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2009年9月,用点样（Point Quatfats）法调查了云南省滇西北贡山县迪麻村色娃龙巴高山牧场的4种不同土大黄覆盖率群落的空间垂直分布,并采用Shannon’s多样性指数（H）和均匀性指数（EH）对物种和群落多样性进行了分析。结果表明,云南省滇西北高山牧场有比较丰富的牧草资源,共25种;中等和中上等的土大黄覆盖率群落里具有最多的物种丰富度和最高的物种多样性指数,同时也具有高的物种均衡性;其次是高等的土大黄覆盖率群落;低等的土大黄覆盖率群落里则具有最低的物种丰富度和物种多样性指数。这些结果表明,土大黄对高山草地的生物多样性的影响并不明显,造成高山草地生物多样性变化的主要原因是家畜的放牧强度和频率。 相似文献
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放牧强度对环青海湖高寒草原群落物种多样性和生产力的影响 总被引：1，自引：0，他引：1
通过2年的连续放牧试验,采用比较样地法,调查了不同放牧强度对环青海湖高寒草原生物多样性和生产力的影响,并探讨了植物物种多样性与草地生产力之间的关系,为高寒草原的合理利用提供基础资料。结果表明:物种丰富度和多样性指数随放牧强度的增加基本呈单峰变化,即在中度放牧下多样性最高,重度放牧下群落物种丰富度、多样性指数和均匀度指数均表现为最小;群落生产力随放牧强度的增加而降低(P<0.05);莎草科地上生物量差异不显著,禾本科和豆科生产力降低(P<0.05),杂类草生物量有增加趋势;禾草和豆科比例减小,莎草和杂类草比例增加;草地生产力与Simpson多样性指数和Alatalo均匀度指数呈显著的单峰函数关系(R2=0.910, P=20.027; R2=0.953, P=20.010),结合Simpson多样性指数和Alatalo均匀度指数才能更好地反映维持草地生产力水平的多样性指标。放牧强度是影响群落物种多样性和生产力及其关系的重要因素。 相似文献
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Tim G. O’Connor Greg Martindale Craig D. Morris Alan Short T.F. Witkowski Rob Scott-Shaw 《Strength and Conditioning Journal》2011,64(2):196-207
Commercial livestock production offers one of the main opportunities for mainstreaming of biodiversity conservation in the grassland biome of South Africa. Grazing management is expected to influence success. With the uses of three long-term grazing trials, effects of stocking rate and cattle-to-sheep ratio on the plant composition and diversity of Highland Sourveld grassland in KwaZulu-Natal were examined. Plant diversity was sampled with the use of modified Whittaker plots. Canonical correspondence analysis was used to test the effects of treatments on compositional variation, and general linear models were used to test individual species’ responses. In a biennial rotation, burned/grazed plots supported lower species richness of forbs and all plants than unburned/ungrazed plots, attributed to the impact of grazing during the season of occupation. A high stocking rate resulted in a long-term decrease of forb richness in one experiment, but an increase in another. An increasing proportion of sheep to cattle resulted in a long-term decrease of the richness of forbs and of total species richness. The three trials identified nongrass species that behaved as increasers or decreasers in response to an increase in stocking rate, and a set of species that behaved as decreasers in response to an increasing proportion of sheep to cattle. Constraints on using long-term trials for identifying the effects of livestock management on plant diversity include lack of baseline data, limited replication, pre-experimental impacts on the study site, and the difficulty of assessing uncommon species. 相似文献
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Maggi Sliwinski Larkin Powell Walter Schacht 《Strength and Conditioning Journal》2019,72(1):136-144.e4
Grassland birds are declining faster than any other guild of birds in North America, in part because of degradation of their breeding habitat. Rangeland managers recommend increasing heterogeneity to improve biodiversity; however, on privately owned rangelands, beef production likely decreases heterogeneity on the landscape. One suggestion has been to use multiple grazing systems across a landscape to increase heterogeneity and provide benefits for avian biodiversity, but there is little research to support this recommendation. Thus, our goal was to examine heterogeneity and songbird abundance in relation to grazing systems used by private producers in a large, intact rangeland region. We measured vegetation structure and conducted avian surveys in the Nebraska Sandhills on 11 management units with five different grazing systems, including season-long continuous, deferred rotation, management intensive, dormant season only, and a fixed rotation. On each management unit we assessed the relationship between vegetation structure or songbird abundance and potential management effects, such as grazing system, stocking rate, and management intensity. Season of use and stocking rate were the most common sources of variation in vegetation structure and songbird abundance. Grazing system did