Cattle Exclusion Research Articles

Cattle exclusion increases encounters of wild herbivores in Neotropical forests

Abstract Ongoing habitat loss and species extinctions require managers to implement and quantify the effectiveness of conservation actions for protecting biodiversity. Fencing, when done properly, is an important management tool for conservation in landscapes where wildlife and domestic animals co‐occur, potentially enhancing habitat use through selective exclusion of domestic species. For instance, the fencing of forest patches in the Neotropics is expected to reduce the degradation of understory vegetation by cattle, releasing these resources for the native community of browsers and fruit consumers. Here, we implemented an ecological experiment using a before‐after control‐impact design to quantify the effect of cattle exclusion on encounter probability of the native community of browsers and fruit consumers, and percent ground cover in multifunctional landscapes of the Colombian Orinoquía. We built 14 km of wildlife‐permeable fences along forest edges in four forest patches (i.e. blocks) containing control and fenced (treatment) sites. We installed 33 camera traps to obtain information about wildlife and cattle encounter probabilities, before and after the fences were constructed. We used Bayesian generalised linear mixed effects models to quantify the effect of fences via the interaction between the time period (before and after the fences were built) and treatment (control or fenced sites). Fencing was effective at reducing encounter probabilities of cattle in the treated sites, and it had a positive impact on relative encounter probabilities of four of seven studied wildlife species (herbivores including the black agouti [dry season only], lowland tapir [dry season only] and spotted paca [both seasons] and an omnivore, the South American coati [rainy season only]). The effect of fencing was negative for the collared peccary but only during the dry season. No statistically significant effect was detected for the white‐lipped peccary or white‐tailed deer. Synthesis and applications: We provide experimental evidence that fences are effective at selectively excluding cattle and increasing encounter rates of wild browsers and fruit consumers in forest patches where these species co‐occur with cattle. Our results highlight an important application of fencing ecology in Neotropical forests, where the implementation of wildlife‐permeable fences is feasible due to smaller body sizes of wildlife compared to domestic animals such as cattle.

Do nurse plants and cattle exclusion help restore Parlatore’s Podocarp forest?

Do nurse plants and cattle exclusion help restore Parlatore’s Podocarp forest?

Determining the depth and rate of soil movement down the soil profile using an environmental tracer: a hillslope scale assessment

Context Soil materials can be delivered to depth from both in situ and ex situ materials. Here, we examine a hillslope in an agricultural environment that has been used for cropping and cattle grazing for over 150 years and a parallel area where cattle have been excluded for approximately 20 years. The exclusion area is a shelterbelt and also provides ecological services. Aims To quantify the depth and rate of down profile soil movement using the environmental tracer 137Cs at points along a hillslope profile. Methods 137Cs concentration is measured to bedrock at regular intervals both inside and outside a fenced of ecological services area pre-drought (2015) and post-drought (2021). In Australia. 137Cs is the by-product of nuclear weapons use and testing from1945 to 1972. Therefore, this places an age constraint on any labelled soil. Key results Results show that soil materials can move down the soil profile to reach bedrock at decadal time scales. An important finding is that materials from the surface can reach depths of up to 80 cm near the hillslope crest and up to 2.2 m at the base of the hillslope. Conclusions This demonstrates a relatively rapid translocation of surface material. Implications The method provides the ability to quantify the rapid movement of soil components and demonstrates the potential for deep sequestration of soil organic carbon. The results demonstrate the potential for soil amendments and agrochemicals to be rapidly transported to depth. The findings suggest that cattle exclusion has no impact on the movement of soil materials down the profile over the 20-year exclusion period.

