Removal Of Livestock Research Articles

Responses of plant and microbial C:N:P stoichiometry to livestock removal

Livestock removal (LR) is considered an effective strategy for recovering ecosystem functions in degraded grasslands. Carbon (C), nitrogen (N), and phosphorus (P), as well as their ratios in plants and microorganisms, act as key regulators of ecosystem stability and nutrient limitation during grassland succession. However, few studies have comprehensively evaluated plant and microbial nutrient limitations through C:N:P stoichiometry following LR over different durations. Here, our study explored the C, N, P contents, and C:N, C:P and N:P ratios of green and senescent leaves, microbial biomass and extracellular enzymes after 33 years of LR on the Loess Plateau, China. The results showed that LR increased the C, N, and P contents of plant and microbial communities. LR (>26 years) enhanced C, N, P contents of green leaves by 364.7 %, 232.2 %, 134.6 %, and C, N, P contents of senescent leaves by 164.8 %, 230.8 %, 86.3 %, respectively. LR also increased plant C:P and N:P ratios and the P reabsorption efficiency, indicating that the plant communities shifted from N to P-limitation during grassland restoration. Compared with the grazing sites, LR26 increased C, N, P contents, C:P and N:P ratios of soil microbial biomass, whereas reduced soil N-acquiring enzyme activity and enzymatic N:P ratio, indicating that the microbial community experienced higher P limitation than that of grazing sites. Plant and microbial communities showed strong plastic relationships with soil resource. Vegetation cover and productivity played strong roles in altering the plant and microbial C:N:P stoichiometry following LR. These findings indicate that long-term LR (>26 years) will exacerbate plant and microbial P limitation during grassland succession.

High resistance to non-native plant invasion exhibited in a maritime alpine environment

AbstractMost alpine ecosystems are subject to non-native species invasion as climate warms and human disturbance increases. Therefore, it is important to identify the main barriers and facilitators of alpine plant invasions. While there is much research in continental alpine areas, there is limited research in maritime environments, which have distinctive biological, edaphic and geomorphologic features due to the scarcity of snow in winter. Here, we examine the contribution of anthropogenic and biotic factors on non-native plant invasions in the alpine areas of lutruwita (Tasmania), Australia. Specifically, we test whether disturbances associated with roads and livestock grazing facilitate non-native plant invasion and if biotic resistance from native plants and wild grazing animals inhibits such invasion. We used floristic data from: a statewide database; data from long-term grazing exclosures, and data from paired quadrats on roadsides and natural vegetation. Our results showed that non-native plants were associated with roadside disturbance and livestock grazing, with the latter having a legacy effect of 50 years. The persistent effect of stock grazing was evident in the exclusion experiment monitored over 30 years, where non-native plants occurred sporadically in time and space. In contrast, we found that the presence of wild grazing mammals, complete vegetation cover and high native richness, restricted non-native plants, emphasizing the importance of biotic resistance in controlling non-native plant invasions. These results indicate that livestock removal and road closure could be effective in reversing non-native plant invasion in this and other areas with wild vertebrate herbivores and high plant cover.

Remote sensing for rangeland conservation monitoring: Impacts of livestock removal after 15 years

Abstract Degradation from overgrazing of global arid rangelands is of significant concern for this widespread terrestrial ecosystem, and the people who rely on its sustainable use. Addressing this degradation requires a better understanding of how livestock removal and conservation management actions affect the rehabilitation of land condition. However, the dominant effect of climate and meteorological variability on arid vegetation makes isolating management‐induced change a difficult task. We present an analytically simple method for measuring relative land condition by assessing differences in remote‐sensing‐derived persistent fractional vegetation between adjacent stocked and destocked regions over time. The 22‐year observation period focusses on vegetation recovery at a long‐established sheep station after the removal of livestock and the introduction of conservation‐focussed management. The study region, in the southern Australian arid rangelands, comprises sparsely vegetated chenopod shrublands and acacia woodlands across low‐lying plains. Comparison is made to immediately surrounding stocked properties in a spatial design where climate and biogeographic variables remain consistent across the study area. We found an unequivocal relative increase in vegetation cover, and reduction of bare ground cover at the destocked property that became evident approximately 8 years after a reduction in grazing pressure. Distinctly higher persistent vegetation cover was maintained, even during periods of drought. Non‐photosynthetic vegetation cover was most indicative of long‐term change and increased by 1.1% relative to surrounding areas. Photosynthetic vegetation cover increased by 0.5%, while bare ground cover decreased by 2.1%. These cover changes, particularly in the non‐photosynthetic vegetation and bare ground components spatially coincide with the fenced boundary of the destocked property. Synthesis and applications: The ability to quantify management‐related impacts in land condition using freely available remote sensing data could support improved management by all stakeholders in these regions. The method leverages readily available satellite remote sensing data in a study design that is not dependent on large geospatial and climatic datasets that are not necessarily available in remote regions.