not explain variation in vegetation structure or bird abundance, except for heterogeneity in live grass cover, litter cover, shrub cover, and abundance of field sparrows. Vegetation structure varied across the landscape we sampled, but the range of heterogeneity was narrow. Thus, managers should not assume that using a variety of grazing systems across a landscape will inevitably result in heterogeneity of vegetation structure. Rather, managers should focus on creating contrasting vegetation structure in large areas to increase large-scale heterogeneity. This may be achieved through the application of more extreme management practices (e.g., long-term heavy grazing and long-term rest or patch-burn grazing) so that a wider variety of vegetation composition and structure is available to support biodiversity. 相似文献
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J. Venter B. Liggitt N.M. Tainton G.P.Y. Clarke 《African Journal of Range and Forage Science》2013,30(2):89-98
A fence‐line contrast study compared erosion levels, herbage production and grass species diversity in Umfolozi Game Reserve (UGR) and adjacent KwaZulu (KWZ). There was no significant difference in soil loss or A‐horizon depths measured in KWZ and UGR, but there were significant differences in both parameters when measurements from upper, mid and lower slope sites were compared. Similarly, there was no significant difference between herbage accumulated in KWZ and UGR in the absence of grazing, but there was a significant difference between the upper, mid and lower slope plots. There was also no significant difference between grass species richness measured on plots in KWZ and UGR, but there was a highly significant difference when the grass species richness was compared between upper, mid and lower slopes. The major conclusion drawn from these results was that differences in the topographical position of the plots, rather than differences in land‐use practices, explained the greater amount of variability in the data. 相似文献
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植物群落特征和生存状态变化能够反映植物群落内种间关系和演替进程。本研究以青海海北地区高寒草甸的冷季放牧场为研究对象,分析比较了禁牧封育(CK,禁牧)、轻度放牧(LG,4.5只羊·hm?2)、中度放牧(MG,7.5只羊·hm?2)和重度放牧(HG,15只羊·hm?2) 4种放牧压力对植物群落特征及各功能群代表性植物生存状态指数的影响。结果表明：1)禾本科的重要值在轻度放牧时最大,莎草科的重要值在禁牧样地中最大,杂草类植物的重要值在重度放牧样地中最大。2) Shannon-Wiener多样性指数、Simpson优势度指数、Patrick丰富度指数随着放牧强度的增加均呈增加趋势。3)轻度放牧样地中垂穗披碱草(Elymus nutans)和山地早熟禾(Poa orinosa)的生存状态指数最高,禁牧样地中矮生嵩草(Kobresia humilis)和钝苞雪莲(Saussurea nigrescens)的生存状态指数最高,但随着放牧强度的增加,钝苞雪莲(Saussurea nigrescens)的生存状态指数也随之增加。研究结果表明放牧强度增加能提高高寒草甸群落多样性,禾草类生存状态和在群落中的优势地位下降,杂草类生存状态和在群落中的优势地位上升,草地质量下降。 相似文献
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Marlene Roellig Augusta Costa Matteo Garbarino Jan Hanspach Tibor Hartel Simon Jakobsson Regina Lindborg Sabine Mayr Tobias Plieninger Marek Sammul Anna Varga Joern Fischer 《Strength and Conditioning Journal》2018,71(5):526-535
Europe’s woodland and savanna rangelands, often part of silvopastoral systems known as wood-pastures, are deteriorating because of abandonment that leads to return to a forested state or lack of tree regeneration from overgrazing or tree and shrub removal. Despite numerous local studies, there has been no broader survey of the stand structure of European wood-pastures showing which systems are at risk of losing their semiopen character. This overview aims to 1) show some of the differences and similarities in wood-pastures from landscapes across Europe and 2) identify which of these wood-pastures are at risk of losing their semiopen character. We collated a dataset of 13 693 trees from 390 plots in wood-pastures from eight different European regions (western Estonia, eastern Greece, northern Germany, Hungary, northern Italy, southern Portugal, central Romania, and southern Sweden), including tree diameters at breast height, tree density, management type, and tree species composition. On the basis of their structural characteristics, we classified wood-pastures using principal component analysis (PCA) and cluster analysis. The PCA showed a gradient from dense wood-pastures with high levels of regeneration (e.g., in Estonia) to sparse