Livestock Exclusion Research Articles

Warming suppresses grassland recovery in biomass but not in community composition after grazing exclusion in a Mongolian grassland

We conducted a 4-year temperature manipulation experiment in a Mongolian grassland to examine the effect of daytime and nighttime warming on grassland recovery after grazing exclusion. After constructing a livestock exclusion fence in the grassland, we established daytime and daytime-and-nighttime warming treatments within the fenced area by a combination of open-top chambers (OTC) and electric heaters. We measured the numbers of plants and aboveground biomass by species after recording percentage vegetation cover every summer for three warming treatments inside the fence—non-warming, daytime warming, and daytime-and-nighttime warming—and for the grassland outside of the fence. OTCs increased daytime temperature by about 2.0 °C, and heaters increased nighttime temperature by 0.9 °C during the growing period. Grazing exclusion had little effect on grassland biomass but reduced the abundance of poorly palatable species and modified plant community composition. Daytime warming decreased soil moisture and lowered aboveground biomass within the fenced grassland but had little effect on plant community composition. Nighttime warming lowered soil moisture further but its effects on grassland biomass and community composition were undetectable. We concluded that recovery of plant biomass in grasslands degraded by grazing would be lowered by future climate warming through soil drying. Because warming had little effect on the recovery of community composition, adverse effects of warming on grassland recovery might be offset by improving plant productivity through mitigation of soil drying by watering. Soil drying due to nighttime warming might have detectable effects on vegetation when warming persists for a long time.

Rethinking livestock encroachment at a protected area boundary

The presence of livestock inside protected areas, or "livestock encroachment," is a global conservation concern because livestock is broadly thought to negatively affect wildlife. The Maasai Mara National Reserve (MMNR), Kenya, exemplifies this tension as livestock is believed to have resulted in the declining wildlife populations, contributing to the strict and sometimes violent exclusion measures targeting Maasai pastoralists. However, research embedded in the real-world setting that draws insights from the social-ecological contexts is lacking. In this study, we conducted 19 mo of ecological monitoring covering 60 sites in MMNR and found that cattle presence inside the reserve did not significantly impact most co-occurring wild herbivores at the current intensity. Using the Hierarchical Modeling of Species Communities and Gaussian copula graphic models, we showed that cattle had no direct associations-neither negative nor positive-with nearly all wild herbivores despite frequently sharing the same space. Moreover, we did not detect resource degradation correlated with cattle presence near the MMNR boundary. Given the colonial legacy and land use history of Mara, entering MMNR becomes the only viable option for many herders. These results corroborate the emerging perspective that the ecological impacts of extensively herded livestock on wildlife might be more nuanced than previously thought. To effectively balance the needs of people, livestock, and wildlife, the current rigid livestock exclusion measures need to be reassessed to holistically consider herbivore ecology, local land use history, and modern politics of protected area management.

Effects of livestock exclusion on the recruitment of cardón (Pachycereus pringlei, Cactaceae) in the south of the Baja California peninsula, Mexico

Antecedentes y Objetivos: El cardón (Pachycereus pringlei) es una cactácea columnar emblemática del Desierto Sonorense, región donde desde hace siglos la ganadería de libre pastoreo ha estado presente, tanto en la península de Baja California como en Sonora. Sin embargo, se desconoce el efecto que pueda tener en la dinámica poblacional del cardón. El objetivo de este estudio fue analizar si la exclusión al ganado por casi tres décadas tuvo algún efecto observable en la probabilidad de reclutamiento del cardón y en la relación de los nuevos reclutas con dos leguminosas nodrizas (Olneya tesota y Prosopis articulata). Métodos: Se registró la presencia y tamaño de cardones y de las dos leguminosas nodrizas en transectos. Estos distribuidos en dos condiciones, con ganado y exclusión de 27 años, en parcelas establecidas en un matorral árido del sur de la península de Baja California, México. Se analizó si existen diferencias entre ambas condiciones en (i) la probabilidad de reclutamiento del cardón y (ii) la asociación de los nuevos reclutas con las leguminosas nodrizas. Resultados clave: No se encontraron diferencias en la probabilidad de reclutamiento entre área con ganado y exclusión de ganado. Sin embargo, sí se observaron diferencias en la asociación de los cardones reclutados y las leguminosas nodrizas, siendo positiva en sitios con ganado y ausente en sitios con exclusión del mismo. Conclusiones: La falta de diferencias en la probabilidad de reclutamiento entre condiciones podría deberse a la influencia de procesos que actúan a escalas espacio-temporales mayores que las de nuestro estudio. Por ejemplo, la escala temporal, potencialmente multidecenal, de los pulsos de reclutamiento del cardón o la escala espacial de los rangos de actividad de polinizadores, dispersores y consumidores de semillas. Nuestros resultados subrayan la importancia de la escala espacio-temporal en el estudio de la dinámica de especies longevas en regiones áridas.