Taxonomic and functional avian diversity vary with cattle management practices in humid Chaco forests of Argentina

AbstractBirds play key roles in forest dynamics, favoring the resilience of forests to cattle ranching. Generalist species may benefit from changes in the vegetation structure caused by cattle grazing while specialist species are usually negatively affected. Therefore, studying changes in taxonomic and functional bird diversity can provide valuable information in order to propose the sustainable cattle management practices. Here, we study the influence of different cattle management practices (Cattle Exclusion: FCE; Continuous grazing: FCG; Rotational grazing: FRG; Seasonal grazing: FSG) on the understory vegetation structure, and the bird taxonomic and functional diversity in humid Chaco forests of Argentina. Forests under grazing had an open (FCG) or semi‐open (FRG and FSG) understory, whereas FCE presented a closed understory with higher plant richness. Generalized linear models revealed a decrease in bird richness and abundance under most cattle management practices compared to FCE. However, FRG was most similar to FCE in terms of vegetation structure and showed no differences in bird richness. FCE presented the lowest values of functional diversity while FCG and FRG showed the highest values. A fourth‐corner analysis showed that FCE was associated with insectivorous species which forage and nest in the shrub layer, reflecting a possible loss of ecosystem services in forests with cattle grazing. We propose FRG as the most appropriate cattle management option and the least detrimental to bird assemblages. However, maintaining protected areas that exclude cattle ranching activities will be key to strike a balance between the conservation of most specialist species and beef production.Abstract in Spanish is available with online material.

Mitigation of impacts of cattle access on stream ecosystems: Efficacy of fencing

AbstractHeadwater streams can constitute up to 80% of river channel length and are vulnerable to anthropogenic pressures due to their high connectivity to adjacent land, large relative catchment size and low dilution capacity. In these environments, unrestricted cattle access is a potentially significant cause of water quality deterioration, resulting from increases in stream bank erosion, riparian damage and sediment deposition among others. Several studies have reported improvements in the physico‐chemical and hydromorphological conditions of streams following the elimination of cattle access; few, however, have focussed on the ecological impacts of such management practices. Here, such impacts are assessed. The study explores the short‐term effects of cattle exclusion by comparing habitat conditions, sediment deposition and instream macroinvertebrate communities upstream and downstream of cattle access points prior to, and 1 year following exclusion via fencing. The long‐term effects are also measured by reassessing a small stream catchment entirely fenced off from cattle access in 2008 under a dedicated management plan. In the short term, cattle exclusion led to a reduction in deposited sediment downstream of cattle access points and a related homogenisation of macroinvertebrate community structure between upstream and downstream of cattle access points. Increased abundances of specific indicator taxa (Ancylus fluviatilis, Glossosomatidae and Elmidae) in the fenced catchment following 9 years of exclusion highlight the long‐term ecological benefits of such mitigation practices. These findings highlight the importance of incentivised agri‐environment measures in reducing the negative impacts of cattle access to vulnerable aquatic ecosystems.

Examining Participation in and Supply of Private Land for Voluntary Conservation in Australia’s Tropical Savannas: A Discrete-Continuous Choice Experiment

Australia’s tropical savannas are a vast landscape of grasslands with high biodiversity value. Effective biodiversity conservation in this landscape requires private contributions to complement the under-sized formal conservation estate. The landscape is dominated by rangelands, in particular extensive cattle grazing on pastoral stations which typically measure hundreds or thousands of square kilometers. The paper reports the results of a discrete–continuous (or “two-stage”) choice experiment conducted with savanna pastoralists. A discrete choice experiment explored the stated willingness to participate in two long-term conservation strategies: (i) total exclusion of cattle from designated parcels of land with management of that land for biodiversity, and (ii) the implementation of rotational grazing systems governed by the requirements of biodiversity, among other contractual attributes. An extension question asked about the area that respondents were willing to supply and a contract they were willing to accept. Double-hurdle (type II tobit) modelling was used for combined data analysis. The results show that potential participation in voluntary conservation contracts by pastoralists is primarily influenced by contract attributes, namely, the conservation action required, the stewardship payment received, contract length and whether the contract contains flexibility provisions. Land productivity is also significant. The level of stewardship payment required to incentivize participation in the conservation of grasslands is in line with opportunity costs, in particular option value. The amount of land that pastoralists are willing to supply is determined by the conservation payment as well as farm size and intrinsic motivation. This research illustrates strategies for integrating biodiversity conservation into cattle grazing operations in Australia’s tropical savannas, which are applicable to grasslands globally. It provides data of an economic nature to inform the development of multi-tenure biodiversity conservation strategies.

Long-term response of wetland plant communities to management intensity, grazing abandonment, and prescribed fire.

