The Role of Rural Communities in Conservation of Rangelands in Mahneshan Township

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Kobra Karimi

2016-05-01

Full Text Available The aim of this study was to investigate the action of rangeland-depended livestock holders regarding rangeland conservation, including protection and rehabilitation activities and to analyse relevant influencing factors, using a mixed method of survey and case study. The data were collected through analysing existing documents, focus groups, semi-structured and structured interviews using questionnaires submitted to 204 rural livestock holders in the Mahneshan Township. The quantitative data were analysed using SPSS and AMOS software. According to the results farmers’ knowledge regarding the role, importance and factors affecting rangeland degradation was relatively high, however they had a low level of knowledge and action about mechanical conservation techniques. The action of livestock holders in terms of biological conservation activities and grazing management showed a positive and signifincat corrletaion with variables such as implementing of rangeland projects, their interaction with external institutions, participating in extension training courses, education level and irrigated and rainfed agricultural land size. Moreover, based on a path analysis, 37% of the variance of the farmers’ actions regarding the rangeland conservation was explained by the variables such as rangeland rehabilitation actions, farmers’ conservation knowledge, farmers’ interaction with natural resources experts, beekeeping, and participating in extension training courses. Promotional and extension activities and farmers’ interaction with experts have a positive effect in enhancing farmers’ knowledge and actions for sustainable rangeland use and conservation.

Basin wildrye (Leymus cinereus) pooled tetraploid accessions for U.S. Intermountain rangeland reclamation

Science.gov (United States)

Stanford A. Young; Jason Vernon; Nancy Shaw

2013-01-01

Basin wildrye (Leymus cinereus [Scribn. & Merr.] A. Love) is an important perennial, hardy, long-lived, cool season C3 native grass of rangeland plant communities throughout much of western United States and Canada. All classes of livestock and wildlife, including large and small birds and mammals, utilise the grass year round for food and protection due to its 2-3...

IMPACT OF WOODY PLANTS SPECIES ON SOIL PHYSIO-CHEMICAL PROPERTIES ALONG GRAZING GRADIENTS IN RANGELANDS OF EASTERN ETHIOPIA

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Mohammed Mussa Abdulahi

2016-12-01

Full Text Available In the lowlands of arid and semiarid rangelands woody plants plays an important role in soil fertility maintenance, providing food, medicine, cosmetics, fodder, fuel wood and pesticides. A better understanding of the interaction of woody plants on their immediate environment is needed to guide optimum management of native vegetation in the production landscapes. However, the impact of woody plant species on soil properties remains poorly understood. This study evaluates the impact of two dominant woody plant species (A. senegal and B. aegyptica on soil physico-chemical properties along grazing gradients in rangelands of eastern Ethiopia. Six trees of each species were selected from light, moderate and heavy grazing sites.  Soil sample data at two depths (0-15 and 16-30 cm were collected from under and open areas of A. senegal and B. aegyptica from each grazing sites, and analysed for nutrient contents. The nutrient status of soil under both woody species was significantly higher especially with regard to soil organic matter (4.37%, total nitrogen (0.313%, and available phosphorus (11.62 than the open grassland with soil organic matter (3.82%, total nitrogen (0.246%, and available phosphorus (10.94 mg/Kg soil for A. Senegal. The soil organic matter (3.93%, total nitrogen (0.285%, available phosphorus (11.66 mg/Kg soil were significantly higher than open grassland with soil organic matter (3.52%, total nitrogen (0.218%, available phosphorus (10.73 mg/Kg soil for B. aegyptica. This was more pronounced in the top 15 cm of soil under A. senegal woody plant species and on the light and moderate grazing site. Therefore, this tree has a significant effect on soil fertility improvement in resource poor rangelands and as a result, it is important to retain scattered A. senegal and B. aegyptica plants in the lowlands of eastern Ethiopia.

Managing the livestock– Wildlife interface on rangelands

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du Toit, Johan T.; Cross, Paul C.; Valeix, Marion

2017-01-01

On rangelands the livestock–wildlife interface is mostly characterized by management actions aimed at controlling problems associated with competition, disease, and depredation. Wildlife communities (especially the large vertebrate species) are typically incompatible with agricultural development because the opportunity costs of wildlife conservation are unaffordable except in arid and semi-arid regions. Ecological factors including the provision of supplementary food and water for livestock, together with the persecution of large predators, result in livestock replacing wildlife at biomass densities far exceeding those of indigenous ungulates. Diseases are difficult to eradicate from free-ranging wildlife populations and so veterinary controls usually focus on separating commercial livestock herds from wildlife. Persecution of large carnivores due to their depredation of livestock has caused the virtual eradication of apex predators from most rangelands. However, recent research points to a broad range of solutions to reduce conflict at the livestock–wildlife interface. Conserving wildlife bolsters the adaptive capacity of a rangeland by providing stakeholders with options for dealing with environmental change. This is contingent upon local communities being empowered to benefit directly from their wildlife resources within a management framework that integrates land-use sectors at the landscape scale. As rangelands undergo irreversible changes caused by species invasions and climate forcings, the future perspective favors a proactive shift in attitude towards the livestock–wildlife interface, from problem control to asset management.

The GEOGLAM Rangelands and Pasture Productivity Activity: Recent Progress and Future Directions

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Guerschman, J. P.; Held, A. A.; Donohue, R. J.; Renzullo, L. J.; Sims, N.; Kerblat, F.; Grundy, M.

2015-12-01

Rangelands and pastures cover about a third of the world's land area and support livestock production which represents ~40% of global agricultural gross domestic product. The global consumption of animal protein shows a clear increasing trend, driven by both total population and per capita income increases, putting a growing pressure on the sustainability of grazing lands worldwide. Despite their relevance, rangelands have received less attention than croplands regarding global monitoring of the resource productivity and condition. The Rangelands and Pasture Productivity (RaPP) activity is a component within the Global Agricultural Monitoring initiative established under the Group on Earth Observations (GEOGLAM) in 2013. GEOGLAM RaPP is aimed at providing the global community with the means to monitor the world's rangelands and pastures on a routine basis, and the capacity to produce animal protein in real-time, at global, regional and national levels. Since its launch two years ago GEOGLAM RAPP has made progress in the four implementation elements. These include: 1- the establishment of community of practice; 2- the development of a global monitoring system for rangeland condition; 3- the establishment of pilot sites in main rangeland systems for satellite data products validation and model testing; and 4- integration with livestock production models. Three international workshops have been held building the community of practice. A prototype monitoring system that provides global visualisations and querying capability of vegetation cover data and anomalies has been established. Pilot sites, mostly in areas with long records of field measurements of rangeland condition and productivity have been proposed for nine countries. The link to global livestock models, including physical and economic components, have been established. Future challenges for GEOGLAM RaPP have also been identified and include: better representation of the areas occupied by rangelands

Using remotely sensed imagery to monitor savanna rangeland deterioration through woody plant proliferation: a case study from communal and biodiversity conservation rangeland sites in Mokopane, South Africa

CSIR Research Space (South Africa)

Munyati, C

2011-05-01

Full Text Available rangeland, whereas the communal rangelands were getting more opened up by livestock trampling. Rangeland management practices of fire utilisation, stocking levels and stock concentration account for the differing trends. Lightly grazed and heavily grazed...

Bush encroachment dynamics and rangeland management implications in the Horn of Africa

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Rangelands in the Horn of Africa have been undergoing a rapid shift from herbaceous to woody plant dominance in the past decades, threatening subsistence livestock herding and pastoral food security. Despite of significant rangeland management implications, quantification of the spatial extent of en...

Opportunities and obstacles for rangeland conservation in San Diego County, California, USA

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Kathleen A. Farley

2017-03-01

Full Text Available Working landscapes such as rangelands are increasingly recognized as having high conservation value, providing a variety of ecosystem services, including food, fiber, habitat, recreation, open space, carbon storage, and water, in addition to a broad range of social benefits. However, conversion of rangelands to other land uses has been prevalent throughout the western United States, leading to greater attention in the conservation community to the importance of collaborating with private landowners. The level of interest in collaborative conservation among private landowners and the types of conservation programs they choose to participate in depend on the social, economic, and environmental context. We used GIS analysis and interviews with ranchers to evaluate rangeland conversion and participation in conservation programs among ranchers in San Diego County, California, USA, which is part of a biodiversity hotspot with high plant species richness and a large number of endemic and rare species. We found that > 25% of rangelands were converted to other uses, primarily urbanization, over the past 25 years while the area of public rangeland increased by 9%. Interviews revealed that ranchers in San Diego County have had limited involvement with most conservation programs, and a critical factor for nonparticipation was providing programs access to private land, along with other issues related to trust and social values. Among ranchers who had participated in conservation programs, the payment level and the agency or organization administering the program were key factors. Our results provide insight into factors influencing whether and when ranchers are likely to participate in conservation initiatives and illustrate that private and public land conservation are strongly linked and would be more effective if the two strategies were better integrated.

Applying a dryland degradation framework for rangelands: the case of Mongolia.

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Jamsranjav, C; Reid, R S; Fernández-Giménez, M E; Tsevlee, A; Yadamsuren, B; Heiner, M

2018-04-01

Livestock-caused rangeland degradation remains a major policy concern globally and the subject of widespread scientific study. This concern persists in part because it is difficult to isolate the effects of livestock from climate and other factors that influence ecosystem conditions. Further, degradation studies seldom use multiple plant and soil indicators linked to a clear definition of and ecologically grounded framework for degradation assessment that distinguishes different levels of degradation. Here, we integrate two globally applicable rangeland degradation frameworks and apply them to a broad-scale empirical data set for the country of Mongolia. We compare our assessment results with two other recent national rangeland degradation assessments in Mongolia to gauge consistency of findings across assessments and evaluate the utility of our framework. We measured livestock-use impacts across Mongolia's major ecological zones: mountain and forest steppe, eastern steppe, steppe, and desert steppe. At 143 sites in 36 counties, we measured livestock-use and degradation indicators at increasing distances from livestock corrals in winter-grazed pastures. At each site, we measured multiple indicators linked to our degradation framework, including plant cover, standing biomass, palatability, species richness, forage quality, vegetation gaps, and soil surface characteristics. Livestock use had no effect on soils, plant species richness, or standing crop biomass in any ecological zone, but subtly affected plant cover and palatable plant abundance. Livestock effects were strongest in the steppe zone, moderate in the desert steppe, and limited in the mountain/forest and eastern steppes. Our results aligned closely with those of two other recent country-wide assessments, suggesting that our framework may have widespread application. All three assessments found that very severe and irreversible degradation is rare in Mongolia (1-18% of land area), with most rangelands

Impact of Rangeland Degradation on Soil Physical, Chemical

African Journals Online (AJOL)

major threats to enhance a sustainable pastoral-livestock production in Ethiopia. ... overall negative impact on the soil physical and chemical characteristics, demanding ... chemical properties (Gemedo et al., 2006) as well as the rangeland .... parameters such as life forms (annuals and perennials), plant forms (woody plant,.

Grazing intensity on the plant diversity of alpine meadow in the eastern Tibetan plateau

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Wu Ning

2004-04-01

Full Text Available Because ofthe remoteness and harsh conditions of the high-altitude rangelands on the eastern Tibetan Plateau, the relationship between yak grazing and plant diversity has not been so clear although livestock increase was thought as the main issue leading to the degradation of rangeland. In the debate of rangeland degradation, biodiversity loss has been assumed as one of the indicators in the last two decades. In this paper authors measured the effects of different grazing intensities on the plant diversity and the structure of Kobresia pygmaea community in the case-study area, northwestern Sichuan. The results indicated that plant diversity of alpine meadow has different changing trends respectively with the change of grazing intensity and seasons. In June the highest plant diversity occurred in the intensively grazed (HG plots, but in July and September species biodiversity index of slightly grazed (LG plots is higher than other experimental treatments. In August the intermediate grazed (IG plots has the highest biodiversity index. Moreover, it was found that intensively grazing always leads to the increase of plant density, but meanwhile the decrease of community height, coverage and biomass. Over-grazing can change the community structure and lead to the succession from Kobresia pygmaea dominated community to Poa pratensis dominated. Analyzing results comprehensively, it can be suggested that the relationship between grazing intensity and plant diversity is not linear, i.e. diversity index is not as good as other characteristics of community structure to evaluate rangeland degradation on the high altitude situation. The change of biodiversity is so complicated that it can not be explained with the simple corresponding causality.

Weather-centric rangeland revegetation planning

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Hardegree, Stuart P.; Abatzoglou, John T.; Brunson, Mark W.; Germino, Matthew; Hegewisch, Katherine C.; Moffet, Corey A.; Pilliod, David S.; Roundy, Bruce A.; Boehm, Alex R.; Meredith, Gwendwr R.

2018-01-01

Invasive annual weeds negatively impact ecosystem services and pose a major conservation threat on semiarid rangelands throughout the western United States. Rehabilitation of these rangelands is challenging due to interannual climate and subseasonal weather variability that impacts seed germination, seedling survival and establishment, annual weed dynamics, wildfire frequency, and soil stability. Rehabilitation and restoration outcomes could be improved by adopting a weather-centric approach that uses the full spectrum of available site-specific weather information from historical observations, seasonal climate forecasts, and climate-change projections. Climate data can be used retrospectively to interpret success or failure of past seedings by describing seasonal and longer-term patterns of environmental variability subsequent to planting. A more detailed evaluation of weather impacts on site conditions may yield more flexible adaptive-management strategies for rangeland restoration and rehabilitation, as well as provide estimates of transition probabilities between desirable and undesirable vegetation states. Skillful seasonal climate forecasts could greatly improve the cost efficiency of management treatments by limiting revegetation activities to time periods where forecasts suggest higher probabilities of successful seedling establishment. Climate-change projections are key to the application of current environmental models for development of mitigation and adaptation strategies and for management practices that require a multidecadal planning horizon. Adoption of new weather technology will require collaboration between land managers and revegetation specialists and modifications to the way we currently plan and conduct rangeland rehabilitation and restoration in the Intermountain West.

Wildlife habitats in managed rangelands—the Great Basin of southeastern Oregon: the relationship of terrestrial vertebrates to plant communities and structural conditions (Part 2).

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Chris Maser; Jack Ward Thomas; Ralph G. Anderson

1984-01-01

The relationships of terrestrial vertebrates to plant communities, structural conditions, and special habitats in the Great Basin of southeastern Oregon are described in a series of appendices. The importance of habitat components to wildlife and the predictability of management activities on wildlife are examined in terms of managed rangelands. ...

Rehabilitation of community-owned, mixed-use rangelands: Lessons from the Ewaso ecosystem in Kenya

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Globally, 10-20% of arid and semi-arid rangelands have been classified as severely degraded (UNCCD 1994; MEA 2005), and in sub-Saharan Africa specifically, 70% of rangelands are considered moderately to severely degraded (Dregne 1992; UNCCD 1994). Given that these drylands make up 43% of Africa’s la...

Wildlife habitats in managed rangelands—the Great Basin of southeastern Oregon: the relationship of terrestrial vertebrates to plant communities and structural conditions (Part 1).

Science.gov (United States)

Chris Maser; Jack Ward Thomas; Ralph G. Anderson

1984-01-01

The relationships of terrestrial vertebrates to plant communities, structural conditions, and special habitats in the Great Basin of southeastern Oregon are described. The importance of habitat components to wildlife and the predictability of management activities on wildlife are examined in terms of managed rangelands. The paper does not provide guidelines but rather...

Livestock-rangeland management practices and community perceptions towards rangeland degradation in South Omo zone of Southern Ethiopia

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Admasu, T.; Abule, E.; Tessema, Z.K.

2010-01-01

A survey was conducted in Hamer and Benna-Tsemay districts of the South Omo zone of Ethiopia, with the objectives of assessing the range-livestock management practices and perceptions of the different pastoral groups (Hamer, Benna, and Tsemay) towards rangeland degradation. This information is

RANGELAND SEQUESTRATION POTENTIAL ASSESSMENT

Energy Technology Data Exchange (ETDEWEB)

Lee Spangler; George F. Vance; Gerald E. Schuman; Justin D. Derner

2012-03-31

Rangelands occupy approximately half of the world's land area and store greater than 10% of the terrestrial biomass carbon and up to 30% of the global soil organic carbon. Although soil carbon sequestration rates are generally low on rangelands in comparison to croplands, increases in terrestrial carbon in rangelands resulting from management can account for significant carbon sequestration given the magnitude of this land resource. Despite the significance rangelands can play in carbon sequestration, our understanding remains limited. Researchers conducted a literature review to identify sustainably management practices that conserve existing rangeland carbon pools, as well as increase or restore carbon sequestration potentials for this type of ecosystem. The research team also reviewed the impact of grazing management on rangeland carbon dynamics, which are not well understood due to heterogeneity in grassland types. The literature review on the impact of grazing showed a wide variation of results, ranging from positive to negative to no response. On further review, the intensity of grazing appears to be a major factor in controlling rangeland soil organic carbon dynamics. In 2003, researchers conducted field sampling to assess the effect of several drought years during the period 1993-2002. Results suggested that drought can significantly impact rangeland soil organic carbon (SOC) levels, and therefore, carbon sequestration. Resampling was conducted in 2006; results again suggested that climatic conditions may have overridden management effects on SOC due to the ecological lag of the severe drought of 2002. Analysis of grazing practices during this research effort suggested that there are beneficial effects of light grazing compared to heavy grazing and non-grazing with respect to increased SOC and nitrogen contents. In general, carbon storage in rangelands also increases with increased precipitation, although researchers identified threshold levels of

Assessing Rangeland Attributes On Semi-Arid Zone Of North Darfur State Sudan

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Mohamed Almontasir A. M. Mohamed

2015-08-01

Full Text Available Abstract The study was conducted over a two years period of 2012 and 2013 at three sites of Alfashir locality Ummarahik 25km north of Alfashir Fashar in eastern part of Alfashir about 5km and Berka 30km west of Alfashir Western Sudan in semi-arid zone. The aim of this study was to assess rangeland attributes. Measurements of plant density vegetation cover range production and carrying capacity were assessed. Results showed that total forage production was low and inadequate to satisfy requirements of livestock for inhabiting the area average range production all over the area was found to be 50.68 kgha and 59.21 kgha for the seasons 2012 and 2013 respectively. The average ground cover was about 34.71 and 42.41 for two seasons. The average plant density for the first season was 27.1 plantm2 while the average plant density for the second season was 29.4 plantm2. The study concluded that unwise utilization and exploitation of the rangelands particularly by man causes range deterioration and serious reduction in range production in both quantity and quality so the study suggested that improvement and rehabilitation such lands rangelands should be done. Further research work is needed to assess rangeland attributes across different ecological zones in North Darfur State.

EVALUATION AND MAPPING OF RANGELANDS DEGRADATION USING REMOTELY SENSED DATA

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Majid Ajorlo

2005-05-01

Full Text Available The empirical and scientifically documents prove that misuse of natural resource causes degradation in it. So natural resources conservation is important in approaching sustainable development aims. In current study, Landsat Thematic Mapper images and grazing gradient method have been used to map the extent and degree of rangeland degradation. In during ground-based data measuring, factors such as vegetation cover, litter, plant diversity, bare soil, and stone & gravels were estimated as biophysical indicators of degradation. The next stage, after geometric correction and doing some necessary pre-processing practices on the study area’s images; the best and suitable vegetation index has been selected to map rangeland degradation among the Normalized Difference Vegetation Index (NDVI, Soil Adjusted Vegetation Index (SAVI, and Perpendicular Vegetation Index (PVI. Then using suitable vegetation index and distance parameter was produced the rangelands degradation map. The results of ground-based data analysis reveal that there is a significant relation between increasing distance from critical points and plant diversity and also percentage of litter. Also there is significant relation between vegetation cover percent and distance from village, i.e. the vegetation cover percent increases by increasing distance from villages, while it wasn’t the same around the stock watering points. The result of analysis about bare soil and distance from critical point was the same to vegetation cover changes manner. Also there wasn’t significant relation between stones & gravels index and distance from critical points. The results of image processing show that, NDVI appears to be sensitive to vegetation changes along the grazing gradient and it can be suitable vegetation index to map rangeland degradation. The degradation map shows that there is high degradation around the critical points. These areas need urgent attention for soil conservation. Generally, it

Improving dynamic global vegetation model (DGVM) simulation of western U.S. rangelands vegetation seasonal phenology and productivity

Science.gov (United States)

Kerns, B. K.; Kim, J. B.; Day, M. A.; Pitts, B.; Drapek, R. J.

2017-12-01

Ecosystem process models are increasingly being used in regional assessments to explore potential changes in future vegetation and NPP due to climate change. We use the dynamic global vegetation model MAPSS-Century 2 (MC2) as one line of evidence for regional climate change vulnerability assessments for the US Forest Service, focusing our fine tuning model calibration from observational sources related to forest vegetation. However, there is much interest in understanding projected changes for arid rangelands in the western US such as grasslands, shrublands, and woodlands. Rangelands provide many ecosystem service benefits and local rural human community sustainability, habitat for threatened and endangered species, and are threatened by annual grass invasion. Past work suggested MC2 performance related to arid rangeland plant functional types (PFT's) was poor, and the model has difficulty distinguishing annual versus perennial grasslands. Our objectives are to increase the model performance for rangeland simulations and explore the potential for splitting the grass plant functional type into annual and perennial. We used the tri-state Blue Mountain Ecoregion as our study area and maps of potential vegetation from interpolated ground data, the National Land Cover Data Database, and ancillary NPP data derived from the MODIS satellite. MC2 historical simulations for the area overestimated woodland occurrence and underestimated shrubland and grassland PFT's. The spatial location of the rangeland PFT's also often did not align well with observational data. While some disagreement may be due to differences in the respective classification rules, the errors are largely linked to MC2's tree and grass biogeography and physiology algorithms. Presently, only grass and forest productivity measures and carbon stocks are used to distinguish PFT's. MC2 grass and tree productivity simulation is problematic, in particular grass seasonal phenology in relation to seasonal patterns

Rangeland monitoring using remote sensing: comparison of cover estimates from field measurements and image analysis

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Ammon Boswell

2017-01-01

Full Text Available Rangeland monitoring is important for evaluating and assessing semi-arid plant communities. Remote sensing provides an effective tool for rapidly and accurately assessing rangeland vegetation and other surface attributes such as bare soil and rock. The purpose of this study was to evaluate the efficacy of remote sensing as a surrogate for field-based sampling techniques in detecting ground cover features (i.e., trees, shrubs, herbaceous cover, litter, surface, and comparing results with field-based measurements collected by the Utah Division of Wildlife Resources Range Trent Program. In the field, five 152 m long transects were used to sample plant, litter, rock, and bare-ground cover using the Daubenmire ocular estimate method. At the same location of each field plot, a 4-band (R,G,B,NIR, 25 cm pixel resolution, remotely sensed image was taken from a fixed-wing aircraft. Each image was spectrally classified producing 4 cover classes (tree, shrub, herbaceous, surface. No significant differences were detected between canopy cover collected remotely and in the field for tree (P = 0.652, shrub (P = 0.800, and herbaceous vegetation (P = 0.258. Surface cover was higher in field plots (P < 0.001, likely in response to the methods used to sample surface features by field crews. Accurately classifying vegetation and other features from remote sensed information can improve the efficiency of collecting vegetation and surface data. This information can also be used to improve data collection frequency for rangeland monitoring and to efficiently quantify ecological succession patterns.

Seasonal food habits of swift fox (Vulpes velox) in cropland and rangeland landscapes in western Kansas

Science.gov (United States)

Sovada, M.A.; Roy, C.C.; Telesco, D.J.

2001-01-01

Food habits of swift foxes (Vulpes velox) occupying two distinct landscapes (dominated by cropland versus rangeland) in western Kansas were determined by analysis of scats collected in 1993 and 1996. Frequencies of occurrence of prey items in scats were compared between cropland and rangeland areas by season. Overall, the most frequently occurring foods of swift foxes were mammals (92% of all scats) and arthropods (87%), followed by birds (24%), carrion (23%), plants (15%) and reptiles (4%). No differences were detected between landscapes for occurrence of mammals, arthropods or carrion in any season (P ≥ 0.100). Plants, specifically commercial sunflower seeds, were consumed more frequently in cropland than in rangeland in spring (P = 0.004) and fall (P = 0.001). Birds were more common in the swift fox diet in cropland than in rangeland during the fall (P = 0.008), whereas reptiles occurred more frequently in the diet in rangeland than in cropland during spring (P = 0.042). Variation in the diet of the swift fox between areas was most likely due to its opportunistic foraging behavior, resulting in a diet that closely links prey use with availability.

Exploring the invasion of rangelands by Acacia mearnsii (black ...

African Journals Online (AJOL)

Reducing A. mearnsii canopy could promote grass production while encouraging carbon sequestration. Given the high AGB and clearing costs, it may be prudent to adopt the 'novel ecosystems' approach in managing infested landscapes. Keywords: grassland, invasive plants, landscape ecology, rangeland condition ...

Plant establishment and soil microenvironments in Utah juniper masticated woodlands

Science.gov (United States)

Kert R. Young

2012-01-01

Juniper (Juniperus spp.) encroachment into sagebrush (Artemisia spp.) and bunchgrass communities has reduced understory plant cover and allowed juniper trees to dominate millions of hectares of semiarid rangelands. Trees are mechanically masticated or shredded to decrease wildfire potential and increase desirable understory plant cover. When trees are masticated after...

Book title: Rangelands systems: Processes, management and challenges - Chapter title: Invasive plant species and novel ecosystems

Science.gov (United States)

Rangelands represent the dominant land use systems in many countries of the world and provide sociological and cultural benefits to millions of people in both rural and urban areas. The undesirable impacts of rangeland weeds have been recognized for well over 100 years and infest between 41 and 51 ...

Introduced and invasive species in novel rangeland ecosystems: friends or foes?

Science.gov (United States)

Belnap, Jayne; Ludwig, John A.; Wilcox, Bradford P.; Betancourt, Julio L.; Dean, W. Richard J.; Hoffmann, Benjamin D.; Milton, Sue J.

2012-01-01

Globally, new combinations of introduced and native plant and animal species have changed rangelands into novel ecosystems. Whereas many rangeland stakeholders (people who use or have an interest in rangelands) view intentional species introductions to improve forage and control erosion as beneficial, others focus on unintended costs, such as increased fire risk, loss of rangeland biodiversity, and threats to conservation efforts, specifically in nature reserves and parks. These conflicting views challenge all rangeland stakeholders, especially those making decisions on how best to manage novel ecosystems. To formulate a conceptual framework for decision making, we examined a wide range of novel ecosystems, created by intentional and unintentional introductions of nonnative species and land-use–facilitated spread of native ones. This framework simply divides decision making into two types: 1) straightforward–certain, and 2) complex–uncertain. We argue that management decisions to retain novel ecosystems are certain when goods and services provided by the system far outweigh the costs of restoration, for example in the case of intensively managed Cenchrus pastures. Decisions to return novel ecosystems to natural systems are also certain when the value of the system is low and restoration is easy and inexpensive as in the case of biocontrol of Opuntia infestations. In contrast, decisions whether to retain or restore novel ecosystems become complex and uncertain in cases where benefits are low and costs of control are high as, for example, in the case of stopping the expansion of Prosopis and Juniperus into semiarid rangelands. Decisions to retain or restore novel ecosystems are also complex and uncertain when, for example, nonnative Eucalyptus trees expand along natural streams, negatively affecting biodiversity, but also providing timber and honey. When decision making is complex and uncertain, we suggest that rangeland managers utilize cost–benefit analyses

Transcending Landscapes: Working Across Scales and Levels in Pastoralist Rangeland Governance.

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Robinson, Lance W; Ontiri, Enoch; Alemu, Tsegaye; Moiko, Stephen S

2017-08-01

Landscape approaches can be subjected to mistakenly targeting a single "best" level of governance, and paying too little attention to the role that cross-scale and cross-level interactions play in governance. In rangeland settings, resources, patterns of use of those resources, and the institutions for managing the resources exist at multiple levels and scales. While the scholarship on commons offers some guidance on how to conceptualize governance in rangeland landscapes, some elements of commons scholarship-notably the "design principles" for effective governance of commons-do not seem to apply neatly to governance in pastoralist rangeland settings. This paper examines three cases where attempts have been made to foster effective landscape governance in such settings to consider how the materiality of commons influences the nature of cross-scale and cross-level interactions, and how these interactions affect governance. In all three cases, although external actors seemed to work appropriately and effectively at community and landscape levels, landscape governance mechanisms have been facing great challenges arising from relationships beyond the landscape, both vertically to higher levels of decision-making and horizontally to communities normally residing in other landscapes. The cases demonstrate that fostering effective landscape-level governance cannot be accomplished only through action at the landscape level; it is a task that must be pursued at multiple levels and in relation to the connections across scales and levels. The paper suggests elements of a conceptual framework for understanding cross-level and cross-scale elements of landscape governance, and offers suggestions for governance design in pastoralist rangeland settings.

Transcending Landscapes: Working Across Scales and Levels in Pastoralist Rangeland Governance

Science.gov (United States)

Robinson, Lance W.; Ontiri, Enoch; Alemu, Tsegaye; Moiko, Stephen S.

2017-08-01

Landscape approaches can be subjected to mistakenly targeting a single "best" level of governance, and paying too little attention to the role that cross-scale and cross-level interactions play in governance. In rangeland settings, resources, patterns of use of those resources, and the institutions for managing the resources exist at multiple levels and scales. While the scholarship on commons offers some guidance on how to conceptualize governance in rangeland landscapes, some elements of commons scholarship—notably the "design principles" for effective governance of commons—do not seem to apply neatly to governance in pastoralist rangeland settings. This paper examines three cases where attempts have been made to foster effective landscape governance in such settings to consider how the materiality of commons influences the nature of cross-scale and cross-level interactions, and how these interactions affect governance. In all three cases, although external actors seemed to work appropriately and effectively at community and landscape levels, landscape governance mechanisms have been facing great challenges arising from relationships beyond the landscape, both vertically to higher levels of decision-making and horizontally to communities normally residing in other landscapes. The cases demonstrate that fostering effective landscape-level governance cannot be accomplished only through action at the landscape level; it is a task that must be pursued at multiple levels and in relation to the connections across scales and levels. The paper suggests elements of a conceptual framework for understanding cross-level and cross-scale elements of landscape governance, and offers suggestions for governance design in pastoralist rangeland settings.

Current stage of the restoration of Chernozems in rangeland ecosystems of the steppe zone

Science.gov (United States)

Rusanov, A. M.

2015-06-01

The results of two rounds of soil and geobotanic surveys of rangeland ecosystems in the steppe zone are presented. The same sites with southern chernozems (Calcic Chernozems) under steppe plant communities at different stages of pasture degradation were investigated at the end of the 1980s, when they suffered maximum anthropogenic loads, and in 2011-2013, after a long period of relative rest. In the 1980s, degradation of soil physical properties in rangeland ecosystems under the impact of long-term unsustainable management was noted. At the same time, it was found that the major qualitative and quantitative properties of humus in the chernozems were preserved independently from the level of pasture degradation. The following period of moderate grazing pressure had a favorable effect on the soil properties. Owing to the good characteristics of the soil humus, the restoration of the physical properties of chernozems-including their structural state, water permeability, and bulk density-took place in a relatively short period. It is argued that the soil bulk density is a natural regulator of the species composition of steppe vegetation, because true grasses (Poaceae)-typical representatives of the steppe flora-have a fibrous root system requiring the soils with low density values. The improvement of the properties of chernozems is related to the development of secondary ecosystems with a higher portion of grasses in place of damaged rangelands and to the increase in the area of nominal virgin phytocenoses.

Earth observation for rangeland monitoring

CSIR Research Space (South Africa)

Ramoelo, Abel

2012-10-01

Full Text Available .kashan.co.za] INTRODUCTION Grass nitrogen (N), as an indicator of rangeland quality, plays a crucial role in understanding the distribution, densities and feeding patterns of both wild herbivores and livestock. Zebras and livestock in the grazing and agricultural lands... ? How can grass nitrogen be mapped for assessing and monitoring of rangeland quality at wider or regional scales? ? Conventional point-based techniques for assessing rangeland quality proved to be expensive, laborious and time consuming...

Carbon fluxes on North American rangelands

Science.gov (United States)

Tony Svejcar; Raymond Angell; James A. Bradford; William Dugas; William Emmerich; Albert B. Frank; Tagir Gilmanov; Marshall Haferkamp; Douglas A. Johnson; Herman Mayeux; Pat Mielnick; Jack Morgan; Nicanor Z. Saliendra; Gerald E. Schuman; Phillip L. Sims; Kereith Snyder

2008-01-01

Rangelands account for almost half of the earth's land surface and may play an important role in the global carbon (C) cycle. We studied net ecosystem exchange (NEE) of C on eight North American rangeland sites over a 6-yr period. Management practices and disturbance regimes can influence NEE; for consistency, we compared ungrazed and undisturbed rangelands...

Criterion III: Maintenance of rangeland productive capacity [Chapter 4

Science.gov (United States)

G. R. Evans; R. A. Washmgton-Allen; R. D. Child; J. E. Mitchell; B. R. Bobowskl; R. V. Loper; B. H. Allen-Diaz; D. W. Thompson; G. R. Welling; T. B. Reuwsaat

2010-01-01

Maintenance of rangeland productive capacity is one of five criteria established by the Sustainable Rangelands Roundtable (SRR) to monitor and assess rangeland sustainable management. Within this criterion, six indicators were developed through the Delphi Process and the expert opinions of academicians, rangeland scientists, rangeland management agency personnel, non-...

The Role of Rangelands in Diversified Farming Systems: Innovations, Obstacles, and Opportunities in the USA

Directory of Open Access Journals (Sweden)

Nathan F. Sayre

2012-12-01

Full Text Available Discussions of diversified farming systems (DFS rarely mention rangelands: the grasslands, shrublands, and savannas that make up roughly one-third of Earth's ice-free terrestrial area, including some 312 million ha of the United States. Although ranching has been criticized by environmentalists for decades, it is probably the most ecologically sustainable segment of the U.S. meat industry, and it exemplifies many of the defining characteristics of DFS: it relies on the functional diversity of natural ecological processes of plant and animal (reproduction at multiple scales, based on ecosystem services generated and regenerated on site rather than imported, often nonrenewable, inputs. Rangelands also provide other ecosystem services, including watershed, wildlife habitat, recreation, and tourism. Even where non-native or invasive plants have encroached on or replaced native species, rangelands retain unusually high levels of plant diversity compared with croplands or plantation forests. Innovations in management, marketing, incentives, and easement programs that augment ranch income, creative land tenure arrangements, and collaborations among ranchers all support diversification. Some obstacles include rapid landownership turnover, lack of accessible U.S. Department of Agriculture certified processing facilities, tenure uncertainty, fragmentation of rangelands, and low and variable income, especially relative to land costs. Taking advantage of rancher knowledge and stewardship, and aligning incentives with production of diverse goods and services, will support the sustainability of ranching and its associated public benefits. The creation of positive feedbacks between economic and ecological diversity should be the ultimate goal.

Rangeland Use Rights Privatisation Based on the Tragedy of the Commons: A Case Study from Tibet

Directory of Open Access Journals (Sweden)

Yonten Nyima Yundannima

2017-01-01

Full Text Available Rangeland use rights privatisation based on a tragedy of the commons assumption has been the backbone of state policy on rangeland management and pastoralism in China. Through an empirical case study from Pelgon county, Tibet Autonomous Region in China, this paper provides an empirical analysis of rangeland use rights privatisation. It shows that the tragedy of the commons is not the correct model to apply to Tibetan pastoralism because pasture use in Tibet has never been an open-access institution. Thus, when the tragedy of the commons model is applied as a rationale for rangeland use rights privatisation, the result is not what is intended by the policy, but rather a misfit to features of pastoralism and thus disruption of the essence of pastoralism, i.e. mobility and flexibility. The paper further shows that a hybrid institution combining household rangeland tenure with community-based use with user fees is a restoration of the pastoralist institution. This demonstrates the capacity of pastoralists to create adaptive new institutions congruent with the interdependent and integrated nature of pastoralism consisting of three components: pastoralists, livestock, and rangeland.

Weather-centric rangeland revegetation planning

Science.gov (United States)

Semiarid rangelands in the western United States have been or are being invaded by introduced annual weeds that negatively impact ecosystem services and pose a major conservation threat. Rehabilitation and restoration of these rangelands are challenging due to inter-annual climate and sub-seasonal ...

