Dung beetle diversity and functions suggest no major impacts of cattle grazing in the Brazilian Pantanal wetlands

1. Dung beetles perform relevant ecological functions in pastures, such as dung removal and parasite control. Livestock farming is the main economic activity in the Brazilian Pantanal. However, the impact of cattle grazing on the Pantanal's native dung beetle community, and functions performed by them, is still unknown. 2. This study evaluated the effects of cattle activity on dung beetle community attributes (richness, abundance, biomass, composition, and functional group) as well as their ecological functions (dung removal and soil bioturbation) in the Pantanal. In January/February 2016, dung beetles were sampled and their ecological functions measured in 16 sites of native grasslands in Aquidauana, Mato Grosso do Sul, Brazil, 10 areas regularly grazed by cattle and six control ungrazed areas (> 20 years of abandonment). 3. In all, 1169 individuals from 30 species of dung beetles were collected. Although abundance, species richness, and biomass did not differ between grasslands with and without cattle activity, species composition and functional groups differed among systems. Large roller beetles were absent from non‐cattle grasslands, and the abundance, richness, and biomass of medium roller beetles was higher in those systems. 4. Despite causing changes in species/functional group composition, the results of this study show that a density compensation of functional groups in cattle‐grazed natural grasslands seems to have conserved the ecological functions (dung removal and soil bioturbation), with no significant differences between systems. 5. Therefore, these results provide evidence that cattle breeding in natural grasslands of the Brazilian Pantanal can integrate livestock production with the conservation of the dung beetle community and its ecological functions.     

Yaks and sheep trigger different changes in the grasshopper assemblages of the Qilian Mountains via differentially altering plant assemblages

1. The Qilian Mountains represent one of the key livestock‐raising grasslands in China. The two main herbivore species raised in this area – yaks and sheep – are of critical economical value. Grasshoppers compete with these animals for available nutrients, creating multifaceted relationships between livestock, grasshoppers and plants. A clear understanding of such relationships is lacking and is urgently needed to guide conservation efforts. 2. This study aims to document the effects of yak and sheep grazing on grasshopper assemblages and to elucidate the underlying mechanisms of such effects. 3. It is shown here that yaks and sheep impact grasshopper assemblages differently. Grasshopper assemblages exhibited lower density, biodiversity, richness, and evenness of distribution in yak‐grazed pastures than in grazing‐free grasslands. Sheep‐grazed pastures exhibited a dramatically divergent picture, with elevated density, biodiversity and richness, and a slightly decreased evenness of distribution. Grasshoppers were generally larger in grazed pastures than in grazing‐free grasslands, especially in yak‐grazed plots. 4. The present study suggests that differences between yak and sheep pastures in plant assemblage structure and plant traits are probably the underlying forces driving the differences in grasshopper assemblage structure and grasshopper traits, respectively. 5. The study shows that the grasshopper habitat indicator species differ between yak and sheep pastures, raising the possibility that such indicators can be used to monitor grassland usage and degradation in the Qilian Mountains. 6. These results provide novel insights into the dynamic interactions of common domesticated herbivore species, grasshoppers and plants in Qilian Mountains, which augment current knowledge and may ultimately lead to better conservation practices.     

Mortality of native grasses after a summer fire in natural temperate grassland suggests ecosystem instability

The exclusion of regular fire and the introduction of livestock grazing have altered native grassland composition on Victoria's volcanic plains, commonly resulting in spear‐grass and wallaby‐grass pastures replacing Kangaroo Grass grasslands. The effect of reintroducing fire to these pastures is currently unknown, although it may be an important part of restoring this ecosystem. We measured the changes in basal area of the dominant grasses in a mixed Spear‐grass/Wallaby‐grass pastures after a summer wildfire, which we assume burnt a relatively homogenous grass sward. We found a 90–95% reduction in the basal area of live spear‐grass tussocks in burnt plots compared with unburned controls, due to the mortality of tussocks. This suggests that caution and structured experimentation should be applied when using fire to manage spear‐grass‐dominated grasslands.     