Effects of livestock on arthropod biodiversity in Iberian holm oak savannas revealed by metabarcoding

Increasing food production while avoiding negative impacts on biodiversity constitutes one of the main challenges of our time. Traditional silvopastoral systems like Iberian oak savannas (“dehesas”) set an example, where free-range livestock has been reared for centuries while preserving a high natural value. Nevertheless, factors decreasing productivity need to be addressed, one being acorn losses provoked by pest insects. An increased and focalized grazing by livestock on infested acorns would kill the larvae inside and decrease pest numbers, but increased livestock densities could have undesired side effects on ground arthropod communities as a whole. We designed an experimental setup including areas under trees with livestock exclosures of different ages (short-term: 1-year exclusion, long-term: 10-year exclusion), along with controls (continuous grazing), using DNA metabarcoding (mitochondrial markers COI and 16S) to rapidly assess arthropod communities’ composition. Livestock removal quickly increased grass cover and arthropod taxonomic richness and diversity, which was already higher in short-term (1-year exclosures) than beneath the canopies of control trees. Interestingly, arthropod diversity was not highest at long-term exclosures (≥10 years), although their community composition was the most distinct. Also, regardless of treatment, we found that functional diversity strongly correlated with the vegetation structure, being higher at trees beneath which there was higher grass cover and taller herbs. Overall, the taxonomic diversity peak at short term exclosures would support the intermediate disturbance hypothesis, which relates it with the higher microhabitat heterogeneity at moderately disturbed areas. Thus, we propose a rotatory livestock management in dehesas: plots with increased grazing should co-exist with temporal short-term exclosures. Ideally, a few long-term excluded areas should be also kept for the singularity of their arthropod communities. This strategy would make possible the combination of biological pest control and arthropod conservation in Iberian dehesas.

Effectiveness of fattening cattle on diets of different energy levels with the use of probiotic feed additive “PROGALplv”

A full-fledged yearling of young cattle should be based on scientifically based standards, guaranteeing their genetic productivity potential, rational use of feed resources, and proper payment for feed with meat products. The current situation regarding the rationing of yearling livestock in global and domestic, both scientific and production practices, has fundamentally changed, which requires a significant revision of traditional provisions on the organization of rationed yearling and feeding of farm animals. At the same time, the conceptual requirements for the organization of standardized feeding of young livestock should be based on the general world experience of the need for energy, nutrients, and biologically active substances of animals, taking into account the age period of the growing season, with an emphasis on the quality and biosafety of products. In the intensive production of meat products, to ensure high productivity, it is only possible to do so by using feed products of natural substance, which should include additives with a phytobiological effect. One of these consists of the feed supplement “PROGALplv,” which contains the probiotic component maltodenstrin and fructooligosaccharides and belongs to the probiotic supplement for ruminants. Based on the research, optimizing the standardized feeding of fattening young animals on diets with different energy levels and using the biological feed additive “PROGALplv” at the rate of 6, 10, and 15 g/head was set a day. The research was conducted on Simmental bulls in the conditions of the farm “Pchany-Denkovych” of the Stryi district of the Lviv region. It was established that using “PROGALplv” bio-additives in the ration against the background of different energy nutrition contributed to an increase in the intensity of physiologically helpful microflora of the rumen, which had a stimulating effect in the processes of additional assimilation of nutrients. A positive result was obtained regarding the average daily gains and quality indicators of meat products and the economic efficiency of the final fattening period. Thus, based on the results of our research, it is possible to recommend the introduction of an increased level of energy nutrition of 110 % of the explicit norms into the intensive technology of livestock removal at the expense of an entirely rational feed mixture with the inclusion of the probiotic feed additive “PROGALplv” at the rate of 10 g/head per day. The optimal introduction dose to compound feed compliance is 10 g/head. The maximum amount can be no more than 15 g/h. daily. No adverse side effects of “PROGALplv” bio-additives on the general functional condition of Bugai residents were found.