Rangelands: Where Anthromes Meet Their Limits

Directory of Open Access Journals (Sweden)

Nathan F. Sayre

2017-05-01

Full Text Available Defining rangelands as anthromes enabled Ellis and Ramankutty (2008 to conclude that more than three-quarters of Earth’s land is anthropogenic; without rangelands, this figure would have been less than half. They classified all lands grazed by domestic livestock as rangelands, provided that human population densities were low; similar areas without livestock were excluded and classified instead as ‘wildlands’. This paper examines the empirical basis and conceptual assumptions of defining and categorizing rangelands in this fashion. Empirically, we conclude that a large proportion of rangelands, although used to varying degrees by domesticated livestock, are not altered significantly by this use, especially in arid, highly variable environments and in settings with long evolutionary histories of herbivory by wild animals. Even where changes have occurred, the dynamics and components of many rangelands remain structurally and functionally equivalent to those that preceded domestic livestock grazing or would be found in its absence. In much of Africa and Asia, grazing is so longstanding as to be inextricable from ‘natural’ or reference conditions for those sites. Thus, the extent of anthropogenic biomes is significantly overstated. Conceptually, rangelands reveal the dependence of the anthromes thesis on outdated assumptions of ecological climax and equilibrium. Coming to terms with rangelands—how they can be classified, understood, and managed sustainably—thus offers important lessons for understanding anthromes and the Anthropocene as a whole. At the root of these lessons, we argue, is not the question of human impacts on ecosystems but property relations among humans.

The Rangeland Hydrology and Erosion Model: A dynamic approach for predicting soil loss on rangelands

Science.gov (United States)

In this study we present the improved Rangeland Hydrology and Erosion Model (RHEM V2.3), a process-based erosion prediction tool specific for rangeland application. The article provides the mathematical formulation of the model and parameter estimation equations. Model performance is assessed agains...

Conserving biodiversity on native rangelands: Symposium proceedings

Science.gov (United States)

Daniel W. Uresk; Greg L. Schenbeck; James T. O' Rourke

1997-01-01

These proceedings are the result of a symposium, "Conserving biodiversity on native rangelands" held on August 17, 1995 in Fort Robinson State Park, NE. The purpose of this symposium was to provide a forum to discuss how elements of rangeland biodiversity are being conserved today. We asked, "How resilient and sustainable are rangeland systems to the...

Rangelands Vegetation under Different Management Systems and Growth Stages in North Darfur State, Sudan (Range Attributes

Directory of Open Access Journals (Sweden)

Mohamed AAMA Mohamed

2014-09-01

Full Text Available This study was conducted at Um Kaddada, North Darfur State, Sudan, at two sites (closed and open for two consecutive seasons 2008 and 2009 during flowering and seed setting stages to evaluate range attributes at the locality. A split plot design was used to study vegetation attributes. Factors studied were management systems (closed and open and growth stages (flowering and seed setting. Vegetation cover, plant density, carrying capacity, and biomass production were assessed. Chemical analyses were done for selected plants to determine their nutritive values. The results showed high significant differences in vegetation attributes (density, cover and biomass production between closed and open areas. Closed areas had higher carrying capacity compared to open rangelands. Crude protein (CP and ash contents of range vegetation were found to decrease while Crude fiber (CF and Dry matter yield (DM had increased with growth. The study concluded that closed rangelands are better than open rangelands because it fenced and protected. Erosion index and vegetation degradation rate were very high. Future research work is needed to assess rangelands characteristics and habitat condition across different ecological zones in North Darfur State, Sudan.DOI: http://dx.doi.org/10.3126/ije.v3i3.11093 International Journal of Environment Vol.3(3 2014: 332-343

75 FR 8036 - Monitor-Hot Creek Rangeland Project

Science.gov (United States)

2010-02-23

... DEPARTMENT OF AGRICULTURE Forest Service Monitor-Hot Creek Rangeland Project AGENCY: Forest... Rangeland Project area. The analysis will determine if a change in management direction for livestock grazing is needed to move existing resource conditions within the Monitor-Hot Creek Rangeland Project area...

A systematic review of US rangeland social science

Science.gov (United States)

Rangeland science aims to create knowledge to sustain rangeland social-ecological systems over the long term. Range science has made substantial progress on understanding ecological dynamics of rangeland systems and the management practices that sustain them, and these findings have been systematica...

Valuation of rangeland ecosystem services

Science.gov (United States)

Gascoigne, W.R.

2011-01-01

Economic valuation lends itself well to the anthropocentric orientation of ecosystem services. An economic perspective on ecosystems portrays them as natural assets providing a flow of goods and services valuable to individuals and society collectively. A few examples include the purification of drinking water, reduced risk from flooding and other extreme events, pollination of agricultural crops, climate regulation, and recreation opportunities from plant and animal habitat maintenance, among many others. Once these goods and services are identified and quantified, they can be monetized to complete the valuation process. The monetization of ecosystem goods and services (in the form of dollars) provides a common metric that allows for cross-comparison of attributes and evaluation of differing ecological scenarios. Complicating the monetization process is the fact that most of these goods and services are public and non-market in nature; meaning they are non-rival and non-exclusive and are typically not sold in a traditional market setting where monetary values are revealed. Instead, one must employ non-market valuation techniques, with primary valuation methods typically being very time and resource consuming, intimidating to non-economists, and often impractical. For these reasons, benefit transfer methods have gained popularity. This methodology harnesses the primary collection results of existing studies to make inferences about the economic values of non-market goods and services at an alternative policy site (in place and/or in time). For instance, if a primary valuation study on oak reestablishment on rangelands in southern California yielded a value of $30 per-acre associated with water regulation, this result can be transferred, with some adjustments, to say something about the value of an acre of oaks on rangelands in northern portions of the state. The economic valuation of rangeland ecosystem services has many roles. Economic values may be used as input

Endemic shrubs in temperate arid and semiarid regions of northern China and their potentials for rangeland restoration.

Science.gov (United States)

Chu, Jianmin; Yang, Hongxiao; Lu, Qi; Zhang, Xiaoyan

2015-06-03

Some endemic shrubs in arid and semiarid ecosystems are in danger of extinction, and yet they can play useful roles in maintaining or restoring these ecosystems, thus practical efforts are needed to conserve them. The shrubs Amygdalus pedunculata Pall., Amygdalus mongolica (Maxim.) Ricker and Ammopiptanthus mongolicus (Maxim. ex Kom.) Cheng f. are endemic species in arid and semiarid regions of northern China, where rangeland desertification is pronounced due to chronic overgrazing. In this study, we tested the hypothesis that these endemic shrubs have developed adaptations to arid and semiarid environments and could play critical roles as nurse species to initiate the process of rangeland recovery. Based on careful vegetation surveys, we analysed the niches of these species in relation to precipitation, temperature and habitats. All sampling plots were categorized by these endemics and sorted by the non-metric multidimensional scaling method. Species ratios of each life form and species co-occurrence rates with the endemics were also evaluated. Annual average temperature and annual precipitation were found to be the key factors determining vegetation diversity and distributions. Amygdalus pedunculata prefers low hills and sandy land in temperate semiarid regions. Amygdalus mongolica prefers gravel deserts of temperate semiarid regions. Ammopiptanthus mongolicus prefers sandy land of temperate arid regions. Communities of A. pedunculata have the highest diversity and the largest ratios of long-lived grass species, whereas those of A. mongolicus have the lowest diversity but the largest ratios of shrub species. Communities of A. mongolica are a transition between the first two community types. These findings demonstrate that our focal endemic shrubs have evolved adaptations to arid and semiarid conditions, thus they can be nurse plants to stabilize sand ground for vegetation restoration. We suggest that land managers begin using these shrub species to restore

A RANGELAND GRASSHOPPER INSURANCE PROGRAM

OpenAIRE

Skold, Melvin D.; Davis, Robert M.

1995-01-01

The incidence of benefits and costs from controlling rangeland grasshoppers on public grazing lands poses problems of economic efficiency and distributional equity. Public grasshopper control programs operate like public disaster assistance. However, grasshopper infestations are an insurable risk. This article proposes a rangeland grasshopper insurance program which reduces the economic inefficiencies and distributional inequities of the existing program.

Developing an operational rangeland water requirement satisfaction index

Science.gov (United States)

Senay, Gabriel B.; Verdin, James P.; Rowland, James

2011-01-01

Developing an operational water requirement satisfaction index (WRSI) for rangeland monitoring is an important goal of the famine early warning systems network. An operational WRSI has been developed for crop monitoring, but until recently a comparable WRSI for rangeland was not successful because of the extremely poor performance of the index when based on published crop coefficients (K c) for rangelands. To improve the rangeland WRSI, we developed a simple calibration technique that adjusts the K c values for rangeland monitoring using long-term rainfall distribution and reference evapotranspiration data. The premise for adjusting the K c values is based on the assumption that a viable rangeland should exhibit above-average WRSI (values >80%) during a normal year. The normal year was represented by a median dekadal rainfall distribution (satellite rainfall estimate from 1996 to 2006). Similarly, a long-term average for potential evapotranspiration was used as input to the famine early warning systems network WRSI model in combination with soil-water-holding capacity data. A dekadal rangeland WRSI has been operational for east and west Africa since 2005. User feedback has been encouraging, especially with regard to the end-of-season WRSI anomaly products that compare the index's performance to ‘normal’ years. Currently, rangeland WRSI products are generated on a dekadal basis and posted for free distribution on the US Geological Survey early warning website at http://earlywarning.usgs.gov/adds/

USDA internet tool to estimate runoff and soil loss on rangelands: rangelands hydrology and erosion model

Science.gov (United States)

Rangelands are the most dominant land cover type in the United States (770 million acres) with approximately 53% of the nation’s rangelands owned and managed by the private sector, while approximately 43% are managed by the federal government. Information on the type, extent, and spatial location of...

Meeting wild bees' needs on rangelands

Science.gov (United States)

Some arid rangeland regions, notably those with warm dry climates of the temperate zones, host great diversities of native bees, primarily non-social species among which are many floral specialists. Rangeland bee faunas are threatened indirectly by invasive exotic weeds wherever these displace nat...

Principles of optimizing animal production from rangeland

International Nuclear Information System (INIS)

Stubbendieck, J.; Waller, S.S.

1983-01-01

Increasing world population is one of the dominant factors escalating demands for the world's natural resources. Range and forage resources, which are used primarily for food and fibre, could be more efficiently used if management techniques were improved. The principles of managing forage resources are directly associated with both the growth and development of plants and the actions and needs of the grazing animal. An understanding of the effects of environmental factors and herbage removal (frequency, intensity and season of defoliation) on growth and regrowth of plants is the first step towards optimizing animal productivity from rangelands. Most potential changes will fit into three categories: (1) increase the quantity of forage, (2) improve the quality of forage, and (3) improve use of forage. The principles of grazing management can be separated into four intricately related categories: (1) proper degree of grazing, (2) proper season of grazing, (3) proper kind of livestock, and (4) proper distribution of grazing. Grazing management is affected by the manner in which both improvements and manipulation of vegetation affect forage yield and quality. The adaptation and application of existing knowledge to individual locations will be one step towards optimizing animal production from rangeland. Some of the problems may be solved through better dissemination of present knowledge through existing educational programmes, while others will require expanded programmes of information dissemination. A third group of problems may also be solved with present technology, but the solutions are not currently economical. Some of the problems will be solved only through expanded research. These research efforts need to be directed towards grazing or browsing animals, plant resources and the interaction between plants and animals. Application of nuclear techniques will be an integral part of this research. (author)

Current situation of rangelands in Mexico

Science.gov (United States)

Alicia Melgoza-Castillo

2006-01-01

Rangelands are natural areas with certain characteristics that make them unsuitable for agriculture. They include several types of vegetation such as deserts, grasslands, shrubs, forests, and riparian areas. Cattle ranching, along with the products and services it engenders, is a prime activity that rangelands have traditionally supported.

Assessing the impacts of livestock production on biodiversity in rangeland ecosystems

Science.gov (United States)

Alkemade, Rob; Reid, Robin S.; van den Berg, Maurits; de Leeuw, Jan; Jeuken, Michel

2013-01-01

Biodiversity in rangelands is decreasing, due to intense utilization for livestock production and conversion of rangeland into cropland; yet the outlook of rangeland biodiversity has not been considered in view of future global demand for food. Here we assess the impact of future livestock production on the global rangelands area and their biodiversity. First we formalized existing knowledge about livestock grazing impacts on biodiversity, expressed in mean species abundance (MSA) of the original rangeland native species assemblages, through metaanalysis of peer-reviewed literature. MSA values, ranging from 1 in natural rangelands to 0.3 in man-made grasslands, were entered in the IMAGE-GLOBIO model. This model was used to assess the impact of change in food demand and livestock production on future rangeland biodiversity. The model revealed remarkable regional variation in impact on rangeland area and MSA between two agricultural production scenarios. The area of used rangelands slightly increases globally between 2000 and 2050 in the baseline scenario and reduces under a scenario of enhanced uptake of resource-efficient production technologies increasing production [high levels of agricultural knowledge, science, and technology (high-AKST)], particularly in Africa. Both scenarios suggest a global decrease in MSA for rangelands until 2050. The contribution of livestock grazing to MSA loss is, however, expected to diminish after 2030, in particular in Africa under the high-AKST scenario. Policies fostering agricultural intensification can reduce the overall pressure on rangeland biodiversity, but additional measures, addressing factors such as climate change and infrastructural development, are necessary to totally halt biodiversity loss. PMID:22308313

Robustness and management adaptability in tropical rangelands: a viability-based assessment under the non-equilibrium paradigm.

Science.gov (United States)

Accatino, F; Sabatier, R; De Michele, C; Ward, D; Wiegand, K; Meyer, K M

2014-08-01

Rangelands provide the main forage resource for livestock in many parts of the world, but maintaining long-term productivity and providing sufficient income for the rancher remains a challenge. One key issue is to maintain the rangeland in conditions where the rancher has the greatest possibility to adapt his/her management choices to a highly fluctuating and uncertain environment. In this study, we address management robustness and adaptability, which increase the resilience of a rangeland. After reviewing how the concept of resilience evolved in parallel to modelling views on rangelands, we present a dynamic model of rangelands to which we applied the mathematical framework of viability theory to quantify the management adaptability of the system in a stochastic environment. This quantification is based on an index that combines the robustness of the system to rainfall variability and the ability of the rancher to adjust his/her management through time. We evaluated the adaptability for four possible scenarios combining two rainfall regimes (high or low) with two herding strategies (grazers only or mixed herd). Results show that pure grazing is viable only for high-rainfall regimes, and that the use of mixed-feeder herds increases the adaptability of the management. The management is the most adaptive with mixed herds and in rangelands composed of an intermediate density of trees and grasses. In such situations, grass provides high quantities of biomass and woody plants ensure robustness to droughts. Beyond the implications for management, our results illustrate the relevance of viability theory for addressing the issue of robustness and adaptability in non-equilibrium environments.

Maintaining ecosystem services through continued livestock production on California rangelands

Science.gov (United States)

Barry, S.; Becchetti, T.

2015-12-01

Nearly 40% of California is rangeland comprising the largest land type in California and providing forage for livestock, primarily beef cattle. In addition to forage, rangelands provide a host of ecosystem systems services, including habitat for common and endangered species, fire fuels management, pollination services, clean water, viewsheds, and carbon sequestration. Published research has documented that most of these ecosystem services are positively impacted by managed livestock grazing and rancher stewardship. Ranchers typically do not receive any monetary reimbursement for their stewardship in providing these ecosystem services to the public. Markets have been difficult to establish with limited ability to adequately monitor and measure services provided. At the same time, rangelands have been experiencing rapid conversion to urbanization and more profitable and intensive forms of agriculture such as almond and walnut orchards. To prevent further conversion of rangelands and the loss of the services they provide, there needs to be a mechanism to identify and compensate landowners for the value of all products and services being received from rangelands. This paper considers two methods (opportunity cost and avoided cost) to determine the value of Payment for Ecosystem Services (PES) for rangelands. PES can raise the value of rangelands, making them more competitive financially. Real estate values and University of California Cooperative Extension Cost Studies, were used to demonstrate the difference in value (lost opportunity cost) between the primary products of rangelands (livestock production) and the products of the converted rangelands (almond and walnut orchards). Avoided costs for vegetation management and habitat creation and maintenance were used to establish the value of managed grazing. If conversion is to be slowed or stopped and managed grazing promoted to protect the ecosystem services rangelands provide, this value could be compensated through

Common garden comparisons of reproductive, forage and weed suppression potential of rangeland rehabilitation grasses of the Great Basin

Science.gov (United States)

Common garden experiments are a means to remove environmental effects. Using 8 species of perennial rangeland grasses, we established a common garden (3 reps x28 plants = 84 plants/species). We found that ‘Hycrest’ crested wheatgrass (Agropyron cristatum) and bluebunch wheatgrass (Pseudoroegneria sp...

Remote sensing applications for monitoring rangeland vegetation ...

African Journals Online (AJOL)

Remote sensing techniques hold considerable promise for the inventory and monitoring of natural resources on rangelands. A significant lack of information concerning basic spectral characteristics of range vegetation and soils has resulted in a lack of rangeland applications. The parameters of interest for range condition ...

Re-creating the commons and re-configuring Maasai women’s roles on the rangelands in the face of fragmentation

Directory of Open Access Journals (Sweden)

Caroline S Archambault

2016-09-01

Full Text Available Throughout the world pastoralists today face a particularly daunting challenge of intensified rangeland fragmentation combined with human population growth and climate change. In many pastoral settings, rangelands are undergoing processes of fragmentation due to tenure transformations, as previously communal lands are privatized into individual holdings. Such processes of enclosure have raised concerns over the long-term costs on pastoral communities and on rangeland eco-systems. This paper explores pastoral responses and adaptations to enclosure based on long-term ethnographic engagement in a Maasai community in Southern Kenya that has recently privatized. Detailed family case studies and herd tracking illuminate the ways in which families try to re-create the commons by relying on social networks for free access to resources. In particular, women’s social networks (for example, their kin, affines, friends, or religious associates seem to play an important role. This paper calls attention to the need to better understand women’s changing roles in pastoral governance and production and the implications these new roles have for women’s well-being and for pastoralism in the face of fragmentation.

Conserving rangeland resources. | Mentis | African Journal of Range ...

African Journals Online (AJOL)

... goal-attainment, (5) try to correct departures, and (6) align individual and societal interests by manipulating market-forces. Keywords: altruism; conservation; Conservation implementation; Conservation properties; human activity; Human values; philosophy; Range resources; rangeland; Rangelands; Science philosophy

Sustainable rangeland management, economic growth, and a cautious role for the SRM

Science.gov (United States)

Interest in the art and science of rangeland management increased dramatically during the 20th century and it was out of this interest that the profession of rangeland management was born. As public interest in rangeland management grew, so did the number, breadth, and depth of rangeland management ...

Pastoral Decision-Making: An Empirical Investigation of Rangeland Use

International Nuclear Information System (INIS)

MacPeak, J.

1999-01-01

Recent research in range ecology suggests that the process of resource degradation in African arid and semi-arid rangelands may be less reliant on how many animals are kept on the rangeland than on where these animals are kept. Analysis of pastoralist land use decisions indicated that rangeland condition influences livestock keeping. However, it was found that food and income production strategies, herd characteristics play critical roles in livestock keeping decisions

A Dynamic Model of California's Hardwood Rangelands

Science.gov (United States)

Richard B. Standiford; Richard E. Howitt

1991-01-01

Low profitability of hardwood rangeland management, and oak tree harvesting for firewood markets and forage enhancement has led to concern about the long-term sustainability of the oak resource on rangelands. New markets for recreational hunting may give value to oaks for the habitat they provide for game species, and broaden the economic base for managers. A ranch...

State-and-transition model archetypes: a global taxonomy of rangeland change

Science.gov (United States)

State and transition models (STMs) synthesize science-based and local knowledge to formally represent the dynamics of rangeland and other ecosystems. Mental models or concepts of ecosystem dynamics implicitly underlie all management decisions in rangelands and thus how people influence rangeland sus...

Sustaining working rangelands: Insights from rancher decision making

Science.gov (United States)

Grazed rangeland ecosystems encompass diverse global land resources, and are complex social-ecological systems from which society demands both goods (e.g., livestock and forage production) and services (e.g., abundant and high quality water). In the dialogue on rangeland conservation and sustainable...

Patterns of vegetation and grasshopper community composition.

Science.gov (United States)

Kemp, W P; Harvey, S J; O'Neill, K M

1990-06-01

A study was conducted to evaluate differences in rangeland grasshopper communities over environmental gradients in Gallatin Valley, Montana, USA. The concept of habitat type (Daubenmire 1966) was used as a basis for discriminating between groupings of patches based on vegetation. A total of 39 patches were selected that represented five recognized grassland habitat types (Mueggler and Stewart 1980), as well as two disturbed types (replanting within a known habitat type). Repeated sampling in 1988 of both the insect and plant communities yielded a total of 40 grasshopper (19 664 individuals) and 97 plant species. Detrended Correspondence Analysis (DCA) indicated that patch classifications based on presence and percent cover of plants were appropriate and showed good between-group (habitat type) separation for patches along gradients of precipitation/elevation and plant community complexity. Results from undisturbed habitats showed that plant and grasshopper species composition changed over observed environmental gradients and suggested that habitat type influenced not only species presence, but also relative abundance. Discussion is presented that relates results with patch-use and core and satellite species paradigms.

Rangeland dynamics in South Omo Zone of Southern Ethiopia: Assessment of rangeland condition in relation to altitude and Grazing types

NARCIS (Netherlands)

Terefe, A.; Ebro, A.; Tessema, Z.K.

2010-01-01

A study was undertaken in Hamer and Benna-Tsemay districts of the Southern Ethiopia with the objective to determine the condition of the rangelands for grazing animals as influenced by altitude and grazing types. The rangelands in each of the study districts were stratified based on altitude and

Effect of canopy cover and canopy background variables on spectral profiles of savanna rangeland bush encroachment species based on selected Acacia species (mellifera, tortilis, karroo) and Dichrostachys cinerea at Mokopane, South Africa

CSIR Research Space (South Africa)

Munyati, C

2013-07-01

Full Text Available The proliferation of woody plant species on savanna rangelands (i.e. bush encroachment) degrades rangeland quality, thereby threatening the biodiversity conservation effort as well as pastoral farming. Hyperspectral remote sensing offers...

Hydrologic Impacts Associated with the Increased Role of Wildland Fire Across the Rangeland-Xeric Forest Continuum of the Great Basin and Intermountain West, USA

Science.gov (United States)

Williams, C. J.; Pierson, F. B.; Robichaud, P. R.; Boll, J.; Al-Hamdan, O. Z.

2011-12-01

The increased role of wildland fire across the rangeland-xeric forest continuum in the western United States (US) presents landscape-scale consequences relative runoff and erosion. Concomitant climate conditions and altered plant community transitions in recent decades along grassland-shrubland-woodland-xeric forest transitions have promoted frequent and large wildland fires, and the continuance of the trend appears likely if current or warming climate conditions prevail. Much of the Great Basin and Intermountain West in the US now exists in a state in which rangeland and woodland wildfires stimulated by invasive cheatgrass and dense, horizontal and vertical fuel layers have a greater likelihood of progressing upslope into xeric forests. Drier moisture conditions and warmer seasonal air temperatures, along with dense fuel loads, have lengthened fire seasons and facilitated an increase in the frequency, severity and area burned in mid-elevation western US forests. These changes potentially increase the overall hydrologic vulnerability across the rangeland-xeric forest continuum by spatially and temporally increasing soil surface exposure to runoff and erosion processes. Plot-to-hillslope scale studies demonstrate burning may increase event runoff and/or erosion by factors of 2-40 over small-plots scales and more than 100-fold over large-plot to hillslope scales. Anecdotal reports of large-scale flooding and debris-flow events from rangelands and xeric forests following burning document the potential risk to resources (soil loss, water quality, degraded aquatic habitat, etc.), property and infrastructure, and human life. Such risks are particularly concerning for urban centers near the urban-wildland interface. We do not yet know the long-term ramifications of frequent soil loss associated with commonly occurring runoff events on repeatedly burned sites. However, plot to landscape-scale post-fire erosion rate estimates suggest potential losses of biologically

Adaptive management for complex communal rangelands in South ...

African Journals Online (AJOL)

Many of the intransigent problems facing the world arise in complex systems. In this paper, I propose that communal rangelands in South Africa be recognised as complex social–ecological systems and that one of the reasons that development initiatives have had little impact on improving livelihoods and rangeland ...

Criterion IV: Social and economic indicators of rangeland sustainability (Chapter 5)

Science.gov (United States)

Daniel W. McCollum; Louis E. Swanson; John A. Tanaka; Mark W. Brunson; Aaron J. Harp; L. Allen Torell; H. Theodore Heintz

2010-01-01

Social and economic systems provide the context and rationale for rangeland management. Sustaining rangeland ecosystems requires attention to the social and economic conditions that accompany the functioning of those systems. We present and discuss economic and social indicators for rangeland sustainability. A brief conceptual basis for each indicator is offered,...

An Integrated Social, Economic, and Ecologic Conceptual (ISEEC) framework for considering rangeland sustainability

Science.gov (United States)

William E. Fox; Daniel W. McCollum; John E. Mitchell; Louis E. Swanson; Urs P. Kreuter; John A. Tanaka; Gary R. Evans; H. Theodore Heintz; Robert P. Breckenridge; Paul H. Geissler

2009-01-01

Currently, there is no standard method to assess the complex systems in rangeland ecosystems. Decision makers need baselines to create a common language of current rangeland conditions and standards for continued rangeland assessment. The Sustainable Rangeland Roundtable (SRR), a group of private and public organizations and agencies, has created a forum to discuss...

Water conservation for semi-arid rangelands

International Nuclear Information System (INIS)

Willis, W.O.

1983-01-01

Water deficiency is most often the cause for low forage production on rangelands in semi-arid and arid regions. Water conservation methods have been developed but additional research is needed to develop the best management practices for various climatic regions. Poor management is another major cause of low rangeland production. Better management, including the application of research findings, depends on attitudes, policies, adaptability of findings, resources for implementation and a good understanding of the governing biotic and abiotic factors. (author)

Energy budgets and resistances to energy transport in sparsely vegetated rangeland

Science.gov (United States)

Nichols, W.D.

1992-01-01

Partitioning available energy between plants and bare soil in sparsely vegetated rangelands will allow hydrologists and others to gain a greater understanding of water use by native vegetation, especially phreatophytes. Standard methods of conducting energy budget studies result in measurements of latent and sensible heat fluxes above the plant canopy which therefore include the energy fluxes from both the canopy and the soil. One-dimensional theoretical numerical models have been proposed recently for the partitioning of energy in sparse crops. Bowen ratio and other micrometeorological data collected over phreatophytes growing in areas of shallow ground water in central Nevada were used to evaluate the feasibility of using these models, which are based on surface and within-canopy aerodynamic resistances, to determine heat and water vapor transport in sparsely vegetated rangelands. The models appear to provide reasonably good estimates of sensible heat flux from the soil and latent heat flux from the canopy. Estimates of latent heat flux from the soil were less satisfactory. Sensible heat flux from the canopy was not well predicted by the present resistance formulations. Also, estimates of total above-canopy fluxes were not satisfactory when using a single value for above-canopy bulk aerodynamic resistance. ?? 1992.

Future scenarios of impacts to ecosystem services on California rangelands

Science.gov (United States)

Byrd, Kristin; Alvarez, Pelayo; Flint, Lorraine; Flint, Alan

2014-01-01

The 18 million acres of rangelands in the Central Valley of California provide multiple benefits or “ecosystem services” to people—including wildlife habitat, water supply, open space, recreation, and cultural resources. Most of this land is privately owned and managed for livestock production. These rangelands are vulnerable to land-use conversion and climate change. To help resource managers assess the impacts of land-use change and climate change, U.S. Geological Survey scientists and their cooperators developed scenarios to quantify and map changes to three main rangeland ecosystem services—wildlife habitat, water supply, and carbon sequestration. Project results will help prioritize strategies to conserve these rangelands and the ecosystem services that they provide.

PERSPECTIVES ON RANGELAND ECOLOGY AND MANAGEMENT

OpenAIRE

Heady, Harold F.

2011-01-01

This paper reviews changes in rangeland ecology and management in the U.S.A. over the last 65 years and speculates on future changes. Emphasis has shifted from livestock management to ecological and environmental concerns, hence "rangeland ecology." The term "range management" may have outlived its usefulness and may also be detrimental to our image. The vision that we have of ourselves is not the same as others have of us. Many members of the Society for Range Management (SRM) and most of ou...

Rangeland and water resources

African Journals Online (AJOL)

Session B3 Management for sustainable use — Rangeland and water resources. ... The theme of optimsing integrated catchment management will be treated ... land system, catchment, basin), with a focus on law, policy and implementation.

Meeting wild bees' needs on Western US rangelands

Science.gov (United States)

James H. Cane

2011-01-01

Rangelands are areas that are too arid, or with soils too shallow, to support either forests or cultivated agriculture, but that nonetheless produce enough vegetation for livestock grazing. Some arid rangeland regions, notably those with warm, dry climates in temperate zones (e.g., the warm deserts of the United States and adjacent Mexico, parts of Australia, South...

Plant-plant competition outcomes are modulated by plant effects on the soil bacterial community.

Science.gov (United States)

Hortal, S; Lozano, Y M; Bastida, F; Armas, C; Moreno, J L; Garcia, C; Pugnaire, F I

2017-12-19

Competition is a key process that determines plant community structure and dynamics, often mediated by nutrients and water availability. However, the role of soil microorganisms on plant competition, and the links between above- and belowground processes, are not well understood. Here we show that the effects of interspecific plant competition on plant performance are mediated by feedbacks between plants and soil bacterial communities. Each plant species selects a singular community of soil microorganisms in its rhizosphere with a specific species composition, abundance and activity. When two plant species interact, the resulting soil bacterial community matches that of the most competitive plant species, suggesting strong competitive interactions between soil bacterial communities as well. We propose a novel mechanism by which changes in belowground bacterial communities promoted by the most competitive plant species influence plant performance and competition outcome. These findings emphasise the strong links between plant and soil communities, paving the way to a better understanding of plant community dynamics and the effects of soil bacterial communities on ecosystem functioning and services.

Plant diversity and plant identity influence Fusarium communities in soil.

Science.gov (United States)

LeBlanc, Nicholas; Kinkel, Linda; Kistler, H Corby

2017-01-01

Fusarium communities play important functional roles in soil and in plants as pathogens, endophytes, and saprotrophs. This study tests how rhizosphere Fusarium communities may vary with plant species, changes in the diversity of the surrounding plant community, and soil physiochemical characteristics. Fusarium communities in soil associated with the roots of two perennial prairie plant species maintained as monocultures or growing within polyculture plant communities were characterized using targeted metagenomics. Amplicon libraries targeting the RPB2 locus were generated from rhizosphere soil DNAs and sequenced using pyrosequencing. Sequences were clustered into operational taxonomic units (OTUs) and assigned a taxonomy using the Evolutionary Placement Algorithm. Fusarium community composition was differentiated between monoculture and polyculture plant communities, and by plant species in monoculture, but not in polyculture. Taxonomic classification of the Fusarium OTUs showed a predominance of F. tricinctum and F. oxysporum as well of the presence of a clade previously only found in the Southern Hemisphere. Total Fusarium richness was not affected by changes in plant community richness or correlated with soil physiochemical characteristics. However, OTU richness within two predominant phylogenetic lineages within the genus was positively or negatively correlated with soil physiochemical characteristics among samples within each lineage. This work shows that plant species, plant community richness, and soil physiochemical characteristics may all influence the composition and richness of Fusarium communities in soil.

Ecologic, Economic, and Social Considerations for Rangeland Sustainability: An Integrated Conceptual Framework

Science.gov (United States)

Daniel W. McCollum; H. Theodore Jr. Heintz; Aaron J. Harp; John A. Tanaka; Gary R. Evans; David Radloff; Louis E. Swanson; William E. III Fox; Michael G. Sherm Karl; John E. Mitchell

2006-01-01

Use and sustainability of rangelands are inherently linked to the health and sustainability of the land. They are also inherently linked to the social and economic infrastructures that complement and support those rangelands and rangeland uses. Ecological systems and processes provide the biological interactions underlying ecosystem health and viability. Social and...

Ecohydrologic impacts of rangeland fire on runoff and erosion: A literature synthesis

Science.gov (United States)

Frederick B. Pierson; C. Jason Williams

2016-01-01

Fire can dramatically influence rangeland hydrology and erosion by altering ecohydrologic relationships. This synthesis presents an ecohydrologic perspective on the effects of fire on rangeland runoff and erosion through a review of scientific literature spanning many decades. The objectives are: (1) to introduce rangeland hydrology and erosion concepts necessary for...

A description of rangeland on commercial and communal land ...

African Journals Online (AJOL)

Analysis of a Landsat TM image from a rangeland near Peddie, Eastern Cape, revealed differences in two vegetation indices (normalised difference vegetation index, NDVI, and moving standard deviation index, MSDI) between communal and commercial rangeland. It was suggested that the difference in the MSDI reflected ...

Bio solids Effects in Chihuahuan Desert Rangelands: A Ten-Year Study

International Nuclear Information System (INIS)

Wester, D.B; Sosebee, R.E; Fish, E.B; Villalobos, J.C; Zartman, R.E; Gonzalez, R.M; Jurado, P.; Moffet, C.A

2011-01-01

Arid and semiarid rangelands are suitable for responsible bio solids application. Topical application is critical to avoid soil and vegetation disturbance. Surface-applied bio solids have long-lasting effects in these ecosystems. We conducted a 10-year research program investigating effects of bio solids applied at rates from 0 to 90 dry Mg ha -1 on soil water infiltration; runoff and leachate water quality; soil erosion; forage production and quality; seedling establishment; plant physiological responses; nitrogen dynamics; bio solids decomposition; and grazing animal behavior and management. Bio solids increased soil water infiltration and reduced erosion. Effects on soil water quality were observed only at the highest application rates. Bio solids increased soil nitrate-nitrogen. Bio solids increased forage production and improved forage quality. Bio solids increased leaf area of grasses; photosynthetic rates were not necessarily increased by bio solids. Bio solids effects on plant establishment are expected only under moderately favorable conditions. Over an 82-mo exposure period, total organic carbon, nitrogen, and total and available phosphorus decreased and inorganic matter increased. Grazing animals spent more time grazing, ruminating, and resting in bio solids-treated areas; positive effects on average daily gain were observed during periods of higher rainfall. Our results suggest that annual bio solids application rates of up to 18 Mg ha -1 are appropriate for desert rangelands.

Managing climate change risks in rangeland systems [Chapter 15

Science.gov (United States)

Linda A. Joyce; Nadine A. Marshall

2017-01-01

The management of rangelands has long involved adapting to climate variability to ensure that economic enterprises remain viable and ecosystems sustainable; climate change brings the potential for change that surpasses the experience of humans within rangeland systems. Adaptation will require an intentionality to address the effects of climate change. Knowledge of...

The usefullness of ERTS-1 and supporting aircraft data for monitoring plant development in rangeland environments

Science.gov (United States)

Carneggie, D. M.; Degloria, S. D.

1972-01-01

The author has identified the following significant results. Preliminary analysis of ERTS-1 MSS imagery of annual and perennial rangeland in California yields the following observations: (1) Sufficient geomorphological detail can be resolved to differentiate upland and bottomland range sites in the foothill range areas. (2) Dry and green meadowland can be differentiated on MSS band 5. (3) Color composites prepared by NASA-Goddard were useful for locating perennial rangeland with varying amounts of herbaceous ground cover. (4) The ERTS-1 images received and interpreted cover nearly 50% of the state of California and show nearly two-thirds of the annual grassland type. (5) Satellite imagery obtained during the late summer season should be optimum for differentiating grassland from brushland and forested land. (6) The ERTS-1 imagery clearly shows areas which at one time were part of the annual grassland but which are now used for dry land farming (cropping of cereal grains). Similarly, the imagery show areas which have been converted from brushland to grassland.

Ecological evaluation of rangeland quality in dry subtropics of Azerbaijan

Science.gov (United States)

Gasanova, A. F.

2014-12-01

The results of ecological evaluation of soil-landscape complexes of winter rangelands of Gobustan with the use of energy criteria are discussed. The diagnostic characteristics of soil fertility and correction coefficients for the thickness of texture of soil horizons, soil salinization, soil erosion, and microelemental composition of soils have been used to separate the soils of winter rangelands into several quality groups. A larger part of the soils belongs to the medium quality group with the mean weighted quality factor (bonitet) of 52. Special assessment scales have been suggested for the differential ecological assessment and monitoring of the rangelands. In the past 40 years, the area of steppe landscapes has decreased from 22.7 to 12%, whereas the area of semideserts has increased up to 64%. The area of best-quality soils within the studied rangelands had decreased by three times, and their average quality factor has decreased from 92 to 86.

