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1.
The combination of abiotic stress and consumer stress can have complex impacts on plant community structure. Effective conservation and management of semi-arid ecosystems requires an understanding of how different stresses interact to structure plant communities. We explored the separate and combined impacts of episodic drought, livestock grazing, and wild ungulate herbivory on species co-occurrence and diversity patterns in a relatively productive, semi-arid Acacia savanna. Specifically, we analyzed 9 years of biannual plant community data from the Kenya long-term exclosure experiment, a broad-scale manipulative experiment that has excluded different combinations of large mammalian herbivores from 18 4-ha plots since 1995. During droughts, we observed low species diversity and random species co-occurrence patterns. However, when rain followed a major drought, areas exposed to moderate cattle grazing displayed high species diversity and evidence of significant species aggregation. These patterns were not apparent in the absence of cattle, even if other large herbivores were present. To explore possible mechanisms, we examined patterns separately for common and rare species. We found that aggregation patterns were likely driven by rare species responding similarly to the availability of open micro-sites. Our results indicate that in a productive, fire-suppressed savanna, the combination of periodic drought and moderate cattle grazing can enhance plant biodiversity and fine-scale spatial heterogeneity by opening up space for species that are otherwise rare or cryptic. Our findings also emphasize that domestic herbivores can have significantly stronger impacts on plant community dynamics than wild herbivores, even in an ecosystem with a long history of grazing.  相似文献   

2.
Published reports of Brucella abortus infections in wild North American ungulates and domestic cattle herds were reviewed to determine if infection in these species was related. Bison (Bison bison) were frequently found infected, but are probably a minor threat to livestock due to their current limited distribution. Most elk (Cervus elaphus) were free of infection except where their range was shared with infected bison or livestock. Deer (Odocoileus spp.), pronghorns (Antilocapra americana), moose (Alces alces), and bighorn sheep (Ovis canadensis) appeared to be insignificant hosts of Brucella abortus. The lack of significant wild ungulate hosts and the distribution of infected livestock herds in the United States suggests that wild ungulates are of little importance in the epidemiology of infections by B. abortus in cattle.  相似文献   

3.
Disturbances and ecosystem recovery from disturbance both involve numerous processes that operate on multiple spatial and temporal scales. Few studies have investigated how gradients of disturbance intensity and ecosystem responses are distributed across multiple spatial resolutions and also how this relationship changes through time during recovery. We investigated how cover of non-native species and soil-aggregate stability (a measure of vulnerability to erosion by water) in surface and subsurface soils varied spatially during grazing by burros and cattle and whether patterns in these variables changed after grazer removal from Mojave National Preserve, California, USA. We compared distance from water and number of ungulate defecations — metrics of longer-term and recent grazing intensity, respectively, — as predictors of our response variables. We used information-theoretic analyses to compare hierarchical linear models that accounted for important covariates and allowed for interannual variation in the disturbance–response relationship at local and landscape scales. Soil stability was greater under perennial vegetation than in bare interspaces, and surface soil stability decreased with increasing numbers of ungulate defecations. Stability of surface samples was more affected by time since removal of grazers than was stability of subsurface samples, and subsurface soil stability in bare spaces was not related to grazing intensity, time since removal, or any of our other predictors. In the high rainfall year (2003) after cattle had been removed for 1–2 years, cover of all non-native plants averaged nine times higher than in the low-rainfall year (2002). Given the heterogeneity in distribution of large-herbivore impacts that we observed at several resolutions, hierarchical analyses provided a more complete understanding of the spatial and temporal complexities of disturbance and recovery processes in arid ecosystems.  相似文献   

4.
Shifts in native ungulate communities on a former cattle ranch in Tanzania   总被引:3,自引:0,他引:3  
When an area is brought under protection, current animal populations and their habitat preferences need to be assessed to predict population trends and future habitat availability. Using data from walking transects, we estimated the size of native ungulate populations on an abandoned cattle ranch in a coastal savannah in Tanzania, now included in the new Saadani National Park. Data were analysed with distance sampling and conventional strip transect techniques and were compared with results of previous wildlife counts. Few individuals of mainly browsing species were present in former cattle grazing areas exhibiting high bush‐encroachment while a ten times higher biomass of browsers and grazers was found in the cattle‐unmodified savannah. Population sizes of some species increased twofold between 1991 and 2001 within the entire area but neither population size nor species richness increased in the abandoned rangeland during our 3‐year study period from 2001 to 2003. We conclude that the former ranch has potential for future recolonization by wild ungulates. Resettlement will take place gradually with ‘pioneer‐species’ facilitating the entry of more demanding species. Habitat restoration through wildlife can be observed and quantified on Mkwaja Ranch which will be of importance for future management of native ungulates reclaiming abandoned rangeland.  相似文献   