Exclusion of livestock decouples the relationship between plant production and diversity, species richness on complex topography in typical steppe in the Loess Plateau, China

Grazing is widely used in more than one-forth of global terrestrial ecosystems, with three quarters are distributed on complex topography. Grazing and topography have both resulted in degradation of approximately 49 % of natural grasslands. However, research on the interaction between topography and livestock exclusion on grassland characteristics is scarce. This study was carried out on a typical steppe to explore the effect of topography and enclosure year on vegetation characteristics. Aboveground biomass, and species richness were examined for three different enclosure years (0, 3, and 6 years), on four slopes (0°, 15°, 30°, and 45° slope), and three aspects (flat, shady and sunny). The results indicated that: The aboveground biomass on the 0° slope had a greater value after 6 years of the enclosure. Aboveground biomass increased with the increasing enclosure year, while it decreased with increasing slope except enclosure for 0 year on shady slope. Aboveground biomass on the shady slopes was greater than on the sunny slopes. Species richness of community and perennial plants increased with increasing slope and enclosure year. The annual plants richness inversely correlated with slope and enclosure year. All plant diversity indexes increased with increasing enclosure year. Margalef and Shannon-wiener indexes decreased with increasing slope, while Simpson and Pielou indexes increased. This paper demonstrates that aspect, slope and enclosure affect aboveground biomass by affecting other vegetation characteristics. In conclusion, grassland production can be improved with moderate livestock exclusion under different topography.

Channel Morphology Change after Restoration: Drone Laser Scanning versus Traditional Surveying Techniques

Accurate and precise measures of channel morphology are important when monitoring a stream post-restoration to determine changes in stability, water quality, and aquatic habitat availability. Practitioners often rely on traditional surveying methods such as a total station for measuring channel metrics (e.g., cross-sectional area, width, depth, and slope). However, these methods have limitations in terms of coarse sampling densities and time-intensive field efforts. Drone-based lidar or drone laser scanning (DLS) provides much higher resolution point clouds and has the potential to improve post-restoration monitoring efforts. For this study, a 1.3-km reach of Stroubles Creek (Blacksburg, VA, USA), which underwent a restoration in 2010, was surveyed twice with a total station (2010 and 2021) and twice with DLS (2017 and 2021). The initial restoration was divided into three treatment reaches: T1 (livestock exclusion), T2 (livestock exclusion and bank treatment), and T3 (livestock exclusion, bank treatment, and inset floodplain). Cross-sectional channel morphology metrics were extracted from the 2021 DLS scan and compared to metrics calculated from the 2021 total station survey. DLS produced 6.5 times the number of cross sections over the study reach and 8.8 times the number of points per cross section compared to the total station. There was good agreement between the metrics derived from both surveying methods, such as channel width (R2 = 0.672) and cross-sectional area (R2 = 0.597). As a proof of concept to demonstrate the advantage of DLS over traditional surveying, 0.1 m digital terrain models (DTMs) were generated from the DLS data. Based on the drone lidar data, from 2017 to 2021, treatment reach T3 showed the most stability, in terms of the least change and variability in cross-sectional metrics as well as the least erosion area and volume per length of reach.