Rangeland -- Plant response to elevated CO{sub 2}. Progress report

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-08-01

An experiment is being designed to examine the influence of elevating CO2 levels on tallgrass prairie rangeland. Changes in biomass production, photosynthesis rates, and species composition (C3 versus C4) over time are to be examined. This report covers the period from August 15, 1988 to January 1, 1989. During this period the authors have had planning meetings in Manhattan, KS, and Washington, DC, with various investigators of the measurement and modeling groups within the elevated CO{sub 2} program. During this period detailed discussions with regard to the methodology were carried out. In addition, short-term experiments and prototype constructions were completed to assess design and materials. Because of changes in the methodology and, to a certain degree, the scope, they are requesting changes in the funding cycle to implement the project at the beginning of the growing cycle of the tallgrass prairie.

Very High Resolution Panoramic Photography to Improve Conventional Rangeland Monitoring 1994

Science.gov (United States)

Rangeland monitoring often includes repeat photographs as a basis for documentation and although photographic equipment and electronics have been evolving rapidly, basic rangeland photo monitoring methods have changed little over time. Ground based digital photography is underutilized, especially s...

Regional Standards for Rangeland Health and Guidelines for Livestock Grazing Management ... A Progress Report

OpenAIRE

1996-01-01

In August 1995, new BLM regulations for rangeland administration went into effect. The new regulations require BLM to establish regional standards for rangeland health and guidelines for grazing management. This publication is a report on the alternatives being considered for the Montana/Dakotas Rangeland Health Standards and Guidelines process.

Fodder Biomass Monitoring in Sahelian Rangelands Using Phenological Metrics from FAPAR Time Series

Directory of Open Access Journals (Sweden)

Abdoul Aziz Diouf

2015-07-01

Full Text Available Timely monitoring of plant biomass is critical for the management of forage resources in Sahelian rangelands. The estimation of annual biomass production in the Sahel is based on a simple relationship between satellite annual Normalized Difference Vegetation Index (NDVI and in situ biomass data. This study proposes a new methodology using multi-linear models between phenological metrics from the SPOT-VEGETATION time series of Fraction of Absorbed Photosynthetically Active Radiation (FAPAR and in situ biomass. A model with three variables—large seasonal integral (LINTG, length of growing season, and end of season decreasing rate—performed best (MAE = 605 kg·DM/ha; R2 = 0.68 across Sahelian ecosystems in Senegal (data for the period 1999–2013. A model with annual maximum (PEAK and start date of season showed similar performances (MAE = 625 kg·DM/ha; R2 = 0.64, allowing a timely estimation of forage availability. The subdivision of the study area in ecoregions increased overall accuracy (MAE = 489.21 kg·DM/ha; R2 = 0.77, indicating that a relation between metrics and ecosystem properties exists. LINTG was the main explanatory variable for woody rangelands with high leaf biomass, whereas for areas dominated by herbaceous vegetation, it was the PEAK metric. The proposed approach outperformed the established biomass NDVI-based product (MAE = 818 kg·DM/ha and R2 = 0.51 and should improve the operational monitoring of forage resources in Sahelian rangelands.

Emerging issues and challenges in conservation of biodiversity in the rangelands of Tanzania

Directory of Open Access Journals (Sweden)

Jafari Kideghesho

2013-11-01

Full Text Available Tanzania rangelands are a stronghold for biodiversity harbouring a variety of animal and plant species of economic, ecological and socio-cultural importance. Efforts to protect these resources against destruction and loss have involved, among other things, setting aside some tracks of land as protected areas in the form of national parks, nature reserves, game reserves, game controlled and wildlife management areas. However, these areas and adjacent lands have long been subjected to a number of emerging issues and challenges, which complicate their management, thus putting the resources at risk of over exploitation and extinction. These issues and challenges include, among other things, government policies, failure of conservation (as a form of land use to compete effectively with alternative land uses, habitat degradation and blockage of wildlife corridors, overexploitation and illegal resource extraction, wildfires, human population growth, poverty, HIV/AIDS pandemic and human-wildlife conflicts. In this paper, we review the emerging issues and challenges in biodiversity conservation by drawing experience from different parts of Tanzania. The paper is based on the premise that, understanding of the issues and challenges underpinning the rangelands is a crucial step towards setting up of plausible objectives, strategies and plans that will improve and lead to effective management of these areas. We conclude by recommending some proactive measures that may enhance the sustainability of the rangeland resources for the benefit of the current and future generations.

Earth stewardship on rangelands: Coping with ecological, economic, and political marginality

Science.gov (United States)

Rangelands encompass 30-40 percent of Earth's land surface and support 1-2 billion people. Their predominant use is extensive livestock production by pastoralists and ranchers. But rangelands are characterized by ecological, economic, and political marginality, and higher-value, more intensive land ...

Mountain Plant Community Sentinels: AWOL

Science.gov (United States)

Malanson, G. P.

2017-12-01

Mountain plant communities are thought to be sensitive to climate change. Because climatic gradients are steep on mountain slopes, the spatial response of plant communities to climate change should be compressed and easier to detect. These expectations have led to identifying mountain plant communities as sentinels for climate change. This idea has, however, been criticized. Two critiques, for alpine treeline and alpine tundra, are rehearsed and supplemented. The critique of alpine treeline as sentinel is bolstered with new model results on the confounding role of dispersal mechanisms and sensitivity to climatic volatility. In alpine tundra, for which background turnover rates have yet to be established, community composition may reflect environmental gradients only for extremes where effects of climate are most indirect. Both plant communities, while primarily determined by energy at broad scales, may respond to water as a proximate driver at local scales. These plant communities may not be in equilibrium with climate, and differently scaled time lags may mean that ongoing vegetation change may not signal ongoing climate change (or lack thereof). In both cases a double-whammy is created by scale dependence for time lags and for drivers leading to confusion, but these cases present opportunities for insights into basic ecology.

Discussion of submitted posters for Section 2.3 (Rangeland Germplasm Resources)

Science.gov (United States)

As part of the IX International Rangeland Congress held in Rosario, Argentina, a total of 70 posters from 17 countries were submitted to Section 2.3 (Rangeland Germplasm Resources). These posters documented research conducted in five major regions of the world: South America, North America, Africa...

Using faecal DNA to determine consumption by kangaroos of plants considered palatable to sheep.

Science.gov (United States)

Ho, K W; Krebs, G L; McCafferty, P; van Wyngaarden, S P; Addison, J

2010-02-01

Disagreement exists within the scientific community with regards to the level of competition for feed between sheep and kangaroos in the Australian rangelands. The greatest challenge to solving this debate is finding effective means of determining the composition of the diets of these potential grazing competitors. An option is to adopt a non-invasive approach that combines faecal collection and molecular techniques that focus on faecal DNA as the primary source of dietary information. As proof-of-concept, we show that a DNA reference data bank on plant species can be established. This DNA reference data bank was then used as a library to identify plant species in kangaroo faeces collected in the southern rangelands of Western Australia. To enhance the method development and to begin the investigation of competitive grazing between sheep and kangaroos, 16 plant species known to be palatable to sheep were initially targeted for collection. To ensure that only plant sequences were studied, PCR amplification was performed using a universal primer pair previously shown to be specific to the chloroplast transfer RNA leucine (trnL) UAA gene intron. Overall, genus-specific, single and differently sized amplicons were reliably and reproducibly generated; enabling the differentiation of reference plants by PCR product length heterogeneity. However, there were a few plants that could not be clearly differentiated on the basis of size alone. This prompted the adoption of a post-PCR step that enabled further differentiation according to base sequence variation. Restriction endonucleases make sequence-specific cleavages on DNA to produce discrete and reproducible fragments having unique sizes and base compositions. Their availability, affordability and simplicity-of-use put restriction enzyme sequence (RES) profiling as a logical post-PCR step for confirming plant species identity. We demonstrate that PCR-RES profiling of plant and faecal matter is useful for the identification

Plant community resistance to invasion by Bromus species – the roles of community attributes, Bromus Interactions with plant communities, and Bromus traits

Science.gov (United States)

Chambers, Jeanne; Germino, Matthew; Belnap, Jayne; Brown, Cynthia; Schupp, Eugene W.; St. Clair, Samuel B

2016-01-01

The factors that determine plant community resistance to exotic annual Bromus species (Bromushereafter) are diverse and context specific. They are influenced by the environmental characteristics and attributes of the community, the traits of Bromus species, and the direct and indirect interactions of Bromus with the plant community. Environmental factors, in particular ambient and soil temperatures, have significant effects on the ability of Bromus to establish and spread. Seasonality of precipitation relative to temperature influences plant community resistance toBromus through effects on soil water storage, timing of water and nutrient availability, and dominant plant life forms. Differences among plant communities in how well soil resource use by the plant community matches resource supply rates can influence the magnitude of resource fluctuations due to either climate or disturbance and thus the opportunities for invasion. The spatial and temporal patterns of resource availability and acquisition of growth resources by Bromus versus native species strongly influence resistance to invasion. Traits of Bromus that confer a “priority advantage” for resource use in many communities include early-season germination and high growth and reproductive rates. Resistance to Bromus can be overwhelmed by high propagule supply, low innate seed dormancy, and large, if short-lived, seed banks. Biological crusts can inhibit germination and establishment of invasive annual plants, including several annual Bromus species, but are effective only in the absence of disturbance. Herbivores can have negative direct effects on Bromus, but positive indirect effects through decreases in competitors. Management strategies can be improved through increased understanding of community resistance to exotic annual Bromus species.

Climate change effects on rangelands and rangeland management: Affirming the need for monitoring

Science.gov (United States)

Daniel W. Mccollum; John A. Tanaka; Jack A. Morgan; John E. Mitchell; William E. Fox; Kristie A. Maczko; Lori Hidinger; Clifford S. Duke; Urs P. Kreuter

2017-01-01

Uncertainty as to the extent and magnitude of changes in conditions that might occur due to climate change poses a problem for land and resource managers as they seek to adapt to changes and mitigate effects of climate variability. We illustrate using scenarios of projected future conditions on rangelands in the Northern Great Plains and Desert Southwest of the United...

Limitations to postfire seedling establishment: The role of seeding technology, water availability, and invasive plant abundance

Science.gov (United States)

Jeremy J. James; Tony Svejcar

2010-01-01

Seeding rangeland following wildfire is a central tool managers use to stabilize soils and inhibit the spread of invasive plants. Rates of successful seeding on arid rangeland, however, are low. The objective of this study was to determine the degree to which water availability, invasive plant abundance, and seeding technology influence postfire seedling establishment...

Management of communal rangelands - the dialogue between science and indigenous knowledge: the case of the Eastern Cape

CSIR Research Space (South Africa)

Dube, S

2010-07-01

Full Text Available Communal area rangeland resource users are an important part of the rangeland ecosystem; rangeland management policies and practice should, therefore, accommodate their socio-cultural practices and knowledge. Indigenous knowledge (IK) is often...

Vegetation - Herbivory Dynamics in Rangeland Ecosystems: Geospatial Modeling for Savanna and Wildlife Conservation in California and Namibia

OpenAIRE

Tsalyuk, Miriam

2014-01-01

Rangelands cover about half of Earth's land surface, encompass considerable biodiversity, and provide pivotal ecosystem services. However, rangelands across the globe face degradation due to changes in climate, land use, and management. Moreover, since herbivory is fundamental to rangeland ecosystem dynamics, shifts in the distribution of herbivores lead to overgrazing and desertification. To better understand, predict, and prevent changes on rangelands it is important to monitor these landsc...

Climate change and North American rangelands: Assessment of mitigation and adaptation strategies

Science.gov (United States)

Linda A. Joyce; David D. Briske; Joel R. Brown; H. Wayne Polley; Bruce A. McCarl; Derek W. Bailey

2013-01-01

Recent climatic trends and climate model projections indicate that climate change will modify rangeland ecosystem functions and the services and livelihoods that they provision. Recent history has demonstrated that climatic variability has a strong influence on both ecological and social components of rangeland systems and that these systems possess substantial...

Estimating Rangeland Forage Production Using Remote Sensing Data from a Small Unmanned Aerial System (sUAS)

Science.gov (United States)

Liu, H.; Jin, Y.; Devine, S.; Dahlgren, R. A.; Covello, S.; Larsen, R.; O'Geen, A. T.

2017-12-01

California rangelands cover 23 million hectares and support a $3.4 billion annual cattle industry. Rangeland forage production varies appreciably from year-to-year and across short distances on the landscape. Spatially explicit and near real-time information on forage production at a high resolution is critical for effective rangeland management, especially during an era of climatic extremes. We here integrated a multispectral MicaSense RedEdge camera with a 3DR solo quad-copter and acquired time-series images during the 2017 growing season over a topographically complex 10-hectare rangeland in San Luis Obispo County, CA. Soil moisture and temperature sensors were installed at 16 landscape positions, and vegetation clippings were collected at 36 plots to quantify forage dry biomass. We built four centimeter-level models for forage production mapping using time series of sUAS images and ground measurements of forage biomass and soil temperature and moisture. The biophysical model based on Monteith's eco-physiological plant growth theory estimated forage production reasonably well with a coefficient of determination (R2) of 0.86 and a root-mean-square error (RMSE) of 424 kg/ha when the soil parameters were included, and a R2 of 0.79 and a RMSE of 510 kg/ha when only remote sensing and topographical variables were included. We built two empirical models of forage production using a stepwise variable selection technique, one with soil variables. Results showed that cumulative absorbed photosynthetically active radiation (APAR) and elevation were the most important variables in both models, explaining more than 40% of the spatio-temporal variance in forage production. Soil moisture accounted for an additional 29% of the variance. Illumination condition was selected as a proxy for soil moisture in the model without soil variables, and accounted for 18% of the variance. We applied the remote sensing-based models to map daily forage production at 30-cm resolution for the

Community-level plant-soil feedbacks explain landscape distribution of native and non-native plants.

Science.gov (United States)

Kulmatiski, Andrew

2018-02-01

Plant-soil feedbacks (PSFs) have gained attention for their potential role in explaining plant growth and invasion. While promising, most PSF research has measured plant monoculture growth on different soils in short-term, greenhouse experiments. Here, five soil types were conditioned by growing one native species, three non-native species, or a mixed plant community in different plots in a common-garden experiment. After 4 years, plants were removed and one native and one non-native plant community were planted into replicate plots of each soil type. After three additional years, the percentage cover of each of the three target species in each community was measured. These data were used to parameterize a plant community growth model. Model predictions were compared to native and non-native abundance on the landscape. Native community cover was lowest on soil conditioned by the dominant non-native, Centaurea diffusa , and non-native community cover was lowest on soil cultivated by the dominant native, Pseudoroegneria spicata . Consistent with plant growth on the landscape, the plant growth model predicted that the positive PSFs observed in the common-garden experiment would result in two distinct communities on the landscape: a native plant community on native soils and a non-native plant community on non-native soils. In contrast, when PSF effects were removed, the model predicted that non-native plants would dominate all soils, which was not consistent with plant growth on the landscape. Results provide an example where PSF effects were large enough to change the rank-order abundance of native and non-native plant communities and to explain plant distributions on the landscape. The positive PSFs that contributed to this effect reflected the ability of the two dominant plant species to suppress each other's growth. Results suggest that plant dominance, at least in this system, reflects the ability of a species to suppress the growth of dominant competitors

Plant community resistance to invasion by Bromus species: The roles of community attributes, Bromus interactions with plant communities, and Bromus traits [Chapter 10

Science.gov (United States)

Jeanne C. Chambers; Matthew J. Germino; Jayne Belnap; Cynthia S. Brown; Eugene W. Schupp; Samuel B. St. Clair

2016-01-01

The factors that determine plant community resistance to exotic annual Bromus species (Bromus hereafter) are diverse and context specific. They are influenced by the environmental characteristics and attributes of the community, the traits of Bromus species, and the direct and indirect interactions of Bromus with the plant community. Environmental factors, in...

PARTICIPATORY CARTOGRAPHY IN A TRADITIONAL GOAT PRODUCTION SYSTEM OF A SMALLHOLDER COMMUNITY IN NORTHERN MÉXICO

Directory of Open Access Journals (Sweden)

Juan Manuel Pinos Rodríguez

2013-08-01

Full Text Available A community mapping procedure was developed to identify and characterize communal land area used for a traditional goat production system. Participatory cartography indicated that producers have good knowledge of their territory; more than 80% of the spatial distribution and localization of the elements and shapes present in the community map agreed with the map constructed with GIS. All flocks were mainly grazed on communal rangelands where the most important native forage plants were Opuntia spp. Yucca filifera, Condalia mexicana, Dalea spp. and Euphorbia cinerasiens, and corn stover the main crop by-product supplement used during dry season.

Restoring Degraded Rangelands in Jordan: Optimizing Mechanized Micro-Water Harvesting Technique Using Rangeland Hydrology and Erosion Model (RHEM)

Science.gov (United States)

Continuous population growth, recent refugee movement and migration as well as boundary restrictions and their implications on the nomadic lifestyle are additive pressure on rangelands throughout the Middle East. In particular, overgrazing through increased livestock herds threatens the Jordanian ra...

Global view of remote sensing of rangelands: Evolution, applications, future pathways [Chapter 10

Science.gov (United States)

Matt Reeves; Robert A. Washington-Allen; Jay Angerer; E. Raymond Hunt; Ranjani Wasantha Kulawardhana; Lalit Kumar; Tatiana Loboda; Thomas Loveland; Graciela Metternicht; R. Douglas. Ramsey

2015-01-01

The term "rangeland" is rather nebulous, and there is no single definition of rangeland that is universally accepted by land managers, scientists, or international bodies (Lund, 2007; Reeves and Mitchell, 2011). Dozens and possibly hundreds (Lund, 2007) of definitions and ideologies exist because various stakeholders often have unique objectives...

Resource analysis of the Chinese society 1980-2002 based on exergy-Part 4: Fishery and rangeland

International Nuclear Information System (INIS)

Chen, B.; Chen, G.Q.

2007-01-01

This fourth part is the continuation of the third part on agricultural products. The major fishery and rangeland products entering the Chinese society from 1980 to 2002 are calculated and analyzed in detail in this paper. The aquatic production, mainly relying on freshwater and seawater breeding, Enhancement policy of fishery resources, including closed fishing season system, construction of artificial fish reefs and ecological fish breeding, etc., is discussed in detail. The degradation of the major rangeland areas, hay yields and intake rangeland resources by the livestock, are also described associated with the strategic adjustment and comprehensive program to protect rangeland resources during the study period

Impact of grazing on range plant community components under arid Mediterranean climate in northern Syria

NARCIS (Netherlands)

Niane, A.A.

2013-01-01

Keywords: Rotational grazing, full protection, continuous grazing species richness,

species diversity, soil seed bank, Bayesian methods, Salsola vermiculata, seed

longevity, rangeland management, Syria.

Rangelands represent 70% of the semi-arid and arid

Heat dosage and oviposition depth influence egg mortality of two common rangeland grasshopper species

Science.gov (United States)

Rangeland fire is a common naturally occurring event and management tool, with the amount and structure of biomass controlling transfer of heat belowground. Temperatures grasshopper eggs are exposed to during rangeland fires are mediated by species specific oviposition traits. This experiment examin...

Bayesian estimation of shrubs diversity in rangelands under two management systems in northern Syria

NARCIS (Netherlands)

Niane, A.A.; Singh, M.; Struik, P.C.

2014-01-01

The diversity of shrubs in rangelands of northern Syria is affected by the grazing management systems restricted by the increase in human and livestock populations. To describe and estimate diversity and compare the rangeland grazing management treatments, two popular indices for diversity, the

Elevated carbon dioxide: impacts on soil and plant water relations

National Research Council Canada - National Science Library

Kirkham, M. B

2011-01-01

.... Focusing on this critical issue, Elevated Carbon Dioxide: Impacts on Soil and Plant Water Relations presents research conducted on field-grown sorghum, winter wheat, and rangeland plants under elevated CO2...

Management of Collective Rangelands in Rhamna (Morocco ...

International Development Research Centre (IDRC) Digital Library (Canada)

Management of Collective Rangelands in Rhamna (Morocco) ... reduce the pressure on natural resources and promote sustainable management. ... Project status ... IDRC congratulates first cohort of Women in Climate Change Science Fellows ... and adaptive water management: Innovative solutions from the Global South”.

Integrating the Indigenous Knowledge of Borana Pastoralists into Rangeland Management Strategies in Southern Ethiopia

OpenAIRE

World Bank

2005-01-01

Pastoralists' indigenous knowledge (IK) about ecology and social organization led to rangeland-management strategies appropriate to deal with the erratic rainfall in African drylands. Herd mobility was traditionally practiced as the key strategy to make use of the scattered rangeland resources on a large scale.

Botanical Criteria of Baharkish Rangeland in Quchan, Khorasan ...

African Journals Online (AJOL)

ADOWIE PERE

University of Mashhad International Campus, Mashhad, I.R of IRAN ... ABSTRACT: Rangelands are natural ecosystems containing a range of resources of genetic ..... Ecology of world vegetation. .... Science Journal of Islamic Azad University,.

Agricultural, Runoff, Erosion and Salinity (ARES) Database to Better Evaluate Rangeland State and Sustainability

Science.gov (United States)

Rangelands comprise approximately 40% of the earth’s surface and are the largest land cover type in the world. Degradation from mismanagement, desertification, and drought impact more than 50% of rangelands across the globe. The USDA Agricultural Research Service (ARS) has been evaluating means of r...

Evaluation of environmental change in rangelands of Uzbekistan with application of nuclear techniques approach

International Nuclear Information System (INIS)

Nasyrov, M.G.; Safarov, A.N.; Osmanov, B.S.

2004-01-01

Full text: Desertification and land degradation are a problem of major importance in the arid and semi-arid regions of the world. Deterioration of soil and plant cover has adversely affected nearly 50% of land areas as a result of extended droughts and human mismanagement of cultivated and rangelands. Due to several factors such as soil erosion, overgrazing, collection of plants and other anthropogenic activities the most part of these biomes are under degradation. The problem of assessments of current status of rangelands becomes very important days after days. Therefore, it needs to work out and implement new time and labor saving methods of assessment of current status of natural biomes. Soil erosion is a natural process caused by water, wind, and ice that have affected the earth's surface since the beginning if time. Man's activities often accelerate soil erosion. Soil erosion and its off-site, downstream damages are major concerns around the world causing losses in soil productivity, degradation of landscape, degradation of water quality, and loss of soil organic carbon. Current techniques for assessing soil erosion are (1) long-term soil erosion plot monitoring, (2) field surveys, and (3) soil erosion models (Evans, 1995). Each of this techniques has strengths and weaknesses. Over the last 30 years, research has shown the potential of using radioactive fallout 137 Cs to provide timely and quantitative estimates of soil erosion and redeposition at point, field, and reconnaissance scales. Applications of 137 Cs o provide an independent measurement of soil erosion rates, patterns, and redepositions are well-documented (Ritchie and McHenry, 1990). The unique advantages of the 137 Cs technique to study soil erosion rates and patterns are that it (a) requires only one trip to the field; (b) provides results quickly; (c) allows retrospective assessment of soil erosion rates; (d) provides average losses for 35 to 40 year period thus is less influenced by extreme

Rangeland resource trends in the United States: A technical document supporting the 2000 USDA Forest Service RPA Assessment

Science.gov (United States)

John E. Mitchell

2000-01-01

This report documents trends in America's rangelands as required by the Renewable Resources Planning Act of 1974. The Forest Service has conducted assessments of the rangeland situation for 30 years. Over this period, rangeland values and uses have gradually shifted from concentrating upon forage production and meeting increasing demand for red meat to a more...

Modelling asymmetric growth in crowded plant communities

DEFF Research Database (Denmark)

Damgaard, Christian

2010-01-01

A class of models that may be used to quantify the effect of size-asymmetric competition in crowded plant communities by estimating a community specific degree of size-asymmetric growth for each species in the community is suggested. The model consists of two parts: an individual size......-asymmetric growth part, where growth is assumed to be proportional to a power function of the size of the individual, and a term that reduces the relative growth rate as a decreasing function of the individual plant size and the competitive interactions from other plants in the neighbourhood....

Ozone sensitivity of plants in natural communities

Energy Technology Data Exchange (ETDEWEB)

Treshow, M; Stewart, D

1973-07-01

Field fumigation studies conducted in grassland, oak, aspen, and conifer, communities established the injury threshold of prevalent plant species to ozone. Several important species, including Bromus tectorum, Quercus gambelii, and Populus tremuloides, were injured by a single 2-hours exposure to 15 pphM ozone. Over half the perennial forbs and woody species studied were visibly injured at concentrations of 30 pphM ozone or less. It is postulated that lower concentrations at prolonged or repeated exposures to ozone may impair growth and affect community vigor and stability. Continued exposure of natural plant communities to ozone is expected to initiate major shifts in the plant composition of communities. 10 references, 4 figures, 1 table.

Recovery of rangelands : the functioning of soil seed banks in a semi-arid African savanna

NARCIS (Netherlands)

Tessema, Z.K.

2011-01-01

Rangelands in Africa provide important forage resources for herbivores; particularly perennial grasses provide grazing for domestic and wild herbivores. However, semi-arid African rangelands experience severe vegetation and soil degradation due to heavy grazing, causing negative impacts

The Effect of the Habitat Type on Soil and Plant Diversity Properties in Natural Ecosystems in the Northern Alborz (Case Study: Vaz Watershed

Directory of Open Access Journals (Sweden)

M. Salarvand

2016-09-01

Full Text Available This study aimed to compare plant species diversity indices (diversity and richness and some physico-chemical properties of soil among forest, ecotone and rangeland habitats. Vegetation sampling was done randomly at each habitat. One dominant community was selected in each habitat and one key area was distinguished in each community and 8×1m2 plots were randomly established in each key area. In each plot, the list of existing plants and cover percentage for each species were determined and soil samples were taken from depths of 0-10 cm. The Shannon-Wiener and Simpson diversity indices and Margalef and Menhinic richness indices were estimated using PAST software. Physical and chemical characteristics of the soil were compared at three sites by analysis of variance (One Way ANOVA. The results showed that the lowest and highest values of all species diversity and richness were occurred in forest and ecotone habitats, respectively. Bulk density, sand and pH value of soil were significantly the highest in the rangeland. The percentage of clay and organic carbon in forest habitat were higher than the two other habitats. This study revealed the importance of ecotone in preserving the diversity and species richness.

An overview of the rangelands atmosphere hydrosphere biosphere interaction study experiment in northeastern Asia (RAISE)

Science.gov (United States)

Sugita, Michiaki; Asanuma, Jun; Tsujimura, Maki; Mariko, Shigeru; Lu, Minjiao; Kimura, Fujio; Azzaya, Dolgorsuren; Adyasuren, Tsokhio

2007-01-01

SummaryIntensive observations, analysis and modeling within the framework of the rangelands atmosphere-hydrosphere-biosphere interaction study experiment in northeastern Asia (RAISE) project, have allowed investigations into the hydrologic cycle in the ecotone of forest-steppe, and its relation to atmosphere and ecosystem in the eastern part of Mongolia. In this region, changes in the climate have been reported and a market oriented economy was introduced recently, but their impact on the natural environment is still not well understood. In this RAISE special issue, the outcome is presented of the studies carried out by six groups within RAISE, namely: (1) Land-atmosphere interaction analysis, (2) ecosystem analysis and modeling, (3) hydrologic cycle analysis, (4) climatic modeling, (5) hydrologic modeling, and (6) integration. The results are organized in five relevant categories comprising (i) hydrologic cycle including precipitation, groundwater, and surface water, (ii) hydrologic cycle and ecosystem, (iii) surface-atmosphere interaction, (iv) effect of grazing activities on soils, plant ecosystem and surface fluxes, and (v) future prediction. Comparison with studies on rangelands in other parts of the world, and some future directions of studies still needed in this region are also summarized.

MBS Native Plant Communities

Data.gov (United States)

Minnesota Department of Natural Resources — This data layer contains results of the Minnesota County Biological Survey (MCBS). It includes polygons representing the highest quality native plant communities...

Emergence of native plant seeds in response to seed pelleting, planting depth, scarification, and soil anti-crusting treatment, 2009

Science.gov (United States)

Clint Shock; Erik Feibert; Lamont Saunders; Nancy Shaw

2010-01-01

Seed of native plants is needed to restore rangelands of the Intermountain West. Reliable commercial seed production is desirable to provide the quantity of seed needed for restoration efforts. Establishment of native seed crops has been difficult, because fall-planted seed is susceptible to bird damage, soil crusting, and soil erosion. Fall planting is important for...

Vegetation restoration on degraded rangelands through the use of microcatchment and brush packs in the communal areas of the Eastern Cape

CSIR Research Space (South Africa)

Lesoli, MS

2010-07-01

Full Text Available Rangeland degradation results in declining functional capacity, increased poverty, and food insecurity. Major changes in rangeland surface morphology and soil characteristics have a drastic effect on the primary productivity of the rangeland...

Community Structure and Productivity in Western Mongolian Steppe

Directory of Open Access Journals (Sweden)

Kiyokazu Kawada

2014-12-01

Full Text Available The people of the Mongolian steppe have maintained a sustainable, nomadic lifestyle. However, several ecological processes are threatening their way of life. Ecological changan be detected through the analysis of quantitative and qualitative data. It is therefore, imperative to develop a sustainable rangeland management system aimed at combating desertifi cation. In this study we quantitatively and qualitatively describe several western Mongolian steppe plant communities by examining species composition, plant volume and community structure. Study sites were located in the Uvs and Khovd provinces and had all been affected by livestock grazing. A total of 48 species were found. Stipa krylovii , S . gobica , Cleistogenes songorica , Koeleria cristata and Ajania achilleoides were dominant. There was a signifi cant relationship between biomass and plant volume at all sites. Study sites were classifi ed into four groups using cluster analysis, based on the presence or absence of several species. More than 90% of plant volumes at all groups were perennial grasses and perennial forbs. The ratio of C 3 to C 4 plants at site 3 was reversed in comparison to the other sites. Species highly palatable to livestock were dominant at all sites. To ensure the sustainable use of biological resources in these arid areas, these fi ndings should be taken into account in designing land-use plans.

Effects of climate change on rangeland vegetation in the Northern Rockies Region [Chapter 7

Science.gov (United States)

Matt C. Reeves; Mary E. Manning; Jeff P. DiBenedetto; Kyle A. Palmquist; William K. Lauenroth; John B. Bradford; Daniel R. Schlaepfer

2018-01-01

Rangelands are dominated by grass, forb, or shrub species, but are usually not modified by using agronomic improvements such as fertilization or irrigation (Lund 2007; Reeves and Mitchell 2011) as these lands would normally be considered pastures. Rangeland includes grassland, shrubland, and desert ecosystems, alpine areas, and some woodlands (box 7.1). This chapter...

Contrasting watershed-scale trends in runoff and sediment yield complicate rangeland water resources planning

Science.gov (United States)

Berg, Matthew D.; Marcantonio, Franco; Allison, Mead A.; McAlister, Jason; Wilcox, Bradford P.; Fox, William E.

2016-06-01

Rangelands cover a large portion of the earth's land surface and are undergoing dramatic landscape changes. At the same time, these ecosystems face increasing expectations to meet growing water supply needs. To address major gaps in our understanding of rangeland hydrologic function, we investigated historical watershed-scale runoff and sediment yield in a dynamic landscape in central Texas, USA. We quantified the relationship between precipitation and runoff and analyzed reservoir sediment cores dated using cesium-137 and lead-210 radioisotopes. Local rainfall and streamflow showed no directional trend over a period of 85 years, resulting in a rainfall-runoff ratio that has been resilient to watershed changes. Reservoir sedimentation rates generally were higher before 1963, but have been much lower and very stable since that time. Our findings suggest that (1) rangeland water yields may be stable over long periods despite dramatic landscape changes while (2) these same landscape changes influence sediment yields that impact downstream reservoir storage. Relying on rangelands to meet water needs demands an understanding of how these dynamic landscapes function and a quantification of the physical processes at work.

Hydrologic ramifications of an increased role of wildland fire across the rangeland-dry forest continuum

Science.gov (United States)

The increased role of wildland fire across the rangeland-dry forest continuum in the western United States (US) presents landscape-scale consequences relative runoff and erosion. Much of the Intermountain West now exists in a state in which rangeland and woodland wildfires stimulated by invasive che...

Conservation and restoration of indigenous plants to improve community livelihoods: the Useful Plants Project

Science.gov (United States)

Ulian, Tiziana; Sacandé, Moctar; Mattana, Efisio

2014-05-01

Kew's Millennium Seed Bank partnership (MSBP) is one of the largest ex situ plant conservation initiatives, which is focused on saving plants in and from regions most at risk, particularly in drylands. Seeds are collected and stored in seed banks in the country of origin and duplicated in the Millennium Seed Bank in the UK. The MSBP also strengthens the capacity of local communities to successfully conserve and sustainably use indigenous plants, which are important for their wellbeing. Since 2007, high quality seed collections and research information have been gathered on ca. 700 useful indigenous plant species that were selected by communities in Botswana, Kenya, Mali, Mexico and South Africa through Project MGU - The Useful Plants Project. These communities range from various farmer's groups and organisations to traditional healers, organic cotton/crop producers and primary schools. The information on seed conservation and plant propagation was used to train communities and to propagate ca. 200 species that were then planted in local gardens, and as species reintroduced for reforestation programmes and enriching village forests. Experimental plots have also been established to further investigate the field performance (plant survival and growth rate) of indigenous species, using low cost procedures. In addition, the activities support revenue generation for local communities directly through the sustainable use of plant products or indirectly through wider environmental and cultural services. This project has confirmed the potential of biodiversity conservation to improve food security and human health, enhance community livelihoods and strengthen the resilience of land and people to the changing climate. This approach of using indigenous species and having local communities play a central role from the selection of species to their planting and establishment, supported by complementary research, may represent a model for other regions of the world, where

Reorienting land degradation towards sustainable land management: linking sustainable livelihoods with ecosystem services in rangeland systems.

Science.gov (United States)

Reed, M S; Stringer, L C; Dougill, A J; Perkins, J S; Atlhopheng, J R; Mulale, K; Favretto, N

2015-03-15

This paper identifies new ways of moving from land degradation towards sustainable land management through the development of economic mechanisms. It identifies new mechanisms to tackle land degradation based on retaining critical levels of natural capital whilst basing livelihoods on a wider range of ecosystem services. This is achieved through a case study analysis of the Kalahari rangelands in southwest Botswana. The paper first describes the socio-economic and ecological characteristics of the Kalahari rangelands and the types of land degradation taking place. It then focuses on bush encroachment as a way of exploring new economic instruments (e.g. Payments for Ecosystem Services) designed to enhance the flow of ecosystem services that support livelihoods in rangeland systems. It does this by evaluating the likely impacts of bush encroachment, one of the key forms of rangeland degradation, on a range of ecosystem services in three land tenure types (private fenced ranches, communal grazing areas and Wildlife Management Areas), before considering options for more sustainable land management in these systems. We argue that with adequate policy support, economic mechanisms could help reorient degraded rangelands towards more sustainable land management. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

A comparison of the effects of different rangeland management ...

African Journals Online (AJOL)

A comparison of the effects of different rangeland management systems on ... Three management systems exploit these areas: commercial livestock ranching, communal livestock ranching and game ranching. ... AJOL African Journals Online.

DEVELOPMENTS IN MONITORING RANGELANDS USING REMOTELY-SENSED CROSS-FENCE COMPARISONS

Directory of Open Access Journals (Sweden)

A. D. Kilpatrick

2012-07-01

Full Text Available This paper presents a new method for the use of earth-observation images to assess relative land condition over broad regions, using a cross-fence comparison methodology. It controls for natural spatial and temporal variables (e.g. rainfall, temperature soils, ecosystem so that we can objectively monitor rangelands and other areas for the effects of management. The method has been tested with small and large scale theoretical models, as well as a case study in South Australian rangelands. This method can also be applied in other systems and experiments such as field trials of crop varieties as a robust spatial statistic.

China's Rangelands under Stress : A comparative study of pasture commons in the Ningxia Hui Autonomous Region

NARCIS (Netherlands)

Ho, P.P.S.

2000-01-01

China's economic reforms have exacerbated the problems of over-grazing and desertification in the country's pastoral areas. In order to deal with rangeland degradation, the Chinese government has resorted to nationalization, or semi-privatization. Since the implementation of rangeland policy has

Forests, rangelands and climate change in Southern Africa

CSIR Research Space (South Africa)

Naidoo, Sasha

2013-09-01

Full Text Available This paper provides an analysis of the implications of climate change for forests and rangelands in southern Africa. The extent of the resources and their economic and social functions and drivers of change is outlined. The vulnerability...