wood-pastures with large trees but a lack of regeneration (e.g., in Romania). Along this gradient, we identified three main groups of wood-pastures: 1) sparse wood-pastures with mostly big trees; 2) dense wood-pastures composed of small trees, and 3) wood-pastures containing a wide range of tree ages. Our results show a large structural gradient in European wood-pastures, as well as regeneration problems varying in their severity, highlighting the importance of social-ecological context for wood-pasture conditions. To maintain the ecological and cultural integrity of European wood-pastures, we suggest 1) more comprehensively considering them in European policies such as the Common Agricultural Policy and EU Habitats Directive, while 2) taking into account their structural characteristics and social-ecological backgrounds. 相似文献
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通过研究不同放牧强度下地上植被群落的物种组成、植物生活型、土壤种子库物种种类和种子数量等特征,探讨了地上植被与土壤种子库之间的关系及种子库在地上植被群落构建中的作用,拟为高寒草甸的管理,特别是高寒地区退化生态系统的恢复与重建提供参考。结果表明：土壤种子库物种多样性指数和丰富度指数在围栏样地和中牧样地之间差异不显著。重牧样地土壤种子库物种多样性指数和丰富度指数显著低于中牧样地（P<0.05）;围栏样地、重牧样地、中牧样地土壤种子库密度表现为重牧 >围栏 >中牧,其中重牧样地土壤种子库密度显著高于中牧样地（P<0.05）,达4952.7粒·m-2;中牧样地和围栏样地的种子库和地上植被之间相似性较低,二者的地上植被与土壤种子库Sorensen相似性指数分别为0.48和0.44。重牧样地上嵩草属（Kobresia）植物严重退化,地上植被群落和土壤种子库均以杂类草物种占优势,地上植被与土壤种子库表现出较高的相似性。因此,对于有退化趋势的嵩草草甸,适当的围栏并考虑利用本地多年生优良牧草种子进行补播将是有利的;嵩草高寒草甸土壤种子库种子主要集中在0~5cm,且各样地中种子数量均随着土壤深度的增加而减少。 相似文献
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Indicators of rangeland health generally do not include a measure of biodiversity. Increasing attention to maintaining biodiversity in rangelands suggests that this omission should be reconsidered, and plant species richness and diversity are two metrics that may be useful and appropriate. Ideally, their response to a variety of anthropogenic and natural drivers in the ecosystem of interest would be clearly understood, thereby providing a means to diagnose the cause of decline in an ecosystem. Conceptual ecological models based on ecological principles and hypotheses provide a framework for this understanding, but these models must be supported by empirical evidence if they are to be used for decision making. To that end, we synthesize results from published studies regarding the responses of plant species richness and diversity to drivers that are of management concern in Great Plains grasslands, one of North America's most imperiled ecosystems. In the published literature, moderate grazing generally has a positive effect on these metrics in tallgrass prairie and a neutral to negative effect in shortgrass prairie. The largest published effects on richness and diversity were caused by moderate grazing in tallgrass prairies and nitrogen fertilization in shortgrass prairies. Although weather is often cited as the reason for considerable annual fluctuations in richness and diversity, little information about the responses of these metrics to weather is available. Responses of the two metrics often diverged, reflecting differences in their sensitivity to different types of changes in the plant community. Although sufficient information has not yet been published for these metrics to meet all the criteria of a good indicator in Great Plains Grasslands, augmenting current methods of evaluating rangeland health with a measure of plant species richness would reduce these shortcomings and provide information critical to managing for biodiversity. 相似文献
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为探明短花针茅荒漠草原土壤线虫群落分布特征及不同放牧强度对土壤线虫群落的影响,该研究对短花针茅荒漠草原4个不同放牧强度草地的线虫群落进行了系统调查。结果表明：试验区共捕获18属7 200条/100 g干土线虫。拟丽突属、丽突属2个属分别占个体总数的22.78%、41.90%,为该地区的优势类群。多样性分析表明：线虫群落个体数、物种丰富度均为轻度放牧草地大于其余放牧强度草地;群落多样性指数为对照样地>轻度放牧草地>重度放牧草地>中度放牧草地;群落均匀度指数为重度放牧草地>对照样地>（轻度放牧草地=中度放牧草地）。生态指数分析表明：成熟度指数为轻度放牧草地>对照样地>中度放牧草地>重度放牧草地,可见轻度放牧草地和对照样地土壤较稳定,而重度放牧草地土壤受外界活动扰动程度最大;通道指数为中度放牧草地>重度放牧草地>轻度放牧草地>对照样地。此外,通过对不同放牧强度草地植物群落多样性、生物量、盖度、平均高度、枯落物干重、土壤含水量、酸碱度、土壤有机质等环境因子与土壤线虫群落特征指数进行多元逐步回归分析,阐明了放牧条件下影响土壤线虫群落的关键生态变量。研究结果可为确定有益于荒漠草原线虫群落生物多样性维护的放牧强度提供参考。 相似文献
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Heidi L. Hillhouse Susan J. Tunnell James Stubbendieck 《Strength and Conditioning Journal》2010,63(5):581-587