5.
We investigated wolf feeding habits in relation to the abundance of wild and domestic ungulates to test the hypothesis that large prey are preferred and that their abundance affects the use of other food categories and diet breadth. We determined diet composition by scat analysis from December 1987 to December 1992. The research was carried out in three study areas located in northern Italy and characterised by marked differences in wild and domestic ungulate abundance. In study area A (low wild and domestic ungulate availability) fruits, livestock, other vertebrates and wild ungulates made up the bulk of the diet (71% in volume). In area B (high availability of livestock) wolf diet was mainly based on sheep and wild boars (80% in volume). In study area C (high availability of wild ungulates) wild ungulates were the main food of wolves (90% in volume). Significant differences were found among study areas in the mean percentage volume of all food categories and in particular for wild ungulates, livestock, other vertebrates and fruits (p < 0.0001 in all cases). Diet breadth decreased in areas with high availability of large wild and domestic herbivores. The use of livestock species was lower where there was high abundance, richness and diversity of the wild ungulate guild. Selection for wild ungulate species was partially affected by their abundance: however other factors as prey social behaviour, adaptability to the habitat (for introduced species), and body size could have an important role in species selection by wolves. In particular in area C wild boars were selected for, roe and red deers avoided, and fallow deers and mouflons used as available. Livestock species were used in relation to their abundance and accessibility, in particular sheep were selected for and cattle avoided; but if calves bom in the pastures were considered as the only available cattle, they were selected for and sheep were used as available. Large and in particular wild herbivores were found to be of great importance for the wolf population maintenance in northern Italy, one of the most important recovery areas of Mediterranean wolves.  相似文献   

6.
Douglas A. Frank 《Oikos》2008,117(11):1718-1724
The importance of top predators in controlling ecological processes in large, intact ecosystems is unclear. In grasslands that support abundant ungulates, top–down control by predators may be particularly important, because of the tight biogeochemical linkages of ungulate prey with plants and soil microbes. Here, I examined the effects of the recent reintroduction of the gray wolf Canis lupus on ecosystem processes in Yellowstone National Park, where herds of grazing ungulates previously have been shown to stimulate several processes, including soil net nitrogen (N) mineralization. Rates of ungulate grazing intensity and soil net N mineralization were compared before and after wolf reintroduction in grasslands ranging five‐fold in aboveground production. Grazing intensity and grassland net N mineralization declined after wolf reintroduction, a likely partial function of fewer ungulates; wolf predation has been one of several factors implicated in causing the decline in Yellowstone ungulates. In addition, the spatial pattern of grazing and net N mineralization changed after reintroduction. A shift in the spatial patterns of grazer‐associated processes is consistent with a growing body of work indicating that wolves have changed habitat use patterns of ungulates in Yellowstone National Park. These findings suggest widespread wolf effects on ungulate prey, plants, and microbial activity that have spatially reorganized grassland energy and nutrient dynamics in Yellowstone Park.  相似文献   

7.
Manier DJ  Hobbs NT 《Oecologia》2007,152(4):739-750
Improving understanding of the connections between vegetation, herbivory, and ecosystem function offers a fundamental challenge in contemporary terrestrial ecology. Using exclosures constructed during the late 1950s, we examined effects of grazing by wild and domestic herbivores on plant community structure, aboveground herbaceous primary production, and nutrient cycling at six sites in semi-arid, sagebrush rangelands during 2001-2002 in Colorado, USA. Enclosures provided three treatments: no grazing, grazing by wild ungulates only, and grazing by wild and domestic ungulates. Excluding all grazing caused an increase in shrub cover (F = 4.97, P = 0.033) and decrease in bare ground (F = 4.74, P = 0.037), but also a decrease in plant species richness (F = 6.19, P = 0.018) and plant diversity (F = 7.93, P = 0.008). Effects of wild ungulate grazing on plant cover and diversity were intermediate to the effects of combined domestic and wild grazing. Aboveground net primary production was higher in both grazed treatments than in the ungrazed one (F(wild + domestic) = 2.98, P = 0.0936 and F(wild only) = 3.55, P = 0.0684). We were unable to detect significant effects of grazing on other ecosystem states and processes including C:N ratios of standing crops, N mineralization potential, or nitrification potential. Best approximating models revealed positive correlation between N availability and herbaceous cover and a negative correlation between herbaceous primary production and the ratio of shrub-herb cover and plant diversity. We conclude that ungulate herbivory, including both wild and domestic ungulates, had significant effects on plant community structure and ecosystem function during this 42-year span. Responses to the wild ungulate treatment were consistently intermediate to responses to the no grazing and wild + domestic grazing treatments. However, we were unable to detect statistical difference between effects of wild ungulates alone and wild ungulates in combination with livestock.  相似文献   