The challenge of integrated rangeland monitoring: synthesis address

African Journals Online (AJOL)

The utility of monitoring and its guiding principles will only work effectively where good environmental governance is practiced by users and producers affecting rangeland ecosystems. Keywords: adaptive management, complex, environmental governance, human impacts, multi-scale, socio-ecological. African Journal of ...

Effect of management on rangeland phytomass, cover and condition ...

African Journals Online (AJOL)

similarity of management effects on rangeland condition and forage provision across major dryland biomes. Taking a macro-ecological perspective, we analysed if management effects differed between South Africa's central grassland and ...

Runoff and soil erosion from two rangeland sites

Science.gov (United States)

Historically over 50 years of rainfall/runoff research using rainfall simulators has been conducted at various rangeland sites in the West, however these sites rarely have consecutive yearly measurements. This limits the understanding of dynamic annual conditions and the interactions of grazing, pla...

Autecology of Astragalus arpilobus Kar. & Kir, a promised species for restoration of the winter rangelands in the northeast of Iran

Directory of Open Access Journals (Sweden)

M. Jankju

2016-04-01

Full Text Available Studying the autecology of range plants provides the basic information on their ecological requirements, cultivation methods and the interactions with the prevailing environment. Such information is necessary for a proper range management. Some ecological characteristics of Astragalus arpilobus Kar. & Kir., were studied in the winter rangelands of Northern Khorasan province. It was naturally growing in Jargalan, Bojnourd, where the altitudinal range varied 500-600 a.s.l, slope 20-100%, and the average annual rainfall 236.85 mm. Soil properties were: loamy texture, average organic matter, low fertility, pH 7.32 and EC 2.30 ds.m-1. A. aripilobus started vegetative growth at the early March, flowering during early May, seed production during June, and terminated its yearly growth at early July. The highest nutritive values and forage quality were at the beginning of growth, which was gradually decreased towards the end of growth season. Crude protein (CP, and ash were decreased whereas acid detergent fiber (ADF, natural detergent fiber (NDF, and dry matter (DM increased by the growing season. Seeds were easily established within pots; however, seed germination rate was low (24%, which by sand paper scarification was increased up to 51%. In conclusion, feasibility of seedling establishment, high nutritive value, and concurrence of plant phenology with the time of maximum need to fodder, by livestocks, propose A. arpilobus as a promising forage plant species for restoration of the winter rangelands in Northern Khorasan province.

Community leaders' perspectives on socio-economic impacts of power-plant development

International Nuclear Information System (INIS)

Hastings, M.; Cawley, M.E.

1981-01-01

The primary focus of this research effort was to identify and measure the socioeconomic impacts of power plant development on non-metropolitan host communities. A mail survey, distributed to community leaders in 100 power plant communities east of the Mississippi River, was utilized to gather information from 713 respondents. Community leaders were questioned as to the plant's impact on (a) community groups, (b) aspects of community life, (c) overall community acceptance and (d) attitudes toward power plant development. Overall, the trends and patterns of plant impact on the host communities were found to be largely positive. Specifically, local employment opportunities were generally enhanced with the advent of the power plant. Directly related to power plant development was the overall improvement of the local economic situation. Off-shoots from such in the economic area included related general improvements in the community quality of life. While the vast majority of community leaders responded with positive comments on power plant presence, adverse impacts were also mentioned. Negative comments focused on environmental problems, deterioration of roads and traffic conditions, and the possibility of nuclear accidents. Despite these negative impacts, almost two-thirds of the community leaders would definitely support the reconstruction of the same energy facility. Power plant development, therefore, is generally perceived as both a positive and beneficial asset for the host area. (author)

Rangeland Ecosystem Services: Nature's Supply and Humans' Demand

Science.gov (United States)

Ecosystem services are the benefits that society receives from nature and they include the regulation of climate, the pollination of crops, the provisioning of intellectual inspiration and recreational environment, as well as many essential goods such as food, fiber, and wood. Rangeland ecosystem se...

Livestock systems and rangeland degradation in the new World Atlas of Desertification

Science.gov (United States)

Zucca, Claudio; Reynolds, James F.; Cherlet, Michael

2015-04-01

Livestock systems and rangeland degradation in the new World Atlas of Desertification Land degradation and desertification (LDD), which are widespread in global rangelands, are complex processes. They are caused by multiple (but limited) number of biophysical and socioeconomic drivers that lead to an unbalance in the capacity of the land to sustainably produce ecosystem services and economic value. Converging evidence indicates that the key biophysical and socioeconomic drivers include agricultural or pastoral land use and management practices, population growth, societal demands (e.g., urbanization), and climate change (e.g., increasing aridity and drought). The new World Atlas of Desertification (WAD) describes these global issues, documents their spatial change, and highlights the importance of these drivers in relation to land degradation processes. The impacts of LDD on the atmosphere, on water and on biodiversity are also covered. The WAD spatially illustrates relevant types of livestock and rangeland management systems, related (over-under) use of resources, various management activities, and some of the common features and transitions that contribute to LDD. For example, livestock grazing in marginal areas is increasing due to competition with agricultural encroachment and, hence, vulnerable lands are under threat. The integration of stratified global data layers facilitates identifying areas where stress on the land system can be linked to underlying causal issues. One of the objectives of the new WAD is to provide synthesis and tools for scientists and stakeholders to design sustainable solutions for efficient land use in global rangelands.

Soil ecosystem functioning under climate change: plant species and community effects

Energy Technology Data Exchange (ETDEWEB)

Kardol, Paul [ORNL; Cregger, Melissa [ORNL; Campany, Courtney E [ORNL; Classen, Aimee T [ORNL

2010-01-01

Feedbacks of terrestrial ecosystems to climate change depend on soil ecosystem dynamics. Soil ecosystems can directly and indirectly respond to climate change. For example, warming directly alters microbial communities by increasing their activity. Climate change may also alter plant community composition, thus indirectly altering the microbial communities that feed on their inputs. To better understand how climate change may directly and indirectly alter soil ecosystem functioning, we investigated old-field plant community and soil ecosystem responses to single and combined effects of elevated [CO2], warming, and water availability. Specifically, we collected soils at the plot level (plant community soils), and beneath dominant plant species (plant-specific soils). We used microbial enzyme activities and soil nematodes as indicators for soil ecosystem functioning. Our study resulted in two main findings: 1) Overall, while there were some interactions, water, relative to increases in [CO2] and warming, had the largest impact on plant community composition, soil enzyme activities, and soil nematodes. Multiple climate change factors can interact to shape ecosystems, but in this case, those interactions were largely driven by changes in water availability. 2) Indirect effects of climate change, via changes in plant communities, had a significant impact on soil ecosystem functioning and this impact was not obvious when looking at plant community soils. Climate change effects on enzyme activities and soil nematode abundance and community structure strongly differed between plant community soils and plant-specific soils, but also within plant-specific soils. In sum, these results indicate that accurate assessments of climate change impacts on soil ecosystem functioning require incorporating the concurrent changes in plant function and plant community composition. Climate change-induced shifts in plant community composition will likely modify or counteract the direct

Plant interactions with multiple insect herbivores: from community to genes

NARCIS (Netherlands)

Stam, J.M.; Kroes, A.; Li, Y.; Gols, R.; Loon, van J.J.A.; Poelman, E.H.; Dicke, M.

2014-01-01

Every plant is a member of a complex insect community that consists of tens to hundreds of species that belong to different trophic levels. The dynamics of this community are critically influenced by the plant, which mediates interactions between community members that can occur on the plant

Herbivory and dominance shifts among exotic and congeneric native plant species during plant community establishment

DEFF Research Database (Denmark)

Engelkes, Tim; Meisner, Annelein; Morriën, Elly

2016-01-01

in a riparian ecosystem during early establishment of invaded communities. We planted ten plant communities each consisting of three individuals of each of six exotic plant species as well as six phylogenetically related natives. Exotic plant species were selected based on a rapid recent increase in regional...... abundance, the presence of a congeneric native species, and their co-occurrence in the riparian ecosystem. All plant communities were covered by tents with insect mesh. Five tents were open on the leeward side to allow herbivory. The other five tents were completely closed in order to exclude insects...... and vertebrates. Herbivory reduced aboveground biomass by half and influenced which of the plant species dominated the establishing communities. Exposure to herbivory did not reduce the total biomass of natives more than that of exotics, so aboveground herbivory did not selectively enhance exotics during...

A conceptual tool for improving rangeland management decision ...

African Journals Online (AJOL)

... the LLM concept should be seen as a continuous and evolving learning process that will be updated over the long term through decision support to include several other components essential to implement effective and sustainable rangeland management practices by local land users. Keywords: desertification; indicators ...

Plant community analysis and ecology of afromontane and ...

African Journals Online (AJOL)

The plant communities of the forests of southwestern Ethiopia were described based on floristic analysis of the data collected between February 1995 and May 1996. Floristic analysis is based on the cover-abundance values of both woody and herbaceous species. Plant community-environment relationship was assessed ...

Interpreting and Correcting Cross-scale Mismatches in Resilience Analysis: a Procedure and Examples from Australia's Rangelands

Directory of Open Access Journals (Sweden)

John A. Ludwig

2005-12-01

Full Text Available Many rangelands around the globe are degraded because of mismatches between the goals and actions of managers operating at different spatial scales. In this paper, we focus on identifying, interpreting, and correcting cross-scale mismatches in rangeland management by building on an existing four-step resilience analysis procedure. Resilience analysis is an evaluation of the capacity of a system to persist in the face of disturbances. We provide three examples of cross-scale resilience analysis using a rangeland system located in northern Australia. The system was summarized in a diagram showing key interactions between three attributes (water quality, regional biodiversity, and beef quality, which can be used to indicate the degree of resilience of the system, and other components that affect these attributes at different scales. The strengths of cross-scale interactions were rated as strong or weak, and the likely causes of mismatches in strength were interpreted. Possible actions to correct cross-scale mismatches were suggested and evaluated. We found this four-step, cross-scale resilience analysis procedure very helpful because it reduced a complex problem down to manageable parts without losing sight of the larger-scale whole. To build rangeland resilience, many such cross-scale mismatches in management will need to be corrected, especially as the global use of rangelands increases over the coming decades.

Plant traits determine the phylogenetic structure of arbuscular mycorrhizal fungal communities.

Science.gov (United States)

López-García, Álvaro; Varela-Cervero, Sara; Vasar, Martti; Öpik, Maarja; Barea, José M; Azcón-Aguilar, Concepción

2017-12-01

Functional diversity in ecosystems has traditionally been studied using aboveground plant traits. Despite the known effect of plant traits on the microbial community composition, their effects on the microbial functional diversity are only starting to be assessed. In this study, the phylogenetic structure of arbuscular mycorrhizal (AM) fungal communities associated with plant species differing in life cycle and growth form, that is, plant life forms, was determined to unravel the effect of plant traits on the functional diversity of this fungal group. The results of the 454 pyrosequencing showed that the AM fungal community composition differed across plant life forms and this effect was dependent on the soil collection date. Plants with ruderal characteristics tended to associate with phylogenetically clustered AM fungal communities. By contrast, plants with resource-conservative traits associated with phylogenetically overdispersed AM fungal communities. Additionally, the soil collected in different seasons yielded AM fungal communities with different phylogenetic dispersion. In summary, we found that the phylogenetic structure, and hence the functional diversity, of AM fungal communities is dependent on plant traits. This finding adds value to the use of plant traits for the evaluation of belowground ecosystem diversity, functions and processes. © 2017 John Wiley & Sons Ltd.

Investigating Effects of Invasive Species on Plant Community Structure

Science.gov (United States)

Franklin, Wilfred

2008-01-01

In this article, the author presents a field study project that explores factors influencing forest community structure and lifts the veil off of "plant blindness." This ecological study consists of three laboratories: (1) preliminary field trip to the study site; (2) plant survey; and (3) analyzing plant community structure with descriptive…

Native plant community response to alien plant invasion and removal

Directory of Open Access Journals (Sweden)

Jara ANDREU

2011-01-01

Full Text Available Given the potential ecological impacts of invasive species, removal of alien plants has become an important management challenge and a high priority for environmental managers. To consider that a removal effort has been successful requires both, the effective elimination of alien plants and the restoration of the native plant community back to its historical composition and function. We present a conceptual framework based on observational and experimental data that compares invaded, non-invaded and removal sites to quantify invaders’ impacts and native plant recover after their removal. We also conduct a meta-analysis to quantitatively evaluate the impacts of plant invaders and the consequences of their removal on the native plant community, across a variety of ecosystems around the world. Our results that invasion by alien plants is responsible for a local decline in native species richness and abundance. Our analysis also provides evidence that after removal, the native vegetation has the potential to recover to a pre-invasion target state. Our review reveal that observational and experimental approaches are rarely used in concert, and that reference sites are scarcely employed to assess native species recovery after removal. However, we believe that comparing invaded, non-invaded and removal sites offer the opportunity to obtain scientific information with relevance for management.

Scale effects on runoff and soil erosion in rangelands: observations and estimations with predictors of different availability

Science.gov (United States)

Runoff and erosion estimates are needed for rangeland management decisions and evaluation of ecosystem services derived from rangeland conservation practices. The information on the effect of scale on the runoff and erosion, and on the choice of runoff and erosion predictors, remains scarce. The obj...

Measuring competition in plant communities where it is difficult to distinguish individual plants

DEFF Research Database (Denmark)

Damgaard, Christian

2011-01-01

A novel method for measuring plant-plant interactions in undisturbed semi-natural and natural plant communities where it is difficult to distinguish individual plants is discussed. It is assumed that the ecological success of the different plant species in the plant community may be adequately...... measured by plant cover and vertical density (a measure that is correlated to the 3-dimensional space occupancy and biomass). Both plant cover and vertical density are measured in a standard pin-point analysis in the beginning and at the end of the growing season. In the outlined competition model....... The method allows direct measurements of the competitive effects of neighbouringzplants on plant performance and the estimation of parameters that describe the ecological processes of plantplant interactions during the growing season as well as the process of survival and recruitment between growing seasons...

Genetic diversity within a dominant plant outweighs plant species diversity in structuring an arthropod community.

Science.gov (United States)

Crawford, Kerri M; Rudgers, Jennifer A

2013-05-01

Plant biodiversity is being lost at a rapid rate. This has spurred much interest in elucidating the consequences of this loss for higher trophic levels. Experimental tests have shown that both plant species diversity and genetic diversity within a plant species can influence arthropod community structure. However, the majority of these studies have been conducted in separate systems, so their relative importance is currently unresolved. Furthermore, potential interactions between the two levels of diversity, which likely occur in natural systems, have not been investigated. To clarify these issues, we conducted three experiments in a freshwater sand dune ecosystem. We (1) independently manipulated plant species diversity, (2) independently manipulated genetic diversity within the dominant plant species, Ammophila breviligulata, and (3) jointly manipulated genetic diversity within the dominant plant and species diversity. We found that genetic diversity within the dominant plant species, Ammophila breviligulata, more strongly influenced arthropod communities than plant species diversity, but this effect was dependent on the presence of other species. In species mixtures, A. breviligulata genetic diversity altered overall arthropod community composition, and arthropod richness and abundance peaked at the highest level of genetic diversity. Positive nonadditive effects of diversity were detected, suggesting that arthropods respond to emergent properties of diverse plant communities. However, in the independent manipulations where A. breviligulata was alone, effects of genetic diversity were weaker, with only arthropod richness responding. In contrast, plant species diversity only influenced arthropods when A. breviligulata was absent, and then only influenced herbivore abundance. In addition to showing that genetic diversity within a dominant plant species can have large effects on arthropod community composition, these results suggest that understanding how species

Yield Response of Mediterranean Rangelands under a Changing Climate

NARCIS (Netherlands)

Daliakopoulos, Ioannis N.; Panagea, Ioanna S.; Tsanis, Ioannis K.; Grillakis, Manolis G.; Koutroulis, Aristeidis G.; Hessel, Rudi; Mayor, Angeles G.; Ritsema, Coen J.

2017-01-01

Understanding the Mediterranean rangelands degradation trends is a key element of mitigating their vulnerability and enhancing their resilience. Climate change and its inherent effects on mean temperature and the precipitation variability can regulate the magnitude, frequency and duration of

Presidential address - 1999 Towards a national rangeland policy ...

African Journals Online (AJOL)

There are some problems with the publication of the journal, but Council hopes to have our ... The first is that all agencies funded through DACST will be reviewed ... to improve our understanding of management issues in communal rangeland. ... All current programmes to rehabilitate degraded land contain budgets for the ...

Monitoring Forage Production of California Rangeland Using Remote Sensing Observations

Science.gov (United States)

Liu, H.; Jin, Y.; Dahlgren, R. A.; O'Geen, A. T.; Roche, L. M.; Smith, A. M.; Flavell, D.

2016-12-01

Pastures and rangeland cover more than 10 million hectares in California's coastal and inland foothill regions, providing feeds to livestock and important ecosystem services. Forage production in California has a large year-to-year variation due to large inter-annual and seasonal variabilities in precipitation and temperature. It also varies spatially due to the variability in climate and soils. Our goal is to develop a robust and cost-effective tool to map the near-real-time and historical forage productivity in California using remote sensing observations from Landsat and MODIS satellites. We used a Monteith's eco-physiological plant growth theory: the aboveground net primary production (ANPP) is determined by (i) the absorbed photosynthetically active radiation (APAR) and the (ii) light use efficiency (LUE): ANPP = APAR * LUEmax * f(T) * f(SM), where LUEmax is the maximum LUE, and f(T) and f(SM) are the temperature and soil moisture constrains on LUE. APAR was estimated with Landsat and MODIS vegetation index (VI), and LUE was calibrated with a statewide point dataset of peak forage production measurements at 75 annual rangeland sites. A non-linear optimization was performed to derive maximum LUE and the parameters for temperature and soil moisture regulation on LUE by minimizing the differences between the estimated and measured ANPP. Our results showed the satellite-derived annual forage production estimates correlated well withcontemporaneous in-situ forage measurements and captured both the spatial and temporal productivity patterns of forage productivity well. This remote sensing algorithm can be further improved as new field measurements become available. This tool will have a great importance in maintaining a sustainable range industry by providing key knowledge for ranchers and the stakeholders to make managerial decisions.

Site and plant species are important determinants of the Methylobacterium community composition in the plant phyllosphere.

Science.gov (United States)

Knief, Claudia; Ramette, Alban; Frances, Lisa; Alonso-Blanco, Carlos; Vorholt, Julia A

2010-06-01

The plant phyllosphere constitutes a habitat for numerous microorganisms; among them are members of the genus Methylobacterium. Owing to the ubiquitous occurrence of methylobacteria on plant leaves, they represent a suitable target for studying plant colonization patterns. The influence of the factor site, host plant species, time and the presence of other phyllosphere bacteria on Methylobacterium community composition and population size were evaluated in this study. Leaf samples were collected from Arabidopsis thaliana or Medicago truncatula plants and from the surrounding plant species at several sites. The abundance of cultivable Methylobacterium clearly correlated with the abundance of other phyllosphere bacteria, suggesting that methylobacteria constitute a considerable and rather stable fraction of the phyllosphere microbiota under varying environmental conditions. Automated ribosomal intergenic spacer analysis (ARISA) was applied to characterize the Methylobacterium community composition and showed the presence of similar communities on A. thaliana plants at most sites in 2 consecutive years of sampling. A substantial part of the observed variation in the community composition was explained by site and plant species, especially in the case of the plants collected at the Arabidopsis sites (50%). The dominating ARISA peaks that were detected on A. thaliana plants were found on other plant species grown at the same site, whereas some different peaks were detected on A. thaliana plants from other sites. This indicates that site-specific factors had a stronger impact on the Methylobacterium community composition than did plant-specific factors and that the Methylobacterium-plant association is not highly host plant species specific.

The role of plant mycorrhizal type and status in modulating the relationship between plant and arbuscular mycorrhizal fungal communities.

Science.gov (United States)

Neuenkamp, Lena; Moora, Mari; Öpik, Maarja; Davison, John; Gerz, Maret; Männistö, Minna; Jairus, Teele; Vasar, Martti; Zobel, Martin

2018-01-25

Interactions between communities of plants and arbuscular mycorrhizal (AM) fungi shape fundamental ecosystem properties. Experimental evidence suggests that compositional changes in plant and AM fungal communities should be correlated, but empirical data from natural ecosystems are scarce. We investigated the dynamics of covariation between plant and AM fungal communities during three stages of grassland succession, and the biotic and abiotic factors shaping these dynamics. Plant communities were characterised using vegetation surveys. AM fungal communities were characterised by 454-sequencing of the small subunit rRNA gene and identification against the AM fungal reference database MaarjAM. AM fungal abundance was estimated using neutral-lipid fatty acids (NLFAs). Multivariate correlation analysis (Procrustes) revealed a significant relationship between plant and AM fungal community composition. The strength of plant-AM fungal correlation weakened during succession following cessation of grassland management, reflecting changes in the proportion of plants exhibiting different AM status. Plant-AM fungal correlation was strong when the abundance of obligate AM plants was high, and declined as the proportion of facultative AM plants increased. We conclude that the extent to which plants rely on AM symbiosis can determine how tightly communities of plants and AM fungi are interlinked, regulating community assembly of both symbiotic partners. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Management applicability of the intermediate disturbance hypothesis across Mongolian rangeland ecosystems.

Science.gov (United States)

Sasaki, Takehiro; Okubo, Satoru; Okayasu, Tomoo; Jamsran, Undarmaa; Ohkuro, Toshiya; Takeuchi, Kazuhiko

2009-03-01

The current growing body of evidence for diversity-disturbance relationships suggests that the peaked pattern predicted by the intermediate disturbance hypothesis (IDH) may not be the rule. Even if ecologists could quantify the diversity-disturbance relationship consistent with the IDH, the applicability of the IDH to land management has rarely been addressed. We examined two hypotheses related to the generality and management applicability of the IDH to Mongolian rangeland ecosystems: that the diversity-disturbance relationship varies as a function of landscape condition and that some intermediate scales of grazing can play an important role in terms of sustainable rangeland management through a grazing gradient approach. We quantified the landscape condition of each ecological site using an ordination technique and determined two types of landscape conditions: relatively benign and harsh environmental conditions. At the ecological sites characterized by relatively benign environmental conditions, diversity-disturbance relationships were generally consistent with the IDH, and maximum diversity was observed at some intermediate distance from the source of the grazing gradient. In contrast, the IDH was not supported at most (but not all) sites characterized by relatively harsh environmental conditions. The intermediate levels of grazing were generally located below the ecological threshold representing the points or zones at which disturbance should be limited to prevent drastic changes in ecological conditions, suggesting that there is little "conundrum" with regard to intermediate disturbance in the studied systems in terms of land management. We suggest that the landscape condition is one of the primary factors that cause inconsistencies in diversity-disturbance relationships. The ecological threshold can extend its utility in rangeland management because it also has the compatibility with the maintenance of species diversity. This study thus suggests that some

Multi-agency Oregon Pilot: Working towards a national inventory and assessment of rangelands using onsite data

Science.gov (United States)

Paul L. Patterson; James Alegria; Leonard Jolley; Doug Powell; J. Jeffery Goebel; Gregg M. Riegel; Kurt H. Riitters; Craig. Ducey

2014-01-01

Rangelands are lands dominated by grasses, forbs, and shrubs and are managed as a natural ecosystem. Although these lands comprise approximately 40 percent of the landmass of the continental United States, there is no coordinated effort designed to inventory, monitor, or assess rangeland conditions at the national scale. A pilot project in central Oregon with the U.S....

Rangeland restoration for Hirola, the world's most endangered antelope

Science.gov (United States)

Rangeland restoration can improve habitat for threatened species such as the hirola antelope (Beatragus hunteri) that inhabit savannas of eastern Kenya. However, restoration success likely varies across soil types and target restoration species, as well as according to restoration approach. We teste...

Traits determining the digestibility-decomposability relationships in species from Mediterranean rangelands.

Science.gov (United States)

Bumb, Iris; Garnier, Eric; Coq, Sylvain; Nahmani, Johanne; Del Rey Granado, Maria; Gimenez, Olivier; Kazakou, Elena

2018-03-05

Forage quality for herbivores and litter quality for decomposers are two key plant properties affecting ecosystem carbon and nutrient cycling. Although there is a positive relationship between palatability and decomposition, very few studies have focused on larger vertebrate herbivores while considering links between the digestibility of living leaves and stems and the decomposability of litter and associated traits. The hypothesis tested is that some defences of living organs would reduce their digestibility and, as a consequence, their litter decomposability, through 'afterlife' effects. Additionally in high-fertility conditions the presence of intense herbivory would select for communities dominated by fast-growing plants, which are able to compensate for tissue loss by herbivory, producing both highly digestible organs and easily decomposable litter. Relationships between dry matter digestibility and decomposability were quantified in 16 dominant species from Mediterranean rangelands, which are subject to management regimes that differ in grazing intensity and fertilization. The digestibility and decomposability of leaves and stems were estimated at peak standing biomass, in plots that were either fertilized and intensively grazed or unfertilized and moderately grazed. Several traits were measured on living and senesced organs: fibre content, dry matter content and nitrogen, phosphorus and tannin concentrations. Digestibility was positively related to decomposability, both properties being influenced in the same direction by management regime, organ and growth forms. Digestibility of leaves and stems was negatively related to their fibre concentrations, and positively related to their nitrogen concentration. Decomposability was more strongly related to traits measured on living organs than on litter. Digestibility and decomposition were governed by similar structural traits, in particular fibre concentration, affecting both herbivores and micro

State and transition models: Theory, applications, and challenges. In: Briske, D.D. Rangeland Systems: Processes, Management and Challenges

Science.gov (United States)

State and transition models (STMs) are used for communicating about ecosystem change in rangelands and other ecosystems, especially the implications for management. The fundamental premise that rangelands can exhibit multiple states is now widely accepted. The current application of STMs for managem...

Rangeland degradation in two watersheds of Lebanon

International Nuclear Information System (INIS)

Darwish, T; Faour, G.

2008-01-01

A complex and rugged nature characterizes the Lebanese mountains.The climatic pattern prevailing in the country, deforestation and man made erosion caused increased rangeland degradation. The purpose of this study was to monitor two contrasting watersheds, representing the Lebanese agro-ecological zones, to analyze the vegetation dynamics and trace the state of rangeland degradation. The Kfarselouane (205 km2) and Aarsal (316.7 km2) watersheds are located in the Lebanon and Anti-Lebanon mountain chain and characterized by sub humid and semi-arid climate respectively.Using multitemporal spot vegetation images between 1999 and 2005 to analyze the normalized differential vegetation index (NDVI) revealed some improvement of the vegetation cover over recent years in Kfaselouane with a steady state in Aarsal. The NDVI trend curve inclines in spring and declines in summer and fall. Judging by the time scale amplitude change and highest magnitude between the peak and lower NDVI level in Aarsal, an increased vulnerability to drought is observed in the dry Lebanese areas. Comparing land cover/use in Aarsal area between 1962 and 2000 using aerial photos and large resolution Indian satellite images (IRS) showed wood fragmentation and slight increase of the degenerated forest cover from 1108 ha to 1168 ha. Landuse change was accompanied by a simultaneous increase of cultivated lands (mostly fruit trees) from 932 ha to 4878 ha with absence of soil conservation and water harvesting practices. On the contrary, grasslands decreased from 29581 ha to 25000 ha. In Kfarselouane, the area of grassland was invaded by forestland where rangeland decreased from 8073 ha to 3568 ha and woodland increased from 5766 ha to 11800 ha. Forest expansion occurred even at the account of unproductive land which decreased from 2668 ha to 248 ha, while cultivated lands did not reveal any substantial change. Based on animals' seasonal feeding pattern, a mismatch between land carrying capacity and grazing

THE EUROPEAN POSITION OF DUTCH PLANT COMMUNITIES

Directory of Open Access Journals (Sweden)

J.A.M. JANSSEN

2007-04-01

Full Text Available In this paper it is analyzed for which plant communities (alliances the Netherlands has an international responsibility. Data has been brought together on the range and distribution of alliances in Europe, the area of plant communities in the Netherlands and surrounding countries and the occurrence of endemic associations in the Netherlands. The analysis resulted in a list of 34 out of 93 alliances in the Netherlands which are important from an international point of view.

Ecology and Conservation of Acacia senegal in the Rangelands ...

African Journals Online (AJOL)

Ecology and Conservation of Acacia senegal in the Rangelands ofLuwero and Nakasongola Districts. Jacob Godfrey Agea, Joseph Obua, Sara Namirembe, Mukadasi Buyinza, Daniel Waiswa. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL ...

Advances in modeling soil erosion after disturbance on rangelands

Science.gov (United States)

Research has been undertaken to develop process based models that predict soil erosion rate after disturbance on rangelands. In these models soil detachment is predicted as a combination of multiple erosion processes, rain splash and thin sheet flow (splash and sheet) detachment and concentrated flo...

Geospatial Data as a Service: The GEOGLAM Rangelands and Pasture Productivity Map Experience

Science.gov (United States)

Evans, B. J. K.; Antony, J.; Guerschman, J. P.; Larraondo, P. R.; Richards, C. J.

2017-12-01

Empowering end-users like pastoralists, land management specialists and land policy makers in the use of earth observation data for both day-to-day and seasonal planning needs both interactive delivery of multiple geospatial datasets and the capability of supporting on-the-fly dynamic queries while simultaneously fostering a community around the effort. The use of and wide adoption of large data archives, like those produced by earth observation missions, are often limited by compute and storage capabilities of the remote user. We demonstrate that wide-scale use of large data archives can be facilitated by end-users dynamically requesting value-added products using open standards (WCS, WMS, WPS), with compute running in the cloud or dedicated data-centres and visualizing outputs on web-front ends. As an example, we will demonstrate how a tool called GSKY can empower a remote end-user by providing the data delivery and analytics capabilities for the GEOGLAM Rangelands and Pasture Productivity (RAPP) Map tool. The GEOGLAM RAPP initiative from the Group on Earth Observations (GEO) and its Agricultural Monitoring subgroup aims at providing practical tools to end-users focusing on the important role of rangelands and pasture systems in providing food production security from both agricultural crops and animal protein. Figure 1, is a screen capture from the RAPP Map interface for an important pasture area in the Namibian rangelands. The RAPP Map has been in production for six months and has garnered significant interest from groups and users all over the world. GSKY, being formulated around the theme of Open Geospatial Data-as-a-Service capabilities uses distributed computing and storage to facilitate this. It works behind the scenes, accepting OGC standard requests in WCS, WMS and WPS. Results from these requests are rendered on a web-front end. In this way, the complexities of data locality and compute execution are masked from an end user. On-the-fly computation of

Influences of Plant Species, Season and Location on Leaf Endophytic Bacterial Communities of Non-Cultivated Plants.

Science.gov (United States)

Ding, Tao; Melcher, Ulrich

2016-01-01

Bacteria are known to be associated endophytically with plants. Research on endophytic bacteria has identified their importance in food safety, agricultural production and phytoremediation. However, the diversity of endophytic bacterial communities and the forces that shape their compositions in non-cultivated plants are largely uncharacterized. In this study, we explored the diversity, community structure, and dynamics of endophytic bacteria in different plant species in the Tallgrass Prairie Preserve of northern Oklahoma, USA. High throughput sequencing of amplified segments of bacterial rDNA from 81 samples collected at four sampling times from five plant species at four locations identified 335 distinct OTUs at 97% sequence similarity, representing 16 phyla. Proteobacteria was the dominant phylum in the communities, followed by the phyla Bacteriodetes and Actinobacteria. Bacteria from four classes of Proteobacteria were detected with Alphaproteobacteria as the dominant class. Analysis of molecular variance revealed that host plant species and collecting date had significant influences on the compositions of the leaf endophytic bacterial communities. The proportion of Alphaproteobacteria was much higher in the communities from Asclepias viridis than from other plant species and differed from month to month. The most dominant bacterial groups identified in LDA Effect Size analysis showed host-specific patterns, indicating mutual selection between host plants and endophytic bacteria and that leaf endophytic bacterial compositions were dynamic, varying with the host plant's growing season in three distinct patterns. In summary, next generation sequencing has revealed variations in the taxonomic compositions of leaf endophytic bacterial communities dependent primarily on the nature of the plant host species.

Influences of Plant Species, Season and Location on Leaf Endophytic Bacterial Communities of Non-Cultivated Plants.

Directory of Open Access Journals (Sweden)

Tao Ding

Full Text Available Bacteria are known to be associated endophytically with plants. Research on endophytic bacteria has identified their importance in food safety, agricultural production and phytoremediation. However, the diversity of endophytic bacterial communities and the forces that shape their compositions in non-cultivated plants are largely uncharacterized. In this study, we explored the diversity, community structure, and dynamics of endophytic bacteria in different plant species in the Tallgrass Prairie Preserve of northern Oklahoma, USA. High throughput sequencing of amplified segments of bacterial rDNA from 81 samples collected at four sampling times from five plant species at four locations identified 335 distinct OTUs at 97% sequence similarity, representing 16 phyla. Proteobacteria was the dominant phylum in the communities, followed by the phyla Bacteriodetes and Actinobacteria. Bacteria from four classes of Proteobacteria were detected with Alphaproteobacteria as the dominant class. Analysis of molecular variance revealed that host plant species and collecting date had significant influences on the compositions of the leaf endophytic bacterial communities. The proportion of Alphaproteobacteria was much higher in the communities from Asclepias viridis than from other plant species and differed from month to month. The most dominant bacterial groups identified in LDA Effect Size analysis showed host-specific patterns, indicating mutual selection between host plants and endophytic bacteria and that leaf endophytic bacterial compositions were dynamic, varying with the host plant's growing season in three distinct patterns. In summary, next generation sequencing has revealed variations in the taxonomic compositions of leaf endophytic bacterial communities dependent primarily on the nature of the plant host species.

Plant succession and approaches to community restoration

Science.gov (United States)

Bruce A. Roundy

2005-01-01

The processes of vegetation change over time, or plant succession, are also the processes involved in plant community restoration. Restoration efforts attempt to use designed disturbance, seedbed preparation and sowing methods, and selection of adapted and compatible native plant materials to enhance ecological function. The large scale of wildfires and weed invasion...

Ranch business planning and resource monitoring for rangeland sustainability

Science.gov (United States)

Kristie A. Maczko; John A. Tanaka; Michael Smith; Cindy Garretson-Weibel; Stanley F. Hamilton; John E. Mitchell; Gene Fults; Charles Stanley; Dick Loper; Larry D. Bryant; J. K. (Rooter) Brite

2012-01-01

Aligning a rancher's business plan goals with the capability of the ranch's rangeland resources improves the viability and sustainability of family ranches. Strategically monitoring the condition of soil, water, vegetation, wildlife, livestock production, and economics helps inform business plan goals. Business planning and resource monitoring help keep...

Phenomapping of rangelands in South Africa using time series of RapidEye data

Science.gov (United States)

Parplies, André; Dubovyk, Olena; Tewes, Andreas; Mund, Jan-Peter; Schellberg, Jürgen

2016-12-01

Phenomapping is an approach which allows the derivation of spatial patterns of vegetation phenology and rangeland productivity based on time series of vegetation indices. In our study, we propose a new spatial mapping approach which combines phenometrics derived from high resolution (HR) satellite time series with spatial logistic regression modeling to discriminate land management systems in rangelands. From the RapidEye time series for selected rangelands in South Africa, we calculated bi-weekly noise reduced Normalized Difference Vegetation Index (NDVI) images. For the growing season of 2011⿿2012, we further derived principal phenology metrics such as start, end and length of growing season and related phenological variables such as amplitude, left derivative and small integral of the NDVI curve. We then mapped these phenometrics across two different tenure systems, communal and commercial, at the very detailed spatial resolution of 5 m. The result of a binary logistic regression (BLR) has shown that the amplitude and the left derivative of the NDVI curve were statistically significant. These indicators are useful to discriminate commercial from communal rangeland systems. We conclude that phenomapping combined with spatial modeling is a powerful tool that allows efficient aggregation of phenology and productivity metrics for spatially explicit analysis of the relationships of crop phenology with site conditions and management. This approach has particular potential for disaggregated and patchy environments such as in farming systems in semi-arid South Africa, where phenology varies considerably among and within years. Further, we see a strong perspective for phenomapping to support spatially explicit modelling of vegetation.