Isolated, seasonal wetlands within agricultural landscapes are important ecosystems. However, they are currently experiencing direct and indirect effects of agricultural management surrounding them. Because wetlands provide important ecosystem services, it is crucial to determine how these factors affect ecological communities. Here, we studied the long-term effects of land-use intensification, cattle grazing, prescribed fires, and their interactions on wetland plant diversity, community dynamics, and functional diversity. To do this, we used vegetation and trait data from a 14-year-old experiment on 40 seasonal wetlands located within seminatural and intensively managed pastures in Florida. These wetlands were allocated different grazing and prescribed fire treatments (grazed vs. ungrazed, burned vs. unburned). Our results showed that wetlands within intensively managed pastures have lower native plant diversity, floristic quality, evenness, and higher nonnative species diversity and exhibited the most resource-acquisitive traits. Wetlands embedded in intensively managed pastures were also characterized by lower species turnover over time. We found that 14 years of cattle exclusion reduced species diversity in both pasture management intensities and had no effect on floristic quality. Fenced wetlands exhibited lower functional diversity and experienced a higher rate of community change, both due to an increase in tall, clonal, and palatable grasses. The effects of prescribed fires were often dependent on grazing treatment. For instance, prescribed fires increased functional diversity in fenced wetlands but not in grazed wetlands. Our study suggests that cattle exclusion and prescribed fires are not enough to restore wetlands in intensively managed pastures and further highlights the importance of not converting seminatural pastures to intensively managed pastures. Our study also suggests that grazing levels applied in seminatural pastures maintained high plant diversity and prevented tree and shrub encroachment and that in the absence of grazing, prescribed fire became crucial to maintaining higher species evenness.

Plant functional traits under cattle grazing and fallow age scenarios in a tropical dry forest of Northwestern Mexico

Evaluating plant functional traits helps to understand how plants respond to changing environmental conditions and resource availability associated with disturbance events. Livestock production is one of the primary drivers of tropical forest loss and degradation. Livestock alter environmental conditions within the forest by grazing, trampling and nutrient inputs, which in turn can influence species composition and functional traits of species. Understanding how livestock influence functional traits along a successional gradient is poorly understood. Here, we studied the effect of cattle grazing and fallow age on plant functional traits and soil nutrients in secondary and old-growth tropical dry forests. We analyzed plant functional traits of the most important species in successional and old-growth forest communities in both cattle present and cattle excluded plots. Our results showed the effects of cattle grazing and fallow age on plant functional traits, with fallow age explaining more variation than cattle grazing. In early succession, functional traits were associated with water conservation (thicker leaves, lower specific leaf area), and in later successional they were linked with sunlight conservation (larger height, higher specific leaf area). The presence of large fruits and seeds in advanced successional sites suggests high resource availability, which may help plants to successfully reproduce. Moreover, under cattle grazing some functional traits are associated with herbivory defense (high foliar dry weight and thick leaves). Even though N and C increased as succession advanced, the sites with cattle grazing had higher NH4 and NO3 concentrations as a result of fecal deposition. Plant functional traits responded to fallow age than to cattle grazing. Our study showed that cattle exclusion, as a management and biodiversity conservation strategy, contributes positively to soil nutrition. Thus, fallow age and cattle exclusion facilitate soil recovery and allows establishing species with suitable functional attributes for overcoming environmental filters in abandoned cattle fields.

Low‐intensity cattle grazing is better than cattle exclusion to drive secondary savannas toward the features of native Cerrado vegetation

AbstractAlthough livestock have been historically associated with land conversion and biodiversity loss, well‐managed cattle grazing has been reported to contribute to conservation of open ecosystems. Knowing the balance between positive and negative effects of livestock (presence or exclusion) on different ecosystems is, therefore, crucial to support management decisions. We conducted an experiment in a secondary savanna with exotic grasses, used as pasture, to assess the effect of cattle presence in low density and cattle exclusion (in paired plots) on the trajectory of these ecosystems. Richness, composition and structure of the woody community, and exotic grass cover and biomass were compared between treatments in the beginning of the experiment and after 7 years. At the end of the experiment, we also compared composition, richness, and density of the native ground layer. We verified that (a) cattle exclusion accelerates the undesirable woody encroachment, changes the species composition and leads to huge grass fuel accumulation, while (b) cattle grazing/browsing hinders changes in savanna structure and composition and reduces the exotic grass cover and biomass, thus favoring native herbaceous plants. By decreasing the grass biomass, cattle grazing also reduces the system flammability and, therefore, the risk and intensity of wildfires. Together, the positive effects of cattle presence and the negative effects of cattle exclusion lead to the conclusion that cattle should be maintained in these systems. Low‐intensity cattle grazing limits woody and exotic grass invasion, improves native forb biodiversity, and help to maintain composition and structural features of secondary savannas of the Cerrado.Abstract in Portuguese is available with online material

