of the possible limiting factors for lesser prairie-chickens, we suggest future conservation strategies be employed by land managersto reduce mesquite abundance in the southern portion of their current range.

Unintended Consequences of Invasive Predator Control in an Australian Forest: Overabundant Wallabies and Vegetation Change

PubMed Central

Dexter, Nick; Hudson, Matt; James, Stuart; MacGregor, Christopher; Lindenmayer, David B.

2013-01-01

Over-abundance of native herbivores is a problem in many forests worldwide. The abundance of native macropod wallabies is extremely high at Booderee National Park (BNP) in south-eastern Australia. This has occurred because of the reduction of exotic predators through an intensive baiting program, coupled with the absence of other predators. The high density of wallabies at BNP may be inhibiting the recruitment of many plant species following fire-induced recruitment events. We experimentally examined the post-fire response of a range of plant species to browsing by wallabies in a forest heavily infested with the invasive species, bitou bush Chrysanthemoides monilifera. We recorded the abundance and size of a range of plant species in 18 unfenced (browsed) and 16 fenced (unbrowsed) plots. We found the abundance and size of bitou bush was suppressed in browsed plots compared to unbrowsed plots. Regenerating seedlings of the canopy or middle storey tree species Eucalyptus pilularis, Acacia implexa, Allocasuarina littoralis, Breynia oblongifolia and Banksia integrifolia were either smaller or fewer in number in grazed plots than treatment plots as were the vines Kennedia rubicunda, Glycine tabacina and Glycine clandestina. In contrast, the understorey fern, Pteridium esculentum increased in abundance in the browsed plots relative to unbrowsed plots probably because of reduced competition with more palatable angiosperms. Twelve months after plots were installed the community structure of the browsed and unbrowsed plots was significantly different (P = 0.023, Global R = 0.091). The relative abundance of C. monilifera and P. esculentum contributed most to the differences. We discuss the possible development of a low diversity bracken fern parkland in Booderee National Park through a trophic cascade, similar to that caused by overabundant deer in the northern hemisphere. We also discuss its implications for broad scale fox control in southern Australian forests. PMID:23990879

25 CFR 700.722 - Grazing associations.

Code of Federal Regulations, 2010 CFR

2010-04-01

... range unit livestock associations in the management of livestock and range resources. (b) These... management plans, (3) To express their wishes through designated officers or committees, (4) To share costs... rules needed to assure cooperation and resource management. (c) The requirements for receiving...

CONTROLS ON WATER CHEMISTRY OF AN OREGON COAST RANGE STREAM

EPA Science Inventory

Numerous factors may control losses of dissolved nutrients from forested basins in the Oregon Coast Range. Potentially important factors include forest composition, stand age, forest management, grazing, agriculture, sewage inputs and bedrock types, as well as others perhaps not...

Effects of anthropogenic fragmentation and livestock grazing on western riparian bird communities

USGS Publications Warehouse

Tewksbury, J.J.; Black, A.E.; Nur, N.; Saab, V.A.; Logan, B.D.; Dobkin, D.S.

2002-01-01

Deciduous vegetation along streams and rivers provides breeding habitat to more bird species than any other plant community in the West, yet many riparian areas are heavily grazed by cattle and surrounded by increasingly developed landscapes. The combination of cattle grazing and landscape alteration (habitat loss and fragmentation) are thought to be critical factors affecting the richness and composition of breeding bird communities. Here, we examine the influence of land use and cattle grazing on deciduous riparian bird communities across seven riparian systems in five western states: Montana, Idaho, Nevada, Oregon and California. These riparian systems are embedded in landscapes ranging from nearly pristine to almost completely agricultural. We conducted landscape analysis at two spatial scales: local landscapes (all land within 500 m of each survey location) and regional landscapes (all land within 5 km of each survey location). Despite the large differences among riparian systems, we found a number of consistent effects of landscape change and grazing. Of the 87 species with at least 15 detections on two or more rivers, 44 species were less common in grazed sites, in heavily settled or agricultural landscapes, or in areas with little deciduous riparian habitat. The Veery (Catharus fuscescens), Song Sparrow (Melospiza melodia), Red-naped Sapsucker (Sphyrapicus nuchalis), Fox Sparrow (Passerella iliaca), and American Redstart (Setophaga ruticilla) were all less common under at least three of these conditions. In contrast, 33 species were significantly more common in one or more of these conditions. Sites surrounded by greater deciduous habitat had higher overall avian abundance and 22 species had significantly higher individual abundances in areas with more deciduous habitat. Yet, areas with more agriculture at the regional scale also had higher total avian abundance, due in large part to greater abundance of European Starling (Sturnus vulgaris), American Robin (Turdus migratorius), Brown-headed Cowbird (Molothrus ater), and Black-billed Magpie (Pica pica), all species that use both agricultural and riparian areas. Grazing effects varied considerably among riparian systems, but avian abundance and richness were significantly lower at grazed survey locations. Fifteen species were significantly less abundant in grazed sites while only five species were more abundant therein. Management should focus on (1) preserving and enlarging deciduous habitats, (2) reducing cattle grazing in deciduous habitats, and (3) protecting the few relatively pristine landscapes surrounding large deciduous riparian areas in the West.

Land cover changes and greenhouse gas emissions in two different soil covers in the Brazilian Caatinga.

PubMed

Ribeiro, Kelly; Sousa-Neto, Eráclito Rodrigues de; Carvalho, João Andrade de; Sousa Lima, José Romualdo de; Menezes, Rômulo Simões Cezar; Duarte-Neto, Paulo José; da Silva Guerra, Glauce; Ometto, Jean Pierre Henry Baulbaud

2016-11-15

The Caatinga biome covers an area of 844,453km(2) and has enormous endemic biodiversity, with unique characteristics that make it an exclusive Brazilian biome. It falls within the earth's tropical zone and is one of the several important ecoregions of Brazil. This biome undergoes natural lengthy periods of drought that cause losses in crop and livestock productivity, having a severe impact on the population. Due to the vulnerability of this ecosystem to climate change, livestock has emerged as the main livelihood of the rural population, being the precursor of the replacement of native vegetation by grazing areas. This study aimed to measure GHG emissions from two different soil covers: native forest (Caatinga) and pasture in the municipality of São João, Pernambuco State, in the years 2013 and 2014. GHG measurements were taken by using static chamber techniques in both soil covers. According to a previous search, so far, this is the first study measuring GHG emissions using the static chamber in the Caatinga biome. N2O emissions ranged from -1.0 to 4.2mgm(-2)d(-1) and -1.22 to 3.4mgm(-2)d(-1) in the pasture and Caatinga, respectively, and they did not significantly differ from each other. Emissions were significantly higher during dry seasons. Carbon dioxide ranged from -1.1 to 14.1 and 1.2 to 15.8gm(-2)d(-1) in the pasture and Caatinga, respectively. CO2 emissions were higher in the Caatinga in 2013, and they were significantly influenced by soil temperature, showing an inverse relation. Methane emission ranged from 6.6 to 6.8 and -6.0 to 4.8mgm(-2)d(-1) in the pasture and Caatinga, respectively, and was significantly higher only in the Caatinga in the rainy season of 2014. Soil gas fluxes seemed to be influenced by climatic and edaphic conditions as well as by soil cover in the Caatinga biome. Copyright © 2016 Elsevier B.V. All rights reserved.

Two-Site Comparison of Transpiration by Larrea Tridentata

NASA Astrophysics Data System (ADS)

Cavanaugh, M. L.; Kurc, S. A.; Scott, R. L.; Bryant, R. B.

2008-12-01

As a result of landscape changes within the desert southwestern U.S. such as increased grazing, reduced wildfire frequency, and changes in atmospheric conditions, the native creosotebush (Larrea tridentata) has encroached upon historically grass-dominated ecosystems, expanding in range and land cover density. To understand how creosotebush influences the water budget of ecosystems, heat balance sap flow sensors were employed on creosotebush stems at both the Santa Rita Experimental Range (SRER) and Walnut Gulch Experimental Watershed (WGEW). Additionally, both sites are equipped with eddy covariance towers, associated micrometeorological measurements, and profiles of water content reflectometers for soil moisture. The differences found between the two sites, including soil type and precipitation regime, are the basis of the following hypotheses. Firstly, we hypothesize that we will not see transpiration (T) responses following storms less than 5 mm at both sites. Secondly, we hypothesize that at both sites we will see a lagged response of T to large precipitation events, with evaporation being the dominate component in the partitioning of evapotranspiration (ET) for the first two days. Thirdly, we hypothesize that the ratio of plant transpiration to total evapotranspiration (T/ET) will be less at SRER due to the larger amount of bare soil exposed at this site. In this study, we show data from one summer at both sites and show how these relate to different precipitation events and soil moisture reservoirs.

Ecological perspectives of land use history: The Arid Lands Ecology (ALE) Reserve

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hinds, N R; Rogers, L E

The objective of this study was to gather information on the land use history of the Arid Land Ecology (ALE) Reserve so that current ecological research could be placed within a historical perspective. The data were gathered in the early 1980s by interviewing former users of the land and from previously published research (where available). Interviews with former land users of the ALE Reserve in Benton County, Washington, revealed that major land uses from 1880 to 1940 were homesteading, grazing, oil/gas production, and road building. Land use practices associated with grazing and homesteading have left the greatest impact on themore » landscape. Disturbed sites where succession is characterized by non-native species, plots where sagebrush was railed away, and sheep trails are major indications today of past land uses. Recent estimates of annual bunchgrass production do ALE do not support the widespread belief that bunchgrass were more productive during the homesteading era, though the invasion of cheatgrass (Bromus tectorum), Jim Hill mustard (Sisymbrium altissium), and other European alien plant species has altered pre-settlement succession patterns. 15 refs., 6 figs., 1 tab.« less

Zoonotic echinostome infections in free-grazing ducks in Thailand.

PubMed

Saijuntha, Weerachai; Duenngai, Kunyarat; Tantrawatpan, Chairat

2013-12-01

Free-grazing ducks play a major role in the rural economy of Eastern Asia in the form of egg and meat production. In Thailand, the geographical location, tropical climate conditions and wetland areas of the country are suitable for their husbandry. These environmental factors also favor growth, multiplication, development, survival, and spread of duck parasites. In this study, a total of 90 free-grazing ducks from northern, central, and northeastern regions of Thailand were examined for intestinal helminth parasites, with special emphasis on zoonotic echinostomes. Of these, 51 (56.7%) were infected by one or more species of zoonotic echinostomes, Echinostoma revolutum, Echinoparyphium recurvatum, and Hypoderaeum conoideum. Echinostomes found were identified using morphological criteria when possible. ITS2 sequences were used to identify juvenile and incomplete worms. The prevalence of infection was relatively high in each region, namely, north, central, and northeast region was 63.2%, 54.5%, and 55.3%, respectively. The intensity of infection ranged up to 49 worms/infected duck. Free-grazing ducks clearly play an important role in the life cycle maintenance, spread, and transmission of these medically important echinostomes in Thailand.

25 CFR 167.6 - Carrying capacities.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Grazing Committee, and the Navajo Tribal Council for review and recommendations prior to presentation to...; recommendations for future adjustments to the established carrying capacities shall be made by Range Technicians based on the best information available through annual utilization studies and range condition studies...

25 CFR 167.6 - Carrying capacities.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Grazing Committee, and the Navajo Tribal Council for review and recommendations prior to presentation to...; recommendations for future adjustments to the established carrying capacities shall be made by Range Technicians based on the best information available through annual utilization studies and range condition studies...

PATTERNS OF NITRATE LOSSES FROM FORESTED BASINS IN THE OREGON COAST RANGE

EPA Science Inventory

Numerous factors may control losses of dissolved nutrients from forested basins in the Oregon Coast Range. Potentially important factors include forest composition, stand age, forest management, grazing, agriculture, sewage inputs and bedrock types, as well as others perhaps not...

High-density native-range species affects the invasive plant Chromolaena odorata more strongly than species from its invasive range.

PubMed

Zheng, Yulong; Liao, Zhiyong

2017-11-22

Invasive plant species often form dense mono-dominant stands in areas they have invaded, while having only sparse distribution in their native ranges, and the reasons behind this phenomenon are a key point of research in invasive species biology. Differences in species composition between native and invasive ranges may contribute to the difference in distribution status. In this study, we found that the high-density condition had a more negative effect on C. odorata than the low-density condition when co-grown with neighbor plants from its native range in Mexico, while this pattern was not in evidence when it was grown with neighbors from its invasive range in China. Different competitive ability and coevolutionary history with C. odorata between native-range neighbors and invasive-range neighbors may lead to the inconsistent patterns.

Changes in vegetation and biological soil crust communities on sand dunes stabilizing after a century of grazing on San Miguel Island, Channel Island National Park, California

USGS Publications Warehouse

Zellman, Kristine L.

2014-01-01

San Miguel Island is the westernmost of the California Channel Islands and one of the windiest areas on the west coast of North America. The majority of the island is covered by coastal sand dunes, which were stripped of vegetation and subsequently mobilized due to droughts and sheep ranching during the late 19th century and early 20th century. Since the removal of grazing animals, vegetation and biological soil crusts have once again stabilized many of the island's dunes. In this study, historical aerial photographs and field surveys were used to develop a chronosequence of the pattern of change in vegetation communities and biological soil crust levels of development (LOD) along a gradient of dune stabilization. Historical aerial photographs from 1929, 1954, 1977, and 2009 were georeferenced and used to delineate changes in vegetation canopy cover and active (unvegetated) dune extent among 5 historical periods (pre-1929, 1929–1954, 1954–1977, 1977–2009, and 2009–2011). During fieldwork, vegetation and biological soil crust communities were mapped along transects distributed throughout San Miguel Island's central dune field on land forms that had stabilized during the 5 time periods of interest. Analyses in a geographic information system (GIS) quantified the pattern of changes that vegetation and biological soil crust communities have exhibited on the San Miguel Island dunes over the past 80 years. Results revealed that a continuing increase in total vegetation cover and a complex pattern of change in vegetation communities have taken place on the San Miguel Island dunes since the removal of grazing animals. The highly specialized native vascular vegetation (sea rocket, dunedelion, beach-bur, and locoweed) are the pioneer stabilizers of the dunes. This pioneer community is replaced in later stages by communities that are dominated by native shrubs (coastal goldenbush, silver lupine, coyote-brush, and giant coreopsis), with apparently overlapping or cyclical succession pathways. Many of the dunes that have been stabilized the longest (since before 1929) are dominated by exotic grasses. Stands of biological soil crusts (cyanobacteria) are found only on dunes where vascular vegetation is already present. Biological soil crusts are not found on dunes exhibiting a closed vascular plant canopy, which may indicate that the role of soil crusts in dune stabilization on the island is transitory. Particle-size analyses of soil samples from the study area reveal that higher biological soil crust LOD is positively correlated with increasing fine grain content. The findings indicate that changes in vegetation communities may be the most rapid at earlier and later stages of dune stabilization and that regular monitoring of dunes may help to identify the interactions between vegetation and soil crusts, as well as the potential transitions between native and exotic plant communities.

Dutchwoman Butte revisited: Examining paradigms for livestock grazing exclusion

Treesearch

Jim Sprinkle; Mick Holder; Chas Erickson; Al Medina; Dan Robinett; George Ruyle; Jim Maynard; Sabrina Tuttle; John Hays; Walt Meyer; Scott Stratton; Alix Rogstad; Kevin Eldredge; Joe Harris; Larry Howery; Wesley Sprinkle

2007-01-01

In 2000, a collaborative range-monitoring program, "Reading the Range," was established with the University of Arizona Cooperative Extension in Gila County, the Gila County Cattle Growers, and the Tonto National Forest with the assistance of the US Department of Agriculture Renewable Resources Extension Act grant program. Funding for Reading the Range has...

Range management research, Fort Valley Experimental Forest

Treesearch

Henry A. Pearson; Warren P. Clary; Margaret M. Moore; Carolyn Hull Sieg

2008-01-01

Range management research at the Fort Valley Experimental Forest during the past 100 years has provided scientific knowledge for managing ponderosa pine forests and forest-range grazing lands in the Southwest. Three research time periods are identified: 1908 to 1950, 1950 to 1978, and 1978 to 2008. Early research (1908-1950) addressed ecological effects of livestock...

25 CFR 168.2 - Authority.

Code of Federal Regulations, 2010 CFR

2010-04-01

... individuals awaiting relocation or authorized to reside on life estates, and (e) To administer conservation practices, including grazing control and range restoration activities on the Hopi Partitioned Lands. ...

Corticosterone metabolite concentrations in greater sage-grouse are positively associated with the presence of cattle grazing

USGS Publications Warehouse

Jankowski, M.D.; Russell, Robin E.; Franson, J. Christian; Dusek, Robert J.; Hines, M.K.; Gregg, M.; Hofmeister, Erik K.

2014-01-01

The sagebrush biome in the western United States is home to the imperiled greater sage-grouse (Centrocercus urophasianus) and encompasses rangelands used for cattle production. Cattle grazing activities have been implicated in the range-wide decline of the sage-grouse, but no studies have investigated the relationship between the physiological condition of sage-grouse and the presence of grazing cattle. We sampled 329 sage-grouse across four sites (two grazed and two ungrazed) encompassing 13 600 km2 during the spring and late summer–early autumn of 2005 to evaluate whether demographic factors, breeding status, plasma protein levels, and residence in a cattle-grazed habitat were associated with the stress hormone corticosterone. Corticosterone was measured in feces as immunoreactive corticosterone metabolites (ICM). Males captured during the lekking season exhibited higher ICM levels than all others. Prenesting female sage-grouse captured in a grazed site had higher ICM levels than those in ungrazed sites and prenesting female plasma protein levels were negatively correlated with ICM concentrations. With the use of a small-scale spatial model, we identified a positive correlation between cattle pat count and sage-grouse ICM levels. Our model indicated that ICM levels increased by 2.60 ng · g-1 dry feces for every increase in the number of cow pats found in the vicinity. Management practices will benefit from future research regarding the consistency and mechanism(s) responsible for this association and, importantly, how ICM levels and demographic rates are related in this species of conservation concern.

Population ecology of the sea lamprey (Petromyzon marinus) as an invasive species in the Laurentian Great Lakes and an imperiled species in Europe

USGS Publications Warehouse

Hansen, Michael J.; Madenjian, Charles P.; Slade, Jeffrey W.; Steeves, Todd B.; Almeida, Pedro R.; Quintella, Bernardo R.

2016-01-01

The sea lamprey Petromyzon marinus (Linnaeus) is both an invasive non-native species in the Laurentian Great Lakes of North America and an imperiled species in much of its native range in North America and Europe. To compare and contrast how understanding of population ecology is useful for control programs in the Great Lakes and restoration programs in Europe, we review current understanding of the population ecology of the sea lamprey in its native and introduced range. Some attributes of sea lamprey population ecology are particularly useful for both control programs in the Great Lakes and restoration programs in the native range. First, traps within fish ladders are beneficial for removing sea lampreys in Great Lakes streams and passing sea lampreys in the native range. Second, attractants and repellants are suitable for luring sea lampreys into traps for control in the Great Lakes and guiding sea lamprey passage for conservation in the native range. Third, assessment methods used for targeting sea lamprey control in the Great Lakes are useful for targeting habitat protection in the native range. Last, assessment methods used to quantify numbers of all life stages of sea lampreys would be appropriate for measuring success of control in the Great Lakes and success of conservation in the native range.

Assessment of range planting as a conservation practice

Treesearch

Stuart P. Hardegree; Bruce A. Roundy; Nancy L. Shaw; Corey A. Moffet; Thomas A. Monaco; Thomas A. Jones; Edward F. Redente

2009-01-01

NRCS range-planting Conservation Practice standards are used to develop management recommendations for improving vegetation composition an productivity of grazed plant communities. Individual Conservation Practice recommendations are implemented within a Conservation-Management-System in areas where the existing plant-community attributes are insufficient to meet...