Ecology and utilization of desert shrub rangelands in Iraq

NARCIS (Netherlands)

Thalen, Derk Catharinus Peter

1979-01-01

When grazing is the accepted land use, vegetation is the key resource. The present study deals with the desert shrub rangelands of lraq, which contain the major characteristics of such an area, having been under grazing for many centuries. Emphasis is given to the ecology and utilization of the

Embracing community ecology in plant microbiome research

NARCIS (Netherlands)

Dini-Andreote, F.; Raaijmakers, J.M.

2018-01-01

Community assembly is mediated by selection, dispersal, drift, and speciation. Environmental selection is mostly used to date to explain patterns in plant microbiome assembly, whereas the influence of the other processes remains largely elusive. Recent studies highlight that adopting community

Interaction of historical and nonhistorical disturbances maintains native plant communities.

Science.gov (United States)

Davies, K W; Svejcar, T J; Bates, J D

2009-09-01

Historical disturbance regimes are often considered a critical element in maintaining native plant communities. However, the response of plant communities to disturbance may be fundamentally altered as a consequence of invasive plants, climate change, or prior disturbances. The appropriateness of historical disturbance patterns under modern conditions and the interactions among disturbances are issues that ecologists must address to protect and restore native plant communities. We evaluated the response of Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh plant communities to their historical disturbance regime compared to other disturbance regimes. The historical disturbance regime of these plant communities was periodic fires with minimal grazing by large herbivores. We also investigated the influence of prior disturbance (grazing) on the response of these communities to subsequent disturbance (burning). Treatments were: (1) ungrazed (livestock grazing excluded since 1936) and unburned, (2) grazed and unburned, (3) ungrazed and burned (burned in 1993), and (4) grazed and burned. The ungrazed-burned treatment emulated the historical disturbance regime. Vegetation cover, density, and biomass production were measured the 12th, 13th, and 14th year post-burning. Prior to burning the presence of Bromus tectorum L., an exotic annual grass, was minimal (resilience to more severe disturbances. Modern deviations from historical conditions can alter ecosystem response to disturbances, thus restoring the historical disturbance regime may not be an appropriate strategy for all ecosystems.

The value of milk in rangelands in Mandera County, Kenya

Science.gov (United States)

Ngugi, Keziah; Ertsen, Maurits

2015-04-01

Lack of water over expansive regions in Greater Horn of Africa created the rangelands and rangelands created pastoralism. Pastoralism involve keeping of large livestock herds and movement in search of resources, mainly water, pasture, medicine and wild foods. Several studies have been done in the last century and findings pointed at pastoralism being primitive and unsustainable. It has been predicted it would die in the last century but in the rangelands, pastoralism lives on and it is resilient. This study is based in Mandera, a pastoralism county in Kenya that neighbors Ethiopia to the North and Somalia to the East. The study sought to investigate contribution of milk to pastoralism resilience. Interviews were conducted in the field among the pastoralists, women groups, transporters, traders, government officials and consumers of milk. These information was corroborated with actual field investigations in the expansive rangelands of Mandera County. Pastoralists rarely slaughter or sell their livestock even when the animals waste away during droughts. This is because they have been through such cycles before and observed livestock make tremendous recovery when the right conditions were restored. Rangelands lack infrastructure, there are no roads, schools, telephone or hospitals. Pastoralists diet is comprised of rice, wheat and milk. It was established milk was the main source of income among pastoralists in Mandera County. From milk, the pastoralists make income that is used to purchase the other foodstuffs. Milk is available on daily basis in large quantities owing to the large number of livestock. Unfortunately, every pastoralist household produce copious amounts of milk, thus no local demand and transport infrastructure is nonexistent, making sale of milk a near impossible task. The findings showed the pastoralists have established unique routes through which milk reach the markets in urban centers where demand is high. Urbanization sustain pastoralism. These

Bottom-up and top-down effects on plant communities

DEFF Research Database (Denmark)

Souza, Lara; Zelikova, Tamara Jane; Sanders, Nate

2016-01-01

-down) and soil nitrogen (bottom-up) were manipulated over six years in an existing old-field community. We tracked plant α and β diversity - within plot richness and among plot biodiversity- and aboveground net primary productivity (ANPP) over the course of the experiment. We found that bottom-up factors...... affected ANPP while top-down factors influenced plant community structure. Across years, while N reduction lowered ANPP by 10%, N reduction did not alter ANPP relative to control plots. Further, N reduction lowered ANPP by 20% relative to N addition plots. On the other hand, the reduction of insect...... community composition via shifts in plant dominance....

Nuclear power plant and the host community

Energy Technology Data Exchange (ETDEWEB)

Olsson, G

1978-10-27

A councillor from a small Swedish community (Kaevlinge) in the vicinity of the Barsebaeck nuclear power plant describes the effects which the plant has had on neighbouring communities. The effect on the labour market has been small at Kaevlinge, both during routine operation and construction phases. This is however, a fairly densely populated area with a population of half a million in a radius of 30 km. The situation is different at Oskarshamn or Oesthammar. Neither has there been any special economic benefit, due to Swedish taxation laws. There has been little local anxiety due to the proximity of the nuclear power plant. Certain local planning problems have been caused by restricted zones and power cables. Cooperation between the local authorities and the utility has been good.

A synoptic review of U.S. rangelands: a technical document supporting the Forest Service 2010 RPA Assessment

Science.gov (United States)

Matthew Clark Reeves; John E. Mitchell

2012-01-01

The Renewable Resources Planning Act of 1974 requires the USDA Forest Service to conduct assessments of resource conditions. This report fulfills that need and focuses on quantifying extent, productivity, and health of U.S. rangelands. Since 1982, the area of U.S. rangelands has decreased at an average rate of 350,000 acres per year owed mostly to conversion to...

Parameterization of erodibility in the Rangeland Hydrology and Erosion Model

Science.gov (United States)

The magnitude of erosion from a hillslope is governed by the availability of sediment and connectivity of runoff and erosion processes. For undisturbed rangelands, sediment is primarily detached and transported by rainsplash and sheetflow (splash-sheet) processes in isolated bare batches, but sedime...

Plant community mediation of ecosystem responses to global change factors

Science.gov (United States)

Churchill, A. C.

2017-12-01

Human alteration of the numerous environmental drivers affecting ecosystem processes is unprecedented in the last century, including changes in climate regimes and rapid increases in the availability of biologically active nitrogen (N). Plant communities may offer stabilizing or amplifying feedbacks mediating potential ecosystem responses to these alterations, and my research seeks to examine the conditions associated with when plant feedbacks are important for ecosystem change. My dissertation research focused on the unintended consequences of N deposition into natural landscapes, including alpine ecosystems which are particularly susceptible to adverse environmental impacts. In particular, I examined alpine plant and soil responses to N deposition 1) across multiple spatial scales throughout the Southern Rocky Mountains, 2) among diverse plant communities associated with unique environmental conditions common in the alpine of this region, and 3) among ecosystem pools of N contributing to stabilization of N inputs within those communities. I found that communities responded to inputs of N differently, often associated with traits of dominant plant species but these responses were intimately linked with the abiotic conditions of each independent community. Even so, statistical models predicting metrics of N processing in the alpine were improved by encompassing both abiotic and biotic components of the main community types.

Use of biosolids to enhance rangeland forage quality.

Science.gov (United States)

McFarland, Michael J; Vasquez, Issaak Romero; Vutran, MaiAnh; Schmitz, Mark; Brobst, Robert B

2010-05-01

Biosolids land application was demonstrated to be a potentially cost-effective means for restoring forage productivity and enhancing soil-moisture-holding capacity on disturbed rangelands. By land-applying aerobically digested, anaerobically digested, composted, and lime-stabilized biosolids on rangeland test plots at rates of up to 20 times (20X) the estimated nitrogen-based agronomic rate, forage yields were found to increase from 132.8 kg/ha (118.2 lb/ac) (control plots) to 1182.3 kg/ha (1052.8 lb/ac). Despite the environmental benefits associated with increased forage yield (e.g., reduced soil erosion, improved drainage, and enhanced terrestrial carbon sequestration), the type of forage generated both before and after biosolids land application was found to be dominated by invasive weeds, all of which were characterized as having fair to poor nutritional value. Opportunistic and shallow rooting invasive weeds not only have marginal nutritional value, they also limit the establishment of native perennial grasses and thus biodiversity. Many of the identified invasive species (e.g., Cheatgrass) mature early, a characteristic that significantly increases the fuel loads that support the increased frequency and extent of western wildfires.

Linking ecosystem services with state-and-transition models to evaluate rangeland management decisions

Science.gov (United States)

Lohani, S.; Heilman, P.; deSteiguer, J. E.; Guertin, D. P.; Wissler, C.; McClaran, M. P.

2014-12-01

Quantifying ecosystem services is a crucial topic for land management decision making. However, market prices are usually not able to capture all the ecosystem services and disservices. Ecosystem services from rangelands, that cover 70% of the world's land area, are even less well-understood since knowledge of rangelands is limited. This study generated a management framework for rangelands that uses remote sensing to generate state and transition models (STMs) for a large area and a linear programming (LP) model that uses ecosystem services to evaluate natural and/or management induced transitions as described in the STM. The LP optimization model determines the best management plan for a plot of semi-arid land in the Empire Ranch in southeastern Arizona. The model allocated land among management activities (do nothing, grazing, fire, and brush removal) to optimize net benefits and determined the impact of monetizing environmental services and disservices on net benefits, acreage allocation and production output. The ecosystem services under study were forage production (AUM/ac/yr), sediment (lbs/ac/yr), water runoff (inches/yr), soil loss (lbs/ac/yr) and recreation (thousands of number of visitors/ac/yr). The optimization model was run for three different scenarios - private rancher, public rancher including environmental services and excluding disservices, and public rancher including both services and disservices. The net benefit was the highest for the public rancher excluding the disservices. A result from the study is a constrained optimization model that incorporates ecosystem services to analyze investments on conservation and management activities. Rangeland managers can use this model to understand and explain, not prescribe, the tradeoffs of management investments.

Plant Communities Rather than Soil Properties Structure Arbuscular Mycorrhizal Fungal Communities along Primary Succession on a Mine Spoil

Science.gov (United States)

Krüger, Claudia; Kohout, Petr; Janoušková, Martina; Püschel, David; Frouz, Jan; Rydlová, Jana

2017-01-01

Arbuscular mycorrhizal fungal (AMF) community assembly during primary succession has so far received little attention. It remains therefore unclear, which of the factors, driving AMF community composition, are important during ecosystem development. We addressed this question on a large spoil heap, which provides a mosaic of sites in different successional stages under different managements. We selected 24 sites of c. 12, 20, 30, or 50 years in age, including sites with spontaneously developing vegetation and sites reclaimed by alder plantations. On each site, we sampled twice a year roots of the perennial rhizomatous grass Calamagrostis epigejos (Poaceae) to determine AMF root colonization and diversity (using 454-sequencing), determined the soil chemical properties and composition of plant communities. AMF taxa richness was unaffected by site age, but AMF composition variation increased along the chronosequences. AMF communities were unaffected by soil chemistry, but related to the composition of neighboring plant communities of the sampled C. epigejos plants. In contrast, the plant communities of the sites were more distinctively structured than the AMF communities along the four successional stages. We conclude that AMF and plant community successions respond to different factors. AMF communities seem to be influenced by biotic rather than by abiotic factors and to diverge with successional age. PMID:28473828

Response of native insect communities to invasive plants.

Science.gov (United States)

Bezemer, T Martijn; Harvey, Jeffrey A; Cronin, James T

2014-01-01

Invasive plants can disrupt a range of trophic interactions in native communities. As a novel resource they can affect the performance of native insect herbivores and their natural enemies such as parasitoids and predators, and this can lead to host shifts of these herbivores and natural enemies. Through the release of volatile compounds, and by changing the chemical complexity of the habitat, invasive plants can also affect the behavior of native insects such as herbivores, parasitoids, and pollinators. Studies that compare insects on related native and invasive plants in invaded habitats show that the abundance of insect herbivores is often lower on invasive plants, but that damage levels are similar. The impact of invasive plants on the population dynamics of resident insect species has been rarely examined, but invasive plants can influence the spatial and temporal dynamics of native insect (meta)populations and communities, ultimately leading to changes at the landscape level.

Agroforestry potential of Acacia senegal in the rangelands of luwero ...

African Journals Online (AJOL)

Agroforestry potential of Acacia senegal in the rangelands of luwero and Nakasongola districts. Jacob Godfrey Agea, Joseph Obua, Sara Namirembe, Mukadasi Buyinza, Daniel Waiswa. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

Session B1 Management for sustainable use — Rangeland auditing ...

African Journals Online (AJOL)

Social, economic and cultural needs, values and expectations will be examined together with the biophysical technologies and approaches which underlie auditing in rangeland science. Adaptive frameworks which enhance sustainable strategic responses, and the state of art in scale dilemmas will be addressed. A hybrid ...

Multi-scale wind erosion monitoring and assessment for US rangelands

Science.gov (United States)

Wind erosion is a major resource concern for rangeland managers. Although wind erosion is a naturally occurring process in many drylands, land use activities, and land management in particular, can accelerate wind-driven soil loss – impacting ecosystem dynamics and agricultural production, air quali...

Session A6 Rangelands as dynamic systems — Fragmentation of ...

African Journals Online (AJOL)

Biological complexity in rangelands arises from spatially-linked ecological states and processes. Herbivores, humans and other agents integrate distinct spatial units into complex systems by moving among and exploiting these units. Spatial heterogeneity plays a central role in the structure and function of grazed ...

Impact of Prosopis (mesquite) invasion and clearing on vegetation ...

African Journals Online (AJOL)

We evaluated the impact of Prosopis invasion and clearing on vegetation species composition and diversity (alien and indigenous species richness and cover) in Nama-Karoo rangeland on two sheep farms in the Beaufort ... Keywords: invasive plants – exotic, Nama-Karoo, plant community ecology, rehabilitation, semi-arid ...

Community attitudes toward nuclear plants

International Nuclear Information System (INIS)

Peelle, E.

1982-01-01

Among the many effects of the accident at Three Mile Island are impacts upon other communities that currently host nuclear-power reactors. Because studies on communities' reactions not immediately available, this chapter reviews existing studies and speculates about possible effects. The patterns and variations in impacts on and responses of nuclear host communities have been the subject of studies at Oak Ridge National Laboratory (Oak Ridge, Tennessee) since 1972. This essay presents results from four post-licensing studies of host communities - Plymouth, Massachusetts, and Waterford, Connecticut (PL-1), and Brunswick, North Carolina, and Appling-Toombs counties, Georgia (PL-2) - along with case study and attitude survey information from two additional communities in which reactors are under construction: Hartsville, Tennessee, and Cherokee County, South Carolina. Differences and similarities between the sites have been assessed in terms of differences in input and social structure; factors affecting the generally favorable attitudes toward local nuclear plants are discussed

Prescribed Fire Effects on Runoff, Erosion, and Soil Water Repellency on Steeply-Sloped Sagebrush Rangeland over a Five Year Period

Science.gov (United States)

Williams, C. J.; Pierson, F. B.; Al-Hamdan, O. Z.

2014-12-01

Fire is an inherent component of sagebrush steppe rangelands in western North America and can dramatically affect runoff and erosion processes. Post-fire flooding and erosion events pose substantial threats to proximal resources, property, and human life. Yet, prescribed fire can serve as a tool to manage vegetation and fuels on sagebrush rangelands and to reduce the potential for large catastrophic fires and mass erosion events. The impact of burning on event hydrologic and erosion responses is strongly related to the degree to which burning alters vegetation, ground cover, and surface soils and the intensity and duration of precipitation. Fire impacts on hydrologic and erosion response may be intensified or reduced by inherent site characteristics such as topography and soil properties. Parameterization of these diverse conditions in predictive tools is often limited by a lack of data and/or understanding for the domain of interest. Furthermore, hydrologic and erosion functioning change as vegetation and ground cover recover in the years following burning and few studies track these changes over time. In this study, we evaluated the impacts of prescribed fire on vegetation, ground cover, soil water repellency, and hydrologic and erosion responses 1, 2, and 5 yr following burning of a mountain big sagebrush community on steep hillslopes with fine-textured soils. The study site is within the Reynolds Creek Experimental Watershed, southwestern Idaho, USA. Vegetation, ground cover, and soil properties were measured over plot scales of 0.5 m2 to 9 m2. Rainfall simulations (0.5 m2) were used to assess the impacts of fire on soil water repellency, infiltration, runoff generation, and splash-sheet erosion. Overland flow experiments (9 m2) were used to assess the effects of fire-reduced ground cover on concentrated-flow runoff and erosion processes. The study results provide insight regarding fire impacts on runoff, erosion, and soil water repellency in the immediate and

A review of climate change effects on terrestrial rangeland birds

Science.gov (United States)

D. M. Finch; K. E. Bagne; M. M. Friggens; D. M. Smith; K. M. Brodhead

2011-01-01

We evaluated existing literature on predicted and known climate change effects on terrestrial rangeland birds. We asked the following questions: 1) How does climate change affect birds? 2) How will birds respond to climate change? 3) Are species already responding? 4) How will habitats be impacted?

Petroleum Contamination and Plant Identity Influence Soil and Root Microbial Communities While AMF Spores Retrieved from the Same Plants Possess Markedly Different Communities.

Science.gov (United States)

Iffis, Bachir; St-Arnaud, Marc; Hijri, Mohamed

2017-01-01

Phytoremediation is a promising in situ green technology based on the use of plants to cleanup soils from organic and inorganic pollutants. Microbes, particularly bacteria and fungi, that closely interact with plant roots play key roles in phytoremediation processes. In polluted soils, the root-associated microbes contribute to alleviation of plant stress, improve nutrient uptake and may either degrade or sequester a large range of soil pollutants. Therefore, improving the efficiency of phytoremediation requires a thorough knowledge of the microbial diversity living in the rhizosphere and in close association with plant roots in both the surface and the endosphere. This study aims to assess fungal ITS and bacterial 16S rRNA gene diversity using high-throughput sequencing in rhizospheric soils and roots of three plant species ( Solidago canadensis, Populus balsamifera , and Lycopus europaeus ) growing spontaneously in three petroleum hydrocarbon polluted sedimentation basins. Microbial community structures of rhizospheric soils and roots were compared with those of microbes associated with arbuscular mycorrhizal fungal (AMF) spores to determine the links between the root and rhizosphere communities and those associated with AMF. Our results showed a difference in OTU richness and community structure composition between soils and roots for both bacteria and fungi. We found that petroleum hydrocarbon pollutant (PHP) concentrations have a significant effect on fungal and bacterial community structures in both soils and roots, whereas plant species identity showed a significant effect only on the roots for bacteria and fungi. Our results also showed that the community composition of bacteria and fungi in soil and roots varied from those associated with AMF spores harvested from the same plants. This let us to speculate that in petroleum hydrocarbon contaminated soils, AMF may release chemical compounds by which they recruit beneficial microbes to tolerate or degrade the

Petroleum Contamination and Plant Identity Influence Soil and Root Microbial Communities While AMF Spores Retrieved from the Same Plants Possess Markedly Different Communities

Directory of Open Access Journals (Sweden)

Bachir Iffis

2017-08-01

Full Text Available Phytoremediation is a promising in situ green technology based on the use of plants to cleanup soils from organic and inorganic pollutants. Microbes, particularly bacteria and fungi, that closely interact with plant roots play key roles in phytoremediation processes. In polluted soils, the root-associated microbes contribute to alleviation of plant stress, improve nutrient uptake and may either degrade or sequester a large range of soil pollutants. Therefore, improving the efficiency of phytoremediation requires a thorough knowledge of the microbial diversity living in the rhizosphere and in close association with plant roots in both the surface and the endosphere. This study aims to assess fungal ITS and bacterial 16S rRNA gene diversity using high-throughput sequencing in rhizospheric soils and roots of three plant species (Solidago canadensis, Populus balsamifera, and Lycopus europaeus growing spontaneously in three petroleum hydrocarbon polluted sedimentation basins. Microbial community structures of rhizospheric soils and roots were compared with those of microbes associated with arbuscular mycorrhizal fungal (AMF spores to determine the links between the root and rhizosphere communities and those associated with AMF. Our results showed a difference in OTU richness and community structure composition between soils and roots for both bacteria and fungi. We found that petroleum hydrocarbon pollutant (PHP concentrations have a significant effect on fungal and bacterial community structures in both soils and roots, whereas plant species identity showed a significant effect only on the roots for bacteria and fungi. Our results also showed that the community composition of bacteria and fungi in soil and roots varied from those associated with AMF spores harvested from the same plants. This let us to speculate that in petroleum hydrocarbon contaminated soils, AMF may release chemical compounds by which they recruit beneficial microbes to tolerate

Petroleum Contamination and Plant Identity Influence Soil and Root Microbial Communities While AMF Spores Retrieved from the Same Plants Possess Markedly Different Communities

Science.gov (United States)

Iffis, Bachir; St-Arnaud, Marc; Hijri, Mohamed

2017-01-01

Phytoremediation is a promising in situ green technology based on the use of plants to cleanup soils from organic and inorganic pollutants. Microbes, particularly bacteria and fungi, that closely interact with plant roots play key roles in phytoremediation processes. In polluted soils, the root-associated microbes contribute to alleviation of plant stress, improve nutrient uptake and may either degrade or sequester a large range of soil pollutants. Therefore, improving the efficiency of phytoremediation requires a thorough knowledge of the microbial diversity living in the rhizosphere and in close association with plant roots in both the surface and the endosphere. This study aims to assess fungal ITS and bacterial 16S rRNA gene diversity using high-throughput sequencing in rhizospheric soils and roots of three plant species (Solidago canadensis, Populus balsamifera, and Lycopus europaeus) growing spontaneously in three petroleum hydrocarbon polluted sedimentation basins. Microbial community structures of rhizospheric soils and roots were compared with those of microbes associated with arbuscular mycorrhizal fungal (AMF) spores to determine the links between the root and rhizosphere communities and those associated with AMF. Our results showed a difference in OTU richness and community structure composition between soils and roots for both bacteria and fungi. We found that petroleum hydrocarbon pollutant (PHP) concentrations have a significant effect on fungal and bacterial community structures in both soils and roots, whereas plant species identity showed a significant effect only on the roots for bacteria and fungi. Our results also showed that the community composition of bacteria and fungi in soil and roots varied from those associated with AMF spores harvested from the same plants. This let us to speculate that in petroleum hydrocarbon contaminated soils, AMF may release chemical compounds by which they recruit beneficial microbes to tolerate or degrade the

Determining termite diversity in arid Namibian rangelands – a ...

African Journals Online (AJOL)

Three methods of sampling termite diversity in arid rangelands were tested in Namibia during the wet (March) and dry (October) seasons of 1998. Six sites were chosen: one pair on each of three farms representing a gradient of land use intensity. At each site, two adjacent plots of 1 ha each were sampled: one plot by a ...

Session B1 Management for sustainable use — Rangeland auditing ...

African Journals Online (AJOL)

We need to monitor the capacity of healthy rangeland to support a broad suite of ecosystem services for a wide range of stakeholders — in a fair, objective and representative way. ... A hybrid session structure will be utilised: distilling wisdom from relevant posters; formal presentations; and stimulating structured debate.

Seed bank characteristics of Dutch plant communities

NARCIS (Netherlands)

Bekker, RM; Schaminee, JHJ; Bakker, JP; Thompson, K

With the recent appearances of a new and well-documented classification of the Dutch plant communities (Schaminee et al 1995a,b; 1996) and a database on the seed longevity of plant species of North West Europe (Thompson ct al. 1997a) it was possible to investigate patterns of seed longevity in Dutch

Genetics-based interactions among plants, pathogens, and herbivores define arthropod community structure.

Science.gov (United States)

Busby, Posy E; Lamit, Louis J; Keith, Arthur R; Newcombe, George; Gehring, Catherine A; Whitham, Thomas G; Dirzo, Rodolfo

2015-07-01

Plant resistance to pathogens or insect herbivores is common, but its potential for indirectly influencing plant-associated communities is poorly known. Here, we test whether pathogens' indirect effects on arthropod communities and herbivory depend on plant resistance to pathogens and/or herbivores, and address the overarching interacting foundation species hypothesis that genetics-based interactions among a few highly interactive species can structure a much larger community. In a manipulative field experiment using replicated genotypes of two Populus species and their interspecific hybrids, we found that genetic variation in plant resistance to both pathogens and insect herbivores modulated the strength of pathogens' indirect effects on arthropod communities and insect herbivory. First, due in part to the pathogens' differential impacts on leaf biomass among the two Populus species and the hybrids, the pathogen most strongly impacted arthropod community composition, richness, and abundance on the pathogen-susceptible tree species. Second, we found similar patterns comparing pathogen-susceptible and pathogen-resistant genotypes within species. Third, within a plant species, pathogens caused a fivefold greater reduction in herbivory on insect-herbivore-susceptible plant genotypes than on herbivore-resistant genotypes, demonstrating that the pathogen-herbivore interaction is genotype dependent. We conclude that interactions among plants, pathogens, and herbivores can structure multitrophic communities, supporting the interacting foundation species hypothesis. Because these interactions are genetically based, evolutionary changes in genetic resistance could result in ecological changes in associated communities, which may in turn feed back to affect plant fitness.

Litter Accumulation and Nutrient Content of Roadside Plant Communities in Sichuan Basin, China.

Science.gov (United States)

He, Huiqin; Monaco, Thomas

2017-08-30

It is widely recognized that feedbacks exist between plant litter and plant community species composition, but this relationship is difficult to interpret over heterogeneous conditions typical of modified environments such as roadways. Given the need to expedite natural recovery of disturbed areas through restoration interventions, we characterized litter accumulation and nutrient content (i.e., organic carbon, total N, and P) and quantified their association with key plant species. Plant species cover and litter characteristics were sampled at 18 successional forest plant communities along major roadways in Sichuan Basin, western China. Variation in litter across communities was assessed with principal component analysis (PCA) and species with the highest correlation to PCA axes were determined with Pearson's r coefficients. Plant communities with the longest time since road construction (i.e., 70 years) were distinctly different in litter total N and organic carbon compared to plant communities with a shorter disturbance history. We encountered 59 plant species across sampling plots, but only four rare species (i.e., frequency plant litter across heavily disturbed landscapes and how litter characteristics and rare plant species are correlated.

Power and limitation of soil properties as predictors of rangeland health and ecosystem functioning in a Northern mixed-grass prairie[Abstract

Science.gov (United States)

Soil properties are thought to affect rangeland ecosystem functioning (e.g. primary productivity, hydrology), and thus soil variables that are consistently correlated with key ecosystem functions may be general indicators of rangeland health. We summarize results from several studies in mixed-grass...

Assessing plant community composition fails to capture impacts of white-tailed deer on native and invasive plant species.

Science.gov (United States)

Nuzzo, Victoria; Dávalos, Andrea; Blossey, Bernd

2017-07-01

Excessive herbivory can have transformative effects on forest understory vegetation, converting diverse communities into depauperate ones, often with increased abundance of non-native plants. White-tailed deer are a problematic herbivore throughout much of eastern North America and alter forest understory community structure. Reducing (by culling) or eliminating (by fencing) deer herbivory is expected to return understory vegetation to a previously diverse condition. We examined this assumption from 1992 to 2006 at Fermilab (Batavia, IL) where a cull reduced white-tailed deer ( Odocoileus virginianus ) abundance in 1998/1999 by 90 % from 24.6 to 2.5/km 2 , and at West Point, NY, where we assessed interactive effects of deer, earthworms, and invasive plants using 30 × 30 m paired fenced and open plots in 12 different forests from 2009 to 2012. We recorded not only plant community responses (species presence and cover) within 1 m 2 quadrats, but also responses of select individual species (growth, reproduction). At Fermilab, introduced Alliaria petiolata abundance initially increased as deer density increased, but then declined after deer reduction. The understory community responded to the deer cull by increased cover, species richness and height, and community composition changed but was dominated by early successional native forbs. At West Point plant community composition was affected by introduced earthworm density but not deer exclusion. Native plant cover increased and non-native plant cover decreased in fenced plots, thus keeping overall plant cover similar. At both sites native forb cover increased in response to deer reduction, but the anticipated response of understory vegetation failed to materialize at the community level. Deer-favoured forbs ( Eurybia divaricata , Maianthemum racemosum , Polygonatum pubescens and Trillium recurvatum ) grew taller and flowering probability increased in the absence of deer. Plant community monitoring fails to capture

Session A5 Rangelands as dynamic systems Role of wildlife in ...

African Journals Online (AJOL)

Rangelands in southern Africa are increasingly being used for conservation, ecotourism, game farming and hunting. This impacts people's livelihoods and the state of natural resources. Complimentarity and competition between wildlife and domestic livestock can be explored. Theme: This session focuses on ecosystem ...

Temperament affects rangeland use patterns and reproductive performance of beef cows

Science.gov (United States)

• The American beef industry is paying more attention to cattle temperament, but studies examining relationships between temperaments and grazing behavior or animal performance on rangelands are limited. • We studied range beef cow temperaments using the behavioral syndromes framework. Cows classifi...

Plants of the fynbos biome harbour host species-specific bacterial communities.

Science.gov (United States)

Miyambo, Tsakani; Makhalanyane, Thulani P; Cowan, Don A; Valverde, Angel

2016-08-01

The fynbos biome in South Africa is globally recognised as a plant biodiversity hotspot. However, very little is known about the bacterial communities associated with fynbos plants, despite interactions between primary producers and bacteria having an impact on the physiology of both partners and shaping ecosystem diversity. This study reports on the structure, phylogenetic composition and potential roles of the endophytic bacterial communities located in the stems of three fynbos plants (Erepsia anceps, Phaenocoma prolifera and Leucadendron laureolum). Using Illumina MiSeq 16S rRNA sequencing we found that different subpopulations of Deinococcus-Thermus, Alphaproteobacteria, Acidobacteria and Firmicutes dominated the endophytic bacterial communities. Alphaproteobacteria and Actinobacteria were prevalent in P. prolifera, whereas Deinococcus-Thermus dominated in L. laureolum, revealing species-specific host-bacteria associations. Although a high degree of variability in the endophytic bacterial communities within hosts was observed, we also detected a core microbiome across the stems of the three plant species, which accounted for 72% of the sequences. Altogether, it seems that both deterministic and stochastic processes shaped microbial communities. Endophytic bacterial communities harboured putative plant growth-promoting bacteria, thus having the potential to influence host health and growth. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The importance of education in managing invasive plant species

Science.gov (United States)

Invasive plant species can establish in diverse environments and with the increase in human mobility, they are no longer restricted to isolated pockets in remote parts of the world. Cheat grass (Bromus tectorum L.) in rangelands, purple loosestrife (Lythrum salicaria L.) in wet lands and Canada this...

Negative Plant-Soil Feedback and Positive Species Interaction in a Herbaceous Plant Community

NARCIS (Netherlands)

Bonanomi, G.; Rietkerk, M.; Dekker, S.C.; Mazzoleni, S.

2005-01-01

Increasing evidence shows that facilitative interaction and negative plant¿soil feedback are driving factors of plant population dynamics and community processes. We studied the intensity and the relative impact of negative feedback on clonal growth and seed germination of Scirpus holoschoenus, a

Plant community variability on a small area in southeastern Montana

Science.gov (United States)

James G. MacCracken; Daniel W. Uresk; Richard M. Hansen

1984-01-01

Plant communities are inherently variable due to a number of environmental and biological forces. Canopy cover and aboveground biomass were determined for understory vegetation in plant communities of a prairie grassland-forest ecotone in southeastern Montana. Vegetation units were described using polar ordination and stepwise discriminant analysis. Nine of a total of...

Vulnerability of amphibians to climate change: implications for rangeland management

Science.gov (United States)

Karen E. Bagne; Deborah M. Finch; Megan M. Friggens

2011-01-01

Many amphibian populations have declined drastically in recent years due to a large number of factors including the emerging threat of climate change (Wake 2007). Rangelands provide important habitat for amphibians. In addition to natural wetlands, stock tanks and other artificial water catchments provide habitat for many amphibian species (Euliss et al. 2004).

Plant Communities Suitable for Green Roofs in Arid Regions

Directory of Open Access Journals (Sweden)

Rachel Gioannini

2018-05-01

Full Text Available In extensive green roof settings, plant communities can be more robust than monocultures. In addition, native plants might be hardier and more ecologically sound choices than non-native plants in green roof systems. The objectives of this research were to (1 compare the performance of plant communities with that of monocultures and (2 compare the growth of natives to non-natives in a simulated green roof setting. We conducted a two-year experiment at an outdoor site in a desert environment using four plant morphological types (groundcover, forb, succulent and grass. Native plants selected were Chrysactinia mexicana, Melampodium leucanthum, Euphorbia antisyphilitica, and Nassella tenuissima, and non-natives were Delosperma nubigenum, Stachys byzantina, Sedum kamtschiaticum and Festuca glauca. Plants were assigned randomly to either monoculture or community and grown in 1 m × 1 m custom-built trays filled with 15 cm of a proprietary blend of 50/20/30 lightweight aggregate/sand/compost (by volume. Native forb, Melampodium, in community had greater coverage for four of the five measurements in the first year over native forb in monoculture and non-native forb regardless of setting. Native forb coverage was also greater than non-native forb for three of the four measurements in year 2, regardless of setting. Coverage of native grass was significantly greater than non-native grasses throughout the experiment. Coverage was also greater for eight of nine measurements for native succulent over non-natives succulent. However, non-native groundcover coverage was significantly greater than native groundcover for seven of nine measurements. On 1 November 2016, relative water content (RWC for succulents (p = 0.0424 was greatest for native Euphorbia in monoculture at 88%. Native Euphorbia also had greater RWC than non-native Sedum on 4 April 2017 (78% and 4 July 2017 (80%. However, non-native Sedum had greater root length (6548 cm, root dry weight (12.1 g

Analysis reveals potential rangeland impacts if Williamson Act eliminated

Directory of Open Access Journals (Sweden)

William C. Wetzel

2012-10-01

Full Text Available California budget cuts have resulted in dramatic reductions in state funding for the Williamson Act, a land protection program that reduces property taxes for the owners of 15 million acres of California farms and rangeland. With state reimbursements to counties eliminated, the decision to continue Williamson Act contracts lies with individual counties. We investigated the consequences of eliminating the Williamson Act, using a geospatial analysis and a mail questionnaire asking ranchers for plans under a hypothetical elimination scenario. The geospatial analysis revealed that 72% of rangeland parcels enrolled in Williamson Act contracts contained habitat important for statewide conservation goals. Presented with the elimination scenario, survey respondents reported an intention to sell 20% of their total 496,889 acres. The tendency of survey participants to respond that they would sell land was highest among full-time ranchers with low household incomes and without off-ranch employment. A majority (76% of the ranchers who reported that they would sell land predicted that the buyers would develop it for nonagricultural uses, suggesting substantial changes to California's landscape in a future without the Williamson Act.

Rural and school community in appreciating knowledge on medical plants

Directory of Open Access Journals (Sweden)

Marcílio Souza Carneiro

2016-05-01

Isolated communities in the urban environment still use medicinal plants, but such knowledge is not always passed on to new generations. In this scenario, we propose a study with students, teachers, and community residents from Córrego da Ema, Amontada, Ceará, Brazil, aiming to know the wisdom of medicinal plants in a small rural community in the Brazilian semi-arid region. We interviewed the medicinal plant connoisseurs, named as local experts, by using the “snow ball” method. We applied questionnaires to investigate Elementary School students’ knowledge on medicinal plants (pre-tour. These actions provided a basis for planning guided-tours, activities aimed at 51 students, which we carried out along with the 10 experts and 2 local school teachers, whose results (post-tour were assessed by using the same pre-tour questionnaire. Most local experts were women (80%, their families had many people and low education level, factors that contribute to using medicinal plants. Experts cited 35 medicinal plant species. Students cited 24 pre-tour plant species and 28 post-tour plant species. Students increased their knowledge, as there was also a post-tour increase in therapeutic indications and preparation methods, as mentioned. The school played an important role in appreciating this intangible heritage, because it enabled actions involving formal and informal education.

Effects of diversity and identity of the neighbouring plant community on the abundance of arthropods on individual ragwort (Jacobaea vulgaris) plants

NARCIS (Netherlands)

Kostenko, O.; Grootemaat, Saskia S.; Van der Putten, W.H.; Bezemer, T.M.