Litter accumulation suppresses grass production but facilitates shrub expansion in a long‐term fenced grassland

AbstractShrub expansion is increasing in grasslands worldwide and has profound effects on biodiversity and ecosystem functions. Shrub expansion has primarily been explained by extrinsic factors such as climate change and human activities, yet the roles of intrinsic shrub demographic population dynamic and shrub–grass interaction remain poorly understood. With a paired mown and exclosure comparison experiment and baseline levels of shrub abundance in a semiarid grassland, we confirmed that long‐term livestock exclusion promotes expansion of two native shrubs, Artemisia sacrorum and Caragana brachypoda. Shrub abundance increased during the livestock exclusion period. Shrub biomass in fenced plots was about 5‐ to 10‐fold greater than in mown plots. Both increase in population density and individual size (especially height) contributed to shrub increase. The mechanism behind this was the divergent effects of litter accumulation on shrubs and grasses. Litter accumulation suppressed grass production, while facilitating shrub recruitment and growth. Our findings highlight the potential role of litter accumulation‐mediated shifts in shrub–grass interactions, which should be incorporated into grazing top‐down control to better predict the restoration outcomes of grassland management changes. The identified internal biotic mechanism raises the possibility that removal of accumulated litter by grazing or mowing may be an alternative way to maintain or restore a grass‐dominated state in shrub expansion areas.

Habitat protection and removal of encroaching shrubs support the recovery of biodiversity and ecosystem functioning

AbstractLivestock overgrazing causes environmental degradation, species invasion, biodiversity loss, and productivity decline, with profound consequences for ecological sustainability and human livelihoods. Habitat protection can mitigate such impacts, but we know little about how the long‐term recovery of plant communities from livestock overgrazing depends on the presence of encroaching shrubs. Here, we explored how shrub encroachment mediates the effects of habitat protection (i.e., livestock exclusion and creation of UNESCO protected areas) on biodiversity recovery and ecosystem functioning (i.e., biomass productivity). We leveraged a long‐term (15–25 years) experiment of livestock exclusion and complemented it with the removal of an encroaching shrub species in pasture areas and protected areas. We reveal that habitat protection has positive effects on patterns of recovery. Yet, the effects of habitat protection are mediated by shrub encroachment. Encroaching shrubs have net positive effects on plant diversity in pasture areas but inhibit biodiversity recovery in protected areas. The combination of habitat protection and the removal of encroaching shrubs best enhances the recovery of plant diversity and biomass productivity. A potential underlying mechanism is the shift in plant interactions from facilitation for recruitment and associated resistance to competition for water. Understanding species interactions is key to guiding conservation and restoration actions which can turn degraded ecosystems back into functional, species‐rich communities.

Monitoring data on the effect of domestic livestock and rabbits on Androcymbiumeuropaeum (Lange) K. Richt. and its xerophytiques pastures for thirteen years.

Dataset of annual monitoring of herbivory effects on the conservation status of the endangered species Androcymbiumeuropaeum (Lange) K. Richt and its associated plant communities is presented in this manuscript. This dataset encompasses the annual monitoring of herbivory effects on the conservation status of the endangered species Androcymbiumeuropaeum. Since 2010, the SERPAM Department (Service of Evaluation, Restoration and Protection of Mediterranean Agrosystems) at the Zaidin Experimental Station, belonging to the Spanish National Research Council (CSIC-EEZ), has conducted annual sampling to assess the impact of both domestic and wild livestock, specifically rabbits, on the pastures where A.europaeum lives. The study consisted of a randomised block design, implementing three distinct treatments to evaluate different management strategies: (1) rabbit and domestic herbivory, (2) exclusion of domestic livestock and (3) exclusion of rabbits and domestic livestock. Within each treatment, two types of monitoring were conducted. Firstly, the abundance of A.europaeum was estimated by counting individuals within 50 cm x 50 cm quadrats. Secondly, plant species diversity was assessed along 2-m long transects using the modified Point-Quadrat method. The research was conducted within the Cabo de Gata-Níjar Natural Park in southern Spain, specifically in the Amoladeras Nature Reserve in Almería. The dataset contains information spanning from 2010 to 2023, providing valuable insights into the annual monitoring of herbivory effects on the conservation status of A.europaeum, contributing to our understanding of the species' interaction with domestic and wild animal in the studied area.