Determination of habitat requirements for Apache Trout

USGS Publications Warehouse

Petre, Sally J.; Bonar, Scott A.

2017-01-01

The Apache Trout Oncorhynchus apache, a salmonid endemic to east-central Arizona, is currently listed as threatened under the U.S. Endangered Species Act. Establishing and maintaining recovery streams for Apache Trout and other endemic species requires determination of their specific habitat requirements. We built upon previous studies of Apache Trout habitat by defining both stream-specific and generalized optimal and suitable ranges of habitat criteria in three streams located in the White Mountains of Arizona. Habitat criteria were measured at the time thought to be most limiting to juvenile and adult life stages, the summer base flow period. Based on the combined results from three streams, we found that Apache Trout use relatively deep (optimal range = 0.15–0.32 m; suitable range = 0.032–0.470 m) pools with slow stream velocities (suitable range = 0.00–0.22 m/s), gravel or smaller substrate (suitable range = 0.13–2.0 [Wentworth scale]), overhead cover (suitable range = 26–88%), and instream cover (large woody debris and undercut banks were occupied at higher rates than other instream cover types). Fish were captured at cool to moderate temperatures (suitable range = 10.4–21.1°C) in streams with relatively low maximum seasonal temperatures (optimal range = 20.1–22.9°C; suitable range = 17.1–25.9°C). Multiple logistic regression generally confirmed the importance of these variables for predicting the presence of Apache Trout. All measured variables except mean velocity were significant predictors in our model. Understanding habitat needs is necessary in managing for persistence, recolonization, and recruitment of Apache Trout. Management strategies such as fencing areas to restrict ungulate use and grazing and planting native riparian vegetation might favor Apache Trout persistence and recolonization by providing overhead cover and large woody debris to form pools and instream cover, shading streams and lowering temperatures.

First-year effects of logging on forage production.

Treesearch

George A. Garrison; Robert S. Rummell

1950-01-01

Significant ecological changes that effect range livestock economy are occurring as a result of logging in the 13,000,000 acres of ponderosa pine forest range lands of the Pacific Northwest. These forests provide 90 percent of the summer range area and 70 percent of the summer range grazing capacity in Eastern Oregon and Washington; about 270,000 acres undergo partial...

25 CFR 166.302 - How is a range unit created?

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 1 2010-04-01 2010-04-01 false How is a range unit created? 166.302 Section 166.302 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.302 How is a range unit created? We create a range unit after we consult with the...

Suspended material availability and filtration-biodeposition processes performed by a native and invasive bivalve species in streams

USGS Publications Warehouse

Atkinson, C.L.; First, M.R.; Covich, A.P.; Opsahl, S.P.; Golladay, S.W.

2011-01-01

Unionid mussels are among the most threatened group of freshwater organisms globally. They are known for their ability to filter food particles from flowing and standing waters. However, invasive bivalve species, such as the Asian clam (Corbicula fluminea) in North America, have the potential to overlap in feeding and potentially out-compete the native species. Yet, the feeding preferences of unionid mussels and C. fluminea are incompletely understood. We hypothesized that Elliptio crassidens (native) and C. fluminea (invasive) would select for specific organic components present within seston. We examined changes in seston (dry mass and ash-free dry mass) resulting from bivalve feeding activity for three size classes of material that were isolated using gravimetric filtration. The treatments were also sub-sampled for flow cytometry (FC) which separated the suspended materials in the stream water into five categories: detritus, heterotrophic bacteria, picoautotrophs, nanoautotrophs, and heterotrophic nanoeukaryotes. Our results indicated that both species of bivalve showed preferences for organic and living materials. E. crassidens preferentially filtered nanoeukaryotes, whose decreases were associated with an increase in bacteria. In contrast, C. fluminea preferred smaller materials through selective filtration of picoautotrophs. In addition, both species increased the concentration of large materials toward the end of the experiment because of the suspension of their pseudofeces biodeposits. To our knowledge, this study is the first to examine grazing by bivalve species on natural stream particulate matter using FC. Our results suggest that native and non-native mussels have different functional roles, which has important implications for organic matter processing and food webs in streams. ?? 2011 Springer Science+Business Media B.V.

Evaluation of biogeographical factors in the native range to improve the success of biological control agents in the introduced range

USDA-ARS?s Scientific Manuscript database

Biogeographical factors associated with Arundo donax in its native range were evaluated in reference to its key herbivore, an armored scale, Rhizaspidiotus donacis. Climate modeling from location data in Spain and France accurately predicted the native range of the scale in the warmer, drier parts o...

Hard X-ray Optics Technology Development for Astronomy at the Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Gubarev, Mikhail; Ramsey, Brian; Kilaru, Kiranmayee

2009-01-01

Grazing-incidence telescopes based on Wolter 1 geometry have delivered impressive advances in astrophysics at soft-x-ray wavelengths, while the hard xray region remains relatively unexplored at fine angular resolution and high sensitivities. The ability to perform ground-breaking science in the hard-x-ray energy range had been the motivation for technology developments aimed at fabricating low-cost, light-weight, high-quality x-ray mirrors. Grazing-incidence x-ray optics for high-energy astrophysical applications is being developed at MSFC using the electroform-nickel replication process.

A novel multi-detection technique for three-dimensional reciprocal-space mapping in grazing-incidence X-ray diffraction.

PubMed

Schmidbauer, M; Schäfer, P; Besedin, S; Grigoriev, D; Köhler, R; Hanke, M

2008-11-01

A new scattering technique in grazing-incidence X-ray diffraction geometry is described which enables three-dimensional mapping of reciprocal space by a single rocking scan of the sample. This is achieved by using a two-dimensional detector. The new set-up is discussed in terms of angular resolution and dynamic range of scattered intensity. As an example the diffuse scattering from a strained multilayer of self-assembled (In,Ga)As quantum dots grown on GaAs substrate is presented.

Vegetation response of a dry shrubland community to feral goat management on the island of Moloka‘i, Hawai‘i

USGS Publications Warehouse

Jacobi, James D.; Stock, Jonathan

2017-12-14

The Hawaiian Islands are well known for their unique ecosystem assemblages that have a high proportion of endemic flora and fauna. However, since human colonization of this archipelago—starting with the arrival of Polynesian sailors approximately 1,200 years ago, and particularly following western contact in 1778—thousands of non-native species have been introduced to the Islands and many of these alien species have had severe impacts on the native ecosystems. Particularly damaging to these ecosystems are large mammals, including goats (Capra hircus), pigs (Sus scrofa), cattle (Bos taurus), deer (Axis axis and Odocoileus hemionus), and sheep (Ovis spp.), which are collectively referred to here as ungulates; they cause extensive damage to the native vegetation by their browsing, grazing, and trampling. Similar impacts have been documented elsewhere, including New Zealand and many other island ecosystems.Previous studies in Hawai‘i have utilized fenced exclosures to assess the impacts of feral or wild ungulates on vegetation and the recovery potential for the native plant communities by comparing plant community composition, structure, and cover inside the fenced area (without ungulates) over time to the vegetation condition outside of the protection of the fence. In some cases, the native vegetation recovered once the animals were removed. However, in other situations alien plants were more competitive and dominated the revegetation process after the impacts of ungulates had been reduced or eliminated.This report describes the response of a highly degraded lowland dry habitat plant community located on the south slope of east Moloka‘i, Hawai‘i, to reduction of browsing and grazing impacts caused by feral goats. For this study, vegetation response inside a fenced exclosure was compared to vegetation change in the area outside of the fence that was still accessible to goats. This study is part of the larger U.S. Geological Survey Ridge-to-Reef (USGS-R2R) research project conducted between 2008 and 2014 to better understand the magnitude of, and factors responsible for, increased erosion on Moloka‘i. The upslope erosion has resulted in heavy sedimentation of the near-shore coral reef ecosystem on the leeward side of the island. The project area and adjacent lands are managed by the East Moloka‘i Watershed Partnership (EMoWP) to restore the vegetation and reduce erosion on the leeward side of the island.Specific questions addressed in this vegetation change study include:How does the vegetation composition, structure, and cover respond to different population levels of feral goats in this area?Are there plant species that can be used as indicators of different population levels of goats?Can native plants recover and become dominant again with the reduction or elimination of goats from this area?Are there invasive plant species that respond favorably to reduction of goat populations and could result in additional management threats to this area over time?How does the succession of vegetation following goat control relate to the original composition and structure of the plant communities that were formerly found in this area?

Key sources and seasonal dynamics of greenhouse gas fluxes from yak grazing systems on the Qinghai-Tibetan Plateau

NASA Astrophysics Data System (ADS)

Liu, Yang; Yan, Caiyu; Matthew, Cory; Wood, Brennon; Hou, Fujiang

2017-01-01

Greenhouse gas (GHG) emissions from livestock grazing systems are contributing to global warming. To examine the influence of yak grazing systems on GHG fluxes and relationships between GHG fluxes and environmental factors, we measured carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes over three key seasons in 2012 and 2013 from a range of potential sources, including: alpine meadows, dung patches, manure heaps and yak night pens, on the Qinghai-Tibetan Plateau. We also estimated the total annual global warming potential (GWP, CO2-equivalents) from family farm grazing yaks using our measured results and other published data. In this study, GHG fluxes per unit area from night pens and composting manure heaps were higher than from dung patches and alpine meadows. Increased moisture content and surface temperature of soil and manure were major factors increasing CO2 and CH4 fluxes. High contributions of CH4 and N2O (21.1% and 44.8%, respectively) to the annual total GWP budget (334.2 tonnes) strongly suggest these GHG other than CO2 should not be ignored when estimating GWP from the family farm grazing yaks on the Qinghai-Tibetan Plateau for the purposes of determining national and regional land use policies or compiling global GHG inventories.

Key sources and seasonal dynamics of greenhouse gas fluxes from yak grazing systems on the Qinghai-Tibetan Plateau

PubMed Central

Liu, Yang; Yan, Caiyu; Matthew, Cory; Wood, Brennon; Hou, Fujiang

2017-01-01

Greenhouse gas (GHG) emissions from livestock grazing systems are contributing to global warming. To examine the influence of yak grazing systems on GHG fluxes and relationships between GHG fluxes and environmental factors, we measured carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes over three key seasons in 2012 and 2013 from a range of potential sources, including: alpine meadows, dung patches, manure heaps and yak night pens, on the Qinghai-Tibetan Plateau. We also estimated the total annual global warming potential (GWP, CO2-equivalents) from family farm grazing yaks using our measured results and other published data. In this study, GHG fluxes per unit area from night pens and composting manure heaps were higher than from dung patches and alpine meadows. Increased moisture content and surface temperature of soil and manure were major factors increasing CO2 and CH4 fluxes. High contributions of CH4 and N2O (21.1% and 44.8%, respectively) to the annual total GWP budget (334.2 tonnes) strongly suggest these GHG other than CO2 should not be ignored when estimating GWP from the family farm grazing yaks on the Qinghai-Tibetan Plateau for the purposes of determining national and regional land use policies or compiling global GHG inventories. PMID:28106070

Key sources and seasonal dynamics of greenhouse gas fluxes from yak grazing systems on the Qinghai-Tibetan Plateau.

PubMed

Liu, Yang; Yan, Caiyu; Matthew, Cory; Wood, Brennon; Hou, Fujiang

2017-01-20

Greenhouse gas (GHG) emissions from livestock grazing systems are contributing to global warming. To examine the influence of yak grazing systems on GHG fluxes and relationships between GHG fluxes and environmental factors, we measured carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) fluxes over three key seasons in 2012 and 2013 from a range of potential sources, including: alpine meadows, dung patches, manure heaps and yak night pens, on the Qinghai-Tibetan Plateau. We also estimated the total annual global warming potential (GWP, CO 2 -equivalents) from family farm grazing yaks using our measured results and other published data. In this study, GHG fluxes per unit area from night pens and composting manure heaps were higher than from dung patches and alpine meadows. Increased moisture content and surface temperature of soil and manure were major factors increasing CO 2 and CH 4 fluxes. High contributions of CH 4 and N 2 O (21.1% and 44.8%, respectively) to the annual total GWP budget (334.2 tonnes) strongly suggest these GHG other than CO 2 should not be ignored when estimating GWP from the family farm grazing yaks on the Qinghai-Tibetan Plateau for the purposes of determining national and regional land use policies or compiling global GHG inventories.

Economic opportunity survey of small scale dairy farms of the north west province of Cameroon.

PubMed

Bayemi, P H; Webb, E C; Manjeli, Y; Naoussi, P

2007-12-01

An Economic Opportunity Survey was conducted on dairy farms in the North West Province of Cameroon. Results showed that median (range) number of cows in milk per farm was zero point six (0-4) and six (3-12) in the zero grazing and transhumance systems, respectively. Medians (range) of three (0-24) and four (3-10) litres of milk were sold per farm per day, corresponding to 30% and 60% of milk produced. 24% and 13% of total cattle per herd were milking cows in the zero grazing and transhumance systems respectively. Median milk production per cow on one day was two (0-25) and two (1-3) litres. Median calf production interval was 14.5 (12-25) and. 21.5 (14-29) months. More milk produced per day represented the best economic opportunity in both systems while reduced age at first calving and longer lactation length were the next in both. Wastage of milk through spoilage from poor hygiene and lack of cooling was a major problem. Holstein cows, which were in the zero grazing system, had unexpectedly short lactations. Constraints identified led to the setting up of interventions of training and advice for farmers and of better nutrition.

Effects of Grazing Management in Brachiaria grass-forage Peanut Pastures on Canopy Structure and Forage Intake.

PubMed

Gomes, F K; Oliveira, M D B L; Homem, B G C; Boddey, R M; Bernardes, T F; Gionbelli, M P; Lara, M A S; Casagrande, D R

2018-06-13

Maintenance of mixed grass-legume pastures for stand longevity and improved animal utilization is a challenge in warm-season climates. The goal of this study was to assess grazing management on stand persistence, forage intake, and N balance of beef heifers grazing mixed pastures of Brachiaria brizantha and Arachis pintoi. A two-year experiment was carried out in Brazil, where four grazing management were assessed: rest period interrupted at 90%, 95%, and 100% of light interception (LI) and a fixed rest period of 42 days (90LI, 95LI, 100LI, and 42D, respectively). The LI were taken at 50 points at ground level and at five points above the canopy for each paddock using a canopy analyzer. For all treatments, the post-grazing stubble height was 15 cm. Botanical composition and canopy structure characteristics such as canopy height, forage mass, and vertical distribution of the morphological composition were evaluated pre-and post-grazing. Forage chemical composition, intake, and microbial synthesis were also determined. A randomized complete block design was used, considering the season of the year as a repeated measure over time. Grazing management and season were considered fixed, while block and year were considered random effects. In the summer, legume mass accounted for 19% of the canopy at 100LI, which was less than other treatments (a mean of 30%). The 100LI treatment had a greater grass stem mass compared with other treatments. In terms of vertical distribution for 100LI, 38.6% of the stem mass was above the stubble height, greater than the 5.7% for other treatments. The canopy structure limited neutral detergent fiber intake (P = 0.007) at 100LI (1.02% of BW/d), whereas 42D, 90LI, and 95LI treatments had NDF intake close to 1.2% of BW/d. The intake of digestible organic matter (OM; P = 0.007) and the ratio of crude protein/digestible OM (P < 0.001) were less at 100LI in relation to the other treatments. The production of microbial N (P < 0.001) and efficiency of microbial synthesis (P = 0.023) were greater at 95LI and 90LI, followed by 42D and less at 100LI. Overall, the range from 90 to 95% of LI is the recommendation to interrupt the rest period, since this strategy enhanced community stability, forage intake, and nutritional value of the diet. Under on-farm conditions, brachiaria grass and forage peanut pastures should be managed at a range height of 24 to 30 cm.

Silvopastoral systems of the Chol Mayan ethnic group in southern Mexico: Strategies with a traditional basis.

PubMed

Pignataro, Ana Genoveva; Levy Tacher, Samuel Israel; Aguirre Rivera, Juan Rogelio; Nahed Toral, José; González Espinosa, Mario; Rendón Carmona, Nelson

2016-10-01

Silvopastoral systems combine trees and/or shrubs with grazing cattle. In the municipality of Salto de Agua, Chiapas, Mexico, some indigenous communities have developed silvopastoral systems based on their traditional knowledge regarding use of local natural resources. Through analysis of classification based on the composition of tree vegetation, two groups of grazing units were identified in the study area. Different attributes of tree and herbaceous vegetation, as well as of agricultural management and production, were compared between the two groups. Results indicate that at least two strategies of silvopastoral management exist. The first - LTD - is characterized by an average density of 22 adult trees ha(-1) in grazing units with an average surface area of 22.4 ha. The second - HTD - has an average of 54.4 trees ha(-1) in grazing units with an average surface area of 12.2 ha. Average richness per grazing unit for the LTD strategy was 7.2 species, and for HTD strategy it was 12.7 species. Average basal area for LTD was 1.7 m2 ha(-1), and for HTD 3.8 m2 ha(-1). Finally, the average level of fixed carbon for LTD was 2.12 mg ha(-1), and for HTD 4.89 mg ha(-1). For all variables, there was a significant difference between the two strategies. In addition, both strategies differ in prairie management. In the HTD strategy, growers spare their preferred spontaneously growing tree species by clearing around them. Many of these species, particularly those harvested for timber, belong to the original vegetation. In these prairies, average coverage of native grasses (60.8 ± 7.85) was significantly greater than in the LTD strategy (38.4 ± 11.32), and neither fertilizers nor fire are used to maintain or improve the pastures; by contrast, in HTD prairies, introduced grasses, principally Cynodon plectostachyus, have a higher average coverage (43.4 ± 13.75) than in the LTD prairies (17.08 ± 9.02). Regardless of the differences in composition of tree and herbaceous vegetation, in both types of grazing units a similar animal load is maintained. Many attributes of these silvopastoral strategies - based on traditional technology of the Chol farmers of the Tulija River Valley - concord with sustainable agriculture and provide a wide variety of services to the farmer and the environment. Diffusion of this technology in areas similar to that of this region could have a positive impact on the economy of conventional cattle raisers while generating environmental services. Copyright © 2016 Elsevier Ltd. All rights reserved.

Managing interior Northwest rangelands: the Oregon Range Evaluation Project.

Treesearch

Thomas M. Quigley; H. Reed Sanderson; Arthur R. Tiedemann

1989-01-01

This report is a synthesis of results from an 11-year study of the effects of increasing intensities of range management strategies on herbage production, water resources, economics, and associated resources-such as wood fiber and recreation-in Grant County, Oregon. Four intensities of management were studied on Federal land (19 grazing allotments) ranging from no...

An Assessment of the Forest and Range Land Situation in the United States.

ERIC Educational Resources Information Center

Hair, Dwight; And Others

This report is a comprehensive analysis of the renewable resources of forest and range land and associated waters prepared in response to provisions of the Forest and Rangeland Renewable Resources Planning Act of 1974. It shows that the nation's demands for outdoor recreation, wildlife and fish, range grazing, timber, and water have been growing…

Range management research, Fort Valley Experimental Forest (P-53)

Treesearch

Henry A. Pearson; Warren P. Clary; Margaret M. Moore; Carolyn Hull Sieg

2008-01-01

Range management research at the Fort Valley Experimental Forest during the past 100 years has provided scientific knowledge for managing ponderosa pine forests and forest-range grazing lands in the Southwest. Three research timeperiods are identified: 1908 to 1950, 1950 to 1978, and 1978 to 2008. Early research (1908-1950) addressed ecological effects of livestock...