Livestock removal increases plant cover across a heterogeneous dryland landscape on the Colorado Plateau

Livestock removal is increasingly used as a management option to mitigate the negative impacts of grazing-related disturbances on rangelands. Removal generally increases plant cover, but it is unclear when, where, and by how much plant and soil cover changes can be expected. On the Colorado Plateau, complex geology, topography, soils, and climate all interact to mediate the relationship between land cover, climate, and disturbance. In this study we used new developments in land cover mapping and analysis to assess landscape plant and bare soil cover up to 30 years after livestock removal from two grazing allotments in Capitol Reef National Park, Utah, USA. Results indicate that livestock removal increases plant cover 0.17%–0.32% per year and reduces bare soil cover 0.34%–0.41% per year, although these rates may be suppressed by warming temperatures. Soils, assessed through soil geomorphic units, played a strong but complex role in mediating land cover changes through time. These results suggest that livestock removal is an effective strategy for increasing plant cover and reducing bare soil on the Colorado Plateau, but including soil information in decision making will enhance efficiency by improving manager’s ability to prioritize management actions effectively across space and through time.

Aquatic invertebrate responses to riparian restoration and flow extremes in three degraded intermittent streams: An eight‐year field experiment

Abstract Worldwide, riparian zones of many intermittent rivers and ephemeral streams (IRES) have been severely degraded. However, compared with perennially flowing waters, there have been few restoration efforts (e.g., revegetation, livestock removal) to halt or reverse this degradation. Even rarer are assessments of whether desired responses occurred and, if so, their underlying mechanisms, especially where flow extremes such as drying and flooding in IRES might alter or delay ecological responses to restoration. In order to assess how aquatic invertebrate communities responded to riparian replanting and livestock removal in three degraded lowland IRES in southeastern Australia, we conducted an eight‐year experiment (2004–2013), sampling paired control (unrestored) and treatment (restored, between 2005 and 2007 across creeks) sites twice yearly before and after restoration. To evaluate likely mechanisms underlying invertebrate responses to riparian restoration, we used a range of structural (e.g., richness) and functional (e.g., trait‐based) metrics. We also monitored environmental variables predicted to be likely drivers of aquatic invertebrate responses such as macrophyte and canopy cover, water quality, instream organic matter and instream wood. The study coincided with the last few years of a decade‐long drought that broke with severe floods (in 2010–2012), so we opportunistically examined how these hydrological extremes affected invertebrate responses to riparian restoration. At all three sites, macrophyte and canopy cover, water quality, organic matter and instream wood were comparable at treatment and control sites throughout the eight‐year experiment. There were also no significant differences in structural or functional metrics to indicate aquatic invertebrate responses to restoration after 6–8 years. This lack of predicted invertebrate responses apparently reflected how severely the drought impeded the riparian restoration, delaying even short‐term responses. Pervasive effects of catchment‐scale degradation may have further diminished the predicted benefits of the reach‐scale restoration efforts. By contrast, invertebrate metrics responded strongly to flow extremes, especially the brief floods that occurred as drought broke. These responses were evident for functional groups and individual families (especially rheophilic ones), but were not detected by a commonly used integrative measure of stream condition. This highlights the importance of selecting appropriate indicators in restoration monitoring programs and recognising their variability in responsiveness to restoration versus flow extremes. IRES are abundant and, in many parts of the world, increasingly common. Understanding how their inherent hydrological extremes may delay, modify and even overwhelm predicted responses to riparian restoration is crucial to setting realistic goals for IRES in the Anthropocene. Furthermore, assessing the success of riparian restoration in IRES requires a long‐term view given the extended time frames over which responses may occur, especially when expectations are often based on results of riparian restoration of perennial streams and rivers.