Urban Grassland Restoration: A Neglected Opportunity for Biodiversity Conservation

Urbanization is one of the most severe threats to biodiversity, so why should not we use green space in cities to counteract the biodiversity loss as much as possible? Urban grasslands provide a large number of social, financial, recreational, and environmental ecosystem services but can also support high biodiversity. In this article, I describe the importance of urban grasslands for (local) biodiversity and recommend strengthening restoration ecological research and efforts to optimize these novel ecosystems for conservation purposes. The management intensity of a high proportion of urban grasslands decreased over the last decades. However, species richness of these grasslands is still low, although there is now a great potential for higher plant, but also animal diversity. While communal authorities are interested in cost‐efficient but at the same time biodiversity‐friendly management of urban grasslands, a well‐founded scientific basis for the restoration of urban grassland is still missing. I argue that besides all challenges associated with the restoration of urban habitats we should urgently proceed in the development of appropriate and effective restoration approaches and communicate knowledge gained to urban planners and stakeholders. Widening the scope of restoration ecological research to novel ecosystems such as urban grasslands is one of the most important recent challenges for biodiversity restoration and it gives urban habitats the significance they deserve .     

Conservation and restoration of Nardus grasslands in the Swiss northern Alps

Aim: Species‐rich Nardus grasslands are high nature‐value habitats. In Switzerland, many of these grasslands are degraded even though they have been under protection since the 1980s. Degradation shows two divergent trends: Nardus grasslands are either dominated by Nardus stricta or by eutrophic plants, both trends leading to the disappearance of typical Nardus grassland species. With this study, we aim to identify the factors that could be adjusted to conserve the integrity of this habitat. Location: Bernese Alps, Switzerland. Methods: In 2016, we investigated the underlying causes of this degradation process by assessing vegetation composition in 48 Nardus grasslands located in the Swiss northern Alps of canton Bern and linking it to soil, management and environmental variables. To explore the effect of the degradation on higher trophic levels, orthopteran species richness and densities were assessed. Results: Results show that Nardus meadows (mown) are rarely degraded compared to Nardus pastures (grazed). Within pastures, eutrophic plants are most abundant on small pastures with low soil carbon/nitrogen ratio, indicating high nutrient availability. Nardus stricta dominance is most problematic on north‐exposed slopes and in summer pastures. A plausible driver of both degradation trends is the grazing management regime: within small pastures at low elevation where the grazing periods are short but intense, soil carbon/nitrogen ratio is low because of high dung deposition, thus the eutrophic species become dominant. Contrastingly, on large summer pastures with low‐intensity and long‐term grazing, N. stricta becomes dominant due to selective grazing. Both degradation trends show a negative impact on the orthopteran density. Conclusion: Species‐rich Nardus grasslands are a precious alpine habitat for specialised plant species and orthopterans. With an extensive mowing regime or a more controlled grazing regime that homogenises intensity in time and space, species‐rich Nardus grasslands can be conserved in Switzerland.     

Restoration of semi-natural grasslands,a success for phytophagous beetles (Curculionidae)

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.     

Short‐term harvesting of biomass from conservation grasslands maintains plant diversity

High yields are a priority in managing biomass for renewable energy, but the environmental impacts of various feedstocks and production systems should be equally considered. Mixed‐species, perennial grasslands enrolled in conservation programs are being considered as a source of biomass for renewable energy. Conservation grasslands are crucial in sustaining native biodiversity throughout the US Upper Midwest, and the effects of biomass harvest on biodiversity are largely unknown. We measured the effect of late‐season biomass harvest on plant community composition in conservation grasslands in three regions of Minnesota, USA from 2009 to 2012. Temporal trends in plant species composition within harvested grasslands were compared to unharvested grasslands using mixed effects models. A before‐after control‐impact approach using effect sizes was applied to focus on pre‐ and postharvest conditions. Production‐scale biomass harvest did not affect plant species richness, species or functional group diversity, nor change the relative abundance of the main plant functional groups. Differences in the relative abundances of plant functional groups were observed across locations; and at some locations, changed through time. The proportion of non‐native species remained constant, while the proportion of noxious weeds decreased through time in both harvested and unharvested grasslands at the central location. Ordination revealed patterns in species composition due to location, but not due to harvest treatment. Therefore, habitat and bioenergy characteristics related to grassland plant communities are not expected to change due to short‐term or intermittent late‐season biomass harvest.     