2012-01-01

The diversity of plant community can greatly affect the abundance and diversity of arthropods associated to that community, but can also influence the composition or abundance of arthropods on individual plants growing in that community. We sampled arthropods and recorded plant size of individual

Fodder Biomass Monitoring in Sahelian Rangelands Using Phenological Metrics from FAPAR Time Series

DEFF Research Database (Denmark)

Diouf, Abdoul Aziz; Brandt, Martin Stefan; Verger, Aleixandre

2015-01-01

Timely monitoring of plant biomass is critical for the management of forage resources in Sahelian rangelands. The estimation of annual biomass production in the Sahel is based on a simple relationship between satellite annual Normalized Difference Vegetation Index (NDVI) and in situ biomass data....... This study proposes a new methodology using multi-linear models between phenological metrics from the SPOT-VEGETATION time series of Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) and in situ biomass. A model with three variables—large seasonal integral (LINTG), length of growing season......, and end of season decreasing rate—performed best (MAE = 605 kg·DM/ha; R2 = 0.68) across Sahelian ecosystems in Senegal (data for the period 1999–2013). A model with annual maximum (PEAK) and start date of season showed similar performances (MAE = 625 kg·DM/ha; R2 = 0.64), allowing a timely estimation...

25 CFR 166.307 - Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not...

Science.gov (United States)

2010-04-01

... § 166.307 Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not... trust or non-trust rangeland in common with the permitted land. Grazing capacity will be established... 25 Indians 1 2010-04-01 2010-04-01 false Will the grazing capacity be increased if I graze...

Reality of rangeland degradation mapping with remote sensing: the South African experience

CSIR Research Space (South Africa)

Wessels, Konrad J

2008-09-01

Full Text Available Globally there is an urgent need for standardized, quantitative measures rangeland degradation. Over the past 10 years in South Africa (SA), significant research efforts have been directed at this challenge, using diverse methods and data...

Evapotranspiration in three plant communities of a Rhigozum ...

African Journals Online (AJOL)

Evapotranspiration losses in three Rhigozum trichotomum plant communities namely, pure grass, pure R. trichotomum and a mixed stand of grass and R. trichotomum were determined during the 1985-86 growing season. Three hydrologically isolated plots in each community type were irrigated and changes in soil water ...

Relationships between phyllosphere bacterial communities and plant functional traits in a neotropical forest

Science.gov (United States)

Kembel, Steven W.; O’Connor, Timothy K.; Arnold, Holly K.; Hubbell, Stephen P.; Wright, S. Joseph; Green, Jessica L.

2014-01-01

The phyllosphere—the aerial surfaces of plants, including leaves—is a ubiquitous global habitat that harbors diverse bacterial communities. Phyllosphere bacterial communities have the potential to influence plant biogeography and ecosystem function through their influence on the fitness and function of their hosts, but the host attributes that drive community assembly in the phyllosphere are poorly understood. In this study we used high-throughput sequencing to quantify bacterial community structure on the leaves of 57 tree species in a neotropical forest in Panama. We tested for relationships between bacterial communities on tree leaves and the functional traits, taxonomy, and phylogeny of their plant hosts. Bacterial communities on tropical tree leaves were diverse; leaves from individual trees were host to more than 400 bacterial taxa. Bacterial communities in the phyllosphere were dominated by a core microbiome of taxa including Actinobacteria, Alpha-, Beta-, and Gammaproteobacteria, and Sphingobacteria. Host attributes including plant taxonomic identity, phylogeny, growth and mortality rates, wood density, leaf mass per area, and leaf nitrogen and phosphorous concentrations were correlated with bacterial community structure on leaves. The relative abundances of several bacterial taxa were correlated with suites of host plant traits related to major axes of plant trait variation, including the leaf economics spectrum and the wood density–growth/mortality tradeoff. These correlations between phyllosphere bacterial diversity and host growth, mortality, and function suggest that incorporating information on plant–microbe associations will improve our ability to understand plant functional biogeography and the drivers of variation in plant and ecosystem function. PMID:25225376

The nuclear power plant and the host community

International Nuclear Information System (INIS)

Olsson, G.

1978-01-01

A councillor from a small Swedish community (Kaevlinge) in the vicinity of the Barsebaeck nuclear power plant describes the effects which the plant has had on neighbouring communities. The effect on the labour market has been small at Kaevlinge, both during routine operation and construction phases. This is however, a fairly densely populated area with a population of half a million in a radius of 30 km. The situation is different at Oskarshamn or Oesthammar. Neither has there been any special economic benefit, due to Swedish taxation laws. There has been little local anxiety due to the proximity of the nuclear power plant. Certain local planning problems have been caused by restricted zones and power cables. Cooperation between the local authorities and the utility has been good. (JIW)

The Root-Associated Microbial Community of the World's Highest Growing Vascular Plants.

Science.gov (United States)

Angel, Roey; Conrad, Ralf; Dvorsky, Miroslav; Kopecky, Martin; Kotilínek, Milan; Hiiesalu, Inga; Schweingruber, Fritz; Doležal, Jiří

2016-08-01

Upward migration of plants to barren subnival areas is occurring worldwide due to raising ambient temperatures and glacial recession. In summer 2012, the presence of six vascular plants, growing in a single patch, was recorded at an unprecedented elevation of 6150 m.a.s.l. close to the summit of Mount Shukule II in the Western Himalayas (Ladakh, India). Whilst showing multiple signs of stress, all plants have managed to establish stable growth and persist for several years. To learn about the role of microbes in the process of plant upward migration, we analysed the root-associated microbial community of the plants (three individuals from each) using microscopy and tagged amplicon sequencing. No mycorrhizae were found on the roots, implying they are of little importance to the establishment and early growth of the plants. However, all roots were associated with a complex bacterial community, with richness and diversity estimates similar or even higher than the surrounding bare soil. Both soil and root-associated communities were dominated by members of the orders Sphingomonadales and Sphingobacteriales, which are typical for hot desert soils, but were different from communities of temperate subnival soils and typical rhizosphere communities. Despite taxonomic similarity on the order level, the plants harboured a unique set of highly dominant operational taxonomic units which were not found in the bare soil. These bacteria have been likely transported with the dispersing seeds and became part of the root-associated community following germination. The results indicate that developing soils act not only as a source of inoculation to plant roots but also possibly as a sink for plant-associated bacteria.

Management of plant communities on set-aside land and its effects on earthworm communities

Czech Academy of Sciences Publication Activity Database

Gormsen, D.; Hedlund, K.; Korthals, G. W.; Mortimer, S. R.; Pižl, Václav; Šmilauerová, M.; Sugg, E.

2004-01-01

Roč. 40, 3-4 (2004), s. 123-128 ISSN 1164-5563 Grant - others:Evropská unie(XE) ENV4-CT95-0002 Keywords : earthworm community * plant community * land use Subject RIV: EH - Ecology, Behaviour Impact factor: 0.776, year: 2004

Lags in the response of mountain plant communities to climate change

DEFF Research Database (Denmark)

Alexander, Jake M; Chalmandrier, Loïc; Lenoir, Jonathan

2018-01-01

Rapid climatic changes and increasing human influence at high elevations around the world will have profound impacts on mountain biodiversity. However, forecasts from statistical models (e.g. species distribution models) rarely consider that plant community changes could substantially lag behind...... plant species' spread along elevational gradients, "establishment lags" following their arrival in recipient communities, and "extinction lags" of resident species. Variation in lags is explained by variation among species in physiological and demographic responses, by effects of altered biotic...... turnover in future communities might lag behind simple expectations based on species' range shifts with unlimited dispersal. The model shows a combined contribution of altered biotic interactions and dispersal lags to plant community turnover along an elevational gradient following climate warming. Our...

Salinity mobilization and transport from rangelands: assessment, recommendations, and knowledge gaps

Science.gov (United States)

The purpose of the salinity project is to improve the understanding of sources and transport mechanisms in rangeland catchments that deliver dissolved solids (salts) to streams within the Upper Colorado River Basin (UCRB) through a review of relevant literature on what is known about the impact of r...

Rural and school community in appreciating knowledge on medical plants

Directory of Open Access Journals (Sweden)

Marcílio Souza Carneiro

2016-05-01

Full Text Available Isolated communities in the urban environment still use medicinal plants, but such knowledge is not always passed on to new generations. In this scenario, we propose a study with students, teachers, and community residents from Córrego da Ema, Amontada, Ceará, Brazil, aiming to know the wisdom of medicinal plants in a small rural community in the Brazilian semi-arid region. We interviewed the medicinal plant connoisseurs, named as local experts, by using the “snow ball” method. We applied questionnaires to investigate Elementary School students’ knowledge on medicinal plants (pre-tour. These actions provided a basis for planning guided-tours, activities aimed at 51 students, which we carried out along with the 10 experts and 2 local school teachers, whose results (post-tour were assessed by using the same pre-tour questionnaire. Most local experts were women (80%, their families had many people and low education level, factors that contribute to using medicinal plants. Experts cited 35 medicinal plant species. Students cited 24 pre-tour plant species and 28 post-tour plant species. Students increased their knowledge, as there was also a post-tour increase in therapeutic indications and preparation methods, as mentioned. The school played an important role in appreciating this intangible heritage, because it enabled actions involving formal and informal education.

Determining RUSLE P-factors for stonebunds and trenches in rangeland and cropland, Northern Ethiopia

Science.gov (United States)

Taye, Gebeyehu; Poesen, Jean; Vanmaercke, Matthias; Van Wesemael, Bas; Tesfay, Samuel; Teka, Daniel; Nyssen, Jan; Deckers, Jozef; Haregeweyn, Nigussie

2017-04-01

The implementation of soil and water conservation (SWC) measures in the Ethiopian highlands is a top priority to reduce soil erosion rates and to enhance the sustainability of agroecosystem. Nonetheless, the effectiveness of many of these measures for different hillslope and land use conditions remains currently poorly understood. As a result, the overall effects of these measures at regional or catchment scale remain hard to quantify. This study addresses this knowledge gap by determining the cover-management (C) and support practice (P) factors of the Revised Universal Soil Loss Equation (RUSLE), for commonly used SWC measures in semi-arid environments (i.e. stone bunds, trenches and a combination of both). Calculations were based on soil loss data collected with runoff plots in Tigray, northern Ethiopia (i.e. 21 runoff plots of 600 to 1000 m2, monitored during 2010, 2011 and 2012). The runoff plots were installed in rangeland and cropland sites corresponding to a gentle (5%), medium (12%) and steep (16%) slope gradients. The C and P factors of the RUSLE were calculated following the recommended standard procedures. Results show that the C-factor for rangeland ranges from 0.31 to 0.98 and from 0.06 to 0.39 for cropland. For rangeland, this large variability is due to variations in vegetation cover caused by grazing. In cropland, C-factors vary with tillage practices and crop types. The calculated P-factors ranged from 0.32 to 0.74 for stone bunds, from 0.07 to 0.65 for trenches and from 0.03 to 0.22 for a combination of both stone bunds and trenches. This variability is partly due to variations in the density of the implemented measures in relation to land use (cropland vs rangeland) and slope angles. However, also annual variations in P factor values are highly significant. Especially trenches showed a very significant decline of effectiveness over time, which is attributable to their reduced static storage capacity as a result of sediment deposition (e.g. for

Ethnobotany of dye plants in Dong communities of China.

Science.gov (United States)

Liu, Yujing; Ahmed, Selena; Liu, Bo; Guo, Zhiyong; Huang, Weijuan; Wu, Xianjin; Li, Shenghua; Zhou, Jiangju; Lei, Qiyi; Long, Chunlin

2014-02-19

Dyes derived from plants have an extensive history of use for coloring food and clothing in Dong communities and other indigenous areas in the uplands of China. In addition to use as coloring agents, Dong communities have historically utilized dye plants for their value for enhancing the nutritive, medicinal and preservative properties of foods. However, the persistence of plant-derived dyes and associated cultural practices and traditional knowledge is threatened with rapid socio-economic change in China. Research is needed to document the ethnobotany of dye plants in indigenous communities towards their conservation and potential commercialization as a sustainable means of supporting local development initiatives. Semi-structured surveys on plants used for coloring agents and associated traditional knowledge were conducted in fifteen Dong villages of Tongdao County in Hunan Province of South Central China during 2011-2012. Transect walks were carried out with key informants identified from semi-structured surveys to collect samples and voucher specimens for each documented plant species for taxonomic identification. Dong households at the study sites utilize the flowers, bark, stems, tubers and roots of 13 plant species from 9 families as dyes to color their customary clothing and food. Out of the documented plants, a total of 7 are used for coloring food, 3 for coloring clothing and 3 for both food and clothing. Documented plants consist of 3 species that yield black pigments, 3 for brownish red/russet pigments, 3 for red pigments, 2 for dark blue pigments and 2 for yellow pigments. In addition to dyes, the plants have multiple uses including medicinal, ornamental, sacrificial, edible, and for timber. The use of dyes derived from plants persists at the study sites for their important role in expressing Dong cultural identity through customary clothing and food. Further research is needed to evaluate the safety of dye plants, their efficacy in enhancing food

Changes in plant species richness induce functional shifts in soil nematode communities in experimental grassland.

Directory of Open Access Journals (Sweden)

Nico Eisenhauer

Full Text Available Changes in plant diversity may induce distinct changes in soil food web structure and accompanying soil feedbacks to plants. However, knowledge of the long-term consequences of plant community simplification for soil animal food webs and functioning is scarce. Nematodes, the most abundant and diverse soil Metazoa, represent the complexity of soil food webs as they comprise all major trophic groups and allow calculation of a number of functional indices.We studied the functional composition of nematode communities three and five years after establishment of a grassland plant diversity experiment (Jena Experiment. In response to plant community simplification common nematode species disappeared and pronounced functional shifts in community structure occurred. The relevance of the fungal energy channel was higher in spring 2007 than in autumn 2005, particularly in species-rich plant assemblages. This resulted in a significant positive relationship between plant species richness and the ratio of fungal-to-bacterial feeders. Moreover, the density of predators increased significantly with plant diversity after five years, pointing to increased soil food web complexity in species-rich plant assemblages. Remarkably, in complex plant communities the nematode community shifted in favour of microbivores and predators, thereby reducing the relative abundance of plant feeders after five years.The results suggest that species-poor plant assemblages may suffer from nematode communities detrimental to plants, whereas species-rich plant assemblages support a higher proportion of microbivorous nematodes stimulating nutrient cycling and hence plant performance; i.e. effects of nematodes on plants may switch from negative to positive. Overall, food web complexity is likely to decrease in response to plant community simplification and results of this study suggest that this results mainly from the loss of common species which likely alter plant-nematode interactions.

Effects of Trampling Limitation on Coastal Dune Plant Communities

Science.gov (United States)

Santoro, Riccardo; Jucker, Tommaso; Prisco, Irene; Carboni, Marta; Battisti, Corrado; Acosta, Alicia T. R.

2012-03-01

Sandy coastlines are sensitive ecosystems where human activities can have considerable negative impacts. In particular, trampling by beach visitors is a disturbance that affects dune vegetation both at the species and community level. In this study we assess the effects of the limitation of human trampling on dune vegetation in a coastal protected area of Central Italy. We compare plant species diversity in two recently fenced sectors with that of an unfenced area (and therefore subject to human trampling) using rarefaction curves and a diversity/dominance approach during a two year study period. Our results indicate that limiting human trampling seems to be a key factor in driving changes in the plant diversity of dune systems. In 2007 the regression lines of species abundance as a function of rank showed steep slopes and high Y-intercept values in all sectors, indicating a comparable level of stress and dominance across the entire study site. On the contrary, in 2009 the regression lines of the two fenced sectors clearly diverge from that of the open sector, showing less steep slopes. This change in the slopes of the tendency lines, evidenced by the diversity/dominance diagrams and related to an increase in species diversity, suggests the recovery of plant communities in the two fences between 2007 and 2009. In general, plant communities subject to trampling tended to be poorer in species and less structured, since only dominant and tolerant plant species persisted. Furthermore, limiting trampling appears to have produced positive changes in the dune vegetation assemblage after a period of only two years. These results are encouraging for the management of coastal dune systems. They highlight how a simple and cost-effective management strategy, based on passive recovery conservation measures (i.e., fence building), can be a quick (1-2 years) and effective method for improving and safeguarding the diversity of dune plant communities.

Towards a remote sensing based indicator of rangeland ecosystem resistance and resilience

Science.gov (United States)

Understanding ecosystem resistance and resilience to disturbance and invasive species is critical to the sustainable management of rangeland systems. In this context, resistance refers to the inherent ability of an ecosystem to resist disturbance, while resilience refers to the capacity of an ecosys...

Effects of migratory geese on plant communities of an Alaskan salt marsh

Science.gov (United States)

Zacheis, Amy B.; Hupp, Jerry W.; Ruess, Roger W.

2001-01-01

1. We studied the effects of lesser snow geese (Anser caerulescens caerulescens) and Canada geese (Branta canadensis) on two salt marsh plant communities in Cook Inlet, Alaska, a stopover area used during spring migration. From 1995 to 1997 we compared plant species composition and biomass on plots where geese were excluded from feeding with paired plots where foraging could occur. 2. Foraging intensity was low (650-1930 goose-days km-2) compared to other goose-grazing systems. 3. Canada geese fed mainly on above-ground shoots of Triglochin maritimum, Puccinellia spp. and Carex ramenskii, whereas the majority of the snow goose diet consisted of below-ground tissues of Plantago maritima and Triglochin maritimum. 4. Plant communities responded differently to goose herbivory. In the sedge meadow community, where feeding was primarily on above-ground shoots, there was no effect of grazing on the dominant species Carex ramenskii and Triglochin maritimum. In the herb meadow community, where snow geese fed on Plantago maritima roots and other below-ground tissues, there was a difference in the relative abundance of plant species between treatments. Biomass of Plantago maritima and Potentilla egedii was lower on grazed plots compared with exclosed, whereas biomass of Carex ramenskii was greater on grazed plots. There was no effect of herbivory on total standing crop biomass in either community. The variable effect of herbivory on Carex ramenskii between communities suggests that plant neighbours and competitive interactions are important factors in a species' response to herbivory. In addition, the type of herbivory (above- or below-ground) was important in determining plant community response to herbivory. 5. Litter accumulation was reduced in grazed areas compared with exclosed in both communities. Trampling of the previous year's litter into the soil surface by geese incorporated more litter into soils in grazed areas. 6. This study illustrates that even light herbivore

Links between plant and fungal communities across a deforestation chronosequence in the Amazon rainforest.

Science.gov (United States)

Mueller, Rebecca C; Paula, Fabiana S; Mirza, Babur S; Rodrigues, Jorge L M; Nüsslein, Klaus; Bohannan, Brendan J M

2014-07-01

Understanding the interactions among microbial communities, plant communities and soil properties following deforestation could provide insights into the long-term effects of land-use change on ecosystem functions, and may help identify approaches that promote the recovery of degraded sites. We combined high-throughput sequencing of fungal rDNA and molecular barcoding of plant roots to estimate fungal and plant community composition in soil sampled across a chronosequence of deforestation. We found significant effects of land-use change on fungal community composition, which was more closely correlated to plant community composition than to changes in soil properties or geographic distance, providing evidence for strong links between above- and below-ground communities in tropical forests.

Herbivory of an invasive slug is affected by earthworms and the composition of plant communities.

Science.gov (United States)

Zaller, Johann G; Parth, Myriam; Szunyogh, Ilona; Semmelrock, Ines; Sochurek, Susanne; Pinheiro, Marcia; Frank, Thomas; Drapela, Thomas

2013-05-13

Biodiversity loss and species invasions are among the most important human-induced global changes. Moreover, these two processes are interlinked as ecosystem invasibility is considered to increase with decreasing biodiversity. In temperate grasslands, earthworms serve as important ecosystem engineers making up the majority of soil faunal biomass. Herbivore behaviour has been shown to be affected by earthworms, however it is unclear whether these effects differ with the composition of plant communities. To test this we conducted a mesocosm experiment where we added earthworms (Annelida: Lumbricidae) to planted grassland communities with different plant species composition (3 vs. 12 plant spp.). Plant communities had equal plant densities and ratios of the functional groups grasses, non-leguminous forbs and legumes. Later, Arion vulgaris slugs (formerly known as A. lusitanicus; Gastropoda: Arionidae) were added and allowed to freely choose among the available plant species. This slug species is listed among the 100 worst alien species in Europe. We hypothesized that (i) the food choice of slugs would be altered by earthworms' specific effects on the growth and nutrient content of plant species, (ii) slug herbivory will be less affected by earthworms in plant communities containing more plant species than in those with fewer plant species because of a more readily utilization of plant resources making the impacts of earthworms less pronounced. Slug herbivory was significantly affected by both earthworms and plant species composition. Slugs damaged 60% less leaves when earthworms were present, regardless of the species composition of the plant communities. Percent leaf area consumed by slugs was 40% lower in communities containing 12 plant species; in communities containing only three species earthworms increased slug leaf area consumption. Grasses were generally avoided by slugs. Leaf length and number of tillers was increased in mesocosms containing more plant

Evaluating new SMAP soil moisture for drought monitoring in the rangelands of the US High Plains

Science.gov (United States)

Velpuri, Naga Manohar; Senay, Gabriel B.; Morisette, Jeffrey T.

2016-01-01

Level 3 soil moisture datasets from the recently launched Soil Moisture Active Passive (SMAP) satellite are evaluated for drought monitoring in rangelands.Validation of SMAP soil moisture (SSM) with in situ and modeled estimates showed high level of agreement.SSM showed the highest correlation with surface soil moisture (0-5 cm) and a strong correlation to depths up to 20 cm.SSM showed a reliable and expected response of capturing seasonal dynamics in relation to precipitation, land surface temperature, and evapotranspiration.Further evaluation using multi-year SMAP datasets is necessary to quantify the full benefits and limitations for drought monitoring in rangelands.

Plant Invasions Associated with Change in Root-Zone Microbial Community Structure and Diversity.

Directory of Open Access Journals (Sweden)

Richard R Rodrigues

Full Text Available The importance of plant-microbe associations for the invasion of plant species have not been often tested under field conditions. The research sought to determine patterns of change in microbial communities associated with the establishment of invasive plants with different taxonomic and phenetic traits. Three independent locations in Virginia, USA were selected. One site was invaded by a grass (Microstegium vimineum, another by a shrub (Rhamnus davurica, and the third by a tree (Ailanthus altissima. The native vegetation from these sites was used as reference. 16S rRNA and ITS regions were sequenced to study root-zone bacterial and fungal communities, respectively, in invaded and non-invaded samples and analyzed using Quantitative Insights Into Microbial Ecology (QIIME. Though root-zone microbial community structure initially differed across locations, plant invasion shifted communities in similar ways. Indicator species analysis revealed that Operational Taxonomic Units (OTUs closely related to Proteobacteria, Acidobacteria, Actinobacteria, and Ascomycota increased in abundance due to plant invasions. The Hyphomonadaceae family in the Rhodobacterales order and ammonia-oxidizing Nitrospirae phylum showed greater relative abundance in the invaded root-zone soils. Hyphomicrobiaceae, another bacterial family within the phyla Proteobacteria increased as a result of plant invasion, but the effect associated most strongly with root-zones of M. vimineum and R. davurica. Functional analysis using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt showed bacteria responsible for nitrogen cycling in soil increased in relative abundance in association with plant invasion. In agreement with phylogenetic and functional analyses, greater turnover of ammonium and nitrate was associated with plant invasion. Overall, bacterial and fungal communities changed congruently across plant invaders, and support the hypothesis that

Nematode community shifts in response to experimental warming and canopy conditions are associated with plant community changes in the temperate-boreal forest ecotone.

Science.gov (United States)

Thakur, Madhav Prakash; Reich, Peter B; Fisichelli, Nicholas A; Stefanski, Artur; Cesarz, Simone; Dobies, Tomasz; Rich, Roy L; Hobbie, Sarah E; Eisenhauer, Nico

2014-06-01

Global climate warming is one of the key forces driving plant community shifts, such as range shifts of temperate species into boreal forests. As plant community shifts are slow to observe, ecotones, boundaries between two ecosystems, are target areas for providing early evidence of ecological responses to warming. The role of soil fauna is poorly explored in ecotones, although their positive and negative effects on plant species can influence plant community structure. We studied nematode communities in response to experimental warming (ambient, +1.7, +3.4 °C) in soils of closed and open canopy forest in the temperate-boreal ecotone of Minnesota, USA and calculated various established nematode indices. We estimated species-specific coverage of understory herbaceous and shrub plant species from the same experimental plots and tested if changes in the nematode community are associated with plant cover and composition. Individual nematode trophic groups did not differ among warming treatments, but the ratio between microbial-feeding and plant-feeding nematodes increased significantly and consistently with warming in both closed and open canopy areas and at both experimental field sites. The increase in this ratio was positively correlated with total cover of understory plant species, perhaps due to increased predation pressure on soil microorganisms causing higher nutrient availability for plants. Multivariate analyses revealed that temperature treatment, canopy conditions and nematode density consistently shaped understory plant communities across experimental sites. Our findings suggest that warming-induced changes in nematode community structure are associated with shifts in plant community composition and productivity in the temperate-boreal forest ecotones.

Changing expectations: a longitudinal study of community attitudes toward a nuclear power plant

International Nuclear Information System (INIS)

Hughey, J.B.; Lounsbury, J.W.; Sundstrom, E.; Mattingly, T.J. Jr.

1983-01-01

Initial and 5-year follow-up interviews were conducted with 213 residents of the host community for a nuclear power plant. The purpose was to determine possible changes in attitudes toward the plant and expectations about potential outcomes associated with construction. Large negative changes in attitudes toward the plant were noted and were accompanied most notably by decreased expectations of positive outcomes. The structure of the expectations remained essentially stable over the 5-year period. Perceptions of hazards, community disruption, and economic benefits as measured early in construction and during peak construction were found to be the best predictors of acceptance of the nuclear plant. Initial expectations were found to predict overall attitude toward the plant 5 years later. Results were discussed in terms of implications for social impact assessment, large-scale community change, and the predictability of community attitudes toward nuclear power plant construction

Grazing management, resilience and the dynamics of a fire driven rangeland system

NARCIS (Netherlands)

Anderies, J.M.; Janssen, M.A.; Walker, B.H.

2002-01-01

We developed a stylized mathematical model to explore the effects of physical, ecological, and economic factors on the resilience of a managed fire-driven rangeland system. Depending on grazing pressure, the model exhibits one of three distinct configurations: a fire-dominated, grazing-dominated, or

Vulnerability of cattle production to climate change on U.S. rangelands

Science.gov (United States)

Matt C. Reeves; Karen E. Bagne

2016-01-01

We examined multiple climate change effects on cattle production for U.S. rangelands to estimate relative change and identify sources of vulnerability among seven regions. Climate change effects to 2100 were projected from published models for four elements: forage quantity, vegetation type trajectory, heat stress, and forage variability. Departure of projections from...

Application of MODIS Land Products to Assessment of Land Degradation of Alpine Rangeland in Northern India with Limited Ground-Based Information

Directory of Open Access Journals (Sweden)

Masahiro Tasumi

2014-09-01

Full Text Available Land degradation of alpine rangeland in Dachigam National Park, Northern India, was evaluated in this study using MODerate resolution Imaging Spectroradiometer (MODIS land products. The park has been used by a variety of livestock holders. With increasing numbers of livestock, the managers and users of the park are apprehensive about degradation of the grazing land. However, owing to weak infrastructure for scientific and statistical data collection and sociopolitical restrictions in the region, a lack of quality ground-based weather, vegetation, and livestock statistical data had prevented scientific assessment. Under these circumstances, the present study aimed to assess the rangeland environment and its degradation using MODIS vegetation, snow, and evapotranspiration products as primary input data for assessment. The result of the analysis indicated that soil water content and the timing of snowmelt play an important role in grass production in the area. Additionally, the possibility of land degradation in heavily-grazed rangeland was indicated via a multiple regression analysis at a decadal timescale, whereas weather conditions, such as rainfall and snow cover, primarily explained year-by-year differences in grass production. Although statistical uncertainties remain in the results derived in this study, the satellite-based data and the analyses will promote understanding of the rangeland environment and suggest the potential for unsustainable land management based on statistical probability. This study provides an important initial evaluation of alpine rangeland, for which ground-based information is limited.

Does a decade of elevated [CO2] affect a desert perennial plant community?

Science.gov (United States)

Newingham, Beth A; Vanier, Cheryl H; Kelly, Lauren J; Charlet, Therese N; Smith, Stanley D

2014-01-01

Understanding the effects of elevated [CO2 ] on plant community structure is crucial to predicting ecosystem responses to global change. Early predictions suggested that productivity in deserts would increase via enhanced water-use efficiency under elevated [CO2], but the response of intact arid plant communities to elevated [CO2 ] is largely unknown. We measured changes in perennial plant community characteristics (cover, species richness and diversity) after 10 yr of elevated [CO2] exposure in an intact Mojave Desert community at the Nevada Desert Free-Air CO2 Enrichment (FACE) Facility. Contrary to expectations, total cover, species richness, and diversity were not affected by elevated [CO2]. Over the course of the experiment, elevated [CO2] had no effect on changes in cover of the evergreen C3 shrub, Larrea tridentata; alleviated decreases in cover of the C4 bunchgrass, Pleuraphis rigida; and slightly reduced the cover of C3 drought-deciduous shrubs. Thus, we generally found no effect of elevated [CO2] on plant communities in this arid ecosystem. Extended drought, slow plant growth rates, and highly episodic germination and recruitment of new individuals explain the lack of strong perennial plant community shifts after a decade of elevated [CO2]. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Soil Moisture Variability and its Effects on Herbage Production in Semi-arid Rangelands of Kenya

International Nuclear Information System (INIS)

Too, D.K.; Trlica, M.J.; Swift, D.M.; Musembi, D.K.

1999-01-01

Results obtained from recent studies focused on rangelands potential as influenced by human activity and climatic factors in the semi-arid and arid pastoral ecosystems of Northern Kenya indicated great temporal and spatial forage production variability. The objective of the studies was to document primary production in relation to water stress (drought), herbivory and direct human activities. Efforts also focused on finding possibilities of increasing productivity while conserving the finite resources for sustainable use. Laboratory, field and numerical methods were employed over several seasons and years. Forb and grass production was more variable than that of the browse (dwarf shrub) layer. Compared to forbs and dwarf shrubs, the grass layer contributed less to the total production in all seasons, indicating that the region had less potential for grazers compared to browsers. Spatial-temporal variation in rangeland carrying capacity reflected the great spatial heterogeneity in vegetation types and production. Similarly, seasonal differences were very evident, with highest estimates in the long rainy and the lowest during the dry and short rainy seasons, respectively. Factors limiting rangeland production potential were identified to be moisture deficiency, resource-use conflicts, an increasing and partially sedentarised nomadic population, overgrazing, tree felling, and land degradation (desert encroachment). Measures that can improve rangeland production potential and provide a better way of life for the inhabitants of the region include: (a) identification of land degradation (e.g. by means of bio-indicators and Geographical Information Systems, GIS); (b) technical interventions (i.e. soil and water conservation, restoration of degraded areas, fodder production); (c) social-economic interventions (i.e. resolution of resource-use conflicts, alleviation of poverty, infrastructure development improvement of livestock marketing channels etc.) and (d) continued

Vertebrate herbivores influence soil nematodes by modifying plant communities

NARCIS (Netherlands)

Veen, G. F. (Ciska); Olff, Han; Duyts, Henk; van der Putten, Wim H.

Abiotic soil properties, plant community composition, and herbivory all have been reported as important factors influencing the composition of soil communities. However, most studies thus far have considered these factors in isolation, whereas they strongly interact in the field. Here, we study how

Forage seeding in rangelands increases production and prevents weed invasion

Directory of Open Access Journals (Sweden)

Josh Davy

2017-07-01

Full Text Available Increasing forage productivity in the Sierra foothill rangelands would help sustain the livestock industry as land availability shrinks and lease rates rise, but hardly any studies have been done on forage selections. From 2009 to 2014, in one of the first long-term and replicated studies of seeding Northern California's Mediterranean annual rangeland, we compared the cover of 22 diverse forages to determine their establishment and survivability over time. Among the annual herbs, forage brassica (Brassica napus L. and chicory (Cichorium intybus L. proved viable options. Among the annual grasses, soft brome (Bromus hordeaceus and annual ryegrass (Lolium multiflorum performed well. However, these species will likely require frequent reseeding to maintain dominance. Long-term goals of sustained dominant cover (> 3 years are best achieved with perennial grasses. Perennial grasses that persisted with greater than 50% cover were Berber orchardgrass (Dactylis glomerata, Flecha tall fescue (Lolium arundinaceum and several varieties of hardinggrass (Phalaris aquatica L., Perla koleagrass, Holdfast, Advanced AT. In 2014, these successful perennials produced over three times more dry matter (pounds per acre than the unseeded control and also suppressed annual grasses and yellow starthistle (Centaurea solstitialis L. cover.

Exploring the plant-associated bacterial communities in Medicago sativa L

Directory of Open Access Journals (Sweden)

Pini Francesco

2012-05-01

Full Text Available Abstract Background Plant-associated bacterial communities caught the attention of several investigators which study the relationships between plants and soil and the potential application of selected bacterial species in crop improvement and protection. Medicago sativa L. is a legume crop of high economic importance as forage in temperate areas and one of the most popular model plants for investigations on the symbiosis with nitrogen fixing rhizobia (mainly belonging to the alphaproteobacterial species Sinorhizobium meliloti. However, despite its importance, no studies have been carried out looking at the total bacterial community associated with the plant. In this work we explored for the first time the total bacterial community associated with M. sativa plants grown in mesocosms conditions, looking at a wide taxonomic spectrum, from the class to the single species (S. meliloti level. Results Results, obtained by using Terminal-Restriction Fragment Length Polymorphism (T-RFLP analysis, quantitative PCR and sequencing of 16 S rRNA gene libraries, showed a high taxonomic diversity as well as a dominance by members of the class Alphaproteobacteria in plant tissues. Within Alphaproteobacteria the families Sphingomonadaceae and Methylobacteriaceae were abundant inside plant tissues, while soil Alphaproteobacteria were represented by the families of Hyphomicrobiaceae, Methylocystaceae, Bradyirhizobiaceae and Caulobacteraceae. At the single species level, we were able to detect the presence of S. meliloti populations in aerial tissues, nodules and soil. An analysis of population diversity on nodules and soil showed a relatively low sharing of haplotypes (30-40% between the two environments and between replicate mesocosms, suggesting drift as main force shaping S. meliloti population at least in this system. Conclusions In this work we shed some light on the bacterial communities associated with M. sativa plants, showing that Alphaproteobacteria may

Stakeholder Theory and Rangeland Management: The Importance of Ranch Income Dependence

Science.gov (United States)

Elias, S.; Roche, L. M.; Elias, E.

2016-12-01

The California drought beginning in 2012 has been driven by reduced precipitation and record high temperatures. Hydrologic drought in the Southwest United States is projected to become the new climatology of the region. While ranchers are considered naturally adaptive, often adeptly altering management based upon conditions, the projected increased aridity may challenge rangeland management. Certain rancher characteristics are likely to impact how well ranchers adapt. Based on Stakeholder Theory (ST), we hypothesize that the extent to which ranchers are dependent on their ranches as a source of income would serve as a predictor of several key variables related to ranching adaptation and success. Data were obtained from 507 ranchers throughout the State of California via the Rangeland Decision-Making Survey implemented by University of California, Davis in 2010, just prior to the unprecedented California drought. Consistent with the ST urgency facet, results of linear regression analyses indicate the more dependent ranchers are on their ranches for their income, the more aware they are of USDA ranching initiatives (β = 0.19, p < .001) and state ranching initiatives (β = 0.10, p < .05). In addition, more dependent ranchers are more likely to use multiple and diverse sources of information about ranching (β = 0.18, p < .001), are more likely to realize the severity and extent of the most recent drought's impacts (β = 0.18, p < .001), and were more likely to have a drought management plan in place during the most recent drought (β = 0.18, p < .001). These findings are important in relation to both outreach/extension efforts and rangeland research. Outreach/extension efforts should take into account that people less dependent on their ranches are less aware of resources, as well as, less prepared to adapt to drought. Researchers should control for the extent to which ranchers are dependent on their ranches for income in order to ensure more accurate findings.

Broad-Scale Comparison of Photosynthesis in Terrestrial and Aquatic Plant Communities

DEFF Research Database (Denmark)

Sand-Jensen, Kaj; Krause-Jensen, D.

1997-01-01

Comparisons of photosynthesis in terrestrial and aquatic habitats have been impaired by differences in methods and time-scales of measurements. We compiled information on gross photosynthesis at high irradiance and photosynthetic efficiency at low irradiance from 109 published terrestrial studies...... communities probably due to more efficient light utilization and gas exchange in the terrestrial habitats. By contrast only small differences were found within different aquatic plant communities or within different terrestrial plant communities....... of forests, grasslands and crops and 319 aquatic studies of phytoplankton, macrophyte and attached microalgal communities to test if specific differences existed between the communities. Maximum gross photosynthesis and photosynthetic efficiency were systematically higher in terrestrial than in aquatic...