Soil aggregate development and associated microbial metabolic limitations alter grassland carbon storage following livestock removal

Natural restoration of degraded grasslands following livestock removal changed soil nutrient and carbon concentrations, soil aggregate distributions, and patterns of extracellular enzyme activities. Here, we used an ecoenzymatic stoichiometry model to quantify microbial resource limitations in semiarid grassland soil aggregates at 0, 11, 26, and 36 years after livestock removal and linked these limitations to microbial carbon use efficiency (CUE), which was estimated from stoichiometry theory (CUEST). Overall, livestock removal altered the size distribution of soil aggregates, increased microbial resources and stimulated extracellular enzyme activities. Long-term livestock removal increased the proportion of small macroaggregates (2–0.25 mm). Microbial carbon (C) and phosphorus (P) limitations in soil aggregates declined to minimum levels at 26 years following livestock removal and then increased after 36 years, with an opposite trend for CUEST. Additionally, the greatest resource limitations to microorganisms were found in smaller aggregates (<2 mm) under long-term livestock removal. Random forest and structural equation models revealed that soil abiotic factors, especially total nitrogen and pH, were key determinants of microbial resource limitation in soil aggregates. Moreover, microbial C and P limitations had significant direct effects on the CUEST. Thus, increasing microbial metabolic limitations after long-term livestock removal could reduce microbial C turnover, potentially reducing soil C sequestration. Overall, this study revealed that livestock removal altered soil aggregate development as well as the allocation of resources in aggregates and consequent microbial resource limitations, providing information that may be useful for developing grassland management strategies to enhance C sequestration.

Differences in population size structures characterize grass response to long‐term livestock removal

AbstractQuestionsHow does desert grassland vegetation respond to long‐term grazing removal? Is grass response the result of differences in the number or the size of plants? Does the response differ over time and in relation to precipitation patterns?LocationSanta Rita Experimental Range, southwestern United States.MethodsFour times between 2011 and 2020, we measured the cover of woody plants and native and non‐native perennial grasses, and the density, size, and biomass of individual perennial grasses on 40 permanent transects inside and outside 10 long‐term (88–104 years old) livestock exclosures (0.1–4.0 ha) occurring on the same ecological site. We used linear mixed models to compare vegetation variables in grazed vs ungrazed transects through time and calculated the cumulative frequency distributions of grass plant diameters.ResultsThe cover of woody plants did not differ by grazing treatment. Instead, the exclosures had a greater cover, density, and biomass of native grasses and cover and biomass of the most abundant native grass Arizona cottontop (Digitaria californica). Moreover, ungrazed populations of natives and Arizona cottontop showed a plant size structure skewed to larger sizes. Non‐native grasses showed no differences between grazing treatments. Patterns of inter‐annual precipitation influenced woody and grass plant abundance, but not their response to livestock removal.ConclusionsLong‐term grazing removal in desert grasslands affected native grass abundance, but not that of non‐native grasses and woody plants. Response of native grasses to livestock removal was characterized more by plant size rather than the number of plants, and, importantly, the population size structure skewed to smaller plants in grazed areas suggests that grazing limits plant vigor and longevity. Absence of a non‐native grass response likely reflects lower palatability and greater grazing resistance of non‐natives. Absence of woody plant response is due to their low palatability and the permeability of exclosures to seed dispersal.

Assessing Asiatic cheetah’s individual diet using metabarcoding and its implication for conservation

Knowledge on diet composition allows defining well-targeted conservation measures of large carnivores. Little is known about ecology of critically endangered Asiatic cheetah, especially the overall diet and its possible regional differences. We used cheetah scats, metabarcoding technique and microsatellite markers to assess the individual and overall diet composition of the species across its entire range in Asia. Cheetahs were primarily predating on mouflon; following by ibex, cape hare and goitered gazelle. Despite their high availability, small-sized livestock was never detected. Goitered gazelles were only detected in an area where the habitat is mainly flatlands. In hilly areas, mouflon was the most frequent prey item taken. Ibex was typically taken in rugged terrain, but mouflon was still the most frequently consumed item in these habitats. High consumption of mouflon in comparison to goitered gazelle suggests that human pressure on lowland habitats has possibly forced Asiatic cheetahs to occupy suboptimal habitats where gazelles are less abundant. The protection of flatlands and the removal of livestock from them are needed to ensure the long-term survival of Asiatic cheetah. The laboratory and bioinformatics pipelines used in this study are replicable and can be used to address similar questions in other threatened carnivores.