北方风沙区生态修复的科学原理、工程实践和恢复效果

北方风沙区位于欧亚草原的东部,是我国生态环境最为脆弱的地区之一,其在北方生态安全屏障和丝绸之路经济带建设中具有十分重要的战略地位。在国家一系列生态保育工程的支持下,该地区的生态环境得到明显改善。但是,由于受人类活动和全球气候变化的影响,该地区仍然面临着严峻的环境压力。在中国科学院科技服务网络计划(STS计划)等项目支持下,开展了北方风沙区土地沙化成因及退化土地空间分布研究,集成了北方风沙区重点脆弱区生态恢复的理论和技术体系,以内蒙古中部的阴山北麓地区、内蒙古浑善达克沙地和蒙辽交界的科尔沁沙地为重点研究区域,进行了高效人工草地建植、天然草地恢复和管理、沙化草地治理等相关工程技术的示范,开展生态恢复模式的效果跟踪监测和生态效益评估,确定生态恢复技术和模式的技术参数和指标,明确不同集成技术与模式在北方风沙区的适用区域和范围,为技术模式的推广应用提供科学依据。通过上述研究,可以为中央和地方政府制定生态系统管理和退化生态系统恢复政策、建立我国北方生态安全屏障提供决策依据,为生态修复产业提供技术指南,为相关研究提供全面系统的基础数据支撑。     

Observations of responses to re‐introducing fire in a Basalt Plains grassland after the removal of grazing: Implications for restoration

Natural grasslands in southern Australia commonly exist in altered states. One widespread altered state is grassland pasture dominated by cool‐season (C3) native grasses maintained by ongoing grazing. This study explores the consequences of removing grazing and introducing fire as a conservation management tool for such a site. We examined the abundance of two native and three exotic species, across a mosaic of fire regimes that occurred over a three‐year period: unburnt, summer wild‐fire (>2 years previous), autumn management fire (<1 year previously) and burnt in both fires. Given that one aim of conservation management is to increase native species at the expense of exotics, the impacts of the fires were largely positive. Native grasses were at higher cover levels in the fire‐managed vegetation than in the unburnt vegetation. Of the three exotic species, one was consistently at lower density in the burnt plots compared to the unburnt plots, while the others were lower only in those plots burnt in summer. The results show that the response of a species varies significantly between different fire events, and that the effects of one fire can persist through subsequent fires. Importantly, some of the effects were large, with changes in the density of plants of over 100‐fold. Fire is potentially a cost‐effective tool to assist the ecological restoration of retired grassland pastures at large scales.     

Co‐occupancy of spider‐engineered burrows within a grassland community changes temporally

Burrow‐digging organisms act as ecosystem engineers, providing potential habitat to other organisms. In the Mid North region of South Australia, wolf and trapdoor spiders in fragmented grassland communities provide this service. Pygmy bluetongue lizards are an endangered skink, endemic to these grasslands. The lizards obligatorily use burrows dug by these spider groups as refuges, basking sites and ambush points. We investigated the occupancy of these spider burrows by lizards and other organisms within the grassland community, identifying the occasions that burrows were shared by multiple taxa. We found that the lizards and trapdoor spiders are predominantly solitary, while wolf spiders co‐shared burrows more frequently with either weevils or snails. There were numerous taxa that were found to regularly co‐share with other taxa, particularly snails, centipedes and weevils. There was a strong temporal influence on burrow sharing, with most co‐sharing occurring late in summer. This study provides an insight into the use of burrows by the lizards and co‐existing taxa within these grassland communities. The dynamics of burrow‐use by other taxa have the potential to influence long‐term conservation of these lizards as burrow availability is crucial to their survival in these grasslands.     

Scale-dependent effects of land use on plant species richness of mountain grassland in the European Alps

Traditionally managed mountain grasslands in the Alps are species‐rich ecosystems that developed during centuries of livestock grazing. However, changes in land use including fertilisation of well accessible pastures and gradual abandonment of remote sites are increasingly threatening this diversity. In five regions of the Swiss and French Alps we assessed the relationship between land use, soil resource availability, cover of the unpalatable species Veratrum album, species richness and vegetation composition of mountain grasslands across four spatial scales ranging from 1 to 1000 m². Mean species richness and the increase in the number of species with increasing area were lower in intensively grazed, fertilised pastures than in traditional pastures or in abandoned pastures. Species composition of abandoned pastures differed from that of the other management types. Plant species richness was influenced by different factors at different spatial scales. At the 1 m² scale, plant species richness was negatively related to soil nitrate and influenced by the cover of V. album, depending on land use: species richness and cover of V. album were negatively correlated in abandoned pastures, but positively correlated in fertilised grasslands. At the 1000 m² scale, a negative effect of fertilization on richness was evident. These results indicate that at small scales species richness in mountain grasslands is determined by competition for light, which should be more important if nutrient availability is high, and by positive and negative interactions with unpalatable plants. In contrast, species richness at the large scale appears to be mainly influenced by land use. This result emphasizes the importance of studying such inter‐relationships at multiple scales. Our study further suggests that the maintenance of the traditional land use scheme is crucial for the conservation of plant species richness of mountain pastures as both intensification and abandonment changed species composition and reduced plant species diversity.     