Biocrusts Indicators of Livestock Grazing Effects on Soil Stability in Sagebrush Steppe: A Case Study from a Long-Term Experiment in the Northern Great Basin

Biocrusts are sensitive to changes in livestock grazing intensity in arid rangelands and may be useful indicators of ecosystem functions, particularly soil properties like soil stability, which may suggest the potential for soil erosion. We compared biocrust community composition and surface soil stability in a big sagebrush (Artemisia tridentata) steppe rangeland in the northwestern Great Basin in several paired sites, with or without long-term cattle grazing exclusion, and similar soils (mostly sandy loams), climate, and vegetation composition. We found that livestock grazing was associated with both lower surface soil stability and cover of several biocrust morphogroups, especially lichens, compared with sites with long-term livestock exclusion. Surface soil stability did not modify the effects of grazing on most biocrust components via interactive effects. Livestock grazing effects on total biocrust cover were partially mediated by changes in surface soil stability. Though lichens were more sensitive to grazing disturbance, our results suggest that moss (mostly Tortula ruralis in this site) might be a more readily observable indicator of grazing-related soil stability change in this area due to their relatively higher abundance compared with lichens (moss: mean, 8.5% cover, maximum, 96.1%, lichens: mean, 1.0% cover, maximum, 14.1%). These results highlight the potential for biocrust components as sensitive indicators of change in soil-related ecosystem functions in sagebrush steppe rangelands. However, further research is needed to identify relevant indicator groups across the wide range of biocrust community composition associated with site environmental characteristics, variable grazing systems, other rangeland health metrics, and other disturbance types such as wildfire.

Long-term livestock exclusion increases plant richness and reproductive capacity in arid woodlands.

Herbivore exclusion is implemented globally to recover ecosystems from grazing by introduced and native herbivores, but evidence for large-scale biodiversity benefits is inconsistent in arid ecosystems. We examined the effects of livestock exclusion on dryland plant richness and reproductive capacity. We collected data on plant species richness and seeding (reproductive capacity), rainfall, vegetation productivity and cover, soil strength and herbivore grazing intensity from 68 sites across 6500 km2 of arid Georgina gidgee (Acacia georginae) woodlands in central Australia between 2018 and 2020. Sites were on an actively grazed cattle station and two destocked conservation reserves. We used structural equation modeling to examine indirect (via soil or vegetation modification) versus direct (herbivory) effects of grazing intensity by two introduced herbivores (cattle, camels) and a native herbivore (red kangaroo), on seasonal plant species richness and seeding of all plants, and the richness and seeding of four plant groups (native grasses, forbs, annual chenopod shrubs, and palatable perennial shrubs). Non-native herbivores had a strong indirect effect on plant richness and seeding by reducing vegetative ground cover, resulting in decreased richness and seeding of native grasses and forbs. Herbivores also had small but negative direct impacts on plant richness and seeding. This direct effect was explained by reductions in annual chenopod and palatable perennial shrub richness under grazing activity. Responses to grazing were herbivore-dependent; introduced herbivore grazing reduced native plant richness and seeding, while native herbivore grazing had no significant effect on richness or seeding of different plant functional groups. Soil strength decreased under grazing by cattle but not camels or kangaroos. Cattle had direct effects on palatable perennial shrub richness and seeding, whereas camels had indirect effects, reducing richness and seeding by reducing the abundance of shrubs. We show that considering indirect pathways improves evaluations of the effects of disturbances on biodiversity, as focusing only on direct effects can mask critical mechanisms of change. Our results indicate substantial biodiversity benefits from excluding livestock and controlling camels in drylands. Reducing introduced herbivore impacts will improve soil and vegetation condition, ensure reproduction and seasonal persistence of species, and protect native plant diversity.