Soil Aggregate Development and Associated Microbial Metabolic Limitations Alter Grassland Carbon Storage Following Livestock Removal

Soil Aggregate Development and Associated Microbial Metabolic Limitations Alter Grassland Carbon Storage Following Livestock Removal

Long-term grazing removal increased invasion and reduced native plant abundance and diversity in a sagebrush grassland

Effects of long-term grazing removal on vegetation are highly variable across ecosystems and grazing contexts. In some cases, long-term exclosures can be used to enhance vegetation production, plant diversity, or wildlife habitat. In other situations, exclosures can become more invaded by undesirable species, less drought-tolerant, or less diverse than grazed sites. Grasslands in North America’s semi-arid Great Plains prairies can tolerate large herbivore grazing and resist invasion, while cold desert shrublands of the Intermountain West are more invisible and sensitive to grazing. These major ecoregions intersect in northeast Wyoming, where a diverse ecotonal plant community supports a wide array of sensitive wildlife. The effects of grazing removal on vegetation and invasive species in this ecotone are poorly understood, despite clear implications for conservation and management. In 2016, we measured effects of long-term (>49 year-old) livestock exclosures on vegetation and soil properties in the ecotone. Compared to adjacent grazed sites, exclosures had 72% less foliar cover of drought-resistant, warm-season perennial grasses, fewer native species, and nearly three times as much invasive annual grass cover. Long-term livestock removal did not affect live sagebrush shrub cover, density or size, but led to taller herbaceous vegetation structure. Findings suggest that although long-term grazing removal may be useful for achieving taller structure, light to moderate levels of large herbivore grazing may be necessary to resist invasion and maintain ecosystem integrity in this ecotone. In the context of ongoing global change, it will be critical to maintain natural disturbance regimes such as grazing in ecosystems that evolved with disturbance. In these systems, a total lack of natural disturbance does not represent a reasonable target or reference state. Instead, management for a range of disturbance frequencies and intensities across the landscape will likely support high vegetation heterogeneity, which in turn will help conserve high biodiversity and ecosystem function.

Using Stubble Height to Monitor Livestock Disturbance Near Streams: How a Recent Critique is Relevant to the Protection of Cold-water Salmonids

On the Ground • The measurement of utilization and residual vegetation (stubble height) is a valuable tool in managing livestock disturbance but it is often improperly measured, and results misinterpreted. A common situation for these concerns is when stubble height protocols and rationales used for terrestrial areas are applied to riparian zones and the protection of fish habitat. • Protocols used to assess stubble height near streams and serve as a surrogate for fish habitat may differ from approaches used to protect upland plant vigor. Measurements of stubble height designed to protect fish habitat can include the measurement of all herbaceous vegetation along the greenline and should be evaluated following the removal of livestock and after the growing season ends. • In allotments with threatened salmonids or other at-risk aquatic species, stubble heights necessary to protect fish habitat may exceed what is necessary to maintain forage production for livestock. Properly determined and applied near stream stubble height standards can protect important fish habitats while providing accountability for grazing management. Consistent livestock management above standards will improve salmonid habitats and undermine arguments used by organizations that would like to limit livestock grazing on public lands. • If range conservationists and fisheries biologists work together to develop monitoring protocols for stubble height or other metrics that can be used to improve fish habitat, the application of proper standards to manage livestock disturbance near streams should benefit the fish, the land management agencies, and the ranchers that rely on grazing public lands.

A resilient system: North American mixed-grass prairie responds rapidly to livestock exclusion

Grasslands are the most threatened terrestrial ecosystem in the world, and as their extent declines so does the abundance of species that depend on them. Periodic resting of rangelands could be used to manipulate plant cover and create wildlife habitat, but its effects may vary with prior grazing intensity. Using a large-scale manipulative grazing experiment conducted from 2006 to 2014 in Grasslands National Park, Canada, we evaluated how the effects of rest on vegetation and songbird abundance varied based on previous cattle stocking rates. Our results indicate that in northern mixed-grass prairies, grazing-induced changes were reversible, even at high stocking rates applied for up to four years. Both vegetation and songbirds were resilient to grazing, generally returning to levels observed prior to livestock reintroduction in three or fewer years following removal of livestock. Songbirds with flexible habitat requirements, such as Passerculus sandwichensis and Ammodramus savannarum, responded more rapidly to livestock exclusion. Recovery of both plant and songbird species occurred more rapidly in lowlands than uplands. The retrogressive nature of succession in North American mixed-grass prairies offers managers an opportunity to take chances when attempting to create wildlife habitat with livestock grazing, as risk of irreversible change is relatively low under moderate climate conditions.