The Standley allotment: a history of range recovery.

Treesearch

Gerald S. Strickler; Wade B. Hall

1980-01-01

One of the first range research programs on National Forest lands was conducted by Dr. Arthur W. Sampson in the Wallowa Mountains, Oregon, between 1907 and 1911. This paper reviews the historical perspective of and the basic range management principles and practices developed from Sampson's studies as well as the land and grazing management of the study area to...

Sub-arctic Wetland Greenhouse Gases (CO2, CH4 & N2O) Emissions are Driven by Interactions of Environmental Controls and Herbivore Grazers

NASA Astrophysics Data System (ADS)

Kelsey, K.; Leffler, A. J.; Beard, K. H.; Choi, R. T.; Welker, J. M.

2015-12-01

Climate change is increasing temperatures, altering precipitation regimes and causing earlier growing seasons, particularly at northern latitudes. Such changes in local environmental conditions have the potential to affect biogeochemical cycling including the exchange of greenhouses gases between the atmosphere and the terrestrial biosphere. In addition to the effects of these environmental controls, animals such as migratory geese also influence biogeochemical cycles through grazing, trampling and delivering nutrient-rich fecal matter. In this work we aimed to quantify how local environmental conditions and the presence of grazing interact as drivers of emissions of three key greenhouse gases, CO2, CH4 and N2O, in coastal wetlands of the Yukon Kuskokwim Delta. We explored the magnitude of emissions across gradients of soil temperature and water table depth, and across vegetation types related to the presence of grazing, ranging from no vegetation through grazed and ungrazed vegetation. We also investigated emissions from grazed areas using experimental manipulations of the timing of grazing and advancement of the growing season. We found that local environmental conditions and use by grazers exert interacting controls on emissions of CO2, CH4 and N2O. Emissions of CO2 and CH4 were positively related to soil temperature and CH4 emissions were inversely related to water table depth, but the relationship varied by vegetation type. Net emissions of CO2 were greatest in ungrazed vegetation types (6.62 umols CO2 m-2 sec-1; p=0.0007) whereas CH4 emissions were greatest in the grazed vegetation (122.56 nmols CH4 m-2 sec-1; p=0.037). Flux of N2O was less than 1 nmol N2O m-2 sec-1 across all landscape positions under typical grazing and temperature conditions, but emissions were stimulated to over 10 nmols m-2 sec-1 when grazing occurred early relative to a typical season. Our results indicate that environmental conditions and the presence of migratory herbivores are both important controls on gas fluxes. Future climate change may alter regional gas flux and biosphere-atmosphere feedbacks both via direct environmental drivers and through climate-driven changes to populations or habits of grazers that also exert important controls on biogeochemical cycling in this region.

Physiological response curves reveal differences among season advancement and timing of grazing experimental treatments in a coastal Alaskan wetland

NASA Astrophysics Data System (ADS)

Leffler, A. J.; Kelsey, K.; Beard, K. H.; Choi, R. T.; Welker, J. M.

2016-12-01

The phenology of northern ecosystems is rapidly changing as high latitude regions warm. Spring green-up has advanced 1-3 days per decade since the early 1980's and sea ice retreat is likely to further accelerate the arrival of spring in coastal Alaska. One result of spring advancement is a phenological mismatch with the arrival of migratory geese that bread in the region. As green-up advances, geese arrive into a phenologically older system where vegetation has a higher C:N ratio than younger grasses with potential consequences for goose nutrition and C and N cycling. In 2014 and 2015 we established a season advancement X timing of grazing experiment to examine the ecosystem consequences of this mismatch. We used a LI-Cor 8100 automated, chamber-based C flux system to monitor hourly net ecosystem exchange (NEE) in eight plots: four were warmed in June to advance the growing season, four received ambient temperatures; two each experienced early, typical, late, or no grazing. The experiment is replicated six times, but the automated system is capable of measuring only one block; other blocks are measured twice weekly with a portable system. We fit physiological light response curves to weekly data and used incident sunlight to estimate daily NEE. Results suggest that daily carbon uptake ranged from ca. 0.6 to 4.5 g m-2 d-1 in the different treatments. Carbon uptake in the season advancement plots was lower than in the ambient plots by ca. 0.5 g m-2 d-1 averaged during the summer. Delaying grazing into the later season, the expectation of climate change, greatly increased NEE to 4.5 g m-2 d-1, a value much greater than the typical grazing period in 2015. Completely eliminating grazing from the system resulted in NEE of 2.9 g m-2 d-1. Differences were likely driven by warmer soils enhancing respiration, removal of photosynthetic biomass, and grazing maintaining tissue in a young, highly photosynthetic form. Overall our results suggest that timing of grazing in the system appears more important for carbon flux than advancement of spring.

Relationships among Body Condition, Insulin Resistance and Subcutaneous Adipose Tissue Gene Expression during the Grazing Season in Mares

PubMed Central

Selim, Shaimaa; Elo, Kari; Jaakkola, Seija; Karikoski, Ninja; Boston, Ray; Reilas, Tiina; Särkijärvi, Susanna; Saastamoinen, Markku; Kokkonen, Tuomo

2015-01-01

Obesity and insulin resistance have been shown to be risk factors for laminitis in horses. The objective of the study was to determine the effect of changes in body condition during the grazing season on insulin resistance and the expression of genes associated with obesity and insulin resistance in subcutaneous adipose tissue (SAT). Sixteen Finnhorse mares were grazing either on cultivated high-yielding pasture (CG) or semi-natural grassland (NG) from the end of May to the beginning of September. Body measurements, intravenous glucose tolerance test (IVGTT), and neck and tailhead SAT gene expressions were measured in May and September. At the end of grazing, CG had higher median body condition score (7 vs. 5.4, interquartile range 0.25 vs. 0.43; P=0.05) and body weight (618 kg vs. 572 kg ± 10.21 (mean ± SEM); P=0.02), and larger waist circumference (P=0.03) than NG. Neck fat thickness was not different between treatments. However, tailhead fat thickness was smaller in CG compared to NG in May (P=0.04), but this difference disappeared in September. Greater basal and peak insulin concentrations, and faster glucose clearance rate (P=0.03) during IVGTT were observed in CG compared to NG in September. A greater decrease in plasma non-esterified fatty acids during IVGTT (P<0.05) was noticed in CG compared to NG after grazing. There was down-regulation of insulin receptor, retinol binding protein 4, leptin, and monocyte chemoattractant protein-1, and up-regulation of adiponectin (ADIPOQ), adiponectin receptor 1 and stearoyl-CoA desaturase (SCD) gene expressions in SAT of both groups during the grazing season (P<0.05). Positive correlations were observed between ADIPOQ and its receptors and between SCD and ADIPOQ in SAT (P<0.01). In conclusion, grazing on CG had a moderate effect on responses during IVGTT, but did not trigger insulin resistance. Significant temporal differences in gene expression profiles were observed during the grazing season. PMID:25938677

Grassland Management and Conversion into Grassland: Effects on Soil Carbon

DOE Data Explorer

Conant, Richard T. [Natural Resource Ecology Laboratory, Colorada State University, Fort Collins, CO (USA); Paustian, Keith [Natural Resource Ecology Laboratory, Colorada State University, Fort Collins, CO (USA); Elliott, Edward T. [Natural Resource Ecology Laboratory, Colorada State University, Fort Collins, CO (USA)

2003-01-01

Grasslands are heavily relied upon for food and forage production. A key component for sustaining production in grassland ecosystems is the maintenance of soil organic matter (SOM), which can be strongly influenced by management. Many management techniques intended to increase forage production may potentially increase SOM, thus sequestering atmospheric carbon (C). Further, conversion from either cultivation or native vegetation into grassland could also sequester atmospheric carbon. We reviewed studies examining the influence of improved grassland management practices and conversion into grasslands on soil C worldwide to assess the potential for C sequestration. Results from 115 studies containing over 300 data points were analyzed. Management improvements included fertilization (39%), improved grazing management (24%), conversion from cultivation (15%) and native vegetation (15%), sowing of legumes (4%) and grasses (2%), earthworm introduction (1%), and irrigation (1%). Soil C content and concentration increased with improved management in 74% of the studies, and mean soil C increased with all types of improvement. Carbon sequestration rates were highest during the first 40 y after treatments began and tended to be greatest in the top 10 cm of soil. Impacts were greater in woodland and grassland biomes than in forest, desert, rain forest, or shrubland biomes. Conversion from cultivation, the introduction of earthworms, and irrigation resulted in the largest increases. Rates of C sequestration by type of improvement ranged from 0.11 to 3.04 Mg C · ha^–1 y^–1, with a mean of 0.54 Mg C · ha ^–1 · y^–1, and were highly influenced by biome type and climate. We conclude that grasslands can act as a significant carbon sink with the implementation of improved management.

Leaf Photosynthesis and Plant Competitive Success in a Mixed-grass Prairie: With Reference to Exotic Grasses Invasion

DOE PAGES

Dong, Dr. Xuejun; Patton, J.; Gu, Lianhong; ...

2014-11-26

The widespread invasion of exotic cool-season grasses in mixed-grass rangeland is diminishing the hope of bringing back the natural native plant communities. However, ecophysiological mechanisms explaining the relative competitiveness of these invasive grasses over the native species generally are lacking. In this study, we used experimental data collected in south-central North Dakota, USA to address this issue. Photosynthetic potential was obtained from the net assimilation (A) vs. internal CO 2 (Ci) response curves from plants grown in a greenhouse. Plant success was defined as the average frequency measured over 25 years (1988 to 2012) on overflow range sites across fivemore » levels of grazing intensity. In addition, estimated leaf area index of individual species under field conditions was used to indicate plant success. The correlation between photosynthetic potential based on A/Ci curves and plant frequency was negative. The correlation between leaf photosynthesis and plant success (defined as leaf area within a unit land area) was also negative, although statistically weak. These results suggest that the two cool-season grasses, Poa pratensis and Bromus inermis, do not rely on superior leaf-level photosynthesis for competitive success. Instead, some other traits, such as early and late-season growth, may be more important for them to gain dominance in the mixed-grass prairie. We propose that the negative photosynthesis-frequency relation as observed in this study results from a strong competition for limited soil nutrients in the mixed-grass prairie. In conclusion, it has implications for the stability and productivity of the grassland under various human disruptions influencing the soil nutrient status.« less

Leaf Photosynthesis and Plant Competitive Success in a Mixed-grass Prairie: With Reference to Exotic Grasses Invasion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, Dr. Xuejun; Patton, J.; Gu, Lianhong

The widespread invasion of exotic cool-season grasses in mixed-grass rangeland is diminishing the hope of bringing back the natural native plant communities. However, ecophysiological mechanisms explaining the relative competitiveness of these invasive grasses over the native species generally are lacking. In this study, we used experimental data collected in south-central North Dakota, USA to address this issue. Photosynthetic potential was obtained from the net assimilation (A) vs. internal CO 2 (Ci) response curves from plants grown in a greenhouse. Plant success was defined as the average frequency measured over 25 years (1988 to 2012) on overflow range sites across fivemore » levels of grazing intensity. In addition, estimated leaf area index of individual species under field conditions was used to indicate plant success. The correlation between photosynthetic potential based on A/Ci curves and plant frequency was negative. The correlation between leaf photosynthesis and plant success (defined as leaf area within a unit land area) was also negative, although statistically weak. These results suggest that the two cool-season grasses, Poa pratensis and Bromus inermis, do not rely on superior leaf-level photosynthesis for competitive success. Instead, some other traits, such as early and late-season growth, may be more important for them to gain dominance in the mixed-grass prairie. We propose that the negative photosynthesis-frequency relation as observed in this study results from a strong competition for limited soil nutrients in the mixed-grass prairie. In conclusion, it has implications for the stability and productivity of the grassland under various human disruptions influencing the soil nutrient status.« less

Experimental studies of adaptation in Clarkia xantiana. II. Fitness variation across a subspecies border.

PubMed

Geber, Monica A; Eckhart, Vincent M

2005-03-01

Because the range boundary is the locale beyond which a taxon fails to persist, it provides a unique opportunity for studying the limits on adaptive evolution. Adaptive constraints on range expansion are perplexing in view of widespread ecotypic differentiation by habitat and region within a species' range (regional adaptation) and rapid evolutionary response to novel environments. In this study of two parapatric subspecies, Clarkia xantiana ssp. xantiana and C. x. ssp. parviflora, we compared the fitness of population transplants within their native region, in a non-native region within the native range, and in the non-native range to assess whether range expansion might be limited by a greater intensity of selection on colonists of a new range versus a new region within the range. The combined range of the two subspecies spans a west-to-east gradient of declining precipitation in the Sierra Nevada of California, with ssp. xantiana in the west being replaced by ssp. parviflora in the east. Both subspecies had significantly higher fitness in the native range (range adaptation), whereas regional adaptation was weak and was found only in the predominantly outcrossing ssp. xantiana but was absent in the inbreeding ssp. parvifilora. Because selection intensity on transplants was much stronger in the non-native range relative to non-native regions, there is a larger adaptive barrier to range versus regional expansion. Three of five sequential fitness components accounted for regional and range adaptation, but only one of them, survivorship from germination to flowering, contributed to both. Flower number contributed to regional adaptation in ssp. xantiana and fruit set (number of fruits per flower) to range adaptation. Differential survivorship of the two taxa or regional populations of ssp. xantiana in non-native environments was attributable, in part, to biotic interactions, including competition, herbivory, and pollination. For example, low fruit set in ssp. xantiana in the east was likely due to the absence of its principal specialist bee pollinators in ssp. parviflora's range. Thus, convergence on self-fertilization may be necessary for ssp. xantiana to invade ssp. parviflora's range, but the evolution of outcrossing would not be required for ssp. parviflora to invade ssp. xantiana's range.

Influence of a dominant consumer species reverses at increased diversity.

PubMed

Brandt, Margarita; Witman, Jon D; Chiriboga, Angel I

2012-04-01

Theory and experiments indicate that changes in consumer diversity affect benthic community structure and ecosystem functioning. Although the effects of consumer diversity have been tested in the laboratory and the field, little is known about effects of consumer diversity in the subtidal zone, one of the largest marine habitats. We investigated the grazing effects of sea urchins on algal abundance and benthic community structure in a natural subtidal habitat of the Galápagos Islands. Three species of urchins (Eucidaris, Lytechinus, and Tripneustes) were manipulated in inclusion cages following a replacement design with three levels of species richness (one, two, and three species) with all possible two-species urchin combinations. Identity was the main factor accounting for changes in the percentage of substrate grazed and benthic community structure. Two out of the three two-species assemblages grazed more than expected, suggesting a richness effect, but analyses revealed that this increased grazing was due to a sampling effect of the largest and commercially valued urchin species, Tripneustes. Benthic community structure in treatments with Eucidaris, Lytechinus, and Tripneustes alone was significantly different at the end of the experiment, suggesting that resource use differentiation occurred. Communities in Tripneustes enclosures were characterized by abundant crustose coralline algae and grazed substrate, while those without it contained abundant green foliose algae (Ulva sp.). An unexpected emergent property of the system was that the most species-rich urchin assemblage underyielded, grazing less than any other assemblage with Tripneustes, effectively reversing its dominant influence observed in the two-species treatments. While further experiments are needed to discern the mechanisms of underyielding, it may be related to changing interspecific interactions as richness increases from two to three species or to density-dependent Tripneustes grazing. This study highlights the general importance of evaluating consumer richness effects across the entire range of species richness considered, as the performance of the most species-rich consumer assemblage could not be predicted by manipulations of intermediate levels of consumer species richness.

How to Create Conditioned Taste Aversion for Grazing Ground Covers in Woody Crops with Small Ruminants

PubMed Central

Manuelian, Carmen L.; Albanell, Elena; Rovai, Maristela; Caja, Gerardo

2016-01-01

Conditioned taste aversion (CTA) is a learning behavior process where animals are trained to reject certain feed after gastrointestinal discomfort has been produced. Lithium chloride (LiCl) is the preferred agent used in livestock to induce CTA because it specifically stimulates the vomit center. In addition, LiCl is commercially available, and easy to prepare and administer using a drenching gun. Nevertheless, some factors have to be considered to obtain an effective long-lasting CTA, which allows small ruminants to graze during the cropping season. A key aspect is to use animals with no previous contact with the target plant (the plant chosen to be avoided; new feed). Due to their native neophobic feeding behavior, small ruminants can easily associate the negative feedback effects with the new feed, resulting in a strong and persistent CTA. The recommended doses are 200 and 225 mg LiCl/kg body weight (BW) for goats and sheep, respectively. To induce CTA, 100 g of the target plant should be individually offered for at least 30 min, and LiCl administered thereafter if the intake is greater than 10 g. Each time the animal eats the target plant without negative consequences, the CTA becomes weaker. Consequently, to minimize the risk of target plant consumption, it is essential to have sufficient palatable ground cover available. The presence of an alternative feed (of quality and quantity) prevents the accidental consumption of the target plant. A close monitoring of the flock is recommended to remove and re-dose any animal consuming more than 4 bites or 10 g of the target plant. At the beginning of each grazing season, check the CTA status of each animal before moving them to the crop. PMID:27167860

Effect of Ecological Restoration on Body Condition of a Predator

PubMed Central

González-Tokman, Daniel; Martínez-Garza, Cristina

2015-01-01

Ecological restoration attempts to recover the structure and function of ecosystems that have been degraded by human activities. A crucial test of ecosystem recovery would be to determine whether individuals in restored environments are as healthy as those in conserved environments. However, the impact of restoration on physiology of terrestrial animals has never been tested. Here, we evaluated the effect of two restoration methods on body condition measured as body size, body mass, lipid and muscle content of the spider Nephila clavipes in a tropical dry forest that has suffered chronic disturbance due to cattle grazing. We used experimental plots that had been excluded from disturbance by cattle grazing during eight years. Plots were either planted with native trees (i. e. maximal intervention), or only excluded from disturbance (i. e. minimal intervention), and were compared with control conserved (remnants of original forest) and disturbed plots (where cattle is allowed to graze). We predicted (1) better body condition in spiders of conserved and restored sites, compared to disturbed sites, and (2) better body condition in plots with maximal intervention than in plots with minimal intervention. The first prediction was not supported in males or females, and the second prediction was only supported in females: body dry mass was higher in planted than in conserved plots for spiders of both sexes and also higher that in disturbed plots for males, suggesting that plantings are providing more resources. We discuss how different life histories and environmental pressures, such as food availability, parasitism, and competition for resources can explain our contrasting findings in male and female spiders. By studying animal physiology in restoration experiments it is possible to understand the mechanistic basis of ecological and evolutionary processes that determine success of ecological restoration. PMID:26226363

Energy, water and space use by free-living red kangaroos Macropus rufus and domestic sheep Ovis aries in an Australian rangeland.

PubMed

Munn, A J; Dawson, T J; McLeod, S R; Dennis, T; Maloney, S K

2013-08-01

We used doubly labelled water to measure field metabolic rates (FMR) and water turnover rates (WTR) in one of Australia's largest native herbivores, the red kangaroo (Macropus rufus) and one of Australia's dominant livestock species, the wool-breed Merino sheep, under free-living conditions in a typical Australian rangeland. Also, we used GPS technology to examine animal space use, along with the comparisons of urine concentration, diet, diet digestibility, and subsequent grazing pressures. We found smaller space-use patterns than previously reported for kangaroos, which were between 14 and 25 % those of sheep. The FMR of a 25-kg kangaroo was 30 % that of a 45-kg sheep, while WTR was 15 % and both were associated with smaller travel distances, lower salt intakes, and higher urine concentration in kangaroos than sheep. After accounting for differences in dry matter digestibility of food eaten by kangaroos (51 %) and sheep (58 %), the relative grazing pressure of a standard (mature, non-reproductive) 25-kg kangaroo was 35 % that of a 45-kg sheep. Even for animals of the same body mass (35 kg), the relative grazing pressure of the kangaroo was estimated to be only 44 % that of the sheep. After accounting for the energetic costs of wool growth by sheep, the FMRs of our sheep and kangaroos were 2-3 times their expected BMRs, which is typical for mammalian FMR:BMRs generally. Notably, data collected from our free-living animals were practically identical to those from animals confined to a semi-natural enclosure (collected in an earlier study under comparable environmental conditions), supporting the idea that FMRs are relatively constrained within species.