Review on Factors Affecting Early Survival of Tree /Shrub Seedlings and it’s Remedy in Restoration Sites of Ethiopia

Abstract Restoration activities in degraded and/or deforested forest landscapes are common and old occurrences around the world. Tree planting is common in most forest landscape restoration initiatives. In Ethiopia, eight seedling-based landscape restoration options are identified to alleviate land degradation and its consequences. The primary purpose of this work was to review factors affecting the early survival of tree and shrub seedlings and their remedies in the restoration sites of Ethiopia. Drought and moisture stress, low soil fertility, poor seedling quality, weak species site matching, termites, livestock grazing, and seasonal frost are the basic factors that hinder the survival and growth of seedlings in the field. In situ rainwater harvesting structures, fertilizer application, the use of quality seedlings, the right species site matching, and the exclusion of livestock and grazing animals from planted seedlings are the remedies that must be employed to increase the success of tree-based restoration practices. Thus, further investigation of the factors affecting the survival of seedlings in the out-planting sites and remediation accordingly is necessary to ensure the productivity and sustainability of restoration practices in Ethiopia.

Grazing regime effects on bird biodiversity overwhelmed by an interference competitor

The majority of the world's mammal biomass is domestic livestock. Intensive livestock grazing can negatively impact some elements of biodiversity. We quantified the effects of grazing management on bird occupancy over a 10-year period in patches of Australian endangered temperate woodland within paddocks subjected to one of three grazing regimes: continuous set stocking, rotational, and total livestock exclusion. Grazing may affect birds through altering resource availability, influencing vegetation structure, or affecting the occurrence of noisy miners (Manorina melanocephala), a native honeyeater that engages in interference competition with other birds.Using Bayesian generalized linear mixed models and multispecies occupancy modelling, we quantified relative and interactive effects on bird biodiversity of grazing, vegetation structure, and noisy miner occupancy. We found only muted grazing regime effects on woodland birds. However, many species responded to vegetation structure. Small invertivorous woodland birds responded positively to sapling abundance, and some (larger) species responded positively to the abundance of trees >50 cm. Furthermore, species richness increased with increased sapling abundance and trees >50 cm. The largest effects were associated with noisy miner occurrence, which drove reductions in small-bodied, invertivorous birds, effectively “swamping” the positive effects of vegetation attributes on these species.The profound impacts of noisy miners present challenges for bird conservation in woodland ecosystems, especially those subject to grazing. Management to reduce grazing pressure by domestic livestock may eventually help limit the impacts of the noisy miner, in part by facilitating natural regeneration of temperate woodlands to which small-bodied woodland birds respond positively.

Free-ranging livestock cause forest understory degradation in giant panda (Ailuropoda melanoleuca) habitat

Free-ranging livestock are common in reserves established for giant pandas (Ailuropoda melanoleuca), which rely almost exclusively on bamboo in the montane forests of southwestern China. Previous studies have showed that overgrazing by livestock had led to a reduction in bamboo abundance. However, there is limited knowledge of how livestock impact the structure of the understory vegetation. Conducted in the Wanglang National Nature Reserve with a livestock exclosure experiment, our study aimed to fill this gap by examining the impact of livestock grazing on two important elements of forest understory bamboo and moss in giant panda habitat, and quantifying their recovery after excluding livestock. Measurements of bamboo and moss showed that both elements were severely degraded. With a closer examination, we found moss growth was worse in areas with dense bamboo or no bamboo at all, but better when there were many dead stems in bamboo clump, suggesting bamboo exerted both negative competition and positive shelter effects from livestock trampling on moss. Livestock exclusion with fence indeed exempted bamboo and moss from continuous damage which were exemplified by more bamboo shoots inside the fence and significantly decreased moss height outside the fence. However, we observed no recovery of damaged bamboo and moss inside fenced quadrats in two years. Neither the sprouted bamboo shoots matured into stems after the growing season, nor the height of moss increased. Collectively, our results suggested that long-term livestock grazing drastically altered understory layer of bamboo and moss and interactions in between, and there was hardly recovery of the understory bamboo and moss in a short term. Therefore, we recommend artificial intervention with bamboo and moss planting in severely degraded areas and long-term monitoring of understory vegetation to restore the habitat of giant panda.