Native lagomorphs suppress grass establishment in a shrub-encroached, semiarid grassland.

Shrub encroachment into arid grasslands has been associated with reduced grass abundance, increased soil erosion, and local declines in biodiversity. Livestock overgrazing and the associated reduction of fine fuels has been a primary driver of shrub encroachment in the southwestern United States, but shrublands continue to persist despite livestock removal and grassland restoration efforts. We hypothesized that an herbivory feedback from native mammals may contribute to continued suppression of grasses after the removal of livestock. Our herbivore exclusion experiment in southeastern Arizona included five treatment levels and allowed access to native mammals based on their relative body size, separating the effects of rodents, lagomorphs, and mule deer. We included two control treatments and replicated each treatment 10 times (n = 50). We introduced uniform divisions of lawn sod (Cynodon dactylon) into each exclosure for 24‐hr periods prior to (n = 2) and following (n = 2) the monsoon rains and used motion‐activated cameras to document herbivore visitations. In the pre‐monsoon trials, treatments that allowed lagomorph access had less sod biomass relative to other treatments (p < 0.001), averaging 44% (SD 36%) and 29% (SD 45%) remaining biomass after the 24‐hr trial periods. Following the onset of monsoons, differences in remaining biomass among treatments disappeared. Desert cottontails (Sylvilagus audubonii) were detected more frequently than any of the other 11 herbivore species present at the site, accounting for 83% of detections during the pre‐monsoon trials. Significantly more (p < 0.001) desert cottontails were detected during the pre‐monsoon trials (2,077) compared to the post‐monsoon trials (174), which coincided with biomass removal from lagomorph accessible treatments. We conclude that desert cottontails are significant consumers of herbaceous vegetation in shrub‐encroached arid grasslands and they, along with other native herbivores, may act as a biotic feedback contributing to the competitive advantage and persistence of shrubs.

Warming and land use change concurrently erode ecosystem services in Tibet.

Alpine meadows on the Tibetan Plateau comprise the largest alpine ecosystem in the world and provide critical ecosystem services, including forage production and carbon sequestration, on which people depend from local to global scales. However, the provision of these services may be threatened by climate warming combined with land use policies that are altering if and how pastoralists can continue to graze livestock, the dominant livelihood practice in this region for millennia. We synthesized findings from a climate warming and yak grazing experiment with landscape-level observations in central Tibet to gain insight into the trajectories of change that Tibet's alpine meadows will undergo in response to expected changes in climate and land use. We show that within 5years, experimental warming drove an alpine community with intact, sedge-dominated turfs into a degraded state. With removal of livestock, consistent with policy intended to reverse degradation, a longer-term shift to a more shrub-dominated community will likely occur. Neither degraded nor shrub meadows produce forage or sequester carbon to the same degree as intact meadows, indicating that climate warming and drying will reduce the ability of Tibet's alpine meadows to provide key ecosystem services, and that livestock reduction policies intended to counteract trajectories of land degradation instead endanger contemporary livelihoods on the Tibetan Plateau.

Plant community responses to bison reintroduction on the Northern Great Plains, United States: a test of the keystone species concept

Keystone species restoration, or the restoration of species whose effect on an ecosystem is much greater than their abundance would suggest, is a central justification for many wildlife reintroduction projects globally. Following restoration, plains bison (Bison bison L.) have been identified as a keystone species in the tallgrass prairie ecoregion, but we know of no research to document similar effects in the mixed‐grass prairie where restoration efforts are ongoing. This study addresses whether Northern Great Plains (NGP) mixed‐grass prairie plant communities exhibit traits consistent with four central keystone effects documented for bison in the tallgrass prairie. We collected species composition, diversity, abundance, bare ground cover, and plant height data in three treatments: where livestock (Bos taurus L.) continuously grazed, livestock were removed for 10 years, and bison have been introduced and resident for 10 years. We observed mixed support for bison acting as keystone species in this system. Supporting the keystone role of bison, we observed higher species richness and compositional heterogeneity (β‐diversity) in the bison treatment than either the livestock retention or livestock removal treatments. However, we observed comparable forb, bare ground, and plant height heterogeneity between bison‐restored sites and sites where livestock were retained, contradicting reported keystone effects in other systems. Our results suggest that after 10 years of being restored, bison partially fulfill their role as a keystone species in the mixed‐grass prairie, and we encourage continued long‐term data collection to evaluate their influence in the NGP.