8.
The abandonment of traditional livestock farming systems in Mediterranean countries is triggering a large-scale habitat transformation, which, in general, consists of the replacement of open grazing areas by woodlands through non-managed regeneration. As a consequence, wild ungulates are occupying rapidly the empty niche left by domestic ungulates. Both types of ungulates represent the main trophic resource for large vertebrate scavengers. However, a comparison of how vertebrate scavengers consume ungulate carcasses in different habitats with different ungulate species composition is lacking. This knowledge is essential to forecast the possible consequences of the current farmland abandonment on scavenger species. Here, we compared the scavenging patterns of 24 wild and 24 domestic ungulate carcasses in a mountainous region of southern Spain monitored through camera trapping. Our results show that carcasses of domestic ungulates, which concentrate in large numbers in open pasturelands, were detected and consumed earlier than those of wild ungulate carcasses, which frequently occur in much lower densities at more heterogenous habitats such as shrublands and forest. Richness and abundance of scavengers were also higher at domestic ungulate carcasses in open habitats. Vultures, mainly griffons (Gyps fulvus), consumed most of the carcasses, although mammalian facultative scavengers, mainly wild boar (Sus scrofa) and red fox (Vulpes vulpes), also contributed importantly to the consumption of wild ungulate carcasses in areas with higher vegetation cover. Our findings evidence that the abandonment of traditional grazing may entail consequences for the scavenger community, which should be considered by ecologists and wildlife managers.  相似文献   

9.
Anthropogenic activities usually trigger changes in the population density of plants. Thus, land management practices can influence density‐dependent demographic parameters and species interactions. We investigated plant‐pollinator interactions and reproduction in Prosopis flexuosa, the largest tree species in the Central Monte desert of Argentina, an important economic and cultural resource for humans and a functionally prominent species. We hypothesized that reproductive output of P. flexuosa would be limited at low densities, and that exclusion of catle grazing would enhance population density and consequently interaction frequency with pollinators and reproductive success. The study was conducted in and around Ñacuñán Biosphere Reserve (Mendoza, Argentina), where cattle grazing has been excluded for over 35 years. Working in five pairs of protected and cattle grazed 1‐ha plots, we recorded density of adult trees, pollinator visitation frequency to inflorescences and seeds per inflorescence in focal trees. Adult tree density was higher in protected plots than in cattle grazed plots. Density of reproductive trees was positively correlated with seed production, suggesting positive density dependence for reproduction (Allee effect). Pollinator visitation to inflorescences and seed production was higher in protected plots compared with plots under cattle grazing. Suppression of anthropogenic degradation has resulted in higher adult tree density in protected plots, indirectly higher pollinator visitation to inflorescences and higher reproductive success of trees. Increased frequency of plant‐pollinator interactions and tree reproduction suggest success of management practices aimed at protecting P. flexuosa woodlands.  相似文献   

10.
Insects and ungulates co‐occur in grasslands, often feeding on the same plants at the same time and potentially having interactive effects on plant growth. Further, ungulate–insect interactions may differ between native ungulate guilds and domesticated cattle. Despite the prevalence of insects and ungulates in native grasslands, experiments simultaneously manipulating the densities of both these groups are rare. Using large, replicated paddocks, as well as insecticide application, we restricted access to vegetation by each group of herbivores. We also manipulated the species identity of the ungulate assemblage, allowing us to determine whether there are differential effects between native ungulate guilds (bison, elk and deer) and cattle on plant biomass. We found interactive effects of insect and ungulate herbivores on root growth. When insects were suppressed, both native ungulates and cattle caused an approximate doubling of root biomass. However, this stimulatory effect of ungulate grazing was eliminated when insects were also present. In contrast, neither insects nor ungulates had significant effects on shoot biomass at these densities. As a result, the dominant effects of above‐ground herbivory was on belowground plant growth. We suggest the effects of insect and ungulate assemblages on root biomass appear important in regulating primary production in this grassland and may account for some of the contradictory plant responses to ungulate herbivory in the literature.  相似文献   