Effect of Ecological Restoration on Body Condition of a Predator.

PubMed

González-Tokman, Daniel; Martínez-Garza, Cristina

2015-01-01

Ecological restoration attempts to recover the structure and function of ecosystems that have been degraded by human activities. A crucial test of ecosystem recovery would be to determine whether individuals in restored environments are as healthy as those in conserved environments. However, the impact of restoration on physiology of terrestrial animals has never been tested. Here, we evaluated the effect of two restoration methods on body condition measured as body size, body mass, lipid and muscle content of the spider Nephila clavipes in a tropical dry forest that has suffered chronic disturbance due to cattle grazing. We used experimental plots that had been excluded from disturbance by cattle grazing during eight years. Plots were either planted with native trees (i. e. maximal intervention), or only excluded from disturbance (i. e. minimal intervention), and were compared with control conserved (remnants of original forest) and disturbed plots (where cattle is allowed to graze). We predicted (1) better body condition in spiders of conserved and restored sites, compared to disturbed sites, and (2) better body condition in plots with maximal intervention than in plots with minimal intervention. The first prediction was not supported in males or females, and the second prediction was only supported in females: body dry mass was higher in planted than in conserved plots for spiders of both sexes and also higher that in disturbed plots for males, suggesting that plantings are providing more resources. We discuss how different life histories and environmental pressures, such as food availability, parasitism, and competition for resources can explain our contrasting findings in male and female spiders. By studying animal physiology in restoration experiments it is possible to understand the mechanistic basis of ecological and evolutionary processes that determine success of ecological restoration.

Data resources for range-wide assessment of livestock grazing across the sagebrush biome

USGS Publications Warehouse

Assal, T.J.; Veblen, K.E.; Farinha, M.A.; Aldridge, Cameron L.; Casazza, Michael L.; Pyke, D.A.

2012-01-01

The data contained in this series were compiled, modified, and analyzed for the U.S. Geological Survey (USGS) report "Range-Wide Assessment of Livestock Grazing Across the Sagebrush Biome." This report can be accessed through the USGS Publications Warehouse (online linkage: http://pubs.usgs.gov/of/2011/1263/). The dataset contains spatial and tabular data related to Bureau of Land Management (BLM) Grazing Allotments. We reviewed the BLM national grazing allotment spatial dataset available from the GeoCommunicator National Integrated Land System (NILS) website in 2007 (http://www.geocommunicator.gov). We identified several limitations in those data and learned that some BLM State and/or field offices had updated their spatial data to rectify these limitations, but maintained the data outside of NILS. We contacted appropriate BLM offices (State or field, 25 in all) to obtain the most recent data, assessed the data, established a data development protocol, and compiled data into a topologically enforced dataset throughout the area of interest for this project (that is, the pre-settlement distribution of Greater Sage-Grouse in the Western United States). The final database includes three spatial datasets: Allotments (BLM Grazing Allotments), OUT_Polygons (nonallotment polygons used to ensure topology), and Duplicate_Polygon_Allotments. See Appendix 1 of the aforementioned report for complete methods. The tabular data presented here consists of information synthesized by the Land Health Standard (LHS) analysis (Appendix 2), and data obtained from the BLM Rangeland Administration System (http://www.blm.gov/ras/). In 2008, available LHS data for all allotments in all regions were compiled by BLM in response to a Freedom of Information Act (FOIA) request made by a private organization. The BLM provided us with a copy of these data. These data provided three major types of information that were of interest: (1) date(s) (if any) of the most recent LHS evaluation for each allotment; (2) whether if evaluated, each region-specific standard (3–8 LHS depending on region) had been met on a given allotment; and (3) whether livestock contributed to any of these standards not being met. A description of how we processed the original data to prepare for analysis is described in Appendix 2, and the synthesized dataset can be found in the table "lhs_x_walk." Permitted use dates, livestock type (horse, sheep or cattle), number of livestock, and Animal Unit Months [the number of animal units (1,000-pound animal equivalents) that can be grazed for 31 days with the available forage in a sustainable manner] are the legal maximum grazing amounts for a given allotment, and legal adjustments to these numbers occur infrequently. We summarized permitted use by BLM allotment in the table "Permitted_Use." Billed use records are used for calculations of permittees' annual grazing bills. We summarized billed use by allotment for BLM grazing year in the table "Billed_Use." All three tables can be joined with the allotment spatial data in a geographic information system (GIS) environment, using the IDENT attribute as the primary key.

25 CFR 161.2 - What are the Secretary's authorities under this part?

Code of Federal Regulations, 2010 CFR

2010-04-01

..., 1980: (i) All conservation practices on the Navajo Partitioned Lands, including control and range restoration activities, must be coordinated and executed with the concurrence of the Navajo Nation; and (ii) All grazing and range restoration matters on the Navajo Reservation lands must be administered by BIA...

Chapter 4: Managing chaparral in Yavapai County

Treesearch

Leonard F. DeBano; Malchus B. Baker; Steven T. Overby

1999-01-01

Yavapai County in central Arizona supports extensive stands of chaparral in the Bradshaw Mountains, Mingus Mountain, and the Santa Maria Range. Chaparral occupies about 400,300 acres of the Prescott National Forest (Anderson 1986). These chaparral communities provide a wide range of benefits including watershed protection, grazing for wildlife and domestic animals,...

Demographic patterns of Ferocactus cylindraceus in relation to substrate age and grazing history

USGS Publications Warehouse

Bowers, Janice E.

1997-01-01

Three subpopulations of Ferocactus cylindraceus, a short-columnar cactus of the Sonoran and Mojave deserts, were sampled in Grand Canyon, Arizona, USA, at sites representing a range of substrate ages and different grazing histories. Age-height relations were determined from annual growth, then used to estimate probable year of establishment for each cohort. Eight years between 1944 and 1992 were especially favorable for establishment. Six of these 8 years coincided with El Nino-Southern Oscillation conditions, indicating that as for many woody plants in arid regions, somewhat unusual climatic conditions are necessary if populations are to replace themselves. Comparison of age structures showed that established and developing populations have somewhat different dynamics in that the rate of population increase was slowest on the youngest terrace. On the ancient terraces, about half the plants were less than 25 years old. Plants older than 40 years were few; however the oldest plants in the study (about 49 years) grew on the ancient terraces. On the recent terrace, 76% of the subpopulation was 25 years or younger, and the oldest living plant was about 36 years of age. The age structures of subpopulations on grazed and ungrazed sites also differed markedly. On ungrazed sites, subpopulations were more or less at equilibrium, with enough young plants to replace old ones as they died. In contrast, the subpopulation on the grazed site was in a state of marked disequilibrium. Grazing before 1981 largely extirpated a palatable subshrub that was probably an important nurse plant. Until the shrub population at Indian Canyon recovers from decades of burro grazing, a rebound in E cylindraceus establishment is not to be expected.

Niche conservatism of Aedes albopictus and Aedes aegypti - two mosquito species with different invasion histories.

PubMed

Cunze, Sarah; Kochmann, Judith; Koch, Lisa K; Klimpel, Sven

2018-05-16

Biological invasions have been associated with niche changes; however, their occurrence is still debated. We assess whether climatic niches between native and non-native ranges have changed during the invasion process using two globally spread mosquitoes as model species, Aedes albopictus and Aedes aegypti. Considering the different time spans since their invasions (>300 vs. 30-40 years), niche changes were expected to be more likely for Ae. aegypti than for Ae. albopictus. We used temperature and precipitation variables as descriptors for the realized climatic niches and different niche metrics to detect niche dynamics in the native and non-native ranges. High niche stability, therefore, no niche expansion but niche conservatism was revealed for both species. High niche unfilling for Ae. albopictus indicates a great potential for further expansion. Highest niche occupancies in non-native ranges occurred either under more temperate (North America, Europe) or tropical conditions (South America, Africa). Aedes aegypti has been able to fill its native climatic niche in the non-native ranges, with very low unfilling. Our results challenge the assumption of rapid evolutionary change of climatic niches as a requirement for global invasions but support the use of native range-based niche models to project future invasion risk on a large scale.

Interannual and seasonal variability in short-term grazing impact of Euphausia superba in nearshore and offshore waters west of the Antarctic Peninsula

NASA Astrophysics Data System (ADS)

Ross, R. M.; Quetin, L. B.; Haberman, K. L.

1998-11-01

Our focus in this paper is the interaction between macrozooplanktonic grazers and primary producers, and the interannual and seasonal variability in the Palmer Long-Term Ecological Research (Palmer LTER) study region from Anvers Island to Adelaide Island. Short-term grazing estimates are calculated by integrating (1) theoretical and experimental estimates of ingestion rates in response to the standing stock of phytoplankton, and (2) field measurements of phytoplankton standing stock and grazer biomass. Field data come from three austral summer cruises (January/February of 1993, 1994, and 1995) and one sequence of seasonal cruises (summer, fall and winter 1993). The relative and absolute abundance of the dominant macrozooplankton grazers, Euphausia superba and Salpa thompsoni, varied by at least an order of magnitude on the spatial and temporal scales observed. Mean grazing rates ranged from 0.4 to 9.0 μg chlorophyll m -2 h -1 for the Antarctic krill and salp populations over the three summer cruises. This leads to variability in the flow of carbon from the primary producers through the grazers on the same scales. Temporal and spatial variability in grazing impact and faecal pellet production are high.

25 CFR 161.301 - What will a grazing permit contain?

Code of Federal Regulations, 2010 CFR

2010-04-01

... permits will contain the following provisions: (1) Name of permit holder; (2) Range management plan...) Animal identification requirements (i.e., brand, microchip, freeze brand, earmark, tattoo, etc.); (6...

36 CFR 222.9 - Range improvements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... performed by a cooperator or permittee on National Forest System lands shall not confer the exclusive right..., to maintain improvements to specified standards. (d) Grazing fees or the number of animal months...

36 CFR 222.9 - Range improvements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... performed by a cooperator or permittee on National Forest System lands shall not confer the exclusive right..., to maintain improvements to specified standards. (d) Grazing fees or the number of animal months...

36 CFR 222.9 - Range improvements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... performed by a cooperator or permittee on National Forest System lands shall not confer the exclusive right..., to maintain improvements to specified standards. (d) Grazing fees or the number of animal months...

36 CFR 222.9 - Range improvements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... performed by a cooperator or permittee on National Forest System lands shall not confer the exclusive right..., to maintain improvements to specified standards. (d) Grazing fees or the number of animal months...

Variability in carbon dioxide fluxes among six winter wheat paddocks managed under different tillage and grazing practices

NASA Astrophysics Data System (ADS)

Wagle, Pradeep; Gowda, Prasanna H.; Northup, Brian K.; Turner, Kenneth E.; Neel, James P. S.; Manjunatha, Priyanka; Zhou, Yuting

2018-07-01

Carbon dioxide (CO2) fluxes from six winter wheat (Triticum aestivum L.) paddocks (grain only, graze-grain, and graze-out) managed under conventional till (CT) and no-till (NT) systems were synthesized for the 2016-2017 growing season to compare the magnitudes and seasonal dynamics of CO2 fluxes and to investigate among-site variability of CO2 fluxes. Large variations in CO2 fluxes were observed among paddocks. Maximum daily (7-day averages) net ecosystem CO2 exchange (NEE) ranged from -3.39 to -8.68 g C m-2, gross primary production (GPP) ranged from 7.33 to 16.92 g C m-2, and ecosystem respiration (ER) ranged from 5.85 to 9.98 g C m-2. Seasonal sums of NEE ranged from -137 to -542 g C m-2. Optimum photosynthetically active radiation (PAR), air temperature (Ta), and vapor pressure deficit (VPD) for NEE were approximately 1700 μmol m-2 s-1, 22 °C, and 1.25 kPa, respectively. Across-site analysis showed percent of canopy cover (Canopy%) was strongly correlated with NEE (R2 = 0.76) and ecosystem light use efficiency (ELUE, R2 = 0.76). Integration of PAR with leaf area index (LAI) and integration of Ta with dry biomass weight (DW) explained 81% and 74% of variations in GPP and ER, respectively. Remotely-sensed enhanced vegetation index (EVI) explained 66% and normalized difference vegetation index (NDVI) explained 69% of the variations in NEE. Integration of PAR with NDVI or EVI explained ∼80% of variations in GPP, while NDVI × Ta explained 58% of variations in ER. Results illustrated that differences in wheat canopies related to paddock management, as indicated by differences in DW, LAI, Canopy%, NDVI, and EVI, must be accounted for explaining among-site variability of CO2 fluxes. Long-term measurements from our clustered and paired eddy covariance towers will provide insights into the effects of tillage and different grazing practices on CO2 dynamics in winter wheat.

Evolution under changing climates: climatic niche stasis despite rapid evolution in a non-native plant.

PubMed

Alexander, Jake M

2013-09-22

A topic of great current interest is the capacity of populations to adapt genetically to rapidly changing climates, for example by evolving the timing of life-history events, but this is challenging to address experimentally. I use a plant invasion as a model system to tackle this question by combining molecular markers, a common garden experiment and climatic niche modelling. This approach reveals that non-native Lactuca serriola originates primarily from Europe, a climatic subset of its native range, with low rates of admixture from Asia. It has rapidly refilled its climatic niche in the new range, associated with the evolution of flowering phenology to produce clines along climate gradients that mirror those across the native range. Consequently, some non-native plants have evolved development times and grow under climates more extreme than those found in Europe, but not among populations from the native range as a whole. This suggests that many plant populations can adapt rapidly to changed climatic conditions that are already within the climatic niche space occupied by the species elsewhere in its range, but that evolution to conditions outside of this range is more difficult. These findings can also help to explain the prevalence of niche conservatism among non-native species.

Bitterbrush in California

Treesearch

August L. Hormay

1943-01-01

Bitterbrush (Purshia tridentata D. C.) is one of the most important range plants in the West. It is grazed by cattle, sheep, and goats, as well as by deer, antelope, and other game animals, and the seeds are an important item in the diet of rodents and birds. The range of bitterbrush (fig. 1) covers about 340,000,000 acres in the 11 western range...

Distribution and interaction of white-tailed deer and cattle in a semi-arid grazing system

Treesearch

Susan M. Cooper; Humberto L. Perotto-Baldivieso; M. Keith Owens; Michael G. Meek; Manuel Figueroa-Pagan

2008-01-01

In order to optimize production, range managers need to understand and manage the spatial distribution of free-ranging herbivores, although this task becomes increasingly difficult as ranching operations diversify to include management of wildlife for recreational hunting. White-tailed deer are sympatric with cattle throughout much of their range and are a valuable...

Forest and range research on the "Wild Bill Plots" (1927-2007)

Treesearch

Daniel C. Laughlin; Margaret M. Moore

2008-01-01

In 1927, the Fort Valley Experimental Forest initiated a range-timber reproduction study. The study was one of the first attempts to experimentally isolate the agents responsible for injury to ponderosa pine regeneration, and at the same time assess the impacts of livestock grazing on herbaceous vegetation. The study was conducted on the USFS range allotments northwest...

Forest and range research on the "Wild Bill Plots" (1927-2007) (P-53)

Treesearch

Daniel C. Laughlin; Margaret M. Moore

2008-01-01

In 1927, the Fort Valley Experimental Forest initiated a range-timber reproduction study. The study was one of the first attempts to experimentally isolate the agents responsible for injury to ponderosa pine regeneration, and at the same time assess the impacts of livestock grazing on herbaceous vegetation. The study was conducted on the USFS range allotments northwest...

No difference in the competitive ability of introduced and native Trifolium provenances when grown with soil biota from their introduced and native ranges

PubMed Central

Shelby, Natasha; Hulme, Philip E.; van der Putten, Wim H.; McGinn, Kevin J.; Weser, Carolin; Duncan, Richard P.

2016-01-01

The evolution of increased competitive ability (EICA) hypothesis could explain why some introduced plant species perform better outside their native ranges. The EICA hypothesis proposes that introduced plants escape specialist pathogens or herbivores leading to selection for resources to be reallocated away from defence and towards greater competitive ability. We tested the hypothesis that escape from soil-borne enemies has led to increased competitive ability in three non-agricultural Trifolium (Fabaceae) species native to Europe that were introduced to New Zealand in the 19th century. Trifolium performance is intimately tied to rhizosphere biota. Thus, we grew plants from one introduced (New Zealand) and two native (Spain and the UK) provenances for each of three species in pots inoculated with soil microbiota collected from the rhizosphere beneath conspecifics in the introduced and native ranges. Plants were grown singly and in competition with conspecifics from a different provenance in order to compare competitive ability in the presence of different microbial communities. In contrast to the predictions of the EICA hypothesis, we found no difference in the competitive ability of introduced and native provenances when grown with soil microbiota from either the native or introduced range. Although plants from introduced provenances of two species grew more slowly than native provenances in native-range soils, as predicted by the EICA hypothesis, plants from the introduced provenance were no less competitive than native conspecifics. Overall, the growth rate of plants grown singly was a poor predictor of their competitive ability, highlighting the importance of directly quantifying plant performance in competitive scenarios, rather than relying on surrogate measures such as growth rate. PMID:26969431

Fall-grown oat to extend the fall grazing season for replacement dairy heifers.

PubMed

Coblentz, W K; Brink, G E; Hoffman, P C; Esser, N M; Bertram, M G

2014-03-01

Our objective was to assess the pasture productivity and forage characteristics of 2 fall-grown oat (Avena sativa L.) cultivars, specifically for extending the grazing season and reducing reliance on harvested forages by replacement dairy heifers. A total of 160 gravid Holstein heifers (80 heifers/yr) were stratified by weight, and assigned to 1 of 10 identical research pens (8 heifers/pen). Initial body weights were 480 ± 43.5 kg in 2011 and 509 ± 39.4 kg in 2012. During both years of the trial, four 1.0-ha pasture replicates were seeded in August with Ogle oat (Schumitsch Seed Inc., Antigo, WI), and 4 separate, but similarly configured, pasture replicates were seeded with Forage Plus oat (Kratz Farms, Slinger, WI). Heifer groups were maintained as units, assigned to specific pastures, and then allowed to graze fall-oat pastures for 6h daily before returning to the barn, where they were offered a forage-based basal total mixed ration. Two heifer groups were retained in confinement (without grazing) as controls and offered the identical total mixed ration as pasture groups. During 2011, available forage mass increased with strong linear and quadratic effects for both cultivars, peaking at almost 9 Mg/ha on October 31. In contrast, forage mass was not affected by evaluation date in 2012, remaining ≤ 2,639 kg/ha across all dates because of droughty climatic conditions. During 2012, Ogle exhibited greater forage mass than Forage Plus across all sampling dates (2,678 vs. 1,856 kg/ha), largely because of its more rapid maturation rate and greater canopy height. Estimates of energy density for oat forage ranged from 59.6 to 69.1% during 2011, and ranged narrowly from 68.4 to 70.4% during 2012. For 2011, responses for both cultivars had strong quadratic character, in which the most energy-dense forages occurred in mid November, largely due to accumulation of water-soluble carbohydrates that reached maximum concentrations of 18.2 and 15.1% for Forage Plus and Ogle, respectively. Across the 2-yr trial, average daily gain for grazing heifer groups tended to be greater than heifers remaining in confinement (0.85 vs. 0.74 kg/d), but both management strategies produced weight gains within reasonable proximity to normal targets for heifers in this weight range. Fall-grown oat should be managed as stockpiled forage for deferred grazing, and good utilization of fall-oat forage can be accomplished by a one-time removal of standing forage, facilitated by a single lead wire advanced daily to prevent waste. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Anthropogenic land use estimates for the Holocene - HYDE 3.2

NASA Astrophysics Data System (ADS)

Klein Goldewijk, Kees; Beusen, Arthur; Doelman, Jonathan; Stehfest, Elke

2017-12-01

This paper presents an update and extension of HYDE, the History Database of the Global Environment (HYDE version 3.2). HYDE is an internally consistent combination of historical population estimates and allocation algorithms with time-dependent weighting maps for land use. Categories include cropland, with new distinctions for irrigated and rain-fed crops (other than rice) and irrigated and rain-fed rice. Grazing lands are also provided, divided into more intensively used pasture and less intensively used rangeland, and further specified with respect to conversion of natural vegetation to facilitate global change modellers. Population is represented by maps of total, urban, rural population, population density and built-up area. The period covered is 10 000 before Common Era (BCE) to 2015 Common Era (CE). All data can be downloaded from https://doi.org/10.17026/dans-25g-gez3. We estimate that global population increased from 4.4 million people (we also estimate a lower range < 0.01 and an upper range of 8.9 million) in 10 000 BCE to 7.257 billion in 2015 CE, resulting in a global population density increase from 0.03 persons (or capita, in short cap) km-2 (range 0-0.07) to almost 56 cap km-2 respectively. The urban built-up area evolved from almost zero to roughly 58 Mha in 2015 CE, still only less than 0.5 % of the total land surface of the globe. Cropland occupied approximately less than 1 % of the global land area (13 037 Mha, excluding Antarctica) for a long time period until 1 CE, quite similar to the grazing land area. In the following centuries the share of global cropland slowly grew to 2.2 % in 1700 CE (ca. 293 Mha, uncertainty range 220-367 Mha), 4.4 % in 1850 CE (578 Mha, range 522-637 Mha) and 12.2 % in 2015 CE (ca. 1591 Mha, range 1572-1604 Mha). Cropland can be further divided into rain-fed and irrigated land, and these categories can be further separated into rice and non-rice. Rain-fed croplands were much more common, with 2.2 % in 1700 CE (289 Mha, range 217-361 Mha), 4.2 % (549 Mha, range 496-606 Mha) in 1850 CE and 10.1 % (1316 Mha, range 1298-1325 Mha) in 2015 CE, while irrigated croplands used less than 0.05 % (4.3 Mha, range 3.1-5.5 Mha), 0.2 % (28 Mha, range 25-31 Mha) and 2.1 % (277 Mha, range 273-278 Mha) in 1700, 1850 and 2015 CE, respectively. We estimate the irrigated rice area (paddy) to be 0.1 % (13 Mha, range 9-16 Mha) in 1700 CE, 0.2 % (28 Mha, range 26-31 Mha) in 1850 CE and 0.9 % (118 Mha, range 117-120 Mha) in 2015 CE. The estimates for land used for grazing are much more uncertain. We estimate that the share of grazing land grew from 5.1 % in 1700 CE (667 Mha, range 507-820 Mha) to 9.6 % in 1850 CE (1192 Mha, range 1068-1304 Mha) and 24.9 % in 2015 CE (3241 Mha, range 3211-3270 Mha). To aid the modelling community we have divided land used for grazing into more intensively used pasture, less intensively used converted rangeland and less or unmanaged natural unconverted rangeland. Pasture occupied 1.1 % in 1700 CE (145 Mha, range 79-175 Mha), 1.9 % in 1850 CE (253 Mha, range 218-287 Mha) and 6.0 % (787 Mha, range 779-795 Mha) in 2015 CE, while rangelands usually occupied more space due to their occurrence in more arid regions and thus lower yields to sustain livestock. We estimate converted rangeland at 0.6 % in 1700 CE (82 Mha range 66-93 Mha), 1 % in 1850 CE (129 Mha range 118-136 Mha) and 2.4 % in 2015 CE (310 Mha range 306-312 Mha), while the unconverted natural rangelands occupied approximately 3.4 % in 1700 CE (437 Mha, range 334-533 Mha), 6.2 % in 1850 CE (810 Mha, range 733-881 Mha) and 16.5 % in 2015 CE (2145 Mha, range 2126-2164 Mha).

Low pasture allowance until late gestation in ewes: behavioural and physiological changes in ewes and lambs from lambing to weaning.

PubMed

Freitas-de-Melo, A; Ungerfeld, R; Hötzel, M J; Orihuela, A; Pérez-Clariget, R

2017-02-01

Low pasture allowance during gestation affects ewes' BW at parturition, the bond with their lamb, lamb development, and thus also may affect their responses to weaning. The objectives were to determine if native pasture allowance from before conception until late pregnancy affects ewe-lamb behaviours at lambing, ewes' milk yield, lambs' BW, and the behavioural and physiological changes of ewes and lambs at weaning. From 23 days before conception until 122 days of pregnancy, 24 ewes grazed on two different native pasture allowances: high (10 to 12 kg of dry matter (DM)/100 kg of BW per day; HPA treatment; n=12) or low (5 to 8 kg of DM/100 kg of BW per day; LPA treatment; n=12). Thereafter, all ewes grazed on Festuca arundinacea and received rice bran and crude glycerine. Ewes' body condition score (BCS) and BW were recorded during pregnancy and postpartum periods. Milk yield was determined on days 32, 41 and 54 after lambing. Lambs' BW was recorded from birth until 72 days after lambing. Latency from parturition until the ewe licked her lamb, maternal behaviour score (a test that evaluates maternal attachment to the lamb) and latency for lamb to stand up and suckle were determined. The behaviour of the lambs and ewes was recorded before and after weaning (at 65 days). The ewes' serum total protein, albumin and globulin concentrations were measured before and after weaning. The HPA ewes presented greater BW (P<0.005) and BCS (P<0.005) than the LPA ewes during pregnancy and postpartum (P<0.04), and had a greater milk yield than the LPA ewes (P<0.03). Treatments did not influence any behaviour at lambing, lambs' BW, neither the ewes' behavioural and physiological changes at weaning. HPA lambs paced and vocalized more than LPA lambs (P<0.0001). The variation of albumin concentration before and after weaning was greater in the HPA lambs than in the LPA lambs (P<0.0001). In conclusion, although ewes' BW, BCS and milk production were affected by pasture allowance until late pregnancy, this did not affect the behaviours that lead to the establishment of the mother-young bond, nor the ewes' behavioural responses at weaning. Lambs reared by ewes that grazed on low pasture allowance during pregnancy presented fewer behavioural changes and a lower decrease of albumin concentration after weaning. Lambs' BW was not affected by the feeding received by their mothers.

National Trade can Drive Range Expansion of Bark- and Wood-Boring Beetles.

PubMed

Rassati, Davide; Haack, Robert A; Knížek, Miloš; Faccoli, Massimo

2018-02-09

Several native species of bark- and wood-boring beetles (Coleoptera) have expanded their range within their native biogeographic regions in the last years, but the role of human activity in driving this phenomenon has been underinvestigated. Here we analyze 3 yr of trapping records of native bark- and wood-boring beetles (Cerambycidae and Scolytinae) collected at 12 Italian ports and their surrounding forests to help elucidate the human role in the movement of native species within their native biogeographic region. We trapped several species that occurred either inside or outside their native distributional range within Italy. Species richness and abundance of those species found in the ports located within their native range were most strongly associated with the amount of forest cover in the surrounding landscape, suggesting that they could have arrived in the ports from the nearby forests. The abundance of the species found outside their native range was instead most strongly linked to the amount of national imports arriving at the port where trapping occurred, suggesting that they were likely introduced to the ports from other parts of Italy. This study demonstrates that national sea transportation can favor species range expansion within a country, and confirms that the forests that surround ports can serve as a source of species that can be potentially moved with exports. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Comparing ecohydrological processes in alien vs. native ranges: perspectives from the endangered shrub Myricaria germanica

NASA Astrophysics Data System (ADS)

Michielon, Bruno; Campagnaro, Thomas; Porté, Annabel; Hoyle, Jo; Picco, Lorenzo; Sitzia, Tommaso

2017-04-01

Comparing the ecology of woody species in their alien and native ranges may provide interesting insights for theoretical ecology, invasion biology, restoration ecology and forestry. The literature which describes the biological evolution of successful plant invaders is rich and increasing. However, no general theories have been developed about the geomorphic settings which may limit or favour the alien woody species expansion along rivers. The aim of this contribution is to explore the research opportunities in the comparison of ecohydrological processes occurring in the alien vs. the native ranges of invasive tree and shrub species along the riverine corridor. We use the endangered shrub Myricaria germanica as an example. Myricaria germanica is an Euro-Asiatic pioneer species that, in the native range, develops along natural rivers, wide and dynamic. These conditions are increasingly limited by anthropogenic constraints in most European rivers. This species has been recently introduced in New Zealand, where it is spreading in some natural rivers of the Canterbury region (South Island). We present the current knowledge about the natural and anthropogenic factors influencing this species in its native range. We compare this information with the current knowledge about the same factors influencing M. germanica invasiveness and invasibility of riparian habitats in New Zealand. We stress the need to identify potential factors which could drive life-traits and growing strategies divergence which may hinder the application to the alien ranges of existing ecohydrological knowledge from native ranges. Moreover, the pattern of expansion of the alien range of species endangered in their native ranges opens new windows for research.

25 CFR 161.301 - What will a grazing permit contain?

Code of Federal Regulations, 2013 CFR

2013-04-01

...) Animal identification requirements (i.e., brand, microchip, freeze brand, earmark, tattoo, etc.); (6..., unless the customary use area extends beyond the range unit boundary; (10) A provision reserving a right...

Productive responses of breeding Cashmere goats and their kids to different stocking rates on improved upland pastures.

PubMed

Celaya, R; Moreno-Gonzalo, J; López López, C; Ferreira, L M M; García, U; Ferre, I; Osoro, K

2016-03-01

Although goat meat production could be an option for diversification in improved upland pastures in northern Spain, precise information on the optimal grazing management to enhance goat performance and maximize production per unit land area is lacking. The objective of this study was to compare the effects of 3 stocking rates, high stocking rate (HSR; 20 goats/ha), medium stocking rate (MSR; 15 goats/ha), and low stocking rate (LSR; 10 goats/ha), on gastrointestinal (GI) nematode infections and productive responses of Cashmere goats grazing such pastures. Treatments were replicated twice on 6 paddocks sown with and and with a high presence of the native grass . The experiment lasted 3 grazing seasons (from spring to autumn). Pastures were sampled for sward height and botanical and proximate composition. Body weight and BCS changes of goats were monitored and GI nematode infections were assessed by fecal egg counts (FEC). The established treatments resulted in lower mean sward height in the HSR than in the MSR and LSR (9.6, 11.5, and 14.4 cm, respectively; < 0.001). Pasture botanical composition and nutritive quality did not differ between treatments. The mean FEC of does across the 3 grazing seasons were greater ( < 0.05) in the HSR than in the LSR. spp., , and were the most prevalent nematode species identified in coprocultures. Does showed more favorable ( < 0.001) BW and BCS changes in the LSR than in the MSR and HSR (-14, -30, and -52 g/d and -0.1, -0.3, and -0.7 BCS units [scale 1 to 5], respectively). Greater ( < 0.001) kids' BW gains were observed in the LSR and MSR (average 94 g/d) compared with the HSR (70 g/d). Inversely, kid output per unit land area was greater in the HSR than in the MSR and LSR (320, 258, and 192 kg∙ha∙yr, respectively; < 0.001), whereas daily kids' BW gains per hectare were greater ( < 0.001) in the HSR and MSR (average 1.37 kg∙d∙ha) compared with the LSR (0.98 kg∙d∙ha). A medium stocking rate of 15 goats/ha could represent the best compromise between animal health, performance, and productivity per unit land area in this type of upland pastures, but stricter controls of parasite levels during the grazing season would be necessary to avoid production losses, unless alternative nutraceuticals are provided.

Effective range of reproductive interference exerted by an alien dandelion, Taraxacum officinale, on a native congener.

PubMed

Takakura, Koh-Ichi; Matsumoto, Takashi; Nishida, Takayoshi; Nishida, Sachiko

2011-03-01

Reproductive interference (RI), defined as the fitness cost of interspecific sexual interactions, such as interspecific pollen transfer (IPT) in plants, is ecologically important. Theoretically, RI could result in competitive exclusion, as it operates in a frequency-dependent manner. Additionally, IPT may have a greater range than resource competition, although information about the range of IPT is lacking. In the present study, we measured the range of IPT exerted by Taraxacum officinale (an alien species) on a native dandelion, T. japonicum. We used two approaches. In one, we analyzed the RI effect on a native seed set at three spatial scales. In the second, we tracked IPT from alien to native flower heads using fluorescent pigments as markers. We estimated that pollination distances were in the order of several meters. These distances exceeded the mean distance from each native plant to the nearest alien. As hypothesized, the effect of RI reached farther than neighboring individuals. These data indicate the spatial range from which alien dandelions should be removed to allow the conservation of natives.

Are invasive plants more competitive than native conspecifics? Patterns vary with competitors

NASA Astrophysics Data System (ADS)

Zheng, Yulong; Feng, Yulong; Valiente-Banuet, Alfonso; Li, Yangping; Liao, Zhiyong; Zhang, Jiaolin; Chen, Yajun

2015-10-01

Invasive plants are sometimes considered to be more competitive than their native conspecifics, according to the prediction that the invader reallocates resources from defense to growth due to liberation of natural enemies [‘Evolution of Increased Competitive Ability’ (EICA) hypothesis]. However, the differences in competitive ability may depend on the identity of competitors. In order to test the effects of competitors, Ageratina adenophora plants from both native and invasive ranges competed directly, and competed with native residents from both invasive (China) and native (Mexico) ranges respectively. Invasive A. adenophora plants were more competitive than their conspecifics from native populations when competing with natives from China (interspecific competition), but not when competing with natives from Mexico. Invasive A. adenophora plants also showed higher competitive ability when grown in high-density monoculture communities of plants from the same population (intrapopulation competition). In contrast, invasive A. adenophora plants showed lower competitive ability when competing with plants from native populations (intraspecific competition). Our results indicated that in the invasive range A. adenophora has evolved to effectively cope with co-occurring natives and high density environments, contributing to invasion success. Here, we showed the significant effects of competitors, which should be considered carefully when testing the EICA hypothesis.

Are invasive plants more competitive than native conspecifics? Patterns vary with competitors.

PubMed

Zheng, Yulong; Feng, Yulong; Valiente-Banuet, Alfonso; Li, Yangping; Liao, Zhiyong; Zhang, Jiaolin; Chen, Yajun

2015-10-22

Invasive plants are sometimes considered to be more competitive than their native conspecifics, according to the prediction that the invader reallocates resources from defense to growth due to liberation of natural enemies ['Evolution of Increased Competitive Ability' (EICA) hypothesis]. However, the differences in competitive ability may depend on the identity of competitors. In order to test the effects of competitors, Ageratina adenophora plants from both native and invasive ranges competed directly, and competed with native residents from both invasive (China) and native (Mexico) ranges respectively. Invasive A. adenophora plants were more competitive than their conspecifics from native populations when competing with natives from China (interspecific competition), but not when competing with natives from Mexico. Invasive A. adenophora plants also showed higher competitive ability when grown in high-density monoculture communities of plants from the same population (intrapopulation competition). In contrast, invasive A. adenophora plants showed lower competitive ability when competing with plants from native populations (intraspecific competition). Our results indicated that in the invasive range A. adenophora has evolved to effectively cope with co-occurring natives and high density environments, contributing to invasion success. Here, we showed the significant effects of competitors, which should be considered carefully when testing the EICA hypothesis.

Plants of the Caloosa Experimental Range

Treesearch

J.B. Hilmon

1964-01-01

The vegetation of southern Florida is poorly described in the literature, and the taxonomy and ecology of the pine-wiregrass type especially has been neglected by plant scientists. These deficiencies in plant knowledge were a serious obstacle when research commenced in 1956 on problems of grazing cutover pine flatwoods at the Caloosa Experimental Range. Since then,...

Effects of past and present livestock grazing on herpetofauna in a landscape-scale experiment.

PubMed

Kay, Geoffrey M; Mortelliti, Alessio; Tulloch, Ayesha; Barton, Philip; Florance, Daniel; Cunningham, Saul A; Lindenmayer, David B

2017-04-01

Livestock grazing is the most widespread land use on Earth and can have negative effects on biodiversity. Yet, many of the mechanisms by which grazing leads to changes in biodiversity remain unresolved. One reason is that conventional grazing studies often target broad treatments rather than specific parameters of grazing (e.g., intensity, duration, and frequency) or fail to account for historical grazing effects. We conducted a landscape-scale replicated grazing experiment (15,000 km 2 , 97 sites) to examine the impact of past grazing management and current grazing regimes (intensity, duration, and frequency) on a community of ground-dwelling herpetofauna (39 species). We analyzed community variables (species richness and composition) for all species and built multiseason patch-occupancy models to predict local colonization and extinction for the 7 most abundant species. Past grazing practices did not influence community richness but did affect community composition and patch colonization and extinction for 4 of 7 species. Present grazing parameters did not influence community richness or composition, but 6 of the 7 target species were affected by at least one grazing parameter. Grazing frequency had the most consistent influence, positively affecting 3 of 7 species (increased colonization or decreased extinction). Past grazing practice affected community composition and population dynamics in some species in different ways, which suggests that conservation planners should examine the different grazing histories of an area. Species responded differently to specific current grazing practices; thus, incentive programs that apply a diversity of approaches rather than focusing on a change such as reduced grazing intensity should be considered. Based on our findings, we suggest that determining fine-scale grazing attributes is essential for advancing grazing as a conservation strategy. © 2016 Society for Conservation Biology.

Viral lysis, flagellate grazing potential, and bacterial production in Lake Pavin.

PubMed

Bettarel, Y; Amblard, C; Sime-Ngando, T; Carrias, J-F; Sargos, D; Garabétian, F; Lavandier, P

2003-02-01

Abundances of different compartments of the microbial loop (i.e., viruses, heterotrophic bacteria, nonpigmented nanoflagellates, and pigmented nanoflagellates), bacterial heterotrophic production (BHP), viral lysis, and potential flagellate grazing impacts on the bacterial assemblages were estimated during a short-term study (24 h) conducted in June 1998 in the epilimnion (5 m) and metalimnion (10 m) of a moderate-altitude oligomesotrophic lake (Lake Pavin, France). Viral and bacterial abundances were higher in the metalimnion than in the epilimnion, whereas pigmented and nonpigmented nanoflagellates were more numerous in the epilimnion. The control of the BHP due to viral lysis (determined by examination of viral-containing bacteria using a transmission electron microscope) was significantly higher in the meta- (range = 6.0-33.7%, mean = 15.6%) than in the epilimnion (3.5-10.3%, 6.4%). The same was for the losses of BHP from the potential predation by nanoflagellates which ranged from 0.5 to 115.4% (mean = 38.7%) in the epilimnion, and from 0.7 to 97.5% (mean = 66.7%) in the metalimnion. Finally, estimated viral mediated mortality rates from the percentage of visibly infected cells and potential nanoflagellate grazing rates based on assumed clearance rates suggest that flagellates consumed a larger proportion of bacterial production than was lost to viral lysis.

Sound Absorption of a 2DOF Resonant Liner with Negative Bias Flow

NASA Technical Reports Server (NTRS)

Ahuja, K. K.; Cataldi, P.; Gaeta, R. J., Jr.

2000-01-01

This report describes an experimental study conducted to determine the effect of negative bias flow on the sound absorption of a two degree-of-freedom liner. The backwall for the liner was designed to act as a double-Helmholtz resonator so as to act as a hard wall at all frequencies except at its resonant frequencies. The effect of bias flow is investigated for a buried septum porosity of 2% and 19.5% for bias flow orifice Mach numbers up to 0.311. The bias flow appears to modify the resistance and reactance of the backwall alone at lower frequencies up to about 2 kHz, with marginal effects at higher frequencies. Absorption coefficients close to unity are achieved for a frequency range of 500 - 4000 Hz for the overall liner for a septum porosity of 2% and orifice Mach number of 0.128. Insertion loss tests performed in a flow duct facility for grazing flow Mach numbers up to 0.2 and septum Mach numbers up to 0.15 showed that negative bias flow can increase insertion loss by as much as 10 dB at frequencies in the range of 500 D 1400 Hz compared to no grazing flow. The effectiveness of the negative bias flow is diminished as the grazing flow velocity is increased.

The evolution of increased competitive ability, innate competitive advantages, and novel biochemical weapons act in concert for a tropical invader.

PubMed

Qin, Rui-Min; Zheng, Yu-Long; Valiente-Banuet, Alfonso; Callaway, Ragan M; Barclay, Gregor F; Pereyra, Carlos Silva; Feng, Yu-Long

2013-02-01

There are many non-mutually exclusive mechanisms for exotic invasions but few studies have concurrently tested more than one hypothesis for the same species. Here, we tested the evolution of increased competitive ability (EICA) hypothesis in two common garden experiments in which Chromolaena odorata plants originating from native and nonnative ranges were grown in competition with natives from each range, and the novel weapons hypothesis in laboratory experiments with leachates from C. odorata. Compared with conspecifics originating from the native range, C. odorata plants from the nonnative range were stronger competitors at high nutrient concentrations in the nonnative range in China and experienced far more herbivore damage in the native range in Mexico. In both China and Mexico, C. odorata was more suppressed by species native to Mexico than by species native to China. Species native to China were much more inhibited by leaf extracts from C. odorata than species from Mexico, and this difference in allelopathic effects may provide a possible explanation for the biogeographic differences in competitive ability. Our results indicate that EICA, innate competitive advantages, and novel biochemical weapons may act in concert to promote invasion by C. odorata, and emphasize the importance of exploring multiple, non-mutually exclusive mechanisms for invasions. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Alfalfa weevil (Coleoptera:Curculionidae) management in alfalfa by spring grazing with cattle.

PubMed

Buntin, G D; Bouton, J H

1996-12-01

The effect of continuous, intensive grazing by cattle in the 1st alfalfa growth cycle on larval densities of the alfalfa weevil, Hyera postica (Gyllenhal), was evaluated in "Alfagraze' and "Apollo' alfalfa, which are tolerant and not tolerant to grazing, respectively. In small-cage exclusion trials, grazing reduced larval numbers in 1991 by 65% in Alfagraze and by 32% in Apollo. Larval numbers in 1992 were low (< or = 0.6 larvae per stem) and were not reduced significantly by grazing. Grazing and use of early insecticide treatments of permethrin or carbofuran at low rates with < or = 7-d grazing restrictions to suppress larval numbers before grazing also were examined in large-plot exclusion trails in 1993 and 1994. Grazing reduced larval densities by 60% in 1993 and 45% in 1994 during a 3-wk period beginning 3 wk after grazing was initiated. However, alfalfa weevil larvae caused moderate leaf injury in 1993 and severe injury in 1994 before grazing reduced larval numbers. Use of permethrin at 0.11 kg (AI)/ha or carbofuran or chlorpyrifos at 0.28 kg (AI)/ha effectively reduced larval numbers and prevented leaf injury before grazing began. Therefore, a combination of an early application of an insecticide treatment with a short grazing restriction followed by continuous grazing will control alfalfa weevil larvae while allowing cattle to graze and directly use forage of grazing-tolerant alfalfa.

Evaluating pasture and soil allowance of manganese for Kajli rams grazing in semi-arid environment.

PubMed

Khan, Zafar Iqbal; Ahmad, Kafeel; Ashraf, Muhammad; Naqvi, Syed Ali Hassan; Seidavi, Alireza; Akram, Nudrat Aisha; Laudadio, Vito; Tufarelli, Vincenzo

2015-03-01

The current research on the manganese (Mn) transfer from soil to plant as well as to grazing Kajli rams in the form of sampling periods was carried out under semi-arid environmental conditions. Forage, soil and blood plasma samples were collected during 4 months of the year after a 1-month interval, and Mn concentrations were assessed after wet digestion using an atomic absorption spectrophotometer. Results showed that Mn concentration in soil ranged from 48.28 to 59.44 mg/kg, with incoherent augment and decline across sampling periods, and effect of sampling period on soil Mn was also found to be significant (P < 0.05). The mean levels of Mn in soil appeared higher than the critical value and sufficient for forage crop requirement. The Mn concentration in forage ranged between 24.8 and 37.2 mg/kg, resulting deficient based on the requirement allowance of Mn for livestock grazing animals, therein with almost unchanged forage Mn concentration. The Mn values in blood plasma of rams varied from 0.066 to 0.089 mg/l, with a consistent increase based on sampling period, and the effect of sampling periods on plasma Mn was found to be highly significant (P < 0.05). The Mn levels in ram blood plasma were lesser than the normal level suggesting reasonable need for supplementation. Our study revealed the role of Mn availability in soil and plant species amassing capability on the transport of Mn in the soil-plant-animal system. Results indicated a much higher accumulation rate at the sampling characterized by vegetation dominated by legumes in comparison to grasses, crop residues and mixed pasture and a pronounced seasonal supply of Mn at the four sampling period of grazing land of diverse botanical composition.

Grazing weakens temporal stabilizing effects of diversity in the Eurasian steppe.

PubMed

Ren, Haiyan; Taube, Friedhelm; Stein, Claudia; Zhang, Yingjun; Bai, Yongfei; Hu, Shuijin

2018-01-01

Many biodiversity experiments have demonstrated that plant diversity can stabilize productivity in experimental grasslands. However, less is known about how diversity-stability relationships are mediated by grazing. Grazing is known for causing species losses, but its effects on plant functional groups (PFGs) composition and species asynchrony, which are closely correlated with ecosystem stability, remain unclear. We conducted a six-year grazing experiment in a semi-arid steppe, using seven levels of grazing intensity (0, 1.5, 3.0, 4.5, 6.0, 7.5, and 9.0 sheep per hectare) and two grazing systems (i.e., a traditional, continuous grazing system during the growing period (TGS), and a mixed one rotating grazing and mowing annually (MGS)), to examine the effects of grazing system and grazing intensity on the abundance and composition of PFGs and diversity-stability relationships. Ecosystem stability was similar between mixed and continuous grazing treatments. However, within the two grazing systems, stability was maintained through different pathways, that is, along with grazing intensity, persistence biomass variations in MGS, and compensatory interactions of PFGs in their biomass variations in TGS. Ecosystem temporal stability was not decreased by species loss but rather remain unchanged by the strong compensatory effects between PFGs, or a higher grazing-induced decrease in species asynchrony at higher diversity, and a higher grazing-induced increase in the temporal variation of productivity in diverse communities. Ecosystem stability of aboveground net primary production was not related to species richness in both grazing systems. High grazing intensity weakened the temporal stabilizing effects of diversity in this semi-arid grassland. Our results demonstrate that the productivity of dominant PFGs is more important than species richness for maximizing stability in this system. This study distinguishes grazing intensity and grazing system from diversity effects on the temporal stability, highlighting the need to better understand how grazing regulates ecosystem stability, plant diversity, and their synergic relationships.

25 CFR 166.304 - Can there be more than one permit for each range unit?

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 1 2010-04-01 2010-04-01 false Can there be more than one permit for each range unit? 166.304 Section 166.304 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.304 Can there be more than one permit for each range...

Models of Experimentally Derived Competitive Effects Predict Biogeographical Differences in the Abundance of Invasive and Native Plant Species

PubMed Central

Xiao, Sa; Ni, Guangyan; Callaway, Ragan M.

2013-01-01

Mono-dominance by invasive species provides opportunities to explore determinants of plant distributions and abundance; however, linking mechanistic results from small scale experiments to patterns in nature is difficult. We used experimentally derived competitive effects of an invader in North America, Acroptilon repens, on species with which it co-occurs in its native range of Uzbekistan and on species with which it occurs in its non-native ranges in North America, in individual-based models. We found that competitive effects yielded relative abundances of Acroptilon and other species in models that were qualitatively similar to those observed in the field in the two ranges. In its non-native range, Acroptilon can occur in nearly pure monocultures at local scales, whereas such nearly pure stands of Acroptilon appear to be much less common in its native range. Experimentally derived competitive effects of Acroptilon on other species predicted Acroptilon to be 4–9 times more proportionally abundant than natives in the North American models, but proportionally equal to or less than the abundance of natives in the Eurasian models. Our results suggest a novel way to integrate complex combinations of interactions simultaneously, and that biogeographical differences in the competitive effects of an invader correspond well with biogeographical differences in abundance and impact. PMID:24265701

Comment on Meisner (1990): Effect of climatic warming on the southern margins of the native range of brook trout, Salvelinus fontinalis

Treesearch

Patricia A. Flebbe

1993-01-01

Meisner (1990) proposed in the Journall that the lower elevational margin of brook trout (Salvelinus fontinalis), in the southern part of their native range is related to the 15 degrees C groundwater isotherm, based on a modelled relationship between minimum elevations at which brook trout occur in this part of the native range and...

25 CFR 161.3 - What is the purpose of this part?

Code of Federal Regulations, 2010 CFR

2010-04-01

... GRAZING PERMITS Definitions, Authority, Purpose, and Scope § 161.3 What is the purpose of this part? The... Navajo tradition and culture. (b) Provide resources to rehabilitate range resources in the preservation...

Comparison of burbot populations across adjacent native and introduced ranges

USGS Publications Warehouse

Walters, Annika W.; Mandeville, Elizabeth G.; Saunders, W. Carl; Gerrity, Paul C.; Skorupski, Joseph A.; Underwood, Zachary E.; Gardunio, Eric I.

2017-01-01

Introduced species are a threat to biodiversity. Burbot, Lota lota, a fish native to the Wind River Drainage, Wyoming and a species of conservation concern, have been introduced into the nearby Green River Drainage, Wyoming, where they are having negative effects on native fish species. We compared these native and introduced burbot populations to evaluate potential mechanisms that could be leading to introduction success. We examined genetic ancestry, physical habitat characteristics, community composition, and burbot abundance, relative weight, and size structure between the native and introduced range to elucidate potential differences. The origin of introduced burbot in Flaming Gorge Reservoir is most likely Boysen Reservoir and several nearby river populations in the native Wind River Drainage. Burbot populations did not show consistent differences in abundance, size structure, and relative weight between drainages, though Fontenelle Reservoir, in the introduced drainage, had the largest burbot. There were also limited environmental and community composition differences, though reservoirs in the introduced drainage had lower species richness and a higher percentage of non-native fish species than the reservoir in the native drainage. Burbot introduction in the Green River Drainage is likely an example of reservoir construction creating habitat with suitable environmental conditions to allow a southwards range expansion of this cold-water species. An understanding of the factors driving introduction success can allow better management of species, both in their introduced and native range.

The Use of Climatic Niches in Screening Procedures for Introduced Species to Evaluate Risk of Spread: A Case with the American Eastern Grey Squirrel

PubMed Central

Di Febbraro, Mirko; Lurz, Peter W. W.; Genovesi, Piero; Maiorano, Luigi; Girardello, Marco; Bertolino, Sandro

2013-01-01

Species introduction represents one of the most serious threats for biodiversity. The realized climatic niche of an invasive species can be used to predict its potential distribution in new areas, providing a basis for screening procedures in the compilation of black and white lists to prevent new introductions. We tested this assertion by modeling the realized climatic niche of the Eastern grey squirrel Sciurus carolinensis. Maxent was used to develop three models: one considering only records from the native range (NRM), a second including records from native and invasive range (NIRM), a third calibrated with invasive occurrences and projected in the native range (RCM). Niche conservatism was tested considering both a niche equivalency and a niche similarity test. NRM failed to predict suitable parts of the currently invaded range in Europe, while RCM underestimated the suitability in the native range. NIRM accurately predicted both the native and invasive range. The niche equivalency hypothesis was rejected due to a significant difference between the grey squirrel’s niche in native and invasive ranges. The niche similarity test yielded no significant results. Our analyses support the hypothesis of a shift in the species’ climatic niche in the area of introductions. Species Distribution Models (SDMs) appear to be a useful tool in the compilation of black lists, allowing identifying areas vulnerable to invasions. We advise caution in the use of SDMs based only on the native range of a species for the compilation of white lists for other geographic areas, due to the significant risk of underestimating its potential invasive range. PMID:23843957

Prevalence and distribution of gastrointestinal nematodes on 32 organic and conventional commercial sheep farms in Ontario and Quebec, Canada (2006-2008).

PubMed

Mederos, A; Fernández, S; VanLeeuwen, J; Peregrine, A S; Kelton, D; Menzies, P; LeBoeuf, A; Martin, R

2010-06-24

In order to characterize the epidemiology of sheep gastrointestinal nematodes in organic and conventional flocks in Canada, a longitudinal study was carried out from May 2006 to March 2008 on 32 purposively selected farms in Ontario (ON) and Quebec (QC): 8 certified organic (CO), 16 non-certified organic (NCO), and 8 conventional (C) farms. On each farm, 10 ewes and 10 female lambs were selected. Farm visits were undertaken monthly during the grazing season, and twice in the winter. At each visit, individual fecal samples were taken, and pasture samples were obtained during the grazing season. In addition, body condition score was recorded for all sheep. Fecal egg counts per gram of feces (EPGs) were determined for all fecal samples, and infective larvae (L(3)) were identified in fecal samples (lambs and ewes separately) and pasture samples from farms. Necropsies of 14 lambs from 7 of the 23 Ontario farms were performed at the end of the grazing season in 2006. The mean EPG for year 1 (May 2006 to March 2007) was 181 (range=0-9840) and 351 (range=0-18,940) for the ewes in ON and QC, respectively, and for the lambs was 509 (range=0-25,020) and 147 (range=0-3060) for ON and QC, respectively. During year 2 (April 2007 to March 2008), the mean EPG was 303 (range=0-21,160) and 512 (range=0-22,340) for the ewes in ON and QC, respectively, and for lambs was 460 (range=0-26,180) and 232 (range=0-8280) for ON and QC, respectively. Although the overall mean EPGs were not remarkably high, there were months of higher EPG such as May-June for ewes and July-August for lambs in both provinces. Pasture infectivity was highest in May-June and September. There was a general trend for the CO farms to have lower mean EPG than NCO and C farms. Fecal cultures demonstrated that the most predominant nematode genera were Teladorsagia sp., Haemonchus sp. and Trichostrongylus spp. Pasture infectivity was highest during June-July (984 L3/kg DM) in ON farms and September (mean=436 L3/kg DM) in QC farms during year 1. In year 2, the highest peak was during October in ON (mean=398 L3/kg DM) and July in QC (239 L3/kg DM). Trichostrongylus axei and Trichostrongylus colubriformis were the species most frequently identified from necropsies (36.44% and 38.26%, respectively) at the end of the grazing season in 2006, with Haemonchus contortus and Teladorsagia circumcincta being the next most commonly identified. (c) 2010 Elsevier B.V. All rights reserved.

Anthropogenically induced adaptation to invade (AIAI): contemporary adaptation to human-altered habitats within the native range can promote invasions

PubMed Central

Hufbauer, Ruth A; Facon, Benoît; Ravigné, Virginie; Turgeon, Julie; Foucaud, Julien; Lee, Carol E; Rey, Olivier; Estoup, Arnaud

2012-01-01

Adaptive evolution is currently accepted as playing a significant role in biological invasions. Adaptations relevant to invasions are typically thought to occur either recently within the introduced range, as an evolutionary response to novel selection regimes, or within the native range, because of long-term adaptation to the local environment. We propose that recent adaptation within the native range, in particular adaptations to human-altered habitat, could also contribute to the evolution of invasive populations. Populations adapted to human-altered habitats in the native range are likely to increase in abundance within areas frequented by humans and associated with human transport mechanisms, thus enhancing the likelihood of transport to a novel range. Given that habitats are altered by humans in similar ways worldwide, as evidenced by global environmental homogenization, propagules from populations adapted to human-altered habitats in the native range should perform well within similarly human-altered habitats in the novel range. We label this scenario ‘Anthropogenically Induced Adaptation to Invade’. We illustrate how it differs from other evolutionary processes that may occur during invasions, and how it can help explain accelerating rates of invasions. PMID:25568032

The effects of timing of grazing on plant and arthropod communities in high-elevation grasslands.

PubMed

Davis, Stacy C; Burkle, Laura A; Cross, Wyatt F; Cutting, Kyle A

2014-01-01

Livestock grazing can be used as a key management tool for maintaining healthy ecosystems. However, the effectiveness of using grazing to modify habitat for species of conservation concern depends on how the grazing regime is implemented. Timing of grazing is one grazing regime component that is less understood than grazing intensity and grazer identity, but is predicted to have important implications for plant and higher trophic level responses. We experimentally assessed how timing of cattle grazing affected plant and arthropod communities in high-elevation grasslands of southwest Montana to better evaluate its use as a tool for multi-trophic level management. We manipulated timing of grazing, with one grazing treatment beginning in mid-June and the other in mid-July, in two experiments conducted in different grassland habitat types (i.e., wet meadow and upland) in 2011 and 2012. In the upland grassland experiment, we found that both early and late grazing treatments reduced forb biomass, whereas graminoid biomass was only reduced with late grazing. Grazing earlier in the growing season versus later did not result in greater recovery of graminoid or forb biomass as expected. In addition, the density of the most ubiquitous grassland arthropod order (Hemiptera) was reduced by both grazing treatments in upland grasslands. A comparison of end-of-season plant responses to grazing in upland versus wet meadow grasslands revealed that grazing reduced graminoid biomass in the wet meadow and forb biomass in the upland, irrespective of timing of grazing. Both grazing treatments also reduced end-of-season total arthropod and Hemiptera densities and Hemiptera biomass in both grassland habitat types. Our results indicate that both early and late season herbivory affect many plant and arthropod characteristics in a similar manner, but grazing earlier may negatively impact species of conservation concern requiring forage earlier in the growing season.

Species-abundance--seed-size patterns within a plant community affected by grazing disturbance.

PubMed

Wu, Gao-lin; Shang, Zhan-huan; Zhu, Yuan-jun; Ding, Lu-ming; Wang, Dong

2015-04-01

Seed size has been advanced as a key factor that influences the dynamics of plant communities, but there are few empirical or theoretical predictions of how community dynamics progress based on seed size patterns. Information on the abundance of adults, seedlings, soil seed banks, seed rains, and the seed mass of 96 species was collected in alpine meadows of the Qinghai-Tibetan Plateau (China), which had different levels of grazing disturbance. The relationships between seed-mass-abundance patterns for adults, seedlings, the soil seed bank, and seed rain in the plant community were evaluated using regression models. Results showed that grazing levels affected the relationship between seed size and abundance properties of adult species, seedlings, and the soil seed bank, suggesting that there is a shift in seed-size--species-abundance relationships as a response to the grazing gradient. Grazing had no effect on the pattern of seed-size-seed-rain-abundance at four grazing levels. Grazing also had little effect on the pattern of seed-size--species-abundance and pattern of seed-size--soil-seed-bank-abundance in meadows with no grazing, light grazing, and moderate grazing), but there was a significant negative effect in meadows with heavy grazing. Grazing had little effect on the pattern of seed-size--seedling-abundance with no grazing, but had significant negative effects with light, moderate, and heavy grazing, and the |r| values increased with grazing levels. This indicated that increasing grazing pressure enhanced the advantage of smaller-seeded species in terms of the abundances of adult species, seedlings, and soil seed banks, whereas only the light grazing level promoted the seed rain abundance of larger-seeded species in the plant communities. This study suggests that grazing disturbances are favorable for increasing the species abundance for smaller-seeded species but not for the larger-seeded species in an alpine meadow community. Hence, there is a clear advantage of the smaller-seeded species over the larger-seeded species with increases in the grazing level.

AmeriFlux US-ARc ARM Southern Great Plains control site- Lamont

DOE Data Explorer

Torn, Margaret [Lawrence Berkeley National Laboratory

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site US-ARc ARM Southern Great Plains control site- Lamont. Site Description - The ARM SGP Control site is located in the native tallgrass prairies of the USDA Grazinglands Research Laboratory near El Reno, OK. One of two adjacent 35 ha plots with identical towers, measurements at the US-ARc unburned plot are used as the experimental control. The second plot, US-Arb, was burned on 2005/03/08. Measurement comparisons between the control and burn plot are used to address questions regarding the effects of burning activities on carbon fluxes. The region evaded burning activities for at least 15 years. Current disturbances consist of only light grazing activities.

Streambank response to simulated grazing

Treesearch

Warren P. Clary; John W. Kinney

2000-01-01

Simulated grazing techniques were used to investigate livestock impacts on structural characteristics of streambanks. The treatments consisted of no grazing, moderate early summer grazing, moderate mid summer grazing, and heavy season-long grazing. The heavy season-long treatment resulted in a 11.5 cm depression of the streambank surface, while the moderate treatments...

25 CFR 167.11 - Tenure of grazing permits.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Tenure of grazing permits. (a) All active regular grazing permits shall be for one year and shall be... § 167.8 may become a livestock operator by obtaining an active grazing permit through negotiability or... handle each matter of unused grazing permit or portions of grazing permits on individual merits. Where...

Effect of Grazing on Plant Attributes and Hydrological Properties in the Sloping Lands of the East African Highlands

NASA Astrophysics Data System (ADS)

Taddese, Girma; Saleem, M. A. Mohamed; Astatke, Abyie; Ayaleneh, Wagnew

2002-09-01

Extending livestock grazing to the steep slopes has led to unstable grazing systems in the East African Highlands, and new solutions and approaches are needed to ameliorate the current situation. This work was aimed at studying the effect of livestock grazing on plant attributes and hydrological properties. The study was conducted from 1996 to 2000 at the International Livestock Research Institute at Debre Ziet Research Station. Two sites were selected: one at 0-4% slope, and the other at 4-8% slope. The treatments were: (1) no grazing (control); (2) light grazing, 0.6 animal unit months per hectare (aum/ha); (3) moderate grazing, 1.8 aum/ha; (4) heavy grazing, 3.0 aum/ha; (5) very heavy grazing, 4.2 aum/ha; (6) initially plowed and continuously very heavily grazed, 4.2 aum/ha. The result showed that species richness, infiltration rate, bare ground, and soil loss significantly varied with grazing pressure. Species richness was higher in grazed plots compared to nongrazed plots. Biomass yield improved on heavily grazed plots as cow dung accumulated over years. Cynodon dactylon plant species persisted with livestock grazing pressure in both sites. Infiltration rate improved and soil erosion declined in all treatments after the first year.

Expansion of deciduous tall shrubs but not evergreen dwarf shrubs inhibited by reindeer in Scandes mountain range.

PubMed

Vowles, Tage; Gunnarsson, Bengt; Molau, Ulf; Hickler, Thomas; Klemedtsson, Leif; Björk, Robert G

2017-11-01

One of the most palpable effects of warming in Arctic ecosystems is shrub expansion above the tree line. However, previous studies have found that reindeer can influence plant community responses to warming and inhibit shrubification of the tundra.We revisited grazed (ambient) and ungrazed study plots (exclosures), at the southern as well as the northern limits of the Swedish alpine region, to study long-term grazing effects and vegetation changes in response to increasing temperatures between 1995 and 2011, in two vegetation types (shrub heath and mountain birch forest).In the field layer at the shrub heath sites, evergreen dwarf shrubs had increased in cover from 26% to 49% but were unaffected by grazing. Deciduous dwarf and tall shrubs also showed significant, though smaller, increases over time. At the birch forest sites, the increase was similar for evergreen dwarf shrubs (20-48%) but deciduous tall shrubs did not show the same consistent increase over time as in the shrub heath.The cover and height of the shrub layer were significantly greater in exclosures at the shrub heath sites, but no significant treatment effects were found on species richness or diversity.July soil temperatures and growing season thawing degree days (TDD) were higher in exclosures at all but one site, and there was a significant negative correlation between mean shrub layer height and soil TDD at the shrub heath sites. Synthesis . This study shows that shrub expansion is occurring rapidly in the Scandes mountain range, both above and below the tree line. Tall, deciduous shrubs had benefitted significantly from grazing exclosure, both in terms of cover and height, which in turn lowered summer soil temperatures. However, the overriding vegetation shift across our sites was the striking increase in evergreen dwarf shrubs, which were not influenced by grazing. As the effects of an increase in evergreen dwarf shrubs and more recalcitrant plant litter may to some degree counteract some of the effects of an increase in deciduous tall shrubs, herbivore influence on shrub interactions is potentially of great importance for shaping arctic shrub expansion and its associated ecosystem effects.

The detectability of nitrous oxide mitigation efficacy in intensively grazed pastures using a multiple-plot micrometeorological technique

NASA Astrophysics Data System (ADS)

McMillan, A. M. S.; Harvey, M. J.; Martin, R. J.; Bromley, A. M.; Evans, M. J.; Mukherjee, S.; Laubach, J.

2014-05-01

Methodologies are required to verify agricultural greenhouse gas mitigation at scales relevant to farm management. Micrometeorological techniques provide a viable approach for comparing fluxes between fields receiving mitigation treatments and control fields. However, they have rarely been applied to spatially verifying treatments aimed at mitigating nitrous oxide emission from intensively grazed pastoral systems. We deployed a micrometeorological system to compare N2O flux among several ~1.5 ha plots in intensively grazed dairy pasture. The sample collection and measurement system is referred to as the Field-Scale Nitrous Oxide Mitigation Assessment System (FS-NOMAS) and used a tuneable diode laser absorption spectrometer to measure N2O gradients to high precision at four locations along a 300 m transect. The utility of the FS-NOMAS to assess mitigation efficacy depends largely on its ability to resolve very small vertical N2O gradients. The performance of the FS-NOMAS was assessed in this respect in laboratory and field-based studies. The FS-NOMAS could reliably resolve gradients of 0.039 ppb between a height of 0.5 and 1.0 m. The gradient resolution achieved corresponded to the ability to detect an inter-plot N2O flux difference of 26 μg N2O-N m-2 h-1 under the most commonly encountered conditions of atmospheric mixing (quantified here by a turbulent transfer coefficient), but this ranged from 11 to 59 μg N2O-N m-2 h-1 as the transfer coefficient ranged between its 5th and 95th percentile. Assuming a likely value of 100 μg N2O-N m-2 h-1 for post-grazing N2O fluxes from intensively grazed New Zealand dairy pasture, the system described here would be capable of detecting a mitigation efficacy of 26% for a single (40 min) comparison. We demonstrate that the system has considerably greater sensitivity to treatment effects by measuring cumulative fluxes over extended periods.

The detectability of nitrous oxide mitigation efficacy in intensively grazed pastures using a multiple plot micrometeorological technique

NASA Astrophysics Data System (ADS)

McMillan, A. M. S.; Harvey, M. J.; Martin, R. J.; Bromley, A. M.; Evans, M. J.; Mukherjee, S.; Laubach, J.

2013-10-01

Methodologies are required to verify agricultural greenhouse gas mitigation at scales relevant to farm management. Micrometeorological techniques provide a viable approach for comparing fluxes between fields receiving mitigation treatments and control fields. However, they have rarely been applied to spatially verifying treatments aimed at mitigating nitrous oxide emission from intensively grazed pastoral systems. We deployed a micrometeorological system to compare N2O flux among several ~ 1.5 ha plots in intensively grazed dairy pasture. The sample collection and measurement system is referred to as the Field-Scale Nitrous Oxide Mitigation Assessment System (FS-NOMAS) and used a tuneable diode laser absorption spectrometer to measure N2O gradients to high precision at four locations along a 300 m transect. The utility of the FS-NOMAS to assess mitigation efficacy depends largely on its ability to resolve very small vertical N2O gradients. The performance of the FS-NOMAS was assessed in this respect in laboratory and field-based studies. The FS-NOMAS could reliably resolve gradients of 0.039 ppb between a height of 0.5 m and 1.0 m. The gradient resolution achieved corresponded to the ability to detect an inter-plot N2O flux difference of 26.4 μg N2O-N m-2 h-1 under the most commonly encountered conditions of atmospheric mixing (quantified here by a turbulent transfer coefficient), but this ranged from 11 to 59 μg N2O-N m-2 h-1 as the transfer coefficient ranged between its 5th and 95th percentile. Assuming a likely value of 100 μg N2O-N m-2 h-1 for post-grazing N2O fluxes from intensively grazed New Zealand dairy pasture, the system described here would be capable of detecting a mitigation efficacy of 26% for a single (40 min) comparison. We demonstrate that the system has considerably greater sensitivity to treatment effects by measuring cumulative fluxes over extended periods.

Effects of elk herbivory on vegetation and nitrogen processes

USGS Publications Warehouse

Schoenecker, Kathryn A.; Singer, Francis J.; Zeigenfuss, Linda C.; Binkley, Dan; Menezes, Romulo S.C.

2004-01-01

We used 35-year and 4-year ungulate exclosures to determine the effects of elk (Cervus elaphus) herbivory on above-ground and below-ground production and soil fertility on the elk winter range in Rocky Mountain National Park (RMNP), Colorado, USA. We used paired grazed and ungrazed plots to evaluate ungulate herbivory effects in short and tall willow (Salix spp.), aspen (Populus spp.), and upland grass/shrub vegetation associations. We measured nitrogen (N) fluxes (litter deposition, fecal and urinary deposition from elk, movements of N by elk, N mineralization, soil N availability, elk consumption rates) within the elk winter, above-ground and below-ground N pools (herbaceous, shrub and root biomass, %N in plants, roots, and soil), and N fluxes on and off the elk winter range (seasonal movement of N by elk). Nitrogen mineralization and soil nitrate (NO3) pools were reduced in the short willow community (P = 0.07 and 0.10, respectively; n = 4 sites) in grazed plots, but not in the upland grass/shrub community or tall willow sites (P >0.10). Annual growth of willows was reduced by 98% in grazed plots, relative to 35-year exclosures, and 66% relative to 4-year exclosures. Thus, height, canopy size, and litter biomass of willows were reduced, and N yield of willows was 64% less in grazed plots. We evaluated movement of N by elk among 6 major vegetation associations and found that elk grazed more and bedded less in willow vegetation association compared to mixed conifer, mesic meadow, and grassland/shrub associations (P = 0.014, 0.001, and 0.026, respectively), suggesting that elk herbivory and movement led to a net loss of N in the willow vegetation association. Elk spent less total time in willows than mesic meadow association, yet they consumed large amounts of willow plant biomass. We recommend management of elk numbers and elk herbivory that takes into consideration impacts to N process function, as negative effects from current levels of herbivory were observed in ≥1 of 3 vegetation associations studied.

Animal responses to herbage allowance: Forage intake and body weight gain of sheep grazing the Inner Mongolian steppe - Results of a six-year study.

PubMed

Dickhoefer, U; Bösing, B M; Hasler, M; Hao, J; Lin, L; Müller, K; Wang, C; Glindemann, T; Tas, B; Gierus, M; Taube, F; Susenbeth, A

2016-05-01

An increasing human population and the growing demand for food of animal origin are leading to an intensification of sheep production and widespread overgrazing of the grassland steppe in Inner Mongolia. The aim of this study was to analyze the effect of herbage allowance (HA) on OM intake (OMI) and BW gain (BWG) of grazing sheep. In July to September 2005 to 2010, a grazing experiment was conducted in the Xilin River Basin using 15-mo-old female Mongolian fat-tailed sheep (31.5 kg BW [SE 0.2]). Six HA classes were tested on 4 experimental plots per HA class that were alternately used for grazing and haymaking each year (i.e., = 2 grazed plots per HA class and year). Mean HA ranged from 15.4 (SD 4.0) to 1.5 kg (SD 0.8) herbage DM/kg BW in HA class 1 to 6, respectively. In 6 sheep per plot (4 sheep in 2009 and 2010), OMI and BWG were determined. Titanium dioxide was used to determine fecal excretion, and digestibility of ingested OM was estimated from CP concentration in feces. Fecal grab samples were collected during 5 d each in July, August, and September. The animals were weighed monthly. Daily OMI of sheep ranged between 68 and 89 g/kg BW and was not affected by HA class ( = 0.373), so that total OMI per hectare was exponentially decreased with increasing HA (root mean square error [RMSE] ≤ 0.31 g/d; ≤ 0.003 for the slope estimates). The BWG of individual sheep increased with increasing HA in 2 of the 6 yr (RMSE 18.4 g/d; ≤ 0.175 for the positive slope estimates). Nevertheless, BWG per hectare strongly decreased with increasing HA (RMSE 0.25 g/d; ≤ 0.006 for the slope estimates). These data support the common practice of farmers to manage the grassland at low HA to allow for greater animal performance per unit of land area.

Transhumant Ranchers in California

NASA Astrophysics Data System (ADS)

Sulak, A.; Forero, L.; Huntsinger, L.

2009-04-01

There is a strong link between some of the richest, most productive lands of the western United States, including California's oak woodlands, and the traditional "transhumance" of ranchers using public ranges. Oak woodland ranchers with government grazing leases report that about half of their income stems from using government -owned montane ranges. For many, loss of these leases reduces their ranch productive capacity to a level insufficient for sustainability, augmenting the sale of ranch lands for development. Many thousands of hectares of oak woodlands are linked to the fate of government leases in this way, and this linkage limits the opportunities for conservation of oak woodlands as "working landscapes" via conservation easements. This type of conservation is the fastest growing type in California today. The first case study shows that over the past 100 years there has been a reduction in access to the natural resources needed for transhumance from three sources: competition from use of the pastures for recreation and nature preservation, management practices that have brought about change in the character of the natural resources themselves, and urban sprawl. Ranchers are leasing other properties, purchasing feed, and transporting animals to other regions to compensate. Most had increased their privately leased land over the previous five years. Though they desire to stay on their ranches, transhumant ranching is becoming increasingly difficult because of land use changes on both public and private lands and a third of ranchers believe that they may need to sell the property for development if they lose their summer permits. There are many "line camps" on Forest Service range—cabins that families or workers would stay in during the summer to tend the cattle. However, the need to support the ranch with work in town limits the ability of the household to participate in transhumance or even travel into the mountains to check on the animals. For ranching to continue, mobility is one of several key factors, but as this case study demonstrates there are many obstacles facing ranchers who need to move their cattle from winter to summer forage. In the second case study many similar factors are operating to suppress transhumance, including fire suppression and stocking reductions. Change in land use, with the construction of a major reservoir on grazing lands, also reduced grazing on the National Forest. Family demographics, with more ranchers working off ranch, were becoming an important factor making transhumance more difficult. As in the first study, regulations were emphasized by some ranchers as a problem, and regulations and economic factors were the main reason former permit holders had given up their permits. The case studies reveal that factors constraining and reducing grazing on transhumance range are fundamentally linked to insecurity of tenure on high elevation range, loss of grazing capacity from vegetation change as traditional management methods are forbidden, development and land use change as the surrounding society encroaches into pastoral areas and other uses take priority on public lands, and changes in family economy and goals. The publically owned range upon which transhumance depends are no longer managed to maintain open lands and grazing areas, and traditional ranch practices like burning vegetation have been suppressed. Goals for these lands have changed away from grazing, as the majority society seeks other things from public lands, and increased regulation reduces grazing flexibility and available forage. As more members of ranch families work longer off the ranch, they are less able to spend summer tending stock in the mountains. Development and land use change not only affect ranchers in general, reducing the amount of forage, displacing infrastructure, and making traditional practices more difficult, these factors seem to affect transhumant ranchers more than those who are more sedentary. Transhumant ranchers have been using rangelands longer, and are more committed to the traditions of pastoralism, than more sedentary pastoralists. Ranchers in general seek to acquire more access to forage through leasing additional lands from a variety of sources. As is apparent from the case studies, many ranchers lease land from private landowners. Ironically these may be properties in transition to development, or ranches where the heirs or owners do not want to engage in ranching directly. But there is more than just a forage base that is needed for ranch production--there is also an infrastructural base that is needed. This may be termed a "critical mass" (Huntsinger and Hopkinson, 1996). Ranchers need the community of ranchers for both what we might call loosely "cultural support," but also for labor needs during particular times of the year (Liffmann et al. 2000). The sale of each range hastens the sale of the next, creating a feedback loop that results in the conversion of wooded lands to housing and urban development.

Are invasive plants more competitive than native conspecifics? Patterns vary with competitors

PubMed Central

Zheng, Yulong; Feng, Yulong; Valiente-Banuet, Alfonso; Li, Yangping; Liao, Zhiyong; Zhang, Jiaolin; Chen, Yajun

2015-01-01

Invasive plants are sometimes considered to be more competitive than their native conspecifics, according to the prediction that the invader reallocates resources from defense to growth due to liberation of natural enemies [‘Evolution of Increased Competitive Ability’ (EICA) hypothesis]. However, the differences in competitive ability may depend on the identity of competitors. In order to test the effects of competitors, Ageratina adenophora plants from both native and invasive ranges competed directly, and competed with native residents from both invasive (China) and native (Mexico) ranges respectively. Invasive A. adenophora plants were more competitive than their conspecifics from native populations when competing with natives from China (interspecific competition), but not when competing with natives from Mexico. Invasive A. adenophora plants also showed higher competitive ability when grown in high-density monoculture communities of plants from the same population (intrapopulation competition). In contrast, invasive A. adenophora plants showed lower competitive ability when competing with plants from native populations (intraspecific competition). Our results indicated that in the invasive range A. adenophora has evolved to effectively cope with co-occurring natives and high density environments, contributing to invasion success. Here, we showed the significant effects of competitors, which should be considered carefully when testing the EICA hypothesis. PMID:26489964

The Imperial Valley of California is critical to wintering Mountain Plovers

USGS Publications Warehouse

Wunder, Michael B.; Knopf, F.L.

2003-01-01

We surveyed Mountain Plovers (Charadrius montanus) wintering in the Imperial Valley of California in January 2001, and also recorded the types of crop fields used by plovers in this agricultural landscape. We tallied 4037 plovers in 36 flocks ranging in size from 4 to 596 birds. Plovers were more common on alfalfa and Bermudagrass fields than other field types. Further, most birds were on alfalfa fields that were currently being (or had recently been) grazed, primarily by domestic sheep. Plovers used Bermudagrass fields only after harvest and subsequent burning. Examination of Christmas Bird Count data from 1950–2000 indicated that the Mountain Plover has abandoned its historical wintering areas on the coastal plains of California. Numbers in the Central Valley seem to have undergone recent declines also. We believe that the cultivated landscape of the Imperial Valley provides wintering habitats for about half of the global population of Mountain Plovers. We attribute the current importance of the Imperial Valley for Mountain Plovers to loss of native coastal and Central Valley habitats rather than to a behavioral switching of wintering areas through time. Future changes in specific cropping or management practices in the Imperial Valley will have a major impact on the conservation status of this species.