Invisible barriers: Differential sanitary regulations constrain vulture movements across country borders

Political boundaries may represent ecological barriers due to differences in wildlife management policies. In the European Union, it might be expected that these differences should be highly diluted, because all countries have to comply with common directives issued by the European Commission. However, the subsidiarity principle may lead to the uneven uptake of European Union regulations, which can impact on biodiversity conservation due to unequal legislation in neighboring countries, particularly in the case of highly mobile organisms. Here we address this issue, by analyzing how EU regulations issued in response to the Bovine Spongiform Encephalopathy (BSE) crisis differentially affected vulture conservation in Portugal and Spain. Taking advantage of the intensive GPS-tracking of 60 griffon (Gyps fulvus) and 11 cinereous vultures (Aegypius monachus) from Spain, we found that the Spanish-Portuguese border acts as a quasi-impermeable barrier. In fact, there was an abrupt decline in the number of vulture locations across the Spanish-Portuguese border, with modelling showing that this was unlikely to be related to differences in land cover or topography. Instead, the pattern found was likely due to differences in trophic resource availability, namely carcasses from extensive livestock husbandry, resulting from the differential application of European sanitary legislation regarding the mandatory removal of dead livestock from the field. Overall, our results should be seen as a warning signal to policy makers and conservation managers, highlighting the need for a stronger integration of sanitary and environmental policies at the European level.

Recovery potential of microwetlands from agricultural land uses

SummaryMany ecosystems located within agricultural landscapes are in decline, particularly woodlands, grasslands and wetlands. Surviving remnants are generally fragmented and unrepresentative of pre‐disturbance states. Here, we investigate the potential for recovery of ecosystem function in a grassy woodland–wetland mosaic in south‐eastern Australia. We focus on the Plains Woodland/Herb‐rich Gilgai Wetland Mosaics which have declined in extent by 85%. The gilgai soils form a distinctive microrelief of mounds and depressions which become seasonally waterlogged, providing important habitat for a large range of aquatic and dryland species. We surveyed 10 remnants subject to agricultural intensification and seven remnants subject to passive restoration (four with cessation of cultivation and three with livestock removal). Gilgai microrelief was homogenized by cultivation, showed some recovery after release from cultivation, and was insensitive to grazing pressure. Floristic diversity, assessed through indicator species, was vulnerable to grazing. Indicator species were more prevalent in previously grazed sites, but further study is required to determine whether this reflects recovery or differing overall management history. We conclude that passive restoration is possible for recovery of wetland function and some biodiversity values. These conservation actions should be encouraged given the important role these microwetlands play in landscape connectivity and as drought refugia.

Passive recovery of small vertebrates following livestock removal in the Australian rangelands

AbstractIn arid environments, grazing by exotic herbivores, including domestic livestock, can greatly influence native, small vertebrate assemblages. Whether the removal of livestock facilitates passive recovery of these assemblages depends on habitat condition and the species present. We explore changes in small mammal and reptile species richness, abundance, and composition in a degraded chenopod shrubland dominated by Acacia victoriae ssp. and open Acacia aneura (mulga) woodland destocked in 1976 and 1984, respectively. Data were obtained between 1997 and 2007, from two grazed and two ungrazed sites in each community. Species richness increased at a faster rate in ungrazed open A. aneura woodland, but did not differ significantly between ungrazed and grazed degraded chenopod shrubland. Subsequent analyses at a finer‐scale detected disparate responses in richness and abundance for microhabitat. At this scale, a greater number of species‐specific responses were also detected, including increased abundance of generalist species and decreased abundance of species requiring low cover. These results reiterate the potential for species‐specific responses to livestock that are more apparent in particular microhabitats. Furthermore, this investigation provides evidence for the gradual passive recovery of small mammal and reptile assemblages in both communities, which is facilitated by the removal of livestock in open A. aneura woodland in fair condition, but not degraded chenopod shrubland in poor condition.