Transient shifts in composition of degraded temperate native grassland following grazing exclusion

AbstractQuestionsGlobally, grassy ecosystems are threatened and are still declining in extent in many areas. Improving the management of degraded native temperate grasslands that are grazed by livestock is important to the conservation of this critically endangered ecosystem. Questions remain about the role of grazing in the management of such grasslands, particularly in the face of climate change and given the sensitivity of these systems to inter‐annual rainfall variability. Here, we investigate the effect of livestock exclusion on grassland composition.LocationTemperate grassland, Victoria, Australia.MethodsOver 9 years (2009–2017), we monitored plant functional groups in plots open‐to‐grazing or ungrazed exclusion plots within five fields of degraded native temperate grassland on private land.ResultsIn the years after grazing had been excluded, we found significant differences in cover between grazed and ungrazed plots for some functional groups (e.g. native perennial graminoids) in some years, but we did not observe long‐term divergence in cover or composition of the treatments. At the final monitoring point there were no significant differences in native or exotic species richness between the grazed and ungrazed plots. We show that the years in which differences were observed correspond with the 2010–2011 La Niña high‐rainfall event, suggesting that grazing exclusion effects are mediated by rainfall, and are likely to be evident only under certain conditions.ConclusionIn grassy ecosystems already degraded by long‐term grazing, excluding grazing has limited potential to shift plant species composition in favour of native dominance. Such grasslands may persist in the medium term in a stable but degraded state with or without continued light to moderate livestock grazing pressure. Hence, managed livestock grazing need not be incompatible with the conservation of degraded temperate grasslands particularly where biomass management is important for the maintenance of faunal habitat. However, improving the function and diversity of these degraded grasslands will seemingly require additional management, including seed addition and experimentation with alternative disturbance regimes.

Herbivores regulate native–alien plants dynamics in sub‐Antarctic beech (Nothofagus antarctica) forests of Tierra del Fuego, Argentina

AbstractQuestionsWhat is the role of native and domestic herbivores in native–alien vegetation changes in sub‐Antarctic forests? Does herbivory suppression increase native while reducing alien species diversity?LocationCentral–eastern Tierra del Fuego Island, Argentina.MethodsIn four sites, we set up three different treatments: excluded grazing by livestock (cattle), by livestock and native (guanaco) herbivores, and grazed control plots in Nothofagus antarctica forests. We then monitored the dynamics of understorey native and alien plants (species richness, abundance) of dicots, monocots, and ferns over 6 years. Generalized Linear Mixed Models were used to determine the effects of herbivore exclusion and time on species richness and abundance. In addition, we calculated the abundance rate of change to quantify temporal dynamics.ResultsOverall species richness did not change in the exclusion plots, but native and alien abundances were affected by herbivory and time since exclusion. The abundance of native monocots changed after herbivore exclusion, increasing its dominance significantly inside exclusion plots. However, the cessation of herbivory did not reduce alien species in general. Only alien dicots significantly declined in the livestock exclusion treatment. Further, we found that the two dominant alien grass species (Holcus lanatus and Poa pratensis) respond differently to grazing exclusion, and their response was modulated by forest basal area.ConclusionsOur results indicate that cattle and guanaco grazing had variable effects on native and alien plants, and that herbivore exclusion has a substantially positive effect on native grasses. However, the magnitude of temporal changes was more significant for vegetation richness and abundance than the effect of exclusion treatments. Herbivore exclusions can initiate a rapid recovery of compositional attributes of native vegetation in N. antarctica forests grazed by livestock.