11.
Livestock grazing is an increasing conservation challenge throughout protected wildlife areas in Africa. We report here on a negative correlation in abundance between cattle and the mountain nyala across seven study areas in the Bale Mountains of Ethiopia, and investigate if this can be explained by similarity in feeding ecology and spatial overlap. Mountain nyala foraging behaviour was studied using scan sampling of 17 GPS/VHF‐collared animals, while faecal sampling of both species was used to quantify abundance and spatial overlap. We found that female and male mountain nyala grazed during 87% and 50% of the feeding observations respectively. Although mountain nyala has earlier been classified as a browser, our findings indicate a feeding ecology closer to a grazer. The overall spatial overlap between mountain nyala and cattle was 22%, with a range of 2.4–100% among areas, and illegal cattle grazing was common. Based on the negative correlation in abundance, the similarity in feeding ecology and the relatively high spatial overlap we speculate that a competitive interaction between mountain nyala and cattle might occur. Our findings points to the potential for existence of a wildlife‐cattle conflict also in the Ethiopian highlands, as frequently reported in savannah ecosystems.  相似文献   

12.
The American Bison (Bison bison Linnaeus) in the Henry Mountains are one of the last free-roaming, genetically pure herds of bison remaining in North America. Anecdotal evidence indicates that this herd is utilising a cattle winter range during the summer and fall, creating a conflict between the state agency that manages the bison, and the Bureau of Land Management (BLM) and local ranchers. In theory, the addition of bison grazing pressure could reduce forage availability in the short term and lead to undesired changes in the plant community in the long term. Our objective was to determine whether bison have altered the plant species composition of the cattle winter range. We characterised plant species composition, percent cover, and grazing intensity on three adjacent, geomorphologically similar mesas. Grazing regimes were different on the three mesas, one with bison and cattle present, one with cattle only present, and the third with neither cattle nor bison present. Vegetation surveys were accompanied by a 28-year remote sensing time series to test for temporal shifts in an index of primary productivity. We found a higher grazing intensity on two dominant forage species on the bison plus cattle grazed mesa in fall, before the cattle were turned out to winter pasture. Despite this difference in grazing intensity, we found few differences in species composition, percent cover, or NDVI across the three grazing regimes. Our results suggest that high intensity summer bison grazing, while likely creating short-term reductions in forage availability, has not caused differences in plant community composition or productive potential. Shifts in community composition can take years to unfold and just as long to correct; therefore, continued monitoring of the combined effects of cattle and bison is needed.  相似文献   

13.
Fear of predators fundamentally shapes the ecology of prey species and drives both inter- and intra-specific interactions. Extensive research has examined the consequences of predation risk from large carnivores on the behavior of wild ungulate prey species. However, many large carnivores not only hunt wild prey but also depredate domestic livestock, especially in pastoralist systems where livestock share land and resources with large carnivores. Northern Tanzania is a hotspot for human–carnivore conflict driven by livestock depredation and interactions are particularly severe between African lions Panthera leo and pastoralist cattle Bos taurus. In this ecosystem, we explored the degree to which pastoralist cattle exhibited anti-predator behaviors during their daily grazing routines. Using focal animal sampling, we compared two typical anti-predator behaviors, vigilance and grouping, among cattle in village rangelands with high and low background depredation rates. We found that cattle in high risk village rangelands formed 21.2% larger groups than cattle in low risk village rangelands. Interestingly, cattle in low risk village rangelands spent 68.4% more time vigilant than cattle in high risk village rangelands. These patterns were influenced significantly by the time of day: as sunset approached, cattle in low risk village rangelands spent more time vigilant and cattle in high risk village rangelands formed larger groups. These results suggest that pastoralist cattle exhibit anti-predator strategies that vary both spatially and temporally, and that such strategies might help livestock optimally tradeoff the costs and benefits of anti-predator behavior across timescales (i.e. the risk allocation hypothesis). We discuss the implications of our results for husbandry techniques that might reduce behavioral costs associated with cattle anti-predator behaviors and help increase tolerance for lions and other large carnivores. These improvements are critical to human–carnivore coexistence given the prevalence of pastoralism globally and the rising potential for conflict with large carnivores such as lions.  相似文献   

14.
In a 20-year-survey, 9364 dairy cattle in 324 herds kept under a zero-grazing management, 1252 beef cattle in 46 herds grazing all the year round, 3347 sheep in 134 herds (only 26 are grazing herds), and 872 goats in 47 herds (only 20 are grazing) were examined. The mites collected from cattle were identified as Chorioptes texanus only, and those from sheep, goats and gazelles were identified as C. bovis. Chorioptic mange was not diagnozed in grazing beef cattle, ibexes and housed animals (as compared to grazing herds), and in rams and billy goats. Holstein-Israeli bulls kept in insemination centres were not clinically infested, whereas four Charolais bulls were infested with chorioptic mange. Infestation rate was higher in older animals than in younger ones. Hoggets and young goats over 10 months and heifers over 13 months were found clinically infested with Choriopic mites. Lesions were not usually extensive and occurred mainly in predilection sites. The ocular form in sheep and the groin form in goats are very uncommon and apparently are reported for the first time. Chorioptic mange was recorded generally throughout the year. In our study seasonal distribution could not be demonstrated in cattle, while in sheep and goats the highest infestation rate occurred in February to March and the lowest in August and September.  相似文献   

15.
Environmental factors may drive tick ecology and therefore tick-borne pathogen (TBP) epidemiology, which determines the risk to animals and humans of becoming infected by TBPs. For this reason, the aim of this study was to analyze the influence of environmental factors on the abundance of immature-stage Ixodes ricinus ticks and on the prevalence of two zoonotic I. ricinus-borne pathogens in natural foci of endemicity. I. ricinus abundance was measured at nine sites in the northern Iberian Peninsula by dragging the vegetation with a cotton flannelette, and ungulate abundance was measured by means of dung counts. In addition to ungulate abundance, data on variables related to spatial location, climate, and soil were gathered from the study sites. I. ricinus adults, nymphs, and larvae were collected from the vegetation, and a representative subsample of I. ricinus nymphs from each study site was analyzed by PCR for the detection of Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum DNA. Mean prevalences of these pathogens were 4.0% ± 1.8% and 20.5% ± 3.7%, respectively. Statistical analyses confirmed the influence of spatial factors, climate, and ungulate abundance on I. ricinus larva abundance, while nymph abundance was related only to climate. Interestingly, cattle abundance rather than deer abundance was the main driver of B. burgdorferi sensu lato and A. phagocytophilum prevalence in I. ricinus nymphs in the study sites, where both domestic and wild ungulates coexist. The increasing abundance of cattle seems to increase the risk of other hosts becoming infected by A. phagocytophilum, while reducing the risk of being infected by B. burgdorferi sensu lato. Controlling ticks in cattle in areas where they coexist with wild ungulates would be more effective for TBP control than reducing ungulate abundance.  相似文献   

16.
Perennially and intermittently available water in lentic, spring-fed herbaceous meadows supports wetland plants that build and maintain absorbent soil organic matter, capture sediment, prevent erosion, and thereby sustain riparian ecosystems. Enhanced forage and available water attract a diversity of wildlife and grazing animals that can degrade riparian vegetation through prolonged overuse. We tested novel monitoring methods and adapted existing methods to obtain quantified vegetation data that have been consistently linked to riparian functionality and compared these data to ungulate species use. We quantified ungulate use with time-lapse cameras at 10 Nevada spring-fed herbaceous meadows where core greater sage-grouse (Centrocercus urophasianus) habitat, public land grazing allotments, and free-roaming horse (Equus caballus) herd management areas (Bureau of Land Management) or territories (U.S. Department of Agriculture Forest Service) overlapped. Free-roaming horses used most study sites over longer periods and grazed more intensely than cattle or domestic sheep. Native ungulate grazing intensity was comparatively negligible. Free-roaming horses selected spring-fed meadow sites on average 51 (±33 [SE]) times more than the surrounding rangelands, and cattle selected them 30 ± 23 times more. Within the wettest area of a site, study sites with longer duration of use and higher intensity of use had more soil alteration and bare ground. Riparian ecosystem degradation occurred where meadows had limited rest or recovery time from grazing during the growing season. At all sites we noted loss of riparian function, especially within the hydric areas with the highest potential to grow abundant cover of stabilizing wetland plant species. Transects for monitoring soil alteration and vegetation cover in this hydric location can provide a leading indicator of riparian recovery or degradation and help in adjusting free-roaming horse population levels or livestock management strategies. © 2021 The Wildlife Society.  相似文献   

17.
Nearly 70% of the world's mountain ungulate taxa are endangered. The availability of a standard set of DNA markers for forensic and molecular ecology studies would help to establish conservation programs and detect poaching activities of these endangered taxa. We tested 60 published microsatellite primer pairs from bovids (cattle, sheep and goat) on 49 individuals from 11 taxa including six wild goat‐like species (Capra spp.), three divergent wild sheep (Ovis spp.), and two chamois (Rupicapra spp.) species. Approximately 30 microsatellites amplified a microsatellite‐like PCR product in all three genera, and with the exception of ILST097, nearly all the loci were polymorphic within most of the 11 species.  相似文献   

18.
Grazing by ungulates can affect seed production in plants, and consequently seed recruitment into seed banks, which is a plant strategy to increase their resilience. The impact of grazing on seed quantity has been well studied; however, the impact of grazing on seed quality has received less attention, despite its role in determining the longevity of a seed bank. Here, we examined the impact of ungulate grazing on seed quality in plants, using two grazing-intolerant grassland species (Hemerocallis dumortieri var. esculenta and Geranium yesoense var. nipponicum). We found that grazing reduced seed length and weight, while increasing the germination rate. These changes in seed quality induced by grazing could reduce the persistence of seed banks and would thus seem to be an important mechanism involved in the impact of ungulate grazing on plant population dynamics.  相似文献   

19.
Abstract. The daily flight activity patterns of one of the main vectors of animal trypanosomiasis in West Africa, Glossina morsitans submorsitans , were assessed using four different methods. Results from all the methods showed that there was some flight activity nearly every hour in all seasons but they differed in the level of contact between grazing cattle herds and G.m.submorsitans. In the late dry season, trap data indicated that there was negligible activity from midday to late afternoon, whereas observations of tsetse contact with cattle herds or hand-net collections on herd followings showed no fall in attack rates on the cattle by G.m.submorsitans.
Differences between trap and animal-baited collection data may be attributable to the type of G.m.submorsitans sampled by each method. Male G.m.submorsitans captured by traps were more fat depleted than those caught on ox-baited flyrounds or by hand-net collections on herd followings. All methods showed that male G.m.submorsitans were most fat depleted in the late dry season and least in the early dry season. It was concluded that the traps were mainly sampling the spontaneous flights of G.m.submorsitans. Hunger and endogenous rhythms increase the likelihood of spontaneous flights towards dusk, particularly in conditions such as those at midday in the very hot, late dry season. However, the presence of cattle herds in infested habitats probably activated nearby G.m.submorsitans and the continual movement through the grazing areas ensured contact with tsetse throughout grazing.
The data indicated that strategic management of herd grazing times cannot eliminate the risk of trypanosomiasis transmission occurring, irrespective of the harshness of the dry season climate. An assessment of the level of this risk could only be measured suitably by collecting tsetse using animal-baited methods, not from trap data.  相似文献   

20.
Interactions between traditional livestock management practices and wildlife activities are important in the conservation of many mountain ecosystems including the summer rangelands in the Spanish Central Pyrenees, where rooting by wild boar (Sus scrofa) is a large disturbance that can reduce the amount of area available to grazing livestock. This study explored the likely impact of wild boar rooting on Pyrenean grasslands. It quantified the extent of wild boar rooting in livestock grazing areas and determined whether wild boars selected or avoided areas depending on the type of livestock and stocking rates. Wild boar rooting affected 16% of livestock grazing area and occurred in sites that were grazed by cattle, rather than by sheep. In addition, a preference for areas that had intermediate stocking rates was found. The relationship between the increase in the number of wild boars and trends in livestock management suggests that the extent of wild boar rooting will increase especially in cattle grazing areas, and therefore, the area available for cattle grazing in Pyrenean mountain rangelands would decrease significantly.  相似文献   

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