Ventenata (Ventenata dubia) Response to Grazing and Prescribed Fire on the Pacific Northwest Bunchgrass Prairie

The exotic annual grass ventenata (Ventenata dubia L.) is raising concern as it rapidly invades multiple ecosystem types within the United States, including sagebrush steppe, ponderosa pine forests, woodlands, and much of the Palouse and Pacific Northwest Bunchgrass Prairie (PNB). Despite increasing attention, little is known about the invasion dynamics of ventenata, especially its response to disturbances such as grazing and fire. In this study, we examined how cattle grazing and prescribed fire affect the abundance (standing crop, cover, frequency, and density) of ventenata and other plant groups on the PNB over time using two separate long-term studies established in 2004. The first study (Cattle Grazing) looked at the 14-yr effect of cattle grazing exclusion on ventenata aboveground biomass and cover. Our second study (Grazing and Prescribed Fire) examined main and interactive effects of cattle exclusion and prescribed fire on ventenata over three sampling periods (2008, 2016, and 2018). We documented a 30% increase in ventenata cover and 55% increase in frequency on the PNB over the past 15 yr, including areas that were not disturbed by fire or cattle grazing. We found only weak evidence that cattle grazing increased ventenata standing crop when compared with cattle-excluded paddocks, something that could be related to timing of use. There was no evidence that prescribed burning impacted the response of ventenata on its own. However, we found some evidence of interactions between cattle grazing and prescribed fire that suggests prescribed burning could help reduce the abundance of ventenata in areas grazed by livestock. These studies reinforce the important differences between ventenata and other invasive winter annuals in grasslands and clarify a need for research that focuses primarily on the dynamics between this relatively new exotic species in grasslands and the many ecosystems it now inhabits.

Restoring riparian forest in the Atlantic Forest: does planting seedlings make a difference?

Planting seedlings remains the most popular method of forest restoration, but passive restoration may become a new promise to reduce costs, despite concerns about its efficacy. Here, we present a study of a riparian forest recovery program in the Southern Atlantic Forest, Brazil. The objective was to compare planting seedlings and passive restoration eight years since restoration started and assess the influence of cattle presence in the restoring areas. We analyzed the structure, diversity, and composition of the woody community in the upper (canopy) and lower strata (understory) versus six environmental variables, including edaphic, landscape and geographical variables, restoration method (planting seedlings versus passive restoration), presence of cattle inside the restoration areas, and presence of adjacent crop plantations. Passive restoration generated a more diverse woody community and a higher proportion of climax and zoochoric species in the lower stratum than active restoration. Cattle presence was significantly associated with lower species richness and density of plants, as well as a higher proportion of pioneer species and low proportion of zoochoric and climax species. The results suggest that cattle can delay forest succession, besides reducing diversity. Passive restoration should be considered suitable for the region, and the efficiency of cattle exclusion needs to be improved.

Rehabilitation effects on gully sediment yields and vegetation in a savanna rangeland