Dairy cattle on Norwegian alpine rangelands – grazing preferences and milk quality

NARCIS (Netherlands)

Sickel, H; Abrahamsen, R K; Eldegard, K; Lunnan, T; Norderhaug, A; Petersen, M.A.; Sickel, M.; Steenhuisen, F.; Ohlson, M.

2014-01-01

The results from the study ‘Effects of vegetation and grazing preferences on the quality of alpine dairy products’ will be presented. The main objective of the project was to investigate the connections bet - ween alpine rangeland vegetation, landscape use and grazing preferences of free ranging

Modeling vegetation heights from high resolution stereo aerial photography: an application for broad-scale rangeland monitoring.

Science.gov (United States)

Gillan, Jeffrey K; Karl, Jason W; Duniway, Michael; Elaksher, Ahmed

2014-11-01

Vertical vegetation structure in rangeland ecosystems can be a valuable indicator for assessing rangeland health and monitoring riparian areas, post-fire recovery, available forage for livestock, and wildlife habitat. Federal land management agencies are directed to monitor and manage rangelands at landscapes scales, but traditional field methods for measuring vegetation heights are often too costly and time consuming to apply at these broad scales. Most emerging remote sensing techniques capable of measuring surface and vegetation height (e.g., LiDAR or synthetic aperture radar) are often too expensive, and require specialized sensors. An alternative remote sensing approach that is potentially more practical for managers is to measure vegetation heights from digital stereo aerial photographs. As aerial photography is already commonly used for rangeland monitoring, acquiring it in stereo enables three-dimensional modeling and estimation of vegetation height. The purpose of this study was to test the feasibility and accuracy of estimating shrub heights from high-resolution (HR, 3-cm ground sampling distance) digital stereo-pair aerial images. Overlapping HR imagery was taken in March 2009 near Lake Mead, Nevada and 5-cm resolution digital surface models (DSMs) were created by photogrammetric methods (aerial triangulation, digital image matching) for twenty-six test plots. We compared the heights of individual shrubs and plot averages derived from the DSMs to field measurements. We found strong positive correlations between field and image measurements for several metrics. Individual shrub heights tended to be underestimated in the imagery, however, accuracy was higher for dense, compact shrubs compared with shrubs with thin branches. Plot averages of shrub height from DSMs were also strongly correlated to field measurements but consistently underestimated. Grasses and forbs were generally too small to be detected with the resolution of the DSMs. Estimates of

PLANT COMMUNITIES OF ALBANIA - A PRELIMINARY OVERVIEW

Directory of Open Access Journals (Sweden)

J. DRING

2002-04-01

Full Text Available The phytosociological analysis of Albania was initiated by F. Markgraf in the 30ies, but still remains incomplete. This is a preliminary list of the plant communities resulting from the literature and from field research carried out during the last years and may represent a first contribution for further research. Many communities are described only by dominant species, other are quoted as nomina nuda. Some further syntaxa. probably present in the study area, are added.

Mapping of aggregated floodplain plant communities using image fusion of CASI and LiDAR data

NARCIS (Netherlands)

Verrelst, J.; Geerling, G.W.; Sykora, K.V.; Clevers, J.G.P.W.

2009-01-01

Combined optical and laser altimeter data offer the potential to map and monitor plant communities based on their spectral and structural characteristics. A problem unresolved is, however, that narrowly defined plant communities, i.e. plant communities at a low hierarchical level of classification

The factors controlling species density in herbaceous plant communities: An assessment

Science.gov (United States)

Grace, J.B.

1999-01-01

This paper evaluates both the ideas and empirical evidence pertaining to the control of species density in herbaceous plant communities. While most theoretical discussions of species density have emphasized the importance of habitat productivity and disturbance regimes, many other factors (e.g. species pools, plant litter accumulation, plant morphology) have been proposed to be important. A review of literature presenting observations on the density of species in small plots (in the vicinity of a few square meters or less), as well as experimental studies, suggests several generalizations: (1) Available data are consistent with an underlying unimodal relationship between species density and total community biomass. While variance in species density is often poorly explained by predictor variables, there is strong evidence that high levels of community biomass are antagonistic to high species density. (2) Community biomass is just one of several factors affecting variations in species density. Multivariate analyses typically explain more than twice as much variance in species density as can be explained by community biomass alone. (3) Disturbance has important and sometimes complex effects on species density. In general, the evidence is consistent with the intermediate disturbance hypothesis but exceptions exist and effects can be complex. (4) Gradients in the species pool can have important influences on patterns of species density. Evidence is mounting that a considerable amount of the observed variability in species density within a landscape or region may result from environmental effects on the species pool. (5) Several additional factors deserve greater consideration, including time lags, species composition, plant morphology, plant density and soil microbial effects. Based on the available evidence, a conceptual model of the primary factors controlling species density is presented here. This model suggests that species density is controlled by the effects of

Nectar-living yeasts of a tropical host plant community: diversity and effects on community-wide floral nectar traits

Science.gov (United States)

2017-01-01

We characterize the diversity of nectar-living yeasts of a tropical host plant community at different hierarchical sampling levels, measure the associations between yeasts and nectariferous plants, and measure the effect of yeasts on nectar traits. Using a series of hierarchically nested sampling units, we extracted nectar from an assemblage of host plants that were representative of the diversity of life forms, flower shapes, and pollinator types in the tropical area of Yucatan, Mexico. Yeasts were isolated from single nectar samples; their DNA was identified, the yeast cell density was estimated, and the sugar composition and concentration of nectar were quantified using HPLC. In contrast to previous studies from temperate regions, the diversity of nectar-living yeasts in the plant community was characterized by a relatively high number of equally common species with low dominance. Analyses predict highly diverse nectar yeast communities in a relatively narrow range of tropical vegetation, suggesting that the diversity of yeasts will increase as the number of sampling units increases at the level of the species, genera, and botanical families of the hosts. Significant associations between specific yeast species and host plants were also detected; the interaction between yeasts and host plants impacted the effect of yeast cell density on nectar sugars. This study provides an overall picture of the diversity of nectar-living yeasts in tropical host plants and suggests that the key factor that affects the community-wide patterns of nectar traits is not nectar chemistry, but rather the type of yeasts interacting with host plants. PMID:28717591

Nectar-living yeasts of a tropical host plant community: diversity and effects on community-wide floral nectar traits

Directory of Open Access Journals (Sweden)

Azucena Canto

2017-07-01

Full Text Available We characterize the diversity of nectar-living yeasts of a tropical host plant community at different hierarchical sampling levels, measure the associations between yeasts and nectariferous plants, and measure the effect of yeasts on nectar traits. Using a series of hierarchically nested sampling units, we extracted nectar from an assemblage of host plants that were representative of the diversity of life forms, flower shapes, and pollinator types in the tropical area of Yucatan, Mexico. Yeasts were isolated from single nectar samples; their DNA was identified, the yeast cell density was estimated, and the sugar composition and concentration of nectar were quantified using HPLC. In contrast to previous studies from temperate regions, the diversity of nectar-living yeasts in the plant community was characterized by a relatively high number of equally common species with low dominance. Analyses predict highly diverse nectar yeast communities in a relatively narrow range of tropical vegetation, suggesting that the diversity of yeasts will increase as the number of sampling units increases at the level of the species, genera, and botanical families of the hosts. Significant associations between specific yeast species and host plants were also detected; the interaction between yeasts and host plants impacted the effect of yeast cell density on nectar sugars. This study provides an overall picture of the diversity of nectar-living yeasts in tropical host plants and suggests that the key factor that affects the community-wide patterns of nectar traits is not nectar chemistry, but rather the type of yeasts interacting with host plants.

Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

NARCIS (Netherlands)

Timmers, R.A.; Rothballer, M.; Strik, D.P.B.T.B.; Engel, M.; Schulz, M.; Hartmann, A.; Hamelers, H.V.M.; Buisman, C.J.N.

2012-01-01

The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into

The economic impact of global climate change on Mediterranean rangeland ecosystems. A Space-for-Time approach

International Nuclear Information System (INIS)

Fleischer, Aliza; Sternberg, Marcelo

2006-01-01

Global Climate Change (GCC) can bring about changes in ecosystems and consequently in their services value. Here we show that the urban population in Israel values the green landscape of rangelands in the mesic Mediterranean climate region and is willing to pay for preserving it in light of the expected increasing aridity conditions in this region. Their valuation of the landscape is higher than that of the grazing services these rangelands provide for livestock growers. These results stem from a Time-for-Space approach with which we were able to measure changes in biomass production and rainfall at four experimental sites along an aridity gradient. (author)

Plant pathogens structure arthropod communities across multiple spatial and temporal scales

NARCIS (Netherlands)

Tack, A.J.M.; Dicke, M.

2013-01-01

Plant pathogens and herbivores frequently co-occur on the same host plants. Despite this, little is known about the impact of their interactions on the structure of plant-based ecological communities. Here, we synthesize evidence that indicates that plant pathogens may profoundly impact arthropod

Analytical approaches to quality assurance and quality control in rangeland monitoring data

Science.gov (United States)

Producing quality data to support land management decisions is the goal of every rangeland monitoring program. However, the results of quality assurance (QA) and quality control (QC) efforts to improve data quality are rarely reported. The purpose of QA and QC is to prevent and describe non-sampling...

Plant reproduction is altered by simulated herbicide drift to constructed plant communities

Science.gov (United States)

Herbicide drift may have unintended impacts on native vegetation, adversely affecting structure and function of plant communities. However, these potential effects have been rarely studied or quantified. To determine potential ecological effects of herbicide drift, we construct...

Rapid plant evolution in the presence of an introduced species alters community composition.

Science.gov (United States)

Smith, David Solance; Lau, Matthew K; Jacobs, Ryan; Monroy, Jenna A; Shuster, Stephen M; Whitham, Thomas G

2015-10-01

Because introduced species may strongly interact with native species and thus affect their fitness, it is important to examine how these interactions can cascade to have ecological and evolutionary consequences for whole communities. Here, we examine the interactions among introduced Rocky Mountain elk, Cervus canadensis nelsoni, a common native plant, Solidago velutina, and the diverse plant-associated community of arthropods. While introduced species are recognized as one of the biggest threats to native ecosystems, relatively few studies have investigated an evolutionary mechanism by which introduced species alter native communities. Here, we use a common garden design that addresses and supports two hypotheses. First, native S. velutina has rapidly evolved in the presence of introduced elk. We found that plants originating from sites with introduced elk flowered nearly 3 weeks before plants originating from sites without elk. Second, evolution of S. velutina results in a change to the plant-associated arthropod community. We found that plants originating from sites with introduced elk supported an arthropod community that had ~35 % fewer total individuals and a different species composition. Our results show that the impacts of introduced species can have both ecological and evolutionary consequences for strongly interacting species that subsequently cascade to affect a much larger community. Such evolutionary consequences are likely to be long-term and difficult to remediate.

Rangeland Brush Estimation Toolbox (RaBET): An Approach for Evaluating Brush Management Conservation Efforts in Western Grazing Lands

Science.gov (United States)

Holifield Collins, C.; Kautz, M. A.; Skirvin, S. M.; Metz, L. J.

2016-12-01

There are over 180 million hectares of rangelands and grazed forests in the central and western United States. Due to the loss of perennial grasses and subsequent increased runoff and erosion that can degrade the system, woody cover species cannot be allowed to proliferate unchecked. The USDA-Natural Resources Conservation Service (NRCS) has allocated extensive resources to employ brush management (removal) as a conservation practice to control woody species encroachment. The Rangeland-Conservation Effects Assessment Project (CEAP) has been tasked with determining how effective the practice has been, however their land managers lack a cost-effective means to conduct these assessments at the necessary scale. An ArcGIS toolbox for generating large-scale, Landsat-based, spatial maps of woody cover on grazing lands in the western United States was developed through a collaboration with NRCS Rangeland-CEAP. The toolbox contains two main components of operation, image generation and temporal analysis, and utilizes simple interfaces requiring minimum user inputs. The image generation tool utilizes geographically specific algorithms developed from combining moderate-resolution (30-m) Landsat imagery and high-resolution (1-m) National Agricultural Imagery Program (NAIP) aerial photography to produce the woody cover scenes at the Major Land Resource (MLRA) scale. The temporal analysis tool can be used on these scenes to assess treatment effectiveness and monitor woody cover reemergence. RaBET provides rangeland managers an operational, inexpensive decision support tool to aid in the application of brush removal treatments and assessing their effectiveness.

Phenology of exotic invasive weeds associated with downy brome

Science.gov (United States)

The exotic and highly invasive annual grass downy brome (Bromus tectorum) has invaded millions of hectares of rangelands throughout the Intermountain West. Downy brome increases the chance, rate, season and spread of wildfires, resulting in the destruction of native plant communities and the wildli...

Resistance to toxic plants: The right animal in the right pasture at the right time

Science.gov (United States)

Neurotoxic poisonous plants negatively impact livestock on many western rangelands, which results in annual economic losses of millions of dollars from animal deaths, increased management and treatment costs, and if animals are deferred from grazing, the underutilization of otherwise highly nutritio...

Challenges of establishing big sgebrush (Artemisia tridentata) in rangeland restoration: effects of herbicide, mowing, whole-community seeding, and sagebrush seed sources

Science.gov (United States)

Brabec, Martha M.; Germino, Matthew J.; Shinneman, Douglas J.; Pilliod, David S.; McIlroy, Susan K.; Arkle, Robert S.

2015-01-01

The loss of big sagebrush (Artemisia tridentata Nutt.) on sites disturbed by fire has motivated restoration seeding and planting efforts. However, the resulting sagebrush establishment is often lower than desired, especially in dry areas. Sagebrush establishment may be increased by addressing factors such as seed source and condition or management of the plant community. We assessed initial establishment of seeded sagebrush and four populations of small outplants (from different geographies, climates, and cytotypes) and small sagebrush outplants in an early seral community where mowing, herbicide, and seeding of other native plants had been experimentally applied. No emergence of seeded sagebrush was detected. Mowing the site before planting seedlings led to greater initial survival probabilities for sagebrush outplants, except where seeding also occurred, and these effects were related to corresponding changes in bare soil exposure. Initial survival probabilities were > 30% greater for the local population of big sagebrush relative to populations imported to the site from typical seed transfer distances of ~320–800 km. Overcoming the high first-year mortality of outplanted or seeded sagebrush is one of the most challenging aspects of postfire restoration and rehabilitation, and further evaluation of the impacts of herb treatments and sagebrush seed sources across different site types and years is needed.

Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

OpenAIRE

Timmers, R.A.; Rothballer, M.; Strik, D.P.B.T.B.; Engel, M.; Schulz, M.; Hartmann, A.; Hamelers, H.V.M.; Buisman, C.J.N.

2012-01-01

The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode-rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) w...

Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

OpenAIRE

Timmers, Ruud A.; Rothballer, Michael; Strik, David P. B. T. B.; Engel, Marion; Schulz, Stephan; Schloter, Michael; Hartmann, Anton; Hamelers, Bert; Buisman, Cees

2012-01-01

The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode–rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) w...

Evaluación del modelo WEPP para predecir la erosión hídrica en pastizales semiáridos del noreste de la Patagonia Evaluation of the WEPP model to predict soil erosion in northeastern Patagonian rangelands

Directory of Open Access Journals (Sweden)

Marcelo P Chartier

2010-07-01

work we examine the efficiency of the WEPP model in predicting the hydrological processes and soil erosion in semiarid rangelands of the northeast Chubut Province. Three plant communities along a soil degradation gradient were identified: grass with scattered shrubs (EH, grass-shrubs (EHA, and degraded shrub steppes (EA. In each of these communities simulated rainfall (100 mm h-1 for 30 min was applied on 1 m² (0.6 x 1.67 m plots and total runoff and sediment production were collected. Using the soil surface condition data from each plot, runoff and sediment production were estimated by means of the WEPP model. We found a low efficiency of the WEPP model to predict runoff (Efficiency, E = 0.14 and soil erosion (E = -0.93. The WEPP-estimated runoff and soil losses showed high sensitivity to changes in rainfall and slope parameters and moderate sensitivity to changes in soil cover, texture, soil erodability and effective hydraulic conductivity. The runoff and sediment production estimated by the WEPP model were significantly different among plant communities (p < 0.05. The difference between the estimated and observed mean values varied in the different plant communities: runoff according to the WEPP model was 55.5% greater in the EH and sediment production was 69.6, 62.7 and 17.5% lower, respectively, in the EH, EHA, and EA than the observed values. These results suggest that it is necessary to calibrate the model for local conditions and to incorporate rangeland stratification according to the different soil-vegetation units.

Study on Rangeland production Potential and its Limitations in the Semi-Arid lands of Northern Kenya

International Nuclear Information System (INIS)

Keya, G.A.; Hornetz, B.

1999-01-01

Results obtained from recent studies focused on rangeland potential as influenced by human activity and climatic factors in the semi-arid and pastoral ecosystems of Northern Kenya indicated great temporal and spatial forage production variability. The objective of the studies was to document the primary production potential in relation to water stress (drought), herbivory and direct human activities. Efforts also focused on finding possibilities of increasing productivity while conserving the finite resources for sustainable use. Laboratory field and numeric methods were employed over several seasons and years. Forb and grass production was more viable than that of the brows (dwarf shrub) layer. Compared to forbs and dwarf shrubs, The grass layer contributed less to the total of production in all seasons, indicating that the region had less potential for grazers compared to browsers. Spatial-temporal variations in rangeland carrying capacity reflected the great spatial heterogeneity in vegetation types and production. Similarly, seasonal difference were very evident, with highest estimates in the long rainy and lowest during the dry and short rainy seasons, respectively. Factors limiting rangeland production potential and were identified to be moisture deficiency, resource-use conflicts, an increasing and partial sedentarised nomadic population, overgrazing, tree felling, and land degradation (desert encroachment). Measures that can increase rangelands production potential and provide a better way of life for the inhabitants of the region include: (a) identification of land degradation (e.g. by means of bio-indicators and Geographical Information systems, GIS); (b) technical interventions (i.e. soil and water conservation,restoration of degraded ares, fodder production); (c)socio-economic interventions (i.e. resolution of resource-use conflicts, alleviation of poverty, infrastructure development, improvement of livestock marketing channels, etc) and (d) continued

Divergent composition but similar function of soil food webs of individual plants: plant species and community effects

NARCIS (Netherlands)

Bezemer, T.M.; Fountain, T.; Barea, J.M.; Christensen, S.; Dekker, S.C.; Duyts, H.; Hal, van R.; Harvey, J.A.; Hedlund, K.; Maraun, M.; Mikola, J.; Mladenov, A.G.; Robin, C.; Ruiter, de P.C.; Scheu, H.; Setälä, S.; šmilauer, P.; Putten, van der W.H.

2010-01-01

Soils are extremely rich in biodiversity, and soil organisms play pivotal roles in supporting terrestrial life, but the role that individual plants and plant communities play in influencing the diversity and functioning of soil food webs remains highly debated. Plants, as primary producers and

Divergent composition but similar function of soil food webs beneath individual plants: plant species and community effects

NARCIS (Netherlands)

Bezemer, T.M.; Fountain, M.T.; Barea, J.M.; Christensen, S.; Dekker, S.C.; Duyts, H.; van Hal, R.; Harvey, J.A.; Hedlund, K.; Maraun, M.; Mikola, J.; Mladenov, A.G.; Robin, C.; de Ruiter, P.C.; Scheu, S.; Setälä, H.; Milauer, P.; Van der Putten, W.H.

2010-01-01

Soils are extremely rich in biodiversity, and soil organisms play pivotal roles in supporting terrestrial life, but the role that individual plants and plant communities play in influencing the diversity and functioning of soil food webs remains highly debated. Plants, as primary producers and

Revolutionary land use change in the 21st century: Is (rangeland) science relevant?

Science.gov (United States)

Rapidly increasing demand for food, fiber and fuel together with new technologies and the mobility of global capital are driving revolutionary changes in land use throughout the world. Efforts to increase land productivity include conversion of millions of hectares of rangelands to crop production, ...

Burn Severity Dominates Understory Plant Community Response to Fire in Xeric Jack Pine Forests

Directory of Open Access Journals (Sweden)

Bradley D. Pinno

2016-04-01

Full Text Available Fire is the most common disturbance in northern boreal forests, and large fires are often associated with highly variable burn severities across the burnt area. We studied the understory plant community response to a range of burn severities and pre-fire stand age four growing seasons after the 2011 Richardson Fire in xeric jack pine forests of northern Alberta, Canada. Burn severity had the greatest impact on post-fire plant communities, while pre-fire stand age did not have a significant impact. Total plant species richness and cover decreased with disturbance severity, such that the greatest richness was in low severity burns (average 28 species per 1-m2 quadrat and plant cover was lowest in the high severity burns (average 16%. However, the response of individual plant groups differed. Lichens and bryophytes were most common in low severity burns and were effectively eliminated from the regenerating plant community at higher burn severities. In contrast, graminoid cover and richness were positively related to burn severity, while forbs did not respond significantly to burn severity, but were impacted by changes in soil chemistry with increased cover at pH >4.9. Our results indicate the importance of non-vascular plants to the overall plant community in this harsh environment and that the plant community is environmentally limited rather than recruitment or competition limited, as is often the case in more mesic forest types. If fire frequency and severity increase as predicted, we may see a shift in plant communities from stress-tolerant species, such as lichens and ericaceous shrubs, to more colonizing species, such as certain graminoids.

Wild plant species growing closely connected in a subalpine meadow host distinct root-associated bacterial communities

Directory of Open Access Journals (Sweden)

Kristin Aleklett

2015-02-01

Full Text Available Plant roots are known to harbor large and diverse communities of bacteria. It has been suggested that plant identity can structure these root-associated communities, but few studies have specifically assessed how the composition of root microbiota varies within and between plant species growing under natural conditions. We assessed the community composition of endophytic and epiphytic bacteria through high throughput sequencing using 16S rDNA derived from root tissues collected from a population of a wild, clonal plant (Orange hawkweed–Pilosella aurantiaca as well as two neighboring plant species (Oxeye daisy–Leucanthemum vulgare and Alsike clover–Trifolium hybridum. Our first goal was to determine if plant species growing in close proximity, under similar environmental conditions, still hosted unique root microbiota. Our results showed that plants of different species host distinct bacterial communities in their roots. In terms of community composition, Betaproteobacteria (especially the family Oxalobacteraceae were found to dominate in the root microbiota of L. vulgare and T. hybridum samples, whereas the root microbiota of P. aurantiaca had a more heterogeneous distribution of bacterial abundances where Gammaproteobacteria and Acidobacteria occupied a larger portion of the community. We also explored the extent of individual variance within each plant species investigated, and found that in the plant species thought to have the least genetic variance among individuals (P. aurantiaca still hosted just as diverse microbial communities. Whether all plant species host their own distinct root microbiota and plants more closely related to each other share more similar bacterial communities still remains to be fully explored, but among the plants examined in this experiment there was no trend that the two species belonging to the same family shared more similarities in terms of bacterial community composition.

Bridging Drought – Resilience in Rangeland Management in Times of Climate Change

OpenAIRE

Isele, Judith

2014-01-01

Organic livestock farming in semiarid regions greatly depends on the sustainable management of the natural rangeland as the resource for livestock sustenance. High stock density in combination with short grazing and long recovery periods achieve effective rainfall utilisation and considerably higher fodder production resulting in a high degree of resilience in drought situations.

Seed bank and big sagebrush plant community composition in a range margin for big sagebrush

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Martyn, Trace E.; Bradford, John B.; Schlaepfer, Daniel R.; Burke, Ingrid C.; Laurenroth, William K.

2016-01-01

The potential influence of seed bank composition on range shifts of species due to climate change is unclear. Seed banks can provide a means of both species persistence in an area and local range expansion in the case of increasing habitat suitability, as may occur under future climate change. However, a mismatch between the seed bank and the established plant community may represent an obstacle to persistence and expansion. In big sagebrush (Artemisia tridentata) plant communities in Montana, USA, we compared the seed bank to the established plant community. There was less than a 20% similarity in the relative abundance of species between the established plant community and the seed bank. This difference was primarily driven by an overrepresentation of native annual forbs and an underrepresentation of big sagebrush in the seed bank compared to the established plant community. Even though we expect an increase in habitat suitability for big sagebrush under future climate conditions at our sites, the current mismatch between the plant community and the seed bank could impede big sagebrush range expansion into increasingly suitable habitat in the future.

Human-modified landscapes: patterns of fine-scale woody vegetation structure in communal savannah rangelands

CSIR Research Space (South Africa)

Fisher, T

2011-11-01

Full Text Available structure in five communal rangelands around 12 settlements in Bushbuckridge, a municipality in the Kruger to Canyons Biosphere Reserve (South Africa). The importance of underlying abiotic factors was evaluated by measuring size class distributions across...

Ecological assembly rules in plant communities--approaches, patterns and prospects.

Science.gov (United States)

Götzenberger, Lars; de Bello, Francesco; Bråthen, Kari Anne; Davison, John; Dubuis, Anne; Guisan, Antoine; Lepš, Jan; Lindborg, Regina; Moora, Mari; Pärtel, Meelis; Pellissier, Loic; Pottier, Julien; Vittoz, Pascal; Zobel, Kristjan; Zobel, Martin

2012-02-01

Understanding how communities of living organisms assemble has been a central question in ecology since the early days of the discipline. Disentangling the different processes involved in community assembly is not only interesting in itself but also crucial for an understanding of how communities will behave under future environmental scenarios. The traditional concept of assembly rules reflects the notion that species do not co-occur randomly but are restricted in their co-occurrence by interspecific competition. This concept can be redefined in a more general framework where the co-occurrence of species is a product of chance, historical patterns of speciation and migration, dispersal, abiotic environmental factors, and biotic interactions, with none of these processes being mutually exclusive. Here we present a survey and meta-analyses of 59 papers that compare observed patterns in plant communities with null models simulating random patterns of species assembly. According to the type of data under study and the different methods that are applied to detect community assembly, we distinguish four main types of approach in the published literature: species co-occurrence, niche limitation, guild proportionality and limiting similarity. Results from our meta-analyses suggest that non-random co-occurrence of plant species is not a widespread phenomenon. However, whether this finding reflects the individualistic nature of plant communities or is caused by methodological shortcomings associated with the studies considered cannot be discerned from the available metadata. We advocate that more thorough surveys be conducted using a set of standardized methods to test for the existence of assembly rules in data sets spanning larger biological and geographical scales than have been considered until now. We underpin this general advice with guidelines that should be considered in future assembly rules research. This will enable us to draw more accurate and general

Interspecific Plant Interactions Reflected in Soil Bacterial Community Structure and Nitrogen Cycling in Primary Succession.

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Knelman, Joseph E; Graham, Emily B; Prevéy, Janet S; Robeson, Michael S; Kelly, Patrick; Hood, Eran; Schmidt, Steve K

2018-01-01

Past research demonstrating the importance plant-microbe interactions as drivers of ecosystem succession has focused on how plants condition soil microbial communities, impacting subsequent plant performance and plant community assembly. These studies, however, largely treat microbial communities as a black box. In this study, we sought to examine how emblematic shifts from early successional Alnus viridus ssp. sinuata (Sitka alder) to late successional Picea sitchensis (Sitka spruce) in primary succession may be reflected in specific belowground changes in bacterial community structure and nitrogen cycling related to the interaction of these two plants. We examined early successional alder-conditioned soils in a glacial forefield to delineate how alders alter the soil microbial community with increasing dominance. Further, we assessed the impact of late-successional spruce plants on these early successional alder-conditioned microbiomes and related nitrogen cycling through a leachate addition microcosm experiment. We show how increasingly abundant alder select for particular bacterial taxa. Additionally, we found that spruce leachate significantly alters the composition of these microbial communities in large part by driving declines in taxa that are enriched by alder, including bacterial symbionts. We found these effects to be spruce specific, beyond a general leachate effect. Our work also demonstrates a unique influence of spruce on ammonium availability. Such insights bolster theory relating the importance of plant-microbe interactions with late-successional plants and interspecific plant interactions more generally.

The interconnectedness between landowner knowledge, value, belief, attitude, and willingness to act: policy implications for carbon sequestration on private rangelands.

Science.gov (United States)

Cook, Seth L; Ma, Zhao

2014-02-15

Rangelands can be managed to increase soil carbon and help mitigate emissions of carbon dioxide. This study assessed Utah rangeland owner's environmental values, beliefs about climate change, and awareness of and attitudes towards carbon sequestration, as well as their perceptions of potential policy strategies for promoting carbon sequestration on private rangelands. Data were collected from semi-structured interviews and a statewide survey of Utah rangeland owners, and were analyzed using descriptive and bivariate statistics. Over two-thirds of respondents reported some level of awareness of carbon sequestration and a generally positive attitude towards it, contrasting to their lack of interest in participating in a relevant program in the future. Having a positive attitude was statistically significantly associated with having more "biocentric" environmental values, believing the climate had been changing over the past 30 years, and having a stronger belief of human activities influencing the climate. Respondents valued the potential ecological benefits of carbon sequestration more than the potential financial or climate change benefits. Additionally, respondents indicated a preference for educational approaches over financial incentives. They also preferred to work with a private agricultural entity over a non-profit or government entity on improving land management practices to sequester carbon. These results suggest potential challenges for developing technically sound and socially acceptable policies and programs for promoting carbon sequestration on private rangelands. Potential strategies for overcoming these challenges include emphasizing the ecological benefits associated with sequestering carbon to appeal to landowners with ecologically oriented management objectives, enhancing the cooperation between private agricultural organizations and government agencies, and funneling resources for promoting carbon sequestration into existing land management and

Investigation on the geographical distribution and life form of plant species in sub alpine zone Karsanak region, Shahrekord

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Jahanbakhsh Pairanj

2011-09-01

Full Text Available This study was carried out in rangelands of Karsanak, Chaharmahal and Bakhtiari province, which is regarded as one of the rich rangelands. Phytogeographically, this region is located in Irano-Turanian (zone of sub alpine. Endemic and rare plants were identified and geographical distribution and life form of identified plant species were investigated as well. Overall, 100 species from 17 families were identified from which 20 percent of identified species was endemic element of Irano-Turanian region. Results indicated that 75.7 percent of identified plants belonged to the Irano-Turanian and only 3 and 2 percent belonged to Euro-Siberian and Mediterranean regions respectively. The reason of high percentage of Irano-Turanian elements is probably the long distance of this region from other regions. Similarities of Irano-Turanian and Mediterranean were included 6.1 percent of identified plants and Irano-Turanian and Euro-Siberian included 2 percent. Results of life forms showed hemichryptophytes including 60 percent of life forms which indicate the cold and mountainous weather.

Plant community responses to simultaneous changes in temperature, nitrogen availability, and invasion.

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Elise S Gornish

Full Text Available Increasing rates of change in climate have been observed across the planet and have contributed to the ongoing range shifts observed for many species. Although ecologists are now using a variety of approaches to study how much and through what mechanisms increasing temperature and nutrient pollution may influence the invasions inherent in range shifts, accurate predictions are still lacking.In this study, we conducted a factorial experiment, simultaneously manipulating warming, nitrogen addition and introduction of Pityopsis aspera, to determine how range-shifting species affect a plant community. We quantified the resident community using ordination scores, then used structural equation modeling to examine hypotheses related to how plants respond to a network of experimental treatments and environmental variables. Variation in soil pH explained plant community response to nitrogen addition in the absence of invasion. However, in the presence of invasion, the direct effect of nitrogen on the community was negligible and soil moisture was important for explaining nitrogen effects. We did not find effects of warming on the native plant community in the absence of invasion. In the presence of invasion, however, warming had negative effects on functional richness directly and invasion and herbivory explained the overall positive effect of warming on the plant community.This work highlights the variation in the biotic and abiotic factors responsible for explaining independent and collective climate change effects over a short time scale. Future work should consider the complex and non-additive relationships among factors of climate change and invasion in order to capture more ecologically relevant features of our changing environment.

Agave salmiana Plant Communities in Central Mexico as Affected by Commercial Use

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Martínez Salvador, Martin; Mata-González, Ricardo; Morales Nieto, Carlos; Valdez-Cepeda, Ricardo

2012-01-01

Agave salmiana is a native plant species harvested for the commercial production of mezcal ( Agave spirits) in the highlands of central Mexico. The objective of this study was to identify vegetation changes in natural communities where A. salmiana has been differentially harvested for commercial purposes. Three plant community categories were identified in the state of Zacatecas based on their history of A. salmiana utilization: short (less than 10 years of use), moderate (about 25 years), and long (60 or more years). Species cover, composition, and density were evaluated in field surveys by use category. A gradient of vegetation structure of the communities parallels the duration of A. salmiana use. A. salmiana density was greatest (3,125 plants ha-1) in the short-use areas and less (892 plants ha-1) in the moderate-use areas, associated with markedly greater density of shrubs (200%) and Opuntia spp. (50%) in moderate-use areas. The main shrubs were Larrea tridentata, Mimosa biuncifera, Jatropha dioica and Buddleia scordioides while the main Opuntia species were Opuntia leucotricha and Opuntia robusta. A. salmiana density was least (652 plants ha-1) in the long-use areas where shrubs were less abundant but Opuntia spp. density was 25% higher than in moderate-use areas. We suggest that shrubs may increase with moderate use creating an intermediate successional stage that facilitates the establishment of Opuntia spp. Long-term Agave use is generating new plant communities dominated by Opuntia spp. (nopaleras) as a replacement of the original communities dominated by A. salmiana (magueyeras).

Land use and soil organic matter in South Africa 1: A review on spatial variability and the influence of rangeland stock production

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Pearson N.S. Mnkeni

2011-05-01

Full Text Available Degradation of soil as a consequence of land use poses a threat to sustainable agriculture in South Africa, resulting in the need for a soil protection strategy and policy. Development of such a strategy and policy require cognisance of the extent and impact of soil degradation processes. One of the identified processes is the decline of soil organic matter, which also plays a central role in soil health or quality. The spatial variability of organic matter and the impact of grazing and burning under rangeland stock production are addressed in this first part of the review. Data from uncoordinated studies showed that South African soils have low organic matter levels. About 58% of soils contain less than 0.5% organic carbon and only 4% contain more than 2% organic carbon. Furthermore, there are large differences in organic matter content within and between soil forms, depending on climatic conditions, vegetative cover, topographical position and soil texture. A countrywide baseline study to quantify organic matter contents within and between soil forms is suggested for future reference. Degradation of rangeland because of overgrazing has resulted in significant losses of soil organic matter, mainly as a result of lower biomass production. The use of fire in rangeland management decreases soil organic matter because litter is destroyed by burning. Maintaining or increasing organic matter levels in degraded rangeland soils by preventing overgrazing and restricting burning could contribute to the restoration of degraded rangelands. This restoration is of the utmost importance because stock farming uses the majority of land in South Africa.

Climate-change adaptation on rangelands: Linking regional exposure with diverse adaptive capacity

Science.gov (United States)

David D. Briske; Linda A. Joyce; H. Wayne Polley; Joel R. Brown; Klaus Wolter; Jack A. Morgan; Bruce A. McCarl; Derek W. Bailey

2015-01-01

The ecological consequences of climate change are predicted to vary greatly throughout US rangelands. Projections show warming and drying in the southern Great Plains and the Southwest, warmer and drier summers with reduced winter snowpack in the Northwest, and warmer and wetter conditions in the northern Great Plains. Primarily through their combined effects on soil...

BITES RATE ON NATIVE VEGETATION BY TRASHUMANCE GOATS GRAZING IN MOUNTAIN RANGELAND IN NUDO MIXTECO, MEXICO

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F.J. Franco-Guerra

2014-08-01

Full Text Available The objective of the present study was to determine the habits of grazing-browsing by the rate of bites and rate of consumption in the dry matter (MS of the diet of goats under transhumance grazing in mountain rangelands of Nudo Mixteco, being the natural vegetation in the different strata. Six animals of different age and sex were randomly chosen. Direct observation of grazing method was used to determine the rate of bites/min and the rate of consumption by layers. Analyzes of variance was performed and the Tukey test was used for mean comparison test was used (HSD Tukey (α, 0.05. The values of both variables were small, which may be due to the great diversity of plants and their varied morphology which induces the goat won on the one hand to spend more time in the choice of food becoming more selective and on the other, to carry out bites smaller in those plants whose leaf surface is of the type megafilia or in those woody whose leaves are very small (microphilia 2.25 cm2 to 20.25 cm2.

Multiscale sagebrush rangeland habitat modeling in southwest Wyoming

Science.gov (United States)

Homer, Collin G.; Aldridge, Cameron L.; Meyer, Debra K.; Coan, Michael J.; Bowen, Zachary H.