Ecological Catastrophes and Disturbance Relicts: A Case Study from Easter Island

NASA Astrophysics Data System (ADS)

Wynne, J.

2014-12-01

Caves are often considered buffered environments in terms of their ability to sustain near constant microclimatic conditions. However, environments within cave entrances are expected to respond most quickly to changing surface conditions. We cataloged a relict assemblage of at least 10 endemic arthropods likely restricted to caves and occurring primarily within cave entranceways. Of these animals, eight were considered new undescribed species. These endemic arthropods have persisted in Rapa Nui (Easter Island) caves despite a catastrophic ecological shift induced by island-wide deforestation, fire intolerance, and drought, as well as intensive livestock grazing and surface ecosystems dominated by invasive species. We consider these animals to be "disturbance relicts" - species whose distributions are now limited to areas that experienced minimal human disturbance historically. Today, these species represent one-third of the Rapa Nui's known endemic arthropods. Given the island's severely depauperate native fauna, these arthropods should be considered among the highest priority targets for biological conservation. In other regions globally, epigean examples of imperiled disturbance relicts persisting within narrow distributional ranges have been documented. As human activity intensifies, and habitat loss and fragmentation continues worldwide, additional disturbance relicts will be identified. We expect extinction debts, global climate change and interactions with invasive species will challenge the persistence of both hypogean and epigean disturbance relict species.

Sustainability of meat production beyond carbon footprint: a synthesis of case studies from grazing systems in Uruguay.

PubMed

Picasso, Valentín D; Modernel, Pablo D; Becoña, Gonzalo; Salvo, Lucía; Gutiérrez, Lucía; Astigarraga, Laura

2014-11-01

Livestock production has been challenged as a large contributor to climate change, and carbon footprint has become a widely used measure of cattle environmental impact. This analysis of fifteen beef grazing systems in Uruguay quantifies the range of variation of carbon footprint, and the trade-offs with other relevant environmental variables, using a partial life cycle assessment (LCA) methodology. Using carbon footprint as the primary environmental indicator has several limitations: different metrics (GWP vs. GTP) may lead to different conclusions, carbon sequestration from soils may drastically affect the results, and systems with lower carbon footprint may have higher energy use, soil erosion, nutrient imbalance, pesticide ecotoxicity, and impact on biodiversity. A multidimensional assessment of sustainability of meat production is therefore needed to inform decision makers. There is great potential to improve grazing livestock systems productivity while reducing carbon footprint and other environmental impacts, and conserving biodiversity. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Marshall Grazing Incidence X-ray Spectrometer

NASA Astrophysics Data System (ADS)

Kobayashi, Ken; Winebarger, Amy R.; Savage, Sabrina; Champey, Patrick; Cheimets, Peter N.; Hertz, Edward; Bruccoleri, Alexander R.; Golub, Leon; Ramsey, Brian; Ranganathan, Jaganathan; Marquez, Vanessa; Allured, Ryan; Parker, Theodore; Heilmann, Ralf K.; Schattenburg, Mark L.

2017-08-01

The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) is a NASA sounding rocket instrument designed to obtain spatially resolved soft X-ray spectra of the solar atmosphere in the 6-24 Å (0.5-2.0 keV) range. The instrument consists of a single shell Wolter Type-I telescope, a slit, and a spectrometer comprising a matched pair of grazing incidence parabolic mirrors and a planar varied-line space diffraction grating. The instrument is designed to achieve a 50 mÅ spectral resolution and 5 arcsecond spatial resolution along a +/-4-arcminute long slit, and launch is planned for 2019. We report on the status and our approaches for fabrication and alignment for this novel optical system. The telescope and spectrometer mirrors are replicated nickel shells, and are currently being fabricated at the NASA Marshall Space Flight Center. The diffraction grating is currently under development by the Massachusetts Institute of Technology (MIT); because of the strong line spacing variation across the grating, it will be fabricated through e-beam lithography.

Influence of fresh alfalfa supplementation on fat skatole and indole concentration and chop odour and flavour in lambs grazing a cocksfoot pasture.

PubMed

Devincenzi, T; Prunier, A; Meteau, K; Nabinger, C; Prache, S

2014-12-01

We investigated the influence of the level of fresh alfalfa supplementation on fat skatole and indole concentration and chop sensory attributes in grazing lambs. Four groups of nine male Romane lambs grazing a cocksfoot pasture were supplemented with various levels of alfalfa for at least 60days before slaughter. Perirenal fat skatole concentration was higher for lambs that consumed alfalfa than for those that consumed only cocksfoot. The intensity of 'animal' odour in the lean part of the chop and of 'animal' flavour in both the lean and fat parts of the chop, evaluated by a trained sensory panel, increased from the lowest level of alfalfa supplementation onwards and did not increase further with increasing levels of alfalfa supplementation. The outcome of this study therefore suggests that these sensory attributes may reach a plateau when perirenal fat skatole concentration is in the range 0.16-0.24μg/g of liquid fat. Copyright © 2014. Published by Elsevier Ltd.

Efficiency of a Grazing-incidence Off-plane Grating in the Soft-x-ray Region

NASA Technical Reports Server (NTRS)

Seely, J. F.; Laming, J. M.; Goray, L. I.; Kjornrattanawanich, B.; Holland, G. E.; Flanagan, K. A.; Heilmann, R. K.; Chang, C.-H.; Schattenburg, M. L.; Rasmussen, A. P.

2006-01-01

Efficiency measurements of a grazing-incidence diffraction grating in the off-plane mount were performed using polarized synchrotron radiation. The grating had 5000 grooves/mm, an effective blaze angle of 14 deg., and was gold coated. The efficiencies in the two polarization orientations (TM and TE) were measured in the 1.5-5.O nm wavelength range and were compared with the efficiencies calculated using the PCGrate-SX code. The TM and TE efficiencies differ, offering the possibility of performing unique science studies of astrophysical, solar, and laboratory sources by exploiting the polarization sensitivity of the off-plane grating.

European Invasion of North American Pinus strobus at Large and Fine Scales: High Genetic Diversity and Fine-Scale Genetic Clustering over Time in the Adventive Range

PubMed Central

Mandák, Bohumil; Hadincová, Věroslava; Mahelka, Václav; Wildová, Radka

2013-01-01

Background North American Pinus strobus is a highly invasive tree species in Central Europe. Using ten polymorphic microsatellite loci we compared various aspects of the large-scale genetic diversity of individuals from 30 sites in the native distribution range with those from 30 sites in the European adventive distribution range. To investigate the ascertained pattern of genetic diversity of this intercontinental comparison further, we surveyed fine-scale genetic diversity patterns and changes over time within four highly invasive populations in the adventive range. Results Our data show that at the large scale the genetic diversity found within the relatively small adventive range in Central Europe, surprisingly, equals the diversity found within the sampled area in the native range, which is about thirty times larger. Bayesian assignment grouped individuals into two genetic clusters separating North American native populations from the European, non-native populations, without any strong genetic structure shown over either range. In the case of the fine scale, our comparison of genetic diversity parameters among the localities and age classes yielded no evidence of genetic diversity increase over time. We found that SGS differed across age classes within the populations under study. Old trees in general completely lacked any SGS, which increased over time and reached its maximum in the sapling stage. Conclusions Based on (1) the absence of difference in genetic diversity between the native and adventive ranges, together with the lack of structure in the native range, and (2) the lack of any evidence of any temporal increase in genetic diversity at four highly invasive populations in the adventive range, we conclude that population amalgamation probably first happened in the native range, prior to introduction. In such case, there would have been no need for multiple introductions from previously isolated populations, but only several introductions from genetically diverse populations. PMID:23874648

Influence of livestock grazing on C sequestration in semi-arid mixed-grass and short-grass rangelands

Treesearch

J.D. Reeder; G.E. Schuman

2001-01-01

We evaluated the effects of livestock grazing on C content of the plant-soil system (to 60 cm) of two semi-arid grasslands: a mixed-grass prairie (grazed 12 years), and a short-grass steppe (grazed 56 years). Grazing treatments included season-long grazing at heavy and light stocking rates, and non-grazed exclosures. Significantly higher soil C (0-30cm) was measured in...

Research issues in grazing lands under changing climate. Volume 12, Part 16. Environmental and societal consequences of a possible CO/sub 2/-induced climate change

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pendleton, D.F.; Van Dyne, G.M.

1982-12-01

A study has been made of issues and researchable questions regarding the influence of potential CO/sub 2/-induced climatic change on grazing lands. Generalized scenarios of possible changes in climate in grazing land regions of the world were constructed based on published and ongoing investigations. These studies were of two general types: (i) general circulation climate, and (ii) analyses of historical data for periods which were warmer than average current conditions, based on the assumption that global warming can be expected. A review of scenarios derived from recent research suggests that surface temperature may increase and precipitation may decrease in somemore » important grazing land regions of the world. Research needs related specifically to climate in grazing lands were discussed. In the second workship, scientists discussed individual abiotic, autotrophic, and heterotrophic processes. Potential studies of these processes which were discussed included (i) work in the laboratory and the field, (ii) modelling, and (iii) analysis and synthesis of existing data bases and scientific literature. Both biological and socio-economic issues were discussed. Several overall conclusions were derived including the following: a planned, time-phased, and integrated study would be desirable to obtain the greatest amount of information for the least amount of funding in future investigations; a relatively small interdisciplinary group should be assembled consisting of individuals with backgrounds in such areas as meteorology, plant ecology, animal ecology, range science, economics, sociology, and systems analysis, and should operate over perhaps 10 years and draw upon specific short-term contractual inputs.« less

Variations in Ixodes ricinus density and Borrelia infections associated with cattle introduced into a woodland in The Netherlands.

PubMed

Gassner, Fedor; Verbaarschot, Patrick; Smallegange, Renate C; Spitzen, Jeroen; Van Wieren, Sipke E; Takken, Willem

2008-12-01

The effect of introduced large herbivores on the abundance of Ixodes ricinus ticks and their Borrelia infections was studied in a natural woodland in The Netherlands. Oak and pine plots, either ungrazed or grazed by cattle, were selected. Ticks were collected weekly by blanket dragging. Borrelia infections were determined by PCR and restriction fragment length polymorphism. Rodent densities were estimated using mark-release-recapture methods. On occasion, the cattle were inspected for tick infestations. Meteorological data were recorded for each habitat. Significantly more ticks were collected in the ungrazed woodland than in the grazed woodland. The ungrazed oak habitat had higher tick densities than the pine habitat, while in the grazed habitats, tick densities were similar. Borrelia infection rates ranged from zero in larvae to 26% in nymphs to 33% in adult ticks, and B. afzelii, B. burgdorferi sensu stricto, B. garinii, and B. valaisiana were the species involved. Coinfections were found in five ticks. There was no effect of the presence of cattle on Borrelia infections in the ticks. In the ungrazed area, Borrelia infections in nymphs were significantly higher in the oak habitat than in the pine habitat. More mice were captured in the ungrazed area, and these had a significantly higher tick burden than mice from the grazed area. Tick burden on cattle was low. The results suggest that grazing has a negative effect on small rodents as well as on ticks but not on Borrelia infections. Implications of these results for management of woodland reserves and risk of Lyme disease are discussed.

Variations in Ixodes ricinus Density and Borrelia Infections Associated with Cattle Introduced into a Woodland in The Netherlands▿ †

PubMed Central

Gassner, Fedor; Verbaarschot, Patrick; Smallegange, Renate C.; Spitzen, Jeroen; Van Wieren, Sipke E.; Takken, Willem

2008-01-01

The effect of introduced large herbivores on the abundance of Ixodes ricinus ticks and their Borrelia infections was studied in a natural woodland in The Netherlands. Oak and pine plots, either ungrazed or grazed by cattle, were selected. Ticks were collected weekly by blanket dragging. Borrelia infections were determined by PCR and restriction fragment length polymorphism. Rodent densities were estimated using mark-release-recapture methods. On occasion, the cattle were inspected for tick infestations. Meteorological data were recorded for each habitat. Significantly more ticks were collected in the ungrazed woodland than in the grazed woodland. The ungrazed oak habitat had higher tick densities than the pine habitat, while in the grazed habitats, tick densities were similar. Borrelia infection rates ranged from zero in larvae to 26% in nymphs to 33% in adult ticks, and B. afzelii, B. burgdorferi sensu stricto, B. garinii, and B. valaisiana were the species involved. Coinfections were found in five ticks. There was no effect of the presence of cattle on Borrelia infections in the ticks. In the ungrazed area, Borrelia infections in nymphs were significantly higher in the oak habitat than in the pine habitat. More mice were captured in the ungrazed area, and these had a significantly higher tick burden than mice from the grazed area. Tick burden on cattle was low. The results suggest that grazing has a negative effect on small rodents as well as on ticks but not on Borrelia infections. Implications of these results for management of woodland reserves and risk of Lyme disease are discussed. PMID:18836006

Larkspur (Delphinium spp.) poisoning in livestock.

PubMed

Pfister, J A; Gardner, D R; Panter, K E; Manners, G D; Ralphs, M H; Stegelmeier, B L; Schoch, T K

1999-02-01

Larkspurs (Delphinium spp.) are toxic plants that contain numerous diterpenoid alkaloids which occur as one of two structural types: (1) lycotonine, and (2) 7,8-methylenedioxylycoctonine (MDL-type). Among the lycoctonine type alkaloids are three N-(methylsuccinimido) anthranoyllycoctonine (MSAL-type) alkaloids which appear to be most toxic: methyllycaconitine (MLA), 14-deacetylnudicauline (DAN), and nudicauline. An ester function at C-18 is an important structural requirement for toxicity. Intoxication results from neuromuscular paralysis, as nicotinic acetylcholine receptors in the muscle and brain are blocked by toxic alkaloids. Clinical signs include labored breathing, rapid and irregular heartbeat, muscular weakness, and collapse. Toxic alkaloid concentration generally declines in tall larkspurs with maturation, but alkaloid concentration varies over years and from plant to plant, and is of little use for predicting consumption by cattle. Knowledge of toxic alkaloid concentration is valuable for management purposes when cattle begin to eat larkspur. Cattle generally begin consuming tall larkspur after flowering racemes are elongated, and consumption increases as larkspur matures. Weather is also a major factor in cattle consumption, as cattle tend to eat more larkspur during or just after summer storms. Management options that may be useful for livestock producers include conditioning cattle to avoid larkspur (food aversion learning), grazing tall larkspur ranges before flowering (early grazing) and after seed shatter (late grazing), grazing sheep before cattle, herbicidal control of larkspur plants, and drug therapy for intoxicated animals. Some potentially fruitful research avenues include examining alkaloid chemistry in low and plains larkspurs, developing immunologic methods for analyzing larkspur alkaloids, developing drug therapy, and devising grazing regimes specifically for low and plains larkspur.

Chinese tallow trees (Triadica sebifera) from the invasive range outperform those from the native range with an active soil community or phosphorus fertilization.

PubMed

Zhang, Ling; Zhang, Yaojun; Wang, Hong; Zou, Jianwen; Siemann, Evan

2013-01-01

Two mechanisms that have been proposed to explain success of invasive plants are unusual biotic interactions, such as enemy release or enhanced mutualisms, and increased resource availability. However, while these mechanisms are usually considered separately, both may be involved in successful invasions. Biotic interactions may be positive or negative and may interact with nutritional resources in determining invasion success. In addition, the effects of different nutrients on invasions may vary. Finally, genetic variation in traits between populations located in introduced versus native ranges may be important for biotic interactions and/or resource use. Here, we investigated the roles of soil biota, resource availability, and plant genetic variation using seedlings of Triadica sebifera in an experiment in the native range (China). We manipulated nitrogen (control or 4 g/m(2)), phosphorus (control or 0.5 g/m(2)), soil biota (untreated or sterilized field soil), and plant origin (4 populations from the invasive range, 4 populations from the native range) in a full factorial experiment. Phosphorus addition increased root, stem, and leaf masses. Leaf mass and height growth depended on population origin and soil sterilization. Invasive populations had higher leaf mass and growth rates than native populations did in fresh soil but they had lower, comparable leaf mass and growth rates in sterilized soil. Invasive populations had higher growth rates with phosphorus addition but native ones did not. Soil sterilization decreased specific leaf area in both native and exotic populations. Negative effects of soil sterilization suggest that soil pathogens may not be as important as soil mutualists for T. sebifera performance. Moreover, interactive effects of sterilization and origin suggest that invasive T. sebifera may have evolved more beneficial relationships with the soil biota. Overall, seedlings from the invasive range outperformed those from the native range, however, an absence of soil biota or low phosphorus removed this advantage.

Chinese Tallow Trees (Triadica sebifera) from the Invasive Range Outperform Those from the Native Range with an Active Soil Community or Phosphorus Fertilization

PubMed Central

Zhang, Ling; Zhang, Yaojun; Wang, Hong; Zou, Jianwen; Siemann, Evan

2013-01-01

Two mechanisms that have been proposed to explain success of invasive plants are unusual biotic interactions, such as enemy release or enhanced mutualisms, and increased resource availability. However, while these mechanisms are usually considered separately, both may be involved in successful invasions. Biotic interactions may be positive or negative and may interact with nutritional resources in determining invasion success. In addition, the effects of different nutrients on invasions may vary. Finally, genetic variation in traits between populations located in introduced versus native ranges may be important for biotic interactions and/or resource use. Here, we investigated the roles of soil biota, resource availability, and plant genetic variation using seedlings of Triadica sebifera in an experiment in the native range (China). We manipulated nitrogen (control or 4 g/m2), phosphorus (control or 0.5 g/m2), soil biota (untreated or sterilized field soil), and plant origin (4 populations from the invasive range, 4 populations from the native range) in a full factorial experiment. Phosphorus addition increased root, stem, and leaf masses. Leaf mass and height growth depended on population origin and soil sterilization. Invasive populations had higher leaf mass and growth rates than native populations did in fresh soil but they had lower, comparable leaf mass and growth rates in sterilized soil. Invasive populations had higher growth rates with phosphorus addition but native ones did not. Soil sterilization decreased specific leaf area in both native and exotic populations. Negative effects of soil sterilization suggest that soil pathogens may not be as important as soil mutualists for T. sebifera performance. Moreover, interactive effects of sterilization and origin suggest that invasive T. sebifera may have evolved more beneficial relationships with the soil biota. Overall, seedlings from the invasive range outperformed those from the native range, however, an absence of soil biota or low phosphorus removed this advantage. PMID:24023930

Does pulse-grazing influence within- and between-grazing season dietary quality of yearling steers in shortgrass steppe?

USDA-ARS?s Scientific Manuscript database

Pulse-grazing, high stock density with short grazing periods (weeks) followed by long (months to > 1 year) rest periods, is a grazing management strategy posited to decrease preferential selection by cattle and increase utilization of forage, but influences on dietary quality of grazing animals in s...

Effects of grazing intensity and chemical seedhead suppression on steers grazing tall fescue pastures

USDA-ARS?s Scientific Manuscript database

The first year of a 2 yr grazing study was conducted to evaluate use of Chaparral™ to suppress reproductive growth in tall fescue grazed with low and moderate grazing intensities. Chaparral applications (0 and 2.0 oz/acre) and grazing intensities were arranged as RCBD with three replications. Variab...