AbstractGully rehabilitation can contribute to catchment management by stabilizing erosion and reducing downstream sediment yields, yet the globally observed responses are variable. Developing the technical basis for gully rehabilitation and establishing guidelines for application requires studies that evaluate individual rehabilitation measures in specific environments. An eight‐year field experiment was undertaken to evaluate sediment yield and vegetation responses to several gully rehabilitation measures. The rehabilitation measures aimed to reduce surface runoff into gully head cuts, trap sediment on gully floors and increase vegetation cover on gully walls and floors. The study occurred in a savanna rangeland in northeast Australia. Two gullies were subject to treatments while four gullies were monitored as untreated controls. A runoff diversion structure reduced headcut erosion from 4.3 to 1.2 m2 yr−1. Small porous check dams and cattle exclusion reduced gully total sediment yields by more than 80%, equivalent to a reduction of 0.3 to 2.4 t ha−1 yr−1, but only at catchment areas less than 10 ha. Fine sediment yields (silt and clay) were reduced by 7 and 19% from the two treated gullies, respectively. The porous check dam deposits contained a lower percentage of the fine fraction than the parent soil. Significant regeneration of gully floor vegetation occurred, associated with trapping of organic litter and fine sediment. Increases in vegetation cover and biomass were comprised of native perennial grasses, trees and shrubs. In variable climates, long‐term gully rehabilitation will progress during wetter periods, and regress during droughts. Understanding linkages between rehabilitation measures, their hydrologic, hydraulic and vegetation effects and gully sediment yields is important to defining the conditions for their success.

Pasture management, grazing, and fire interact to determine wetland provisioning in a subtropical agroecosystem

AbstractWetlands in agroecosystems provide multiple ecosystem services, including provisioning services such as forage production. Here, we examine how pasture management intensity (semi‐natural pastures vs. highly managed pastures (fertilized, heavily drained, planted with productive grasses), cattle exclusion (grazed vs. fenced), prescribed fire (burned vs. unburned), and their interactions affect provisioning services provided by small, isolated, and seasonally flooded wetlands in subtropical pastures and rangelands. We used a replicated, full‐factorial experiment on 40 seasonally flooded wetlands located in Florida (USA), and measured standing plant biomass and annual net primary productivity in each wetland. Biomass was sorted by species to calculate species abundance of palatable and unpalatable plants. We used general linear mixed models to evaluate the effect of treatments and their interactions on biomass quantity, plant tissue nutrients (% C, % N, and % P), and forage nutritive value (using in vitro organic matter digestibility). Plant standing biomass and productivity were greatest in wetlands embedded in highly managed pastures, but in grazed wetlands, a large proportion of this biomass was unpalatable to cattle. Excluding cattle from wetlands in highly managed pastures increased productivity, standing biomass, and the amount of palatable species (~6.3 t/ha) compared to grazed wetlands (~3.3 t/ha), especially when these wetlands were also exposed to prescribed fire. Total P in plant tissue was consistently higher in wetlands within highly managed pastures, but total N responses to treatments varied between years. In vitro digestibility was higher in vegetation from wetlands within highly managed pastures, but not in fenced wetlands despite the higher amount of palatable species, suggesting that palatability and digestibility were decoupled. Subtropical wetlands in agroecosystems provide substantial provisioning services, and our study suggests that targeted management can increase these services. However, the pasture type surrounding a wetland interacts with grazing and fire management to affect provisioning services. We propose that fencing off selected wetlands (specifically in highly managed pastures) followed by low‐intensity grazing with adequate resting periods could benefit ranchers and have less persistent impacts on this ecosystem.

How does cattle raising affect bird communities in the delta of the Paraná River?

We hypothesize that the presence of cattle should increase environmental heterogeneity and therefore maintain more diverse bird communities. Therefore, we analyzed the changes in the structure of vegetation and diversity of bird species that inhabit the fluvial forests in the Delta region of the Paraná River in relation to the different cattle raising management (islands with cattle, islands without cattle, islands with recent cattle exclusion). In the islands with cattle we found lower height of the herbaceous layer, less coverage of the shrub layer and lower presence of climbing plants, which were associated with birds assemblages with greater richness, abundance and diversity. We consider that this region has evolved under a context of significant herbivory pressure, which in pre-Columbian times was possibly dominated by Blastocerus dichotomus and Ozotoceros bezoarticus (locally extinct at present), Hydrochoerus hydrochaeris and Myocastor coypus. In this context, the complete exclusion of cattle in protected areas and the absence of the cervids that inhabited this region in the past, would lead to deterioration the natural condition of the environment and seems to be generating a decrease in the diversity of these sites. We consider that a reintroduction plan for these cervids should be implemented in the area.