2009-01-01

Sagebrush-steppe ecosystems in North America have experienced dramatic elimination and degradation since European settlement. As a result, sagebrush-steppe dependent species have experienced drastic range contractions and population declines. Coordinated ecosystem-wide research, integrated with monitoring and management activities, would improve the ability to maintain existing sagebrush habitats. However, current data only identify resource availability locally, with rigorous spatial tools and models that accurately model and map sagebrush habitats over large areas still unavailable. Here we report on an effort to produce a rigorous large-area sagebrush-habitat classification and inventory with statistically validated products and estimates of precision in the State of Wyoming. This research employs a combination of significant new tools, including (1) modeling sagebrush rangeland as a series of independent continuous field components that can be combined and customized by any user at multiple spatial scales; (2) collecting ground-measured plot data on 2.4-meter imagery in the same season the satellite imagery is acquired; (3) effective modeling of ground-measured data on 2.4-meter imagery to maximize subsequent extrapolation; (4) acquiring multiple seasons (spring, summer, and fall) of an additional two spatial scales of imagery (30 meter and 56 meter) for optimal large-area modeling; (5) using regression tree classification technology that optimizes data mining of multiple image dates, ratios, and bands with ancillary data to extrapolate ground training data to coarser resolution sensors; and (6) employing rigorous accuracy assessment of model predictions to enable users to understand the inherent uncertainties. First-phase results modeled eight rangeland components (four primary targets and four secondary targets) as continuous field predictions. The primary targets included percent bare ground, percent herbaceousness, percent shrub, and percent litter. The

Inoculation effects on root-colonizing arbuscular mycorrhizal fungal communities spread beyond directly inoculated plants

Science.gov (United States)

Krak, Karol; Vosátka, Miroslav; Püschel, David; Štorchová, Helena

2017-01-01

Inoculation with arbuscular mycorrhizal fungi (AMF) may improve plant performance at disturbed sites, but inoculation may also suppress root colonization by native AMF and decrease the diversity of the root-colonizing AMF community. This has been shown for the roots of directly inoculated plants, but little is known about the stability of inoculation effects, and to which degree the inoculant and the inoculation-induced changes in AMF community composition spread into newly emerging seedlings that were not in direct contact with the introduced propagules. We addressed this topic in a greenhouse experiment based on the soil and native AMF community of a post-mining site. Plants were cultivated in compartmented pots with substrate containing the native AMF community, where AMF extraradical mycelium radiating from directly inoculated plants was allowed to inoculate neighboring plants. The abundances of the inoculated isolate and of native AMF taxa were monitored in the roots of the directly inoculated plants and the neighboring plants by quantitative real-time PCR. As expected, inoculation suppressed root colonization of the directly inoculated plants by other AMF taxa of the native AMF community and also by native genotypes of the same species as used for inoculation. In the neighboring plants, high abundance of the inoculant and the suppression of native AMF were maintained. Thus, we demonstrate that inoculation effects on native AMF propagate into plants that were not in direct contact with the introduced inoculum, and are therefore likely to persist at the site of inoculation. PMID:28738069

Inoculation effects on root-colonizing arbuscular mycorrhizal fungal communities spread beyond directly inoculated plants.

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Martina Janoušková

Full Text Available Inoculation with arbuscular mycorrhizal fungi (AMF may improve plant performance at disturbed sites, but inoculation may also suppress root colonization by native AMF and decrease the diversity of the root-colonizing AMF community. This has been shown for the roots of directly inoculated plants, but little is known about the stability of inoculation effects, and to which degree the inoculant and the inoculation-induced changes in AMF community composition spread into newly emerging seedlings that were not in direct contact with the introduced propagules. We addressed this topic in a greenhouse experiment based on the soil and native AMF community of a post-mining site. Plants were cultivated in compartmented pots with substrate containing the native AMF community, where AMF extraradical mycelium radiating from directly inoculated plants was allowed to inoculate neighboring plants. The abundances of the inoculated isolate and of native AMF taxa were monitored in the roots of the directly inoculated plants and the neighboring plants by quantitative real-time PCR. As expected, inoculation suppressed root colonization of the directly inoculated plants by other AMF taxa of the native AMF community and also by native genotypes of the same species as used for inoculation. In the neighboring plants, high abundance of the inoculant and the suppression of native AMF were maintained. Thus, we demonstrate that inoculation effects on native AMF propagate into plants that were not in direct contact with the introduced inoculum, and are therefore likely to persist at the site of inoculation.

Indigenous knowledge of medicinal plants used by Saperas community of Khetawas, Jhajjar District, Haryana, India

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Kumar Sunil

2010-01-01

Full Text Available Abstract Background Plants have traditionally been used as a source of medicine in India by indigenous people of different ethnic groups inhabiting various terrains for the control of various ailments afflicting human and their domestic animals. The indigenous community of snake charmers belongs to the 'Nath' community in India have played important role of healers in treating snake bite victims. Snake charmers also sell herbal remedies for common ailments. In the present paper an attempt has been made to document on ethno botanical survey and traditional medicines used by snake charmers of village Khetawas located in district Jhajjar of Haryana, India as the little work has been made in the past to document the knowledge from this community. Methods Ethno botanical data and traditional uses of plants information was obtained by semi structured oral interviews from experienced rural folk, traditional herbal medicine practitioners of the 'Nath' community. A total of 42 selected inhabitants were interviewed, 41 were male and only one woman. The age of the healers was between 25 years and 75 years. The plant specimens were identified according to different references concerning the medicinal plants of Haryana and adjoining areas and further confirmation from Forest Research Institute, Dehradun. Results The present study revealed that the people of the snake charmer community used 57 medicinal plants species that belonged to 51 genera and 35 families for the treatment of various diseases. The study has brought to light that the main diseases treated by this community was snakebite in which 19 different types of medicinal plants belongs to 13 families were used. Significantly higher number of medicinal plants was claimed by men as compared to women. The highest numbers of medicinal plants for traditional uses utilized by this community were belonging to family Fabaceae. Conclusion This community carries a vast knowledge of medicinal plants but as

Movement and spatial proximity patterns of rangeland-raised Raramuri Criollo cow-calf pairs

Science.gov (United States)

The objective of this study was to compare movement patterns of nursing vs. nonnursing mature cows and to characterize cow-calf proximity patterns in two herds of Raramuri Criollo cattle. Herds grazed rangeland pastures in southern New Mexico (4355 ha) and west-central Chihuahua, Mexico (633 ha)'' A...

Searls prairie clover (Dalea searlsiae) for rangeland revegetation: Phenotypic and genetic evaluations

Science.gov (United States)

Kishor Bhattarai; Shaun Bushman; Douglas A. Johnson; John G. Carman

2011-01-01

Few North American legumes are available for use in rangeland revegetation in the western USA, but Searls prairie clover [Dalea searlsiae (A. Gray) Barneby] is one that holds promise. Commercial-scale seed production of this species could address the issues of unreliable seed availability and high seed costs associated with its wildland seed collection. To evaluate its...

Fine and Coarse-Scale Patterns of Vegetation Diversity on Reclaimed Surface Mine-land Over a 40-Year Chronosequence.

Science.gov (United States)

Bohrer, Stefanie L; Limb, Ryan F; Daigh, Aaron L; Volk, Jay M; Wick, Abbey F

2017-03-01

Rangelands are described as heterogeneous, due to patterning in species assemblages and productivity that arise from species dispersal and interactions with environmental gradients and disturbances across multiple scales. The objectives of rangeland reclamation are typically vegetation establishment, plant community productivity, and soil stability. However, while fine-scale diversity is often promoted through species-rich seed mixes, landscape heterogeneity and coarse-scale diversity are largely overlooked. Our objectives were to evaluate fine and coarse-scale vegetation patterns across a 40-year reclamation chronosequence on reclaimed surface coalmine lands. We hypothesized that both α-diversity and β-diversity would increase and community patch size and species dissimilarity to reference sites would decrease on independent sites over 40 years. Plant communities were surveyed on 19 post-coalmine reclaimed sites and four intact native reference sites in central North Dakota mixed-grass prairie. Our results showed no differences in α or β-diversity and plant community patch size over the 40-year chronosequence. However, both α-diversity and β-diversity on reclaimed sites was similar to reference sites. Native species establishment was limited due to the presence of non-native species such as Kentucky bluegrass (Poa pratensis) on both the reclaimed and reference sites. Species composition was different between reclaimed and reference sites and community dissimilarity increased on reclaimed sites over the 40-year chronosequence. Plant communities resulting from reclamation followed non-equilibrium succession, even with consistent seeds mixes established across all reclaimed years. This suggests post-reclamation management strategies influence species composition outcomes and land management strategies applied uniformly may not increase landscape-level diversity.

Structure and composition of oligohaline marsh plant communities exposed to salinity pulses

Science.gov (United States)

Howard, R.J.; Mendelssohn, I.A.

2000-01-01

The response of two oligohaline marsh macrophyte communities to pulses of increased salinity was studied over a single growing season in a greenhouse experiment. The plant communities were allowed a recovery period in freshwater following the pulse events. The experimental treatments included: (1) salinity influx rate (rate of salinity increase from 0 to 12 gl-1); (2) duration of exposure to elevated salinity; and (3) water depth. The communities both included Sagittaria lancifolia L.; the codominant species were Eleocharis palustris (L.) Roemer and J.A. Schultes in community 1 and Schoenoplectus americanus (Pers.) Volk. ex Schinz and R. Keller in community 2. Effects of the treatments on sediment chemical characteristics (salinity, pH, redox potential, and sulfide and ammonium concentrations) and plant community attributes (aboveground and belowground biomass, stem density, leaf tissue nutrients, and species richness) were examined. The treatment effects often interacted to influence sediment and plant communities characteristics following recovery in fresh water. Salinity influx rate per se, however, had little effect on the abiotic or biotic response variables; significant influx effects were found when the 0 gl-1 (zero influx) treatment was compared to the 12 gl-1 treatments, regardless of the rate salinity was raised. A salinity level of 12 gl-1 had negative effects on plant community structure and composition; these effects were usually associated with 3 months of salinity exposure. Water depth often interacted with exposure duration, but increased water depth did independently decrease the values of some community response measures. Community 1 was affected more than community 2 in the most extreme salinity treatment (3 months exposure/15-cm water depth). Although species richness in both communities was reduced, structural changes were more dramatic in community 1. Biomass and stem density were reduced in community 1 overall and in both dominant species

Alien roadside species more easily invade alpine than lowland plant communities in a subarctic mountain ecosystem.

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Jonas J Lembrechts

Full Text Available Effects of roads on plant communities are not well known in cold-climate mountain ecosystems, where road building and development are expected to increase in future decades. Knowledge of the sensitivity of mountain plant communities to disturbance by roads is however important for future conservation purposes. We investigate the effects of roads on species richness and composition, including the plant strategies that are most affected, along three elevational gradients in a subarctic mountain ecosystem. We also examine whether mountain roads promote the introduction and invasion of alien plant species from the lowlands to the alpine zone. Observations of plant community composition were made together with abiotic, biotic and anthropogenic factors in 60 T-shaped transects. Alpine plant communities reacted differently to road disturbances than their lowland counterparts. On high elevations, the roadside species composition was more similar to that of the local natural communities. Less competitive and ruderal species were present at high compared with lower elevation roadsides. While the effects of roads thus seem to be mitigated in the alpine environment for plant species in general, mountain plant communities are more invasible than lowland communities. More precisely, relatively more alien species present in the roadside were found to invade into the surrounding natural community at high compared to low elevations. We conclude that effects of roads and introduction of alien species in lowlands cannot simply be extrapolated to the alpine and subarctic environment.

Alien roadside species more easily invade alpine than lowland plant communities in a subarctic mountain ecosystem.

Science.gov (United States)

Lembrechts, Jonas J; Milbau, Ann; Nijs, Ivan

2014-01-01

Effects of roads on plant communities are not well known in cold-climate mountain ecosystems, where road building and development are expected to increase in future decades. Knowledge of the sensitivity of mountain plant communities to disturbance by roads is however important for future conservation purposes. We investigate the effects of roads on species richness and composition, including the plant strategies that are most affected, along three elevational gradients in a subarctic mountain ecosystem. We also examine whether mountain roads promote the introduction and invasion of alien plant species from the lowlands to the alpine zone. Observations of plant community composition were made together with abiotic, biotic and anthropogenic factors in 60 T-shaped transects. Alpine plant communities reacted differently to road disturbances than their lowland counterparts. On high elevations, the roadside species composition was more similar to that of the local natural communities. Less competitive and ruderal species were present at high compared with lower elevation roadsides. While the effects of roads thus seem to be mitigated in the alpine environment for plant species in general, mountain plant communities are more invasible than lowland communities. More precisely, relatively more alien species present in the roadside were found to invade into the surrounding natural community at high compared to low elevations. We conclude that effects of roads and introduction of alien species in lowlands cannot simply be extrapolated to the alpine and subarctic environment.

Rhizosphere microbial community structure in relation to root location and plant iron nutritional status.

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Yang, C H; Crowley, D E

2000-01-01

Root exudate composition and quantity vary in relation to plant nutritional status, but the impact of the differences on rhizosphere microbial communities is not known. To examine this question, we performed an experiment with barley (Hordeum vulgare) plants under iron-limiting and iron-sufficient growth conditions. Plants were grown in an iron-limiting soil in root box microcosms. One-half of the plants were treated with foliar iron every day to inhibit phytosiderophore production and to alter root exudate composition. After 30 days, the bacterial communities associated with different root zones, including the primary root tips, nonelongating secondary root tips, sites of lateral root emergence, and older roots distal from the tip, were characterized by using 16S ribosomal DNA (rDNA) fingerprints generated by PCR-denaturing gradient gel electrophoresis (DGGE). Our results showed that the microbial communities associated with the different root locations produced many common 16S rDNA bands but that the communities could be distinguished by using correspondence analysis. Approximately 40% of the variation between communities could be attributed to plant iron nutritional status. A sequence analysis of clones generated from a single 16S rDNA band obtained at all of the root locations revealed that there were taxonomically different species in the same band, suggesting that the resolving power of DGGE for characterization of community structure at the species level is limited. Our results suggest that the bacterial communities in the rhizosphere are substantially different in different root zones and that a rhizosphere community may be altered by changes in root exudate composition caused by changes in plant iron nutritional status.

Granivory of invasive, naturalized, and native plants in communities differentially susceptible to invasion.

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Connolly, B M; Pearson, D E; Mack, R N

2014-07-01

Seed predation is an important biotic filter that can influence abundance and spatial distributions of native species through differential effects on recruitment. This filter may also influence the relative abundance of nonnative plants within habitats and the communities' susceptibility to invasion via differences in granivore identity, abundance, and food preference. We evaluated the effect of postdispersal seed predators on the establishment of invasive, naturalized, and native species within and between adjacent forest and steppe communities of eastern Washington, USA that differ in severity of plant invasion. Seed removal from trays placed within guild-specific exclosures revealed that small mammals were the dominant seed predators in both forest and steppe. Seeds of invasive species (Bromus tectorum, Cirsium arvense) were removed significantly less than the seeds of native (Pseudoroegneria spicata, Balsamorhiza sagittata) and naturalized (Secale cereale, Centaurea cyanus) species. Seed predation limited seedling emergence and establishment in both communities in the absence of competition in a pattern reflecting natural plant abundance: S. cereale was most suppressed, B. tectorum was least suppressed, and P. spicata was suppressed at an intermediate level. Furthermore, seed predation reduced the residual seed bank for all species. Seed mass correlated with seed removal rates in the forest and their subsequent effects on plant recruitment; larger seeds were removed at higher rates than smaller seeds. Our vegetation surveys indicate higher densities and canopy cover of nonnative species occur in the steppe compared with the forest understory, suggesting the steppe may be more susceptible to invasion. Seed predation alone, however, did not result in significant differences in establishment for any species between these communities, presumably due to similar total small-mammal abundance between communities. Consequently, preferential seed predation by small

Herbicide and fertilizers promote analogous phylogenetic responses but opposite functional responses in plant communities

DEFF Research Database (Denmark)

Pellissier, Loïc; Wisz, Mary S.; Strandberg, Beate

2014-01-01

on long-term experiment we show that fertilizer and herbicides (glyphosate) have contrasting effects on functional structure, but can increase phylogenetic diversity in semi-natural plant communities. We found that an increase in nitrogen promoted an increase in the average specific leaf area and canopy...... height at the community level, but an increase in glyphosate promoted a decrease in those traits. Phylogenetic diversity of plant communities increased when herbicide and fertilizer were applied together, likely because functional traits facilitating plant success in those conditions were......Throughout the world, herbicides and fertilizers change species composition in agricultural communities, but how do the cumulative effects of these chemicals impact the functional and phylogenetic structure of non-targeted communities when they drift into adjacent semi-natural habitats? Based...

Evaluating Structural and Functional Characteristics of Various Ecological Patches in Different Range Conditions (Case Study: Semi -Steppe Rangeland of Aghche-Isfahan

Directory of Open Access Journals (Sweden)

F. Jafari

2015-03-01

Full Text Available Rangeland condition assessment plays an important role in determining range health and applying appropriate management programs. This study aimed to evaluate the structure and function of a semi-steppe rangeland using Landscape Function Analysis technique (LFA in different land conditions in western Isfahan province, Iran. For this purpose, 4, 3 and 7 sites in different rangeland condition classes including very poor, poor, and moderate were selected respectively. In each site, a 30-meter transect was established and all kinds of patches and inter patches were identified and their lengths and widths were recorded. Also, in each ecological patch, 11 indicators of soil surface characteristics with three replications were measured, and their status was scored according to LFA method. The functionality indices of all the sites including soil stability, infiltration and nutrient cycling were measured. According to the statistical analysis results, most of the structural characteristics (number of patches, patch length, patch area index, landscape organization index and functional indices (infiltration, stability and nutrient cycling status varied significantly (α= 5% between rangeland sites with moderate and very poor condition. The changes of these structural and functional characteristics were not significant between range sites with moderate and poor, and also poor and very poor range conditions. According to the findings of this study, patch types' functionalities did not vary significantly in both rangeland sites with moderate and very poor conditions. The nutrient cycling index in patches formed by ‘forb, shrub and grass’ with poor range condition was significantly more than ‘forb’ and ‘grass’ patches. The study of range site functionality can assist managers in identifying possible ecological thresholds and prioritizing the sub-catchments and vegetation types for implementing range improvement practices.

Limits to understory plant restoration following fuel-reduction treatments in a piñon-juniper woodland.

Science.gov (United States)

Redmond, Miranda D; Zelikova, Tamara J; Barger, Nichole N

2014-11-01

National fuel-reduction programs aim to reduce the risk of wildland fires to human communities and to restore forest and rangeland ecosystems to resemble their historical structure, function, and diversity. There are a number of factors, such as seed bank dynamics, post-treatment climate, and herbivory, which determine whether this latter goal may be achieved. Here, we examine the short-term (2 years) vegetation response to fuel-reduction treatments (mechanical mastication, broadcast burn, and pile burn) and seeding of native grasses on understory vegetation in an upland piñon-juniper woodland in southeast Utah. We also examine how wildlife herbivory affects the success of fuel-reduction treatments. Herbaceous cover increased in response to fuel-reduction treatments in all seeded treatments, with the broadcast burn and mastication having greater increases (234 and 160 %, respectively) in herbaceous cover than the pile burn (32 %). In the absence of seeding, herbaceous cover only increased in the broadcast burn (32 %). Notably, fuel-reduction treatments, but not seeding, strongly affected herbaceous plant composition. All fuel-reduction treatments increased the relative density of invasive species, especially in the broadcast burn, which shifted the plant community composition from one dominated by perennial graminoids to one dominated by annual forbs. Herbivory by wildlife reduced understory plant cover by over 40 % and altered plant community composition. If the primary management goal is to enhance understory cover while promoting native species abundance, our study suggests that mastication may be the most effective treatment strategy in these upland piñon-juniper woodlands. Seed applications and wildlife exclosures further enhanced herbaceous cover following fuel-reduction treatments.

Competition for light and nutrients in layered communities of aquatic plants.

Science.gov (United States)

van Gerven, Luuk P A; de Klein, Jeroen J M; Gerla, Daan J; Kooi, Bob W; Kuiper, Jan J; Mooij, Wolf M

2015-07-01

Dominance of free-floating plants poses a threat to biodiversity in many freshwater ecosystems. Here we propose a theoretical framework to understand this dominance, by modeling the competition for light and nutrients in a layered community of floating and submerged plants. The model shows that at high supply of light and nutrients, floating plants always dominate due to their primacy for light, even when submerged plants have lower minimal resource requirements. The model also shows that floating-plant dominance cannot be an alternative stable state in light-limited environments but only in nutrient-limited environments, depending on the plants' resource consumption traits. Compared to unlayered communities, the asymmetry in competition for light-coincident with symmetry in competition for nutrients-leads to fundamentally different results: competition outcomes can no longer be predicted from species traits such as minimal resource requirements ([Formula: see text] rule) and resource consumption. Also, the same two species can, depending on the environment, coexist or be alternative stable states. When applied to two common plant species in temperate regions, both the model and field data suggest that floating-plant dominance is unlikely to be an alternative stable state.

A review of concentrated flow erosion processes on rangelands: fundamental understanding and knowledge gaps

Science.gov (United States)

Concentrated flow erosion processes are distinguished from splash and sheetflow processes in their enhanced ability to mobilize and transport large amounts of soil, water and dissolved elements. On rangelands, soil, nutrients and water are scarce and only narrow margins of resource losses are tolera...

Composted manure application promotes long-term invasion of semi-arid rangeland by Bromus tectorum

Science.gov (United States)

Composted organic matter derived from sewage treatment facilities or livestock manure from feedlots is often applied to rangelands of western North America to increase soil fertility, forage production, forage quality, and soil carbon (C) storage. This practice can have a number of undesirable side ...

Microbe-mediated plant-soil feedback in pioneer stages of secondary succession causes long-lasting historical contingency effects in plant community composition.

NARCIS (Netherlands)

Kardol, P.; Bezemer, T.M.; Putten, van der W.H.

2006-01-01

Soil microbes and soil fauna have been assumed to play a key role in interspecific plant competition and successional community development. It has been suggested that plants can influence their performance by changing the composition of their associated soil communities. Such feedback effects may

Ethnomedicinal plants of the Bauri tribal community of Moulvibazar District, Bangladesh.

Science.gov (United States)

Das, Protiva Rani; Islam, Md Tabibul; Mostafa, Mohd Nabil; Rahmatullah, Mohammed

2013-01-01

Bangladesh reportedly has more than 100 tribal communities; however, documentation of their medicinal practices is markedly absent. The aim of the present study was to conduct an ethnomedicinal survey among the little known Bauri tribe of Bangladesh, whose tribal medicinal practices are yet to be documented. The survey was carried out among the Bauri tribal community of Purbo Tila village in Moulvibazar District. The community is believed to be the only Bauri community in the country and had four tribal healers who continue their traditional medicinal practices. Interviews of the healers were carried out with the help of a semi-structured questionnaire and the guided field-walk method where the healers took the interviewers on guided field-walks through areas from where they collected their medicinal plants. Here they identified the plants and described their uses. The Bauri healers were observed to use 40 different plant species and one bird species for treatment of ailments such as fever, respiratory tract disorders, pain, gastrointestinal disorders, eye problems like cataract and conjunctivitis, jaundice, abscess, cardiovascular disorders, urinary problems, paralysis, dog bite, snake bite, helminthiasis, lesions on the tongue or lips and piles. Leaves were the major plant part used and constituted 38.3% of total uses followed by fruits at 14.9%. A review of the relevant scientific literature showed that a number of medicinal plants used by the Bauri healers possess pharmacological activities, which were in line with the traditional uses, thus validating their use by the Bauri tribe.

Climate interacts with soil to produce beta diversity in Californian plant communities.

Science.gov (United States)

Fernandez-Going, B M; Harrison, S P; Anacker, B L; Safford, H D

2013-09-01

Spatially distinct communities can arise through interactions and feedbacks between abiotic and biotic factors. We suggest that, for plants, patches of infertile soils such as serpentine may support more distinct communities from those in the surrounding non-serpentine matrix in regions where the climate is more productive (i.e., warmer and/or wetter). Where both soil fertility and climatic productivity are high, communities may be dominated by plants with fast-growing functional traits, whereas where either soils or climate impose low productivity, species with stress-tolerant functional traits may predominate. As a result, both species and functional composition may show higher dissimilarity between patch and matrix in productive climates. This pattern may be reinforced by positive feedbacks, in which higher plant growth under favorable climate and soil conditions leads to higher soil fertility, further enhancing plant growth. For 96 pairs of sites across a 200-km latitudinal gradient in California, we found that the species and functional dissimilarities between communities on infertile serpentine and fertile non-serpentine soils were higher in more productive (wetter) regions. Woody species had more stress-tolerant functional traits on serpentine than non-serpentine soil, and as rainfall increased, woody species functional composition changed toward fast-growing traits on non-serpentine, but not on serpentine soils. Soil organic matter increased with rainfall, but only on non-serpentine soils, and the difference in organic matter between soils was positively correlated with plant community dissimilarity. These results illustrate a novel mechanism wherein climatic productivity is associated with higher species, functional, and landscape-level dissimilarity (beta diversity).

Changes in uranium plant community leaders' attitudes toward nuclear power: before and after TMI

International Nuclear Information System (INIS)

Winfield-Laird, I.; Hastings, M.; Cawley, M.E.

1982-01-01

The results of an investigation of the reactions of community leaders in nuclear power plant host communities toward nuclear power following the accident at Three Mile Island (TMI) are reported. Public and private sector officials were surveyed in ten general areas covering their attitudes toward and the continued use of nuclear power as compared to other fuel types, and the reassessment of the local plant impact on different community groups and aspects of community life. Information is compared with findings from a similar study conducted with the same community leaders prior to the TMI accident. The results indicate that community leaders' attitudes remained highly favorable toward the continued use of nuclear power. Three-fourths of the sample indicated that they would probably or definitely allow the continued use of nuclear power as compared to other fuel types, and the reassessment of the local majority still view the plant presence as having a positive impact on their communities. (author)

Ecological site-based assessments of wind and water erosion: informing accelerated soil erosion management in rangelands

Science.gov (United States)

Webb, Nicholas P.; Herrick, Jeffrey E.; Duniway, Michael C.

2014-01-01

Accelerated soil erosion occurs when anthropogenic processes modify soil, vegetation or climatic conditions causing erosion rates at a location to exceed their natural variability. Identifying where and when accelerated erosion occurs is a critical first step toward its effective management. Here we explore how erosion assessments structured in the context of ecological sites (a land classification based on soils, landscape setting and ecological potential) and their vegetation states (plant assemblages that may change due to management) can inform systems for reducing accelerated soil erosion in rangelands. We evaluated aeolian horizontal sediment flux and fluvial sediment erosion rates for five ecological sites in southern New Mexico, USA, using monitoring data and rangeland-specific wind and water erosion models. Across the ecological sites, plots in shrub-encroached and shrub-dominated vegetation states were consistently susceptible to aeolian sediment flux and fluvial sediment erosion. Both processes were found to be highly variable for grassland and grass-succulent states across the ecological sites at the plot scale (0.25 Ha). We identify vegetation thresholds that define cover levels below which rapid (exponential) increases in aeolian sediment flux and fluvial sediment erosion occur across the ecological sites and vegetation states. Aeolian sediment flux and fluvial erosion in the study area can be effectively controlled when bare ground cover is 100 cm in length is less than ~35%. Land use and management activities that alter cover levels such that they cross thresholds, and/or drive vegetation state changes, may increase the susceptibility of areas to erosion. Land use impacts that are constrained within the range of natural variability should not result in accelerated soil erosion. Evaluating land condition against the erosion thresholds identified here will enable identification of areas susceptible to accelerated soil erosion and the development of

Ecological site‐based assessments of wind and water erosion: informing accelerated soil erosion management in rangelands.

Science.gov (United States)

Webb, Nicholas P; Herrick, Jeffrey E; Duniway, Michael C

Accelerated soil erosion occurs when anthropogenic processes modify soil, vegetation, or climatic conditions causing erosion rates at a location to exceed their natural variability. Identifying where and when accelerated erosion occurs is a critical first step toward its effective management. Here we explored how erosion assessments structured in the context of ecological sites (a land classification based on soils, landscape setting, and ecological potential) and their vegetation states (plant assemblages that may change due to management) can inform systems for reducing accelerated soil erosion in rangelands. We evaluated aeolian horizontal sediment flux and fluvial sediment erosion rates for five ecological sites in southern New Mexico, USA, using monitoring data and rangeland-specific wind and water erosion models. Across the ecological sites, plots in shrub-encroached and shrub-dominated vegetation states were consistently susceptible to aeolian sediment flux and fluvial sediment erosion. Both processes were found to be highly variable for grassland and grass–succulent states across the ecological sites at the plot scale (0.25 ha). We identified vegetation thresholds that define cover levels below which rapid (exponential) increases in aeolian sediment flux and fluvial sediment erosion occur across the ecological sites and vegetation states. Aeolian sediment flux and fluvial erosion in the study area could be effectively controlled when bare ground cover was 100 cm in length was less than ∼35%. Land use and management activities that alter cover levels such that they cross thresholds, and/or drive vegetation state changes, may increase the susceptibility of areas to erosion. Land use impacts that are constrained within the range of natural variability should not result in accelerated soil erosion. Evaluating land condition against the erosion thresholds identified here will enable identification of areas susceptible to accelerated soil erosion and the

Scales of snow depth variability in high elevation rangeland sagebrush

Science.gov (United States)

Tedesche, Molly E.; Fassnacht, Steven R.; Meiman, Paul J.

2017-09-01

In high elevation semi-arid rangelands, sagebrush and other shrubs can affect transport and deposition of wind-blown snow, enabling the formation of snowdrifts. Datasets from three field experiments were used to investigate the scales of spatial variability of snow depth around big mountain sagebrush ( Artemisia tridentata Nutt.) at a high elevation plateau rangeland in North Park, Colorado, during the winters of 2002, 2003, and 2008. Data were collected at multiple resolutions (0.05 to 25 m) and extents (2 to 1000 m). Finer scale data were collected specifically for this study to examine the correlation between snow depth, sagebrush microtopography, the ground surface, and the snow surface, as well as the temporal consistency of snow depth patterns. Variograms were used to identify the spatial structure and the Moran's I statistic was used to determine the spatial correlation. Results show some temporal consistency in snow depth at several scales. Plot scale snow depth variability is partly a function of the nature of individual shrubs, as there is some correlation between the spatial structure of snow depth and sagebrush, as well as between the ground and snow depth. The optimal sampling resolution appears to be 25-cm, but over a large area, this would require a multitude of samples, and thus a random stratified approach is recommended with a fine measurement resolution of 5-cm.

Seasonal Variations in the Structure of Phytoplankton Communities near Nuclear Power Plants

International Nuclear Information System (INIS)

Lee, S.-K.; Choi, H.-C.; Moon, H.-T.

2015-01-01

To investigate effects of thermal discharge effluent from nuclear power plants on the surrounding marine environment, especially on the phytoplankton community, environmental data gained by seasonal survey around Hanbit and Hanul nuclear power plants during the periods of 11 years from 1999 to 2009 were analysed. The data used were from environmental survey and assessment around Hanbit and Hanul nuclear power plants of Korea during the period of 11 years from 1999 to 2009. The purposes of this study are (1) to evaluate the effect of operation of nuclear power plants on phytoplankton community, (2) to find out whether the thermal discharge affected negatively phytoplankton community, and (3) to evaluate the difference of thermal discharge influence on phytoplankton community between West and East coastal area, Korea. Through this study, (1) quantitative evaluation of the effect of thermal discharge effluent on marine ecology, especially on abundance and biomass of phytoplankton were performed, (2) found that depending on the season, the effect of thermal discharge effluent from nuclear power plant on the marine environment is not always negative (i.e. warm water may increase or prevent decline of abundance in seasons with low temperature such as winter in Hanbit area), and (3) found that same thermal discharge effluent rate to different marine environments, such as west and east coast of Korea, does not result in same effect on the marine ecosystem. (author)

Comparing arbuscular mycorrhizal communities of individual plants in a grassland biodiversity experiment

NARCIS (Netherlands)

Van de Voorde, T.F.J.; Van der Putten, W.H.; Gamper, H.A.; Hol, W.H.G.; Bezemer, T.M.

2010-01-01

Plants differ greatly in the soil organisms colonizing their roots. However, how soil organism assemblages of individual plant roots can be influenced by plant community properties remains poorly understood. We determined the composition of arbuscular mycorrhizal fungi (AMF) in Jacobaea vulgaris

Success of seeding native compared with introduced perennial vegetation for revegetating medusahead-invaded sagebrush rangeland

Science.gov (United States)

Millions of hectares of Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle &Young) rangeland have been invaded by medusahead (Taeniatherum caput-medusae [L.] Nevski), an exotic annual grass that degrades wildlife habitat, reduces forage production, and decreases biodiversity....

Separating the cows from the trees: toward development of national definitions of forest and rangeland

Science.gov (United States)

H. Gyde Lund

2007-01-01

This paper introduces issues surrounding the need for national definitions of forest and rangeland, and it review types of definitions in use, reviews past agreements and their status, and finally gives recommendations as to what should be done next.

Combined effects of leaf litter and soil microsite on decomposition process in arid rangelands.

Science.gov (United States)

Carrera, Analía Lorena; Bertiller, Mónica Beatriz

2013-01-15

The objective of this study was to analyze the combined effects of leaf litter quality and soil properties on litter decomposition and soil nitrogen (N) mineralization at conserved (C) and disturbed by sheep grazing (D) vegetation states in arid rangelands of the Patagonian Monte. It was hypothesized that spatial differences in soil inorganic-N levels have larger impact on decomposition processes of non-recalcitrant than recalcitrant leaf litter (low and high concentration of secondary compounds, respectively). Leaf litter and upper soil were extracted from modal size plant patches (patch microsite) and the associated inter-patch area (inter-patch microsite) in C and D. Leaf litter was pooled per vegetation state and soil was pooled combining vegetation state and microsite. Concentrations of N and secondary compounds in leaf litter and total and inorganic-N in soil were assessed at each pooled sample. Leaf litter decay and soil N mineralization at microsites of C and D were estimated in 160 microcosms incubated at field capacity (16 month). C soils had higher total N than D soils (0.58 and 0.41 mg/g, respectively). Patch soil of C and inter-patch soil of D exhibited the highest values of inorganic-N (8.8 and 8.4 μg/g, respectively). Leaf litter of C was less recalcitrant and decomposed faster than that of D. Non-recalcitrant leaf litter decay and induced soil N mineralization had larger variation among microsites (coefficients of variation = 25 and 41%, respectively) than recalcitrant leaf litter (coefficients of variation = 12 and 32%, respectively). Changes in the canopy structure induced by grazing disturbance increased leaf litter recalcitrance, and reduced litter decay and soil N mineralization, independently of soil N levels. This highlights the importance of the combined effects of soil and leaf litter properties on N cycling probably with consequences for vegetation reestablishment and dynamics, rangeland resistance and resilience with implications

Comparison of bacterial and fungal communities between natural and planted pine forests in subtropical China.

Science.gov (United States)

Nie, Ming; Meng, Han; Li, Ke; Wan, Jia-Rong; Quan, Zhe-Xue; Fang, Chang-Ming; Chen, Jia-Kuan; Li, Bo

2012-01-01

To improve our understanding of the changes in bacterial and fungal diversity in natural pine and planted forests in subtropical region of China, we examined bacterial and fungal communities from a native and a nearby planted pine forest of the Mt. Lushan by constructing clone libraries of 16S and 18S rRNA genes. For bacterial communities, Proteobacteria and Acidobacteria were dominant bacterial taxa in both two types of forest soils. The Shannon-Wiener diversity index, rarefaction curve analysis, and LibShuff analysis suggest that these two forests contained similar diversity of bacterial communities. Low soil acidity (pH ≈ 4) of our study forests might be one of the most important selection factors determining growth of acidophilic Acidobacteria and Proteobacteria. However, the natural forest harbored greater level of fungal diversity than the planted forest according to the Shannon-Wiener diversity index and rarefaction curve analysis. Basidiomycota and Ascomycota were dominant fungal taxa in the soils of natural and planted forests, respectively. Our results suggest that fungal community was more sensitive than the bacterial community in characterizing the differences in plant cover impacts on the microbial flora in the natural and planted forests. The natural and planted forests may function differently due to the differences in soil fungal diversity and relative abundance.

Seasonal movements of wildlife and livestock in a heterogenous pastoral landscape: Implications for coