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1.
There is a major risk that many of the remaining semi-natural pastures in Swedish forest dominated regions will lose their grazing in the near future with lost biodiversity as a result. The reason is the high costs of grazing small pastures with cattle from generally small herds. The approaching decoupling of the present EU income support per head of cattle will increase the risk. Calculations based on economies of scale in beef production and opportunity cost of forest and arable land suggest that re-creating extensive pasture-forest mosaics consisting of existing semi-natural pastures and adjacent arable fields and forests can secure economically sustainable grazing. The risk of local extinction of grassland species due to habitat isolation is also lower in large mosaics than in small, scattered pastures.  相似文献   

2.
Interannual differences in zooplankton parameters of the drying lake Orog depend on the water level and the influence of the lake’s tributary. When the water level is high and pastures are especially close to the shoreline, the zooplankton structure indicates a hypertrophic status. When the water level decreases, pastures are far from the shoreline, and a large proportion of the body of water comes from the tributary, the zooplankton structure characterizes the lake as an oligotrophic waterbody; when the tributary dries up, it is characterized as mesotrophic.  相似文献   

3.
Schlaepfer MA 《Oecologia》2003,137(2):304-311
As humans extend their influence to an increasingly large portion of the globe, it becomes of both theoretical and practical interest to understand the consequences of our activities on wildlife populations. Norops polylepis is a small anoline lizard native to rainforest of southern Costa Rica. It is also found and known to lay eggs in cattle pastures immediately adjacent to forest. I predicted that N. polylepis eggs would fare poorly in pastures because of the important abiotic and biotic differences with their native forest habitat. I obtained eggs from captive females and estimated an egg's probability of hatching, daily survival rate, and incubation time at various distances along a forest-to-pasture gradient. Contrary to expectation, egg survival rates were higher in pastures than in forest areas. Furthermore, egg incubation times were significantly shorter in pastures than in their native forest. As a result, eggs were at least as likely to hatch in pastures as in forested areas. Thus, pastures may represent a benign or even beneficial habitat for the eggs of some reptile species. High survival of eggs will facilitate range expansion into human-altered habitats such as pastures, but does not guarantee it. Indeed, pastures could represent an ecological trap and a population sink if adults are drawn there (e.g., in search of favorable ovipositioning sites) yet suffer higher mortality than in forests.  相似文献   

4.
Ecological constraints on effective dispersal have been suggested to be a key factor influencing social evolution in animal societies as well as the shift from single queen colonies (monogyny) to multiple queen colonies (polygyny) in ants. However, little is known about the effective dispersal patterns of ant queens. Here we investigate the microgeographic genetic structure of mitochondrial haplotypes in polygynous populations of the ant Formica exsecta, both between pastures and among nests within pastures. An analysis of molecular variance revealed a very high genetic differentiation (phiST = 0.72) between pastures, indicating that queens rarely disperse successfully between pastures, despite the fact that pastures were sometimes as close as 1 km. Most of the pastures contained only a single haplotype, and haplotypes were frequently distinct between nearby pastures and even between groups of nests within the same pasture. In the three pastures that contained several haplotypes, haplotypes were not randomly distributed, the genetic differentiation between nests being phiST = 0.17, 0.52, and 0.69. This indicates that most queens are recruited within their parental colonies. However, a large proportion of nests contained more than one haplotype, demonstrating that colonies will sometimes accept foreign queens. The relatedness of mitochondrial genes among nestmates varied between 0.62 and 0.75 when relatedness was measured within each pasture and ranged between 0.72 and 1.0 when relatedness was assessed with all pastures as a reference population. Neighboring nests were more genetically similar than distant ones, and there was significant isolation by distance. This pattern may be due to new nests being formed by budding or by limited effective queen dispersal, probably on foot between neighboring nests. These results show that effective queen dispersal is extremely restricted even at a small geographical scale, a pattern consistent with the idea that ecological constraints are an important selective force leading to the evolution and maintenance of polygyny.  相似文献   

5.
The primary objective of this study was to identify herd management and cow characteristics that are associated with abortion in cow-calf herds in Western Canada. Reproductive events were closely monitored in 29,713 cows in 203 herds from the beginning of the breeding season in 2001 through the calving season in 2002. Herd management and cow-level risk factors such as age, body condition score, and previous reproductive history were measured through a series of herd visits by project personnel and detailed individual animal records maintained by the herd owner. Pregnancy status was assessed in fall of 2001 by the herd veterinarian. Cows most likely to abort were replacement heifers, cows that were more than 10 years of age, cows with a body condition score of less than or equal to or 5 of 9 at pregnancy testing, or with twin pregnancies. Cows vaccinated for bovine viral diarrhea virus and infectious bovine rhinotracheitis and bred on community pastures were less likely to abort than cows from community pastures that were not vaccinated. Cows bred on community pastures that were not vaccinated were also more likely to abort than cows that were not on community pastures regardless of vaccination status. Adverse calving-associated events such as severe dystocia, problems such as uterine prolapse or retained placentas, abortion or calf death within 1 hour of birth were also associated with an increased risk of abortion the subsequent calving season after accounting for all other factors.  相似文献   

6.
Conversion of forests to agriculture often fragments distributions of forest species and can disrupt gene flow. We examined effects of prevalent land uses on genetic connectivity of two amphibian species in northeastern Costa Rica. We incorporated data from field surveys and experiments to develop resistance surfaces that represent local mechanisms hypothesized to modify dispersal success of amphibians, such as habitat‐specific predation and desiccation risk. Because time lags can exist between forest conversion and genetic responses, we evaluated landscape effects using land‐cover data from different time periods. Populations of both species were structured at similar spatial scales but exhibited differing responses to landscape features. Litter frog population differentiation was significantly related to landscape resistances estimated from abundance and experiment data. Model support was highest for experiment‐derived surfaces that represented responses to microclimate variation. Litter frog genetic variation was best explained by contemporary landscape configuration, indicating rapid population response to land‐use change. Poison frog genetic structure was strongly associated with geographic isolation, which explained up to 45% of genetic variation, and long‐standing barriers, such as rivers and mountains. However, there was also partial support for abundance‐ and microclimate response‐derived resistances. Differences in species responses to landscape features may be explained by overriding effects of population size on patterns of differentiation for poison frogs, but not litter frogs. In addition, pastures are likely semi‐permeable to poison frog gene flow because the species is known to use pastures when remnant vegetation is present, but litter frogs do not. Ongoing reforestation efforts will probably increase connectivity in the region by increasing tree cover and reducing area of pastures.  相似文献   

7.
Coastal pastures are common agroecosystems adjacent to estuarine areas that can provide valuable habitat for wildlife, particularly for migratory shorebirds. Disentangling the factors that influence coastal pasture use by wintering shorebirds will provide new insights into its role for buffering human disturbances and habitat loss in intertidal areas. We examined whether numbers of two shorebirds (Eurasian curlew and Black-tailed godwit) foraging actively on coastal pastures was affected by weather conditions, tidal stage (low/high tide) and number of harvesters at intertidal areas throughout winter. Both species frequently used coastal pastures and most individuals foraged actively there. The average percentage of the total wintering population of curlews and godwits foraging on coastal pastures was 27.4 and 7.8 %, respectively, and was significantly higher during high tide compared to low tide. The number of harvesters on mudflats also had a positive significant effect in explaining the presence of curlews, and to a lesser extent for godwits, on coastal pastures, and accumulated rainfall had a positive effect for both species too. These supratidal areas were consistently used as alternative foraging grounds during low tide by curlews, as well as supplementary foraging areas during high tide by wintering populations of both large shorebirds. By supplementary foraging, wintering curlews, and probably godwits, seemed to compensate for a negative effect of the presence of harvesters on their foraging activity. We recommend managing of those coastal agricultural fields adjacent to intertidal foraging grounds in order to increase the availability of supratidal foraging habitats for declining shorebird populations. These habitats may thus have a beneficial role in sustaining populations of wintering shorebirds, but further studies are needed to estimate if birds can compensate for any shortfall in daily energy budget by supplementary foraging on coastal pastures, thus providing insights into whether they are involved in large-scale population regulation of migratory birds.  相似文献   

8.
Biological nitrogen fixation in mixed legume/grass pastures   总被引:18,自引:2,他引:16  
Biological nitrogen fixation (BNF) in mixed legume/grass pastures is reviewed along with the importance of transfer of fixed nitrogen (N) to associated grasses. Estimates of BNF depend on the method of measurement and some of the advantages and limitations of the main methods are outlined. The amounts of N fixed from atmospheric N2 in legume/grass pastures throughout the world is summarised and range from 13 to 682 kg N ha-1 yr-1. the corresponding range for grazed pastures, which have been assessed for white clover pastures only, is 55 to 296 kg N ha-1 yr-1.Biological nitrogen fixation by legumes in mixed pastures is influenced by three primary factors; legume persistence and production, soil N status, and competition with the associated grass(es). These factors and the interactions between them are discussed. Legume persistence, production and BNF is also influenced by many factors and this review centres on the important effects of soil moisture status, soil acidity, nutrition, and pests and disease.Soil N status interacts directly with BNF in the short and long term. In the short-term, increases in soil inorganic N occurs during dry conditions and where N fertiliser is used, and these will reduce BNF. In the long-term, BNF leads to accumulation of soil N, grass dominance, and reduced BNF. However, cyclical patterns of legume and grass dominance can occur due, at least in part, to temporal changes in plant-available N levels in soil. Thus, there is a dynamic relationship between legumes and grasses whereby uptake of soil N by grass reduces the inhibitory effect of soil N on BNF and competition by grasses reduces legume production and BNF. Factors affecting the competition between legumes and grasses are considered including grass species, grazing animals, and grazing or cutting management.Some fixed N is transferred from legumes to associated grasses. The amount of N transferred below-ground, predominantly through decomposition of legume roots and nodules, has been estimated at 3 to 102 kg N ha-1 yr-1 or 2 to 26% of BNF. In grazed pasture, N is also transferred above-ground via return in animal excreta and this can be of a similar magnitude to below-ground transfer.Increased BNF in mixed legume/grass pastures is being obtained through selection or breeding of legumes for increased productivity and/or to minimise effects of nutrient limitations, low soil moisture, soil acidity, and pests and disease. Ultimately, this will reduce the need to modify the pasture environment and increase the role of legumes in low-input, sustainable agriculture.  相似文献   

9.
The stable fly, Stomoxys calcitrans (L.), historically has been a pest of livestock in confined operations but seldom of animals on pastures or rangelands. In the past two decades, however, S. calcitrans has become a major pest of cattle and horses on pastures in the midwestern United States. Although there usually is an overabundance of diverse stable fly and house fly, Musca domestica L., larval habitats in confined livestock operations, no larval habitat for stable flies has been clearly identified in the pasture-range environment. Because the winter feeding of hay in round bales results in significant amounts of hay wastage that when mixed with manure, might develop into suitable larval habitats, this study evaluated these areas as developmental sites for the abundant stable flies in pastures. There was a trend for fly traps placed in the vicinity of hay feeding sites to catch more stable flies than those placed distant from these sites. Estimates of stable flies emerging from these sites ranged from 102 to 1225 flies per core sample (25 by 25 cm). The mean number of adult stable flies during May and June 2001 through 2004 correlated negatively with the average minimum temperatures during the preceding winter (November-February) but not with rainfall or temperatures during the spring. These results support the hypothesis that winter feeding sites of hay in round bales are the main source of stable flies in pastures.  相似文献   

10.
A consistent vegetation classification is an essential tool for conservation and monitoring purposes, also for semi-natural habitats such as pastures and hay meadows that are linked to traditional land use and generally considered crucial to maintain biodiversity within agricultural systems. Indeed, these habitats can be strongly affected by land abandonment or agriculture intensification. Despite their importance in the framework of the EU Habitats Directive (43/92/EEC), information on distribution, species composition, and conservation status is still lacking for many regions. To fill these gaps, we investigated from a phytosociological point of view the sheep pastures of the North-Western Sardinian trachy-basaltic sector. Three main communities were described as new: (i) perennial montane (meso-supratemperate) cattle and sheep pastures (Loto alpini-Festucetum morisianae); (ii) mixed (annual and perennial) Mediterranean (lower Thermomediterranean to lower supratemperate) sheep pastures (Ornithogalo corsici-Poetum bulbosae); and (iii) annual ploughed subnitrophilous Mediterranean and Temperate pastures (Cynosuro polybracteati-Vulpietum ligusticae). As the first two host numerous endemic taxa and show a peculiar floristic composition, we assign them a higher conservation value, testified also by their classification in two new syntaxa: Danthonio decumbentis-Caricenion insularis (Molinio-Arrhenatheretea) and Ornithogalo corsici-Trifolienion subterranei (Poetea bulbosae), respectively.  相似文献   

11.
Impact of historical changes in land-use on the soil fauna   总被引:1,自引:0,他引:1       下载免费PDF全文
Replacing native forests and grasslands with plantations, pastures and crops has resulted in both contraction of ranges and exploitation of modified habitats by native species, and both general and restricted dispersal of introduced species of soil fauna. Contraction is shown by native earthworms, land snails, ring nematodes and various arthropods, while the areas with changed land use suggest certain native insects are more numerous than 150 years ago. Damage to pastures by grass grub and porina show clearly how native species can exploit modified habitats. Introduced Lumbricidae make a positive contribution to soil processes in pastures throughout New Zealand. The distribution of cyst nematodes reflects the distribution and intensity of cultivation of the hosts with which they arrived. Changes in soil structure, such as with the elimination or introduction of earthworms, can have marked effects on other soil structure, such as with the elimination or introduction of earthworms, can have marked effects on other soil animals. The faunal changes found are consistent with changes in land use; habitat protection for floristic and scenic reasons will help preserve both known and unknown elements of the soil fauna.  相似文献   

12.
During the mid‐1900s, most of the island of Puerto Rico was deforested, but a shift in the economy from agriculture to small industry beginning in the 1950s resulted in the abandonment of agricultural lands and recovery of secondary forest. This unique history provides an excellent opportunity to study secondary forest succession and suggest strategies for tropical forest restoration. To determine the pattern of secondary succession, we describe the woody vegetation in 71 abandoned pastures and forest sites in four regions of Puerto Rico. The density, basal area, aboveground biomass, and species richness of the secondary forest sites were similar to those of the old growth forest sites (>80 yr) after approximately 40 years. The dominant species that colonized recently abandoned pastures occurred over a broad elevational range and are widespread in the neotropics. The species richness of Puerto Rican secondary forests recovered rapidly, but the species composition was quite different in comparison with old growth forest sites, suggesting that enrichment planting will be necessary to restore the original composition. Exotic species were some of the most abundant species in the secondary forest, but their long‐term impact depended on life history characteristics of each species. These data demonstrate that one restoration strategy for tropical forest in abandoned pastures is simply to protect the areas from fire, and allow natural regeneration to produce secondary forest. This strategy will be most effective if remnant forest (i.e., seed sources) still exist in the landscape and soils have not been highly degraded. Patterns of forest recovery also suggest strategies for accelerating natural recovery by planting a suite of generalist species that are common in recently abandoned pastures in Puerto Rico and throughout much of the neotropics.  相似文献   

13.
Grasslands dominate land cover nationally and globally, and their composition, structure and habitat value are strongly influenced by the actions of domestic and wild grazing animals that feed on them. Different pastures are characterised by varying opportunities for selective feeding by livestock; agronomically improved, sown swards generally consist of a limited range of plant species whereas longer-term leys and semi-natural grasslands are characterised by a more diverse mixture of plants. In the case of botanically diverse permanent pastures/grazing lands, the dietary preferences of different grazers have a more pronounced effect on the botanical composition of the sward in the longer term. Selection of a dominant species within the sward can give less abundant components a chance to compete, increasing community evenness and species richness. Conversely, the selection of minor components reduces sward compositional heterogeneity and hence plant species richness and evenness. Body size, gut type (foregut vs hindgut fermentation), physiological status (growing, pregnant, lactating), metabolic status (extent of body reserves) and environmental conditions all influence the nutrient requirements of a given animal and related foraging priorities. The diet selected is also strongly influenced by the availability of preferred food items, and their vertical and horizontal distribution within the sward. In general, larger animals, such as cattle and horses, are less selective grazers than smaller animals, such as sheep and goats. They are quicker to switch to consuming less-preferred sward components as the availability of preferred resources declines due to their greater forage demands, and as a result can be very effective in controlling competitive plant species consistently avoided by more selective grazers. As a result, low-intensity mixed grazing of cattle and sheep has been shown to improve the diversity and abundance of a range of taxa within grazed ecosystems. Mixed/co-species grazing with different animals exploiting different grassland resources is also associated with increased pasture use efficiency in terms of the use of different sward components and related improvements in nutritional value. In situations where cattle are not available, for example if they are not considered commercially viable, alternative species such as goats, ponies or South American camelids may offer an opportunity to diversify income streams and maintain productive and biodiverse pastures/grazing lands. Stocking rate and timing of grazing also have a considerable role in determining the impact of grazing. Regardless of the species grazing or the pasture grazed, grazing systems are dynamic since selective grazing impacts the future availability of sward components and subsequently dietary choices. New technologies under development provide opportunities to monitor plant/animal interactions more closely and in real time, which will in future support active management to deliver targeted biodiversity gains from specific sites.  相似文献   

14.
Natural restoration of historical wetland plant communities in fallow fields with a degraded seed bank has been assumed to be possible only if source populations of the target species are present adjacent to the abandoned fields and a high density of suitable microsites is available. However, few studies have monitored both factors simultaneously and verified this assumption. We hypothesized that plant communities that are similar to historical wetlands, including back marshes, back swamps, and bogs, will reestablish in abandoned pasturelands in cases when (1) gaps for new recruitment emerge, followed by the decline of pastures; and (2) seeds with longevity are supplied from the surrounding remnant plant communities of wetlands. We conducted a survey of vegetation and microsites in pastures, abandoned pastures, and reference wetlands followed by structural equation modeling to verify our hypothesis for the natural restoration of Phragmites australis–Phalaris arundinacea and Alnus japonica–Spiraea salicifolia communities. These communities represent historical back marshes and back swamps along a river. However, our hypothesis was not verified for the natural restoration of Vaccinium oxycoccos–Sphagnum spp. communities, which represent plant communities in historical bogs grown on acidic peat that are maintained by rainfall and fog. Our findings partly support our hypothesis that decline in pastures creates gaps and that cumulative seed dispersal from nearby remnant wetlands allows the original wetland plant communities to regenerate. Further case studies are needed to determine how the natural restoration of bog plant communities occurs.  相似文献   

15.
Bahram Tavakolian 《Ethnos》2013,78(1-2):180-199
The Sheikhanzai are goat‐and‐sheep‐herding pastoralists who migrate from winter pastures near the Iranian and Soviet borders of Afghanistan to highland summer pastures in the western Hindu Kush. The article sets out to show that among the Sheikhanzai, women's management of economic resources provides a source of power which is frequently unavailable to women in sedentary communities. The domestic work and productive activities of Sheikhanzai women will be examined in the context of their roles as power‐wielders and power‐brokers. Attention is drawn to intra‐societal variation between different categories of women.  相似文献   

16.
Garippa G 《Parassitologia》2006,48(3):419-422
Gastrointestinal strongylosis are the dominant parasitic infections of sheep and goats. The successful control of these parasites cannot be done exclusively with anthelmintics, but the first step is an integrated program for environmental prophylaxis. The correct planning of the prophylaxis program has to be preceded by the analysis of the related problems: (1) the parasitological status of farm livestock; (2) knowledge of the farm management; (3) hydrogeological, pedological and climatic-environmental aspects. The environmental control strategies can be resumed as follows: avoiding animals from different farms to share the same pasture; avoiding animals of different age classes to graze together; parcel the pastures to permit a rational rotation; rotational grazing of pastures according to the seasonal development of parasites; stocking rate; young animals grazing ahead of the older animal ones; crop management practices (draining, ploughing, harrowing, scrub clearing, fertilizing, etc.). These measures make the habitat less suitable for the free-living stages of gastrointestinal strongyles, reducing the potential of infection of the same pastures.  相似文献   

17.
Livestock trails frequently evolve in pastures when plant growth or establishment cannot keep pace with vegetation disturbance. In some instances, man-made trails are established in rangeland settings to encourage uniform use of forages or facilitate livestock passage through dense vegetation or across rugged terrain. A long-term assumption has been that livestock establish pathways of least resistance between frequented areas of their pastures, but this hypothesis has never been tested. We mapped cattle trails in three 800+ ha pastures with global positioning units. A geographic information system (GIS) helped quantify characteristics of trails and the landscape and was used to plot least-effort pathways between water sources and distant points on selected trails in the pastures. Characteristics of the cattle trails and least-effort pathways were compared to test the hypothesis that cattle develop least-effort routes of travel in rugged terrain. The mean slope of the three pastures was 13.5%, and the average slope of the topography traversed by the cattle trails was 8%. The slope of the trails was reduced to 5.2% by selection of cross-slope routes. When we compared the characteristics of 10 selected cattle trails and least-effort pathways generated by our GIS, the cattle trails were 11% shorter (P=0.046) than the least-effort pathways, and the topography traversed by cattle had a gradient about 1% less than the least-effort pathways (P=0.02). The slope of the selected trails (5.5%) and pathways (5.6%) were similar (P=0.74), however. Analyses of values extracted from cost surfaces indicated that, on the average, 183 units of effort were needed to traverse the trails and 170 units of effort expended to traverse the least-effort pathways (P=0.07). These data support the hypothesis that cattle establish least-effort routes between distant points in rugged terrain and suggest that GIS software may be useful in designing systems of livestock trails in extensive settings.  相似文献   

18.
Models of nutrient cycles (PKS) in grazed pastures are used to estimate fertiliser requirements for New Zealand farmers. Work relevant to the development of these models is reviewed. Fertiliser recommendations should be based on the long-term economic maintenance rate. Short-term modifications based on current soil nutrient status (PS) estimated by either soil tests or dynamic cycling models are probably not justified unless current fertiliser use differs greatly from the estimated maintenance rate. The effect of maintenance recommendations should be monitored, and if necessary modified, by soil testing and plant analysis.  相似文献   

19.
Aim Assessing potential response of alpine plant species distribution to different future climatic and land‐use scenarios. Location Four mountain ranges totalling 150 km2 in the north‐eastern Calcareous Alps of Austria. Methods Ordinal regression models of eighty‐five alpine plant species based on environmental constraints and land use determining their abundance. Site conditions are simulated spatially using a GIS, a Digital Terrain Model, meteorological station data and existing maps. Additionally, historical records were investigated to derive data on time spans since pastures were abandoned. This was then used to assess land‐use impacts on vegetation patterns in combination with climatic changes. Results A regionalized GCM scenario for 2050 (+ 0.65 °C, ?30 mm August precipitation) will only lead to local loss of potential habitat for alpine plant species. More profound changes (+ 2 °C, ?30 mm August precipitation; + 2 °C, ?60 mm August precipitation) however, will bring about a severe contraction of the alpine, non‐forest zone, because of range expansion of the treeline conifer Pinus mugo Turra and many alpine species will loose major parts of their habitat. Precipitation change significantly influences predicted future habitat patterns, mostly by enhancing the general trend. Maintenance of summer pastures facilitates the persistence of alpine plant species by providing refuges, but existing pastures are too small in the area to effectively prevent the regional extinction risk of alpine plant species. Main conclusions The results support earlier hypotheses that alpine plant species on mountain ranges with restricted habitat availability above the treeline will experience severe fragmentation and habitat loss, but only if the mean annual temperature increases by 2 °C or more. Even in temperate alpine regions it is important to consider precipitation in addition to temperature when climate impacts are to be assessed. The maintenance of large summer farms may contribute to preventing the expected loss of non‐forest habitats for alpine plant species. Conceptual and technical shortcomings of static equilibrium modelling limit the mechanistic understanding of the processes involved.  相似文献   

20.
Semi-natural pastures have rich plant and animal communities of high conservation value which depend on extensive management. As the area of such land decreases, abandoned semi-natural grasslands have been restored to re-establish biodiversity. Restoration schemes, which include thinning of woody plants and reintroduction of grazing, are mainly designed according to the responses of well-studied groups (such as vascular plants and birds). Weevils (Curculionidae) are a very diverse phytophagous beetle family. Here, we evaluated the restoration success of pastures for weevils (Curculionidae), by comparing their species diversity in abandoned, restored, and continuously grazed semi-natural pastures on 24 sites in central Sweden. Weevils were sampled by sweep-netting. We recorded 3019 weevil individuals belonging to 104 species. There was no statistically significant difference in species numbers between the pasture management treatments. However, weevil species composition of abandoned pastures differed from those in restored and continuously managed pastures, but there was no significant difference in community composition between restored and continuously grazed pastures. The abandoned sites tended to be dominated by polyphagous species, whereas the grazed sites contained more monophagous and oligophagous species. The number of weevil species was positively related to understory vegetation height and connectivity to other semi-natural grasslands and negatively related to the cover of trees and shrubs in the pastures. We conclude that restoration of abandoned semi-natural pastures is a good approach to restore weevil communities. To maintain a species rich weevil community, pastures should be managed to be relatively open, but still have patches of tall field-layer vegetation. Restoration and conservation measures should primarily be targeted on regions and landscapes where a high proportion of semi-natural grassland still remains.  相似文献   

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