Sediment-related water quality of small hill-country streams near Whatawhata, New Zealand. Response to integrated catchment management (ICM)

ABSTRACT Degradation of aquatic ecosystems by fine sediment is a global environmental problem, and damages reflect particle properties as well as mass concentration. We studied sediment-related water quality (SRWQ) of small streams in hill-country near Whatawhata, NZ, that have been monitored since 1995. In 2001, an integrated catchment management (ICM) plan was implemented in the Mangaotama (originally sheep-beef) catchment – including conversion of steep headwaters to pine plantation, cattle exclusion, and native riparian plantings. The long-term SRWQ within the Mangaotama catchment was examined with reference to a nearby native-forested control catchment. Correlations between visual clarity, suspended particulate matter concentration and related variables were moderate to fairly strong. The ICM has not improved SRWQ as expected – plausibly because removal of cattle disturbance has been offset by decline in pasture ground cover under increasing shade of tree plantings. Worsening SRWQ is expected over the next several decades as channels widen towards a ‘forest’ morphology.

Selective and taxon-dependent effects of semi-feral cattle grazing on tree regeneration in an old-growth Mediterranean mountain forest

BackgroundIn Mediterranean mountain socio-ecosystems, both grazing by livestock and the dry season may influence tree regeneration. However, the relative contributions of these drivers are poorly known, even though present and future canopy composition might result from past and present variations in climate and herbivore density. This study aims to test how semi-feral cattle presence and season affect tree regeneration.MethodsThe study was conducted using permanent plots inside and outside a cattle exclosure in an old-growth Mediterranean forest. Saplings and seedlings were counted five times per year (winter, early spring, middle spring, summer, fall) and monitored over 7 yrs.ResultsSemi-feral cattle exclusion increased Acer, Fagus, Ilex, Pinus, Prunus and Quercus sapling densities and increased Acer, Fraxinus, Ilex, Quercus and Sorbus seedling densities. Interestingly, the dry season did not exert any noticeable effects on the sapling or seedling densities of any of the studied taxa.DiscussionSemi-feral cattle presence may limit tree regeneration through taxon-dependent effects, which suggests that the current decrease in grazing livestock across the Mediterranean basin will modify recruitment processes and, likely, future forest composition.ConclusionsSemi-feral cattle presence acts as a selective driver of tree community composition.

Initial response of understorey vegetation and tree regeneration to a mixed‐severity fire in old‐growth Araucaria–Nothofagus forests

AbstractQuestionsFire is a key factor influencing Araucaria araucana forests, but the impact of fire severity on the understorey vegetation is not well understood. In this study we seek to answer the following questions: (a) how do initial plant diversity, composition and spatial distribution of the understorey vegetation change in response to different levels of fire severity; and (b) does the abundance of dominant tree species exhibit different patterns across a fire severity gradient shortly after fire?LocationOld‐growth Araucaria araucana–Nothofagus pumilio forests in the Andes of south‐central Chile (38° S, 71° W) burned in 2015.MethodsWe evaluated the post‐fire plant regeneration across a fire severity gradient ranging from unburned forests to areas of high fire severity. One year after fire (in February 2016), we measured woody and herbaceous species richness, abundance, height, origin (native vs exotic species), life forms and the spatial pattern of plant recovery.ResultsPlant species richness and abundance were significantly higher within the unburned forest and low fire severity areas one year after fire, compared to areas of high and moderate fire severity. Overall, nearly 50% of the species present in the unburned forest were not found in areas of high severity, including the tree Nothofagus pumilio. Rapid vegetative resprouting of pioneer species such as Chusquea culeou resulted in an aggregated spatial distribution of plants after fire.ConclusionsPlant diversity and the abundance of Araucaria araucana and Nothofagus pumilio were reduced in areas of high fire severity one year after fire. Exotic species were more abundant within areas of low severity, being likely mediated by cattle browsing. Our research makes clear the potential changes in forest composition and structure if dominant tree species are not capable of recovering after fire. We recommend the exclusion of cattle within fire‐affected areas and planting Nothofagus pumilio in areas of high fire severity.