Impact of climate change on pasture quality in Mediterranean dehesas subjected to different grazing histories

Background and aimsForecasted climate change and overgrazing are threatening the sustainability of dehesas, human-managed ecosystems where pastures, livestock and scattered trees coexist. Pasture quality is particularly sensitive to these global-change drivers, but there are still many gaps to broaden knowledge about the interactive effects of both factors on it. In addition, scattered trees might play a relevant role in maintaining high levels of pasture quality under future scenarios of higher aridity, but its role remains largely unexplored.MethodsWe designed a field manipulative experiment of rainfall exclusion and increased temperature aimed to evaluate the impact of forecasted climate on pasture quality under different historical grazing intensities. To test the potential buffering effect of trees, experimental plots were installed equally in two habitat types: under trees and open grassland.ResultsWarming reduced the nutrient concentration of pasture, while drought increased it. Tree canopy improved soil fertility, which translated into an increase in pasture quality. Livestock exclusion and high grazing intensity caused a decrease in pasture quality, whereas moderate grazing intensity exerted positive effects on it. Finally, warming beneath tree canopy negatively affected the P concentration of pasture, specifically in the site subjected to moderate grazing intensity.ConclusionOur findings suggest that communities subjected to moderate grazing are more sensitive to climate change from a nutritional standpoint, likely because this management type provides high levels of P to the soil. In addition, we highlight the essential role of trees in agroforestry ecosystems to maintain high values of nutritional quality of pasture.

Effects of Livestock Exclusion on Stream Habitat and Aquatic Biota: A Review and Recommendations for Implementation and Monitoring

AbstractTo inform riparian restoration, research, and monitoring and to provide management recommendations, we reviewed published studies evaluating the physical and biological effectiveness of livestock exclusion and grazing reduction on various metrics in riparian and aquatic areas. We identified 95 North American studies that reported the effects of livestock grazing reduction on physical habitat (channel morphology, mesohabitats, substrate, and bank stability), biological assemblages (riparian vegetation, macroinvertebrates, fish, and birds), and water quality metrics (temperature, nitrates, phosphorus, and turbidity). Most studies reported that methods to reduce or exclude livestock decreased channel width, width‐to‐depth ratio, bank erosion, soil bulk density, bare ground, water temperature, nitrogen, and phosphorus and increased riparian vegetation (cover, height, productivity, biomass, and abundance), riparian bird abundance, and young‐of‐the‐year fishes. Results for channel depth, instream substrate, mesohabitats, water depth, juvenile and adult fishes, and macroinvertebrates showed no consistent response to exclusion. Project success was influenced by the time since exclusion; whether there was complete exclusion or continued grazing; and local climate, geology, and soils. Apart from bank erosion and stability, most of the physical and biological metrics took more than a decade to respond to livestock exclusion. However, coupling exclusion with planting and other restoration measures decreased the recovery time. Complete exclusion of livestock produced more consistent improvements in riparian condition and other metrics than rest–rotation or other grazing management strategies. Understanding how physical and biological metrics respond to livestock exclusion will require (1) focused, long‐term studies using before–after or before–after, control–impact designs; and (2) monitoring of metrics that most consistently respond to exclusion. Ultimately, the design of exclusions should be driven by local climate, geology, biophysical conditions, and management history. Our results highlight the need for watershed‐scale approaches to excluding livestock from broad areas and the need for implementation monitoring to ensure that fencing and other exclusion measures continue to exclude livestock and produce the desired responses.

Effects of Livestock Exclusion on Pollutant Export From a North Carolina Beef Cow Pasture