The Rainwater Basin region in Nebraska is critically important stopover habitat for spring waterfowl migrations, but the ability of these sites to produce sufficient food for migrating waterfowl is endangered by the invasion of reed canarygrass (Phalaris arundinacea L.). This species produces thick litter layers and abundant aboveground biomass, reducing germination and seedling survival of the annual plant species responsible for much of the seed production in the area. Cattle grazing often is used as a management tool in the Rainwater Basin to slow or reverse reed canarygrass invasion and to improve growing conditions for more desirable plant species. However, there has been little research on the impact of grazing on these factors. We studied the impacts of one-time, early-season (between April and June) cattle grazing on the abundance of reed canarygrass, bare ground, and litter. We hypothesized that cattle grazing would result in reduced reed canarygrass by the end of the 2-yr study, and that grazing would increase the abundance of bare ground and decrease the abundance of litter. Because grazing was expected to improve conditions for seed germination, we expected to find higher species richness in grazed areas. We found that grazing did not reduce the abundance of reed canarygrass, but the application of early-season grazing for two consecutive years did reduce litter and increase bare ground. Litter abundance decreased by 7.5% in ungrazed plots and litter increased by 8.6% in grazed plots. Bare ground in grazed plots increased 10.7% in grazed plots but decreased 1.2% in ungrazed plots. Species richness was not affected by grazing during this study. We concluded that grazing, as utilized in this study, is not sufficient to reduce reed canarygrass abundance, but can be used to mitigate some of the negative impacts of reed canarygrass invasion. 相似文献
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Grazing lands and their management in livestock systems are a matter of special importance in the search for sustainability. Socio-economic and ecological objectives should be considered jointly in considering livestock production. In addition to the general issues of biodiversity and habitat preservation, the challenges for their management vary according to the regional conditions. In Southern European environments, where the past changes in livestock farming have led to a general decrease in their use, the questions under study are how to find ways to meet the threats to landscape amenity, biodiversity, the sustainability of local animal feeding resources and the rural population. Grazing lands and their management is also an important target of EU agri-environmental policy. The multifunctional use of this land, which is currently sought, reinforces the need for animal scientists to consider the use and management of grazing lands in reference not only to the techno-economical efficiency of animal feeding systems but also in reference to the long-term (e.g. biodiversity change) and at larger spatial scales (for example the landscape and watershed). An overview of the current challenges attached to grazing lands and their management in livestock farming systems in South European environments, an understanding of the ways to jointly meet production objectives and the realisation of sociological and ecological functions is presented. 相似文献
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选择甘肃省肃南裕固族自治县甘肃马鹿(Cervus elaphus kansuensis)养殖场冬季牧场不同牧压梯度的6个样地,采用巢式样方法调查草地植物群落的物种数,研究了甘肃马鹿山地草原放牧系统放牧率与草地群落物种丰富度的关系。结果表明,放牧强度梯度上,冬季牧场物种数随取样面积的增大而逐渐增加,放牧减轻导致物种增幅上升,放牧对物种丰富度的贡献率提高。高山草原的最小取样面积为0.71～1.54 m2,各放牧率样地物种数的变化分别在0.16～0.32和0.32～0.64 m2范围内最剧烈。物种数随放牧增强呈下降趋势,在放牧率2.45 AUM·hm-2出现拐点,拐点两侧放牧对物种多样性具有不同的作用规律,2.45 AUM·hm-2为高山草原适宜的放牧率。在牧场尺度上,当面积超过2.56 m2,改善放牧管理对物种丰富度的增加没有作用。 相似文献
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Csaba Tölgyesi Zoltán Bátori Róbert Gallé István Urák Tibor Hartel 《Strength and Conditioning Journal》2018,71(5):571-577