Livestock exclusion from watercourses: Policy effectiveness and implications

The deterioration of water quality in Ireland over the past thirty years and the nutrient losses from agriculture are of particular concern to policy makers. Agri-environmental schemes (AES) are designed to improve the environment and water quality. One of the more common AES measures is the exclusion of cattle from watercourses. Cattle exclusion provides a number of benefits such as reduction in nitrogen, phosphorus and sediment run-off, riverbank stability and improved vegetation cover and biodiversity. Using GIS methods a new national farm boundary spatial database SLIDE (Spatial Land Identification Database for Éire) is created utilising national administrative data and a spatial data storage model. This is the first examination of cattle exclusion and its cost effectiveness at the individual farm level across a national population of farms. Benefits are measured in the form of reduced in-stream faecal deposits. The spatial distribution of cost-effectiveness at the sub-catchment level highlights the differences between areas in terms of costs, benefits and extent. A cluster analysis is used to aggregate results. This information is utilised to undertake an ex-ante examination of the implications of a national policy to restrict cattle access to waterbodies for specific categories of farmers, under the EU Nitrates Directive. The analysis of the clusters show that due to the reduction of faecal deposition in watercourses, fencing on medium and high intensity farms is ∼20 % more cost effective relative to farms with lower livestock densities. This study makes an important contribution to the literature in broadening our understanding of the impacts of policy decision making at the individual farm level and also the costs and scale of AES measures at a national level.

Strategic Grazing in Beef-Pastures for Improved Soil Health and Reduced Runoff-Nitrate-A Step towards Sustainability

Generally, improvement in the soil health of pasturelands can result in amplified ecosystem services which can help improve the overall sustainability of the system. The extent to which specific best management practices have this effect has yet to be established. A farm-scale study was conducted in eight beef-pastures in the Southern Piedmont of Georgia, from 2015 to 2018, to assess the effect of strategic-grazing (STR) and continuous-grazing hay distribution (CHD) on soil health indicators and runoff nitrate losses. In 2016, four pastures were converted to the STR system and four were grazed using the CHD system. Post-treatment, in 2018, the STR system had significantly greater POXC (by 87.1, 63.4, and 55.6 mg ha−1 at 0–5, 5–10, and 10–20 cm, respectively) as compared to CHD system. Soil respiration was also greater in the STR system (by 235 mg CO2 m-2 24 h−1) and less nitrate was lost in the runoff (by 0.21 kg ha−1) as compared to the CHD system. Cattle exclusion and overseeding vulnerable areas of pastures in STR pastures facilitated nitrogen mineralization and uptake. Our results showed that the STR grazing system could improve the sustainability of grazing systems by storing more labile carbon, efficiently mineralizing soil nitrogen, and lowering runoff nitrate losses.

Deforestation and current management practices reduce soil organic carbon in the semi-arid Chaco, Argentina

The soil is a fundamental component of the C cycle. Land use changes can alter the soil organic carbon (SOC) content, a key determinant of several regulation ecosystem services. Here, we analyzed the effects of land cover (e.g. from forest to cropland) and land use (i.e. management practices) change on SOC in the semi-arid Chaco of Argentina, a global deforestation hotspot. Using the CENTURY model, we analyzed SOC changes over 20 years for two sites with contrasting rainfall (600 and 800 mm). For each site, we evaluated the effect of different combination of management practices (e.g. fertilization, grazing intensity) and land uses (i.e. annual crops and sown pastures). 98.5% of the simulations performed for cropping systems showed a reduction in SOC, with an average reduction of 25% respect to the native forest. Wheat proportion in the crop rotation had the highest relative influence on SOC variation (54%), higher than the proportion of maize (26.4%) and nitrogen fertilization (9.8%). For sown pastures, <40% of the simulations showed SOC decreases up to 18%. Grazing intensity had the greatest relative influence on SOC variation in both sites (>60%), followed by burning (19%), temporary exclusion of cattle (12%) and nitrogen fertilization (4.3%). In most cases SOC changes were mainly explained by changes in C inputs (i.e. NPP) rather than by changes in outputs (i.e. respiration and erosion). Therefore, delta SOC showed a strong negative relationship with the Human Appropriation of NPP (R2 = 0.54 and 0.67 in cropping systems and pastures, respectively). Overall, our results suggest that land use change has negative effects on SOC regardless of the management practices implemented. The few combinations that balanced food production and carbon sequestration were maize monocultures with annual N fertilization, and cattle raising with temporary exclusion and burning suppression. Our results may be used to define management practices that allow maintaining soil carbon stocks in the upper soil layer.