Passive restoration contributes to bird conservation in Brazilian Pampa grasslands

The global decline of biodiversity makes it important to find affordable ways to conserve and restore habitats. Restoration is useful for conserving native grasslands, with passive restoration defined as either natural colonization or unassisted recovery. Grasslands in southeastern South America have been transformed into croplands and impacted by other human activities. We describe the first assessment of passive restoration as a management tool to conserve birds in the Pampa grasslands of Brazil. We compared bird species richness using coverage‐based rarefaction and extrapolation, applying PERMANOVA for composition, and the abundance of bird communities between sites undergoing passive restoration (PR) and sites with native grasslands (NG). We employed fitted generalized linear mixed models (GLMM) to quantify relationships between bird occurrence and vegetation structure and cover. We recorded 61 species of birds during our study (45 in PR and 46 in NG) and 762 individuals (333 in PR and 429 in NG). Of these species, 15 were restricted to PR and 16 to NG. Grassland specialists and threatened species were found in both PR and NG, and only vegetation height differed between PR and NG. We detected eight species of conservation concern, including three recorded only in PR, three only in NG, and two in both PR and NG. The absence of marked differences in species richness and composition of bird communities between passive‐restoration and native grasslands in our study suggests that grasslands in the process of passive restoration can provide habitat for many species of grassland birds and that passive restoration is an appropriate management tool for biodiversity conservation in Brazilian grasslands.     

Effects of different fencing regimes on community structure of degraded desert grasslands on Mu Us desert,China

Grazing is one of the major anthropogenic driving factors influencing community structure and ecological function of grasslands. Fencing has been proved to be one of the main measures for rehabilitating degraded grasslands in northwestern China. However, data from combined empirical studies on the effects of different management regimes in desert grasslands are lacking. So we selected long‐term fencing (fenced since 1991), mid‐term fencing and seasonal fencing (fenced since 2002), and adjacent free‐grazing grasslands to investigate vegetation and soil properties on southwest Mu Us desert. Our results showed that fencing increased plant cover, height, aboveground biomass (AGB) of different plant life‐form groups, Shannon–Wiener diversity index, Evenness index, Simpson index, total soil nitrogen, total soil phosphorus, and soil organic matter, but decreased plant density, species richness, Richness index, soil bulk density, water content, and pH. However, 22–24 years of long‐term complete fencing might cause redegradation of vegetation and soil nutrients, characterized by the reduction of some vegetation properties, biodiversity, total AGB, and some soil properties. Seasonal fencing with 11–13 year was more beneficial to vegetation restoration than that with completely fencing measures. Our study suggests that appropriate artificial disturbances, such as seasonal fencing (winter grazing and summer fencing), should be used after long‐term fencing in order to maintain grassland productivity and biodiversity. These findings will help to provide theoretical support for vegetation restoration and sustainable management in grassland under grazing prohibition at Mu Us desert.     

Plants, insects and birds in semi-natural pastures in relation to local habitat and landscape factors

The preservation of remaining semi-natural grasslands in Europe has a high conservation priority. Previously, the effects of artificial fertilisation and grazing intensity on grassland animal and plant taxa have been extensively investigated. In contrast, little is known of the effects of tree and shrub cover within semi-natural grasslands and composition of habitats in the surrounding landscape on grassland taxa. We evaluated the effect that each of these factors has on species richness and community structure of vascular plants, butterflies, bumble bees, ground beetles, dung beetles and birds surveyed simultaneously in 31 semi-natural pastures in a farmland landscape in south-central Sweden. Partial correlation analyses showed that increasing proportion of the pasture area covered by shrubs and trees had a positive effect on species richness on most taxa. Furthermore, species richness of nectar seeking butterflies and bumble bees were negatively associated with grazing intensity as reflected by grass height. At the landscape level, species richness of all taxa decreased (butterflies and birds significantly so) with increasing proportion of urban elements in a 1-km² landscape area centred on each pasture, while the number of plant and bird species were lower in landscapes with large proportion of arable fields. Our results differed markedly depending on whether the focus was on species richness or community structure. Canonical correspondence analyses (CCA) showed that the abundance of most taxa was ordered along a gradient describing tree cover within pastures and proportion of arable fields in the landscape. However, subsets of grassland birds and vascular plants, respectively, showed markedly different distribution patterns along axis one of the CCA. In contrast to current conservation policy of semi-natural pastures in Sweden, our results strongly advise against using a single-taxon approach (i.e., grassland vascular plants) to design management and conservation actions in semi-natural pastures. Careful consideration of conservation values linked to the tree and shrub layers in grasslands should always precede decisions to remove trees and shrubs on the grounds of promoting richness of vascular plants confined to semi-natural grasslands. Finally, the importance of landscape composition for mobile organisms such as birds entails that management activities should focus on the wider countryside and not exclusively on single pastures.     

Influence of soil properties on coastal sandplain grassland establishment on former agricultural fields

The decline in species‐rich grasslands across the United States has increased the importance of conservation and restoration efforts to preserve the biodiversity supported by these habitats. Abandoned agricultural fields often provide practical locations for the reestablishment of species‐rich grasslands. However, these fields often retain legacies of agriculture both in their soils, which may have higher pH and nitrogen (N) contents than soils that were never farmed, and in their plant communities, which are dominated by non‐native species and poor in native seed stock. We considered methods of reversing these legacies to create native‐species‐rich grassland on former agricultural land. We tested seeding and tilling combined with additions of sulfur (S), carbon (C), N or water to establish diverse sandplain grassland vegetation on an old field on Martha's Vineyard, Massachusetts. We measured soil pH, extractable nitrate and ammonium, and total and native species richness and native species cover for 5 years after treatment. S additions lowered pH to values typical of never‐tilled sandplain ecosystems and increased native species cover, but had no effect on species richness. C, N, and water additions had no significant effects on the soil or vegetation. Seeding and tilling were more effective at restoring native species richness than any soil amendments and indicated a greater importance of biotic factors compared with soil conditions in promoting sandplain vegetation establishment. S amendment accelerated establishment of native species cover for several years but the effect of S additions compared with seeding and tilling alone declined over time.     

Restoration of riverine inland sand dune complexes: implications for the conservation of wild bees

1.  The evaluation of restoration measures is an important task of conservation biology. Inland sand dunes and dry, oligotrophic grasslands have become rare habitat types in large parts of Central Europe and their restoration and management is of major importance for the preservation of many endangered plant and insect species. Within such habitats, it is important to restore key ecosystem services, such as pollination networks. As wild bees are the most important pollinators in many ecosystems, they represent a suitable key group to evaluate restoration measures. Furthermore, the recent decline of many bee species and the potential ecological and economic consequences are currently topics of strong scientific interest.
2.  We studied the succession of bee communities in response to restoration measures of sand dunes and sand grasslands and compared these communities with those of old sand dune complexes.
3.  Our results show that wild bees respond rapidly to restoration measures indicated by a high species richness and abundance. The community structure of bees at restoration sites converged only slightly to those of the target sites. A higher similarity was found between bee communities at the restoration sites (sand dunes and grasslands), indicating that their close proximity was an important determinant of species overlap. Environmental factors such as the number of entomophilous plant species and moisture had a strong influence on wild bee species composition.
4.   Synthesis and applications . The restoration of inland sand dune complexes provides opportunities for colonization by a diverse wild bee community. Although it is difficult to establish a given target community, restoration measures gave rise to a high pollinator diversity and abundance, suggesting that community function can be re-established.     

Seasonality constraints to livestock grazing intensity

Increasing food production is essential to meet the future food demand of a growing world population. In light of pressing sustainability challenges such as climate change and the importance of the global livestock system for food security as well as GHG emissions, finding ways to increasing food production sustainably and without increasing competition for food crops is essential. Yet, many unknowns relate to livestock grazing, in particular grazing intensity, an essential variable to assess the sustainability of livestock systems. Here, we explore ecological limits to grazing intensity (GI; i.e. the fraction of net primary production consumed by grazing animals) by analysing the role of seasonality in natural grasslands. We estimate seasonal limitations to GI by combining monthly net primary production data and a map of global livestock distribution with assumptions on the length of nonfavourable periods that can be bridged by livestock (e.g. by browsing dead standing biomass, storage systems or biomass conservation). This allows us to derive a seasonality‐limited potential GI, which we compare with the GI prevailing in 2000. We find that GI in 2000 lies below its potential on 39% of the total global natural grasslands, which has a potential for increasing biomass extraction of up to 181 MtC/yr. In contrast, on 61% of the area GI exceeds the potential, made possible by management. Mobilizing this potential could increase milk production by 5%, meat production by 4% or contribute to free up to 2.8 Mio km² of grassland area at the global scale if the numerous socio‐ecological constraints can be overcome. We discuss socio‐ecological trade‐offs, which may reduce the estimated potential considerably and require the establishment of sound monitoring systems and an improved understanding of livestock system's role in the Earth system.     

THE UTILIZATION OF NATURAL PASTURES BY WILD ANIMALS IN THE RUKWA VALLEY, TANGANYIKA

The object of this paper is to elucidate the principles involved in the utilization of natural grasslands by an indigenous community of animals. The studies were carried out in the Rukwa valley during a period of fourteen years and it is suggested that the results are applicable to other similar ecological areas.
The various types of grassland and pasture which occur are described, and their ecology and seasonal development are discussed in relation to the climate and drainage in the valley. The incidence of fire is recorded and its influence is compared with the effects of grazing.
The utilization of the pastures by herbivorous animals is described, and it is explained how grazing pressure results in pasture rejuvenation which is manifest by the development of a grazing mosaic. It is shown that a sequence of animals, heavier ones followed by lighter ones, use the different pastures in rotation during the year and as a consequence alternate periods of optimum use and rest occur, and the harmful effects of over-grazing do not appear.
The species of animals which form the Rukwa valley grazing community are listed and the ecological stresses which they experience in a changeable environment are noted. Examples are quoted to support the view that dry periods favour the fauna whereas extremely wet ones are unfavourable. It is shown how the ability of the animals to establish biotic pressure on the pastures enables them to become rehabilitated even though conditions remain unfavourable.
It is opined that if the same principles are made use of in game management schemes elsewhere, successful conservation of both grasslands and animals is likely to be achieved.     

北方牧区草地资源分类经营机制与可持续发展

草地是畜牧业生产和生态保护的重要资源.在短期经济利益的驱动下造成北方牧区草地大面积退化和荒漠化、生产力下降、自我恢复能力降低、水土流失加剧和涵养功能减弱,对牧区经济发展、社会稳定和生态安全构成了威胁,严重影响着草地畜牧业的可持续发展.以新疆阿勒泰为例,依据草地资源的生产经济性能、生态服务价值重要性和季节放牧利用特征,构建了基于GIS 技术的草地生产力指数、草地生态服务价值指数和草地资源分类经营的功能分区模型,建立以主导功能和时空格局为主的草地资源分类经营调控机制,将阿勒泰牧区的草地从空间上划分为经济功能区、混合功能区和生态功能区.结果表明:(1)经济功能区,以获取最大的经济效益为目的,面积约648.69万hm2,占总可利用草地面积的65.8%,主要分布在平原荒漠;(2)生态功能区,以生态保护和社会效益为目的,面积约136.4万hm2,占总可利用草地面积的13.9%,主要分布在平原荒漠草原、山地草原、高寒草甸;(3)混合功能区,在适度利用条件下,生态效益与经济效益并重,面积约200.1万hm2,占总可利用草地面积的20.3%,主要分布在山地草原化荒漠、山地草甸草原、平地草甸、山地荒漠草原、山地草甸和高寒草原.通过对草地资源的分类经营,将畜牧业生产重心转向经济功能区,转移生态功能区的放牧家畜,减轻混合功能区的放牧压力,形成草地资源在功能、系统、时序和空间的耦合结构,实现牧区草地资源利用的可持续发展.     

Conservation of Grassland Leafhoppers: A Brief Review

The leafhoppers, planthoppers and their allies (collectively known as the Auchenorrhyncha) are presented as a group of insects that are highly appropriate for studying grassland ecology and conservation, evaluating the conservation status of sites and monitoring environmental and habitat change. Semi-natural grasslands typically support dense populations and a wide range of species with diverse ecological strategies. Their numerical dominance in many grasslands means that they have considerable functional significance, both as herbivores and as prey for higher trophic levels. Population and assemblage studies are supported by good ecological knowledge about most species and modern identification keys. Hitherto, most studies have focused on the composition and structure of assemblages and how they are affected by conservation management. However, grasslands support many rare species with small and fragmented populations which deserve conservation attention in their own right, and recent work has started to reflect this. The effects of management on the composition and structure of grassland leafhopper populations and assemblages are described and an assessment is given of the main threats facing individual species and overall diversity. There is a need to synthesise the scattered literature on grassland leafhoppers, to provide a model for how the composition and structure of populations and assemblages respond to major environmental and anthropogenic gradients across large biogeographic areas. Such an analysis could help predict the impact of likely future changes in land use and climate.