Highlights Exclusion of beef cattle from two streams resulted in significant reductions in nitrogen, phosphorus, and sediment exports. Reductions in nutrient and sediment export improved following four or more years of exclusion. Nitrogen and phosphorus concentrations in storm samples decreased more than those in baseflow samples. Abstract. Fences were installed to exclude cattle from two adjacent small streams on a beef and swine farm located in central North Carolina. The two streams, referred to as UTA and North, originated in a pasture used for beef cow production and the application of swine waste. Rainfall and discharge were continuously monitored for 1.34 years prior to and 1.8 years after the fencing was installed in order to quantify the effect of the livestock exclusion on pollutant export/loads in the two streams originating in the pasture. Monitoring results documented reductions in total nitrogen (TN), phosphorus (TP), and total suspended solids (TSS) exports via the North stream of 15%, 54%, and 67%, respectively. Monitoring on the UTA stream was restarted 3.7 years after the initial 1.8 years and continued for about 1 year to assess the effect of natural vegetation growth and stream channel soil recovery. The combined reductions for the two periods were 39%, 64%, and 74% for TN, TP, and TSS, respectively. Exports of TN, TP, and TSS during the later monitoring period decreased by 13%, 60%, and 22%, respectively, compared to the initial 1.8-year monitoring period. These results indicated that exclusion fencing was effective at reducing pollutant exports during the first 1.8 years and that its effectiveness increased after about four years. Consequently, studies that report effectiveness during the first 2 to 4 years after exclusion likely underestimate the long-term effectiveness of the exclusion fencing. Keywords: Best management practices, Discharge monitoring, Livestock exclusion.

Influence of a cattle access point on temporal changes in stream turbidity

Unrestricted cattle access can have negative impacts on aquatic systems, including increases in stream water turbidity and suspended sediment levels. Many agri-environmental policies require the exclusion of livestock from waterbodies; however, data that quantify these impacts are scarce. This study used sensors measuring turbidity, a proxy for suspended sediment, together with motion-detecting cameras, to examine the influence of cattle in-stream activity on water quality in north-east Ireland. Two nephelometers, which automatically measured and logged turbidity, were placed upstream and downstream of a cattle access point in July 2017, while cameras were used to record cattle behaviour. A second deployment was made during February 2018 when cattle were absent. During low flows, frequent short-lived increases in turbidity were recorded at the downstream nephelometer only. These coincided with cattle accessing the water. There was a significant positive relationship between the longitudinal differences (downstream − upstream) in turbidity and the total number of cattle accessing the stream. There was no relationship between turbidity and stream discharge in July (when cattle were present), although that period was dominated by lower flow levels, with only 2 days in which discharge increased above baseflow. In contrast, there were no similar short-lived increases in turbidity in February 2018 when cattle were absent from the field, but there was a strong significant positive relationship between stream discharge and turbidity. These results highlight the consequences of cattle access for water column turbidity levels, particularly during periods of low streamflow, and therefore inform future agri-environmental policy in Ireland.

Climate overrides fencing and soil mineral nutrients to affect plant diversity and biomass of alpine grasslands across North Tibet.

Overgrazing and warming are thought to be responsible for the loss of species diversity, declined ecosystem productivity and soil nutrient availability of degraded grasslands on the Tibetan Plateau. Mineral elements in soils critically regulate plant individual's growth, performance, reproduction, and survival. However, it is still unclear whether plant species diversity and biomass production can be improved indirectly via the recovery of mineral element availability at topsoils of degraded grasslands, via grazing exclusion by fencing for years. To answer this question, we measured plant species richness, Shannow-Wiener index, aboveground biomass, and mineral element contents of Ca, Cu, Fe, Mg, Mn, Zn, K and P at the top-layer (0 - 10 cm) soils at 15 pairs of fenced vs grazed matched sites from alpine meadows (n = 5), alpine steppes (n = 6), and desert-steppes (n = 4) across North Tibet. Our results showed that fencing only reduced the Shannon-Wiener index of alpine meadows, and did not alter aboveground biomass, species richness, and soil mineral contents within each grassland type, compared to adjacent open sites grazed by domestic livestock. Aboveground biomass first decreased and then increased along with the gradient of increasing Ca content but did not show any clear relationship with other mineral elements across the three different alpine grassland types. More than 45% of the variance in plant diversity indices and aboveground biomass across North Tibet can be explained by the sum precipitation during plant growing months. Structural equation modelling also confirmed that climatic variables could regulate biomass production directly and indirectly via soil mineral element (Ca) and plant diversity indices. Overall, the community structure and biomass production of alpine grasslands across North Tibet was weakly affected by fencing, compared to the robst climatic control. Therefore, medium-term livestock exclusion by fencing might have limited contribution to the recovery of ecosystem structure and functions of degraded alpine grasslands.