Rangelands with scattered trees are complex and dynamic systems with a long history in Europe. Generally referred to as “wood-pastures,” they are considered to have outstanding conservation value. Thorny shrubs are important for supporting the biodiversity of these wooded rangelands, as well as facilitating the regeneration of trees by acting as nurse species. We assess the direct effects of temporary shrub encroachment under the cover of mature sparse trees on overall plant and habitat diversity. We surveyed the herb layer of the main landscape features of a wood-pasture: open pasture, trees with a grass understory, trees with shrubs, and adjacent forest edges. The herb layer under trees with shrubs resembled that of forest edges more than open pastures and trees with grass. Trees with grass had a higher cover of ruderal species than trees with shrubs, while forest edges and open pastures had a lower cover of them. Forest species were absent from open pastures but were well represented in the other sites. The herb layer of trees with shrubs and forest edges had similar cover values, while trees with grass had a significantly lower cover of herbs than the other types. Trees with shrubs had higher species richness than any of the other three landscape features and had a much higher proportion of diagnostic species. We conclude that the scattered trees and shrubs of the studied silvopastoral system have additive facilitative effects on their understory, probably through modifying the microenvironment and grazing pressure, leading to the formation of temporary diversity hot spots with distinct vegetation. Thus maintaining a moderate level of shrub-encroachment under sparse trees is recommended for not only creating safe havens for tree recruitment but also increasing the overall species and habitat diversity of wood-pastures. 相似文献
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人类放牧活动与气候变化对科尔沁沙质草地植物多样性的影响 总被引：16，自引：7，他引：9
为了解人类放牧活动和气候变化对我国北方沙质草地植物多样性的影响,笔者于1992-2006年在科尔沁沙地开展了草地放牧和封育试验,分析研究了人类放牧活动和降水、气温变化对草地植物多样性的影响.结果表明,1)放牧干扰对草地物种丰富度和多样性有着明显的影响,随着草地放牧干扰强度的增加,草地物种丰富度和植物多样性呈下降趋势,但只有持续重牧才会导致草地物种丰富度和多样性的明显降低;2)放牧干扰对草地不同生活型多样性和不同经济类群多样性的影响有很大差异,表现为随着放牧强度的增加,一年生植物多样性和禾本科植物多样性明显增加,多年生植物及菊科、藜科和杂类草植物多样性明显下降;3)不同放牧强度下的不同生活型多样性和经济类群多样性对气候变化的反应有很大差异,但除了重牧区菊科植物多样性与降水变化、中牧区杂类草植物多样性与气温变化达到显著相关外,其他相关性均未达到显著水平;4)在草地自然恢复演替过程中,暖湿气候有利于草地物种丰富度和多样性的增加,特别是可以明显促进多年生植物以及菊科、豆科植物多样性的增加,而持续暖干气候可以降低草地的物种丰富度和多样性,但对禾本科和藜科植物多样性的不利影响较小. 相似文献
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围封年限对藏北退化高寒草原植物群落特征和生物量的影响 总被引：1，自引：0，他引：1
为了评估西藏生态安全屏障工程-围封禁牧工程对高寒退化草地植被恢复效益,本研究在申扎高寒草原与湿地生态系统观测试验站附近,采用样线法和样方法对围封8年、围封4年和自由放牧的藏北高寒草原群落特征和生物量进行调查与采样分析。结果表明:自由放牧样地经过围封后,群落结构由杂类草矮火绒草(Leontopodium nanum)和昆仑蒿(Artemisia nanschanica)转变为多年生禾草紫花针茅(Stipapurpurea)和青藏苔草(Carex moorcrofii)为优势种的植物群落,植被高度、盖度、丰富度和多样性均增加。但是,围封后地上生物量却呈降低趋势。因此,应结合各个指标与群落结构特征综合评价退化草地的恢复状况。 相似文献
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J. Lasseur 《Livestock Production Science》2005,96(1):87-95
For the past ten years, sheep farmers from the French Mediterranean area have been able to use agri-environmental farming schemes to prevent the development of forest on rangelands and to preserve biodiversity in these open areas. These new environmental concerns are the background for an investigation into the management of long-term interactions between farm practices and systems on grazed land. This includes an analysis of how farmers change their management practices.Considering these practices in their socio-technical dimension, we carried out a survey among sheep farmers within the Luberon Natural Regional Park to analyse the process of transformation in practice, as sheep farm sizes are also roughly increasing. We will show how changes in practice are linked with the ability of farmers to integrate these into new farming systems. But it is also related to the social status of these practices in relation to local professional groups, who define the social framework concerning farming activities and who attribute value to different practices.Integrating these links between the technical and social dimensions of practices is a challenge for producing indicators able to evaluate the abilities of farming systems to change in order to participate in the medium term environmental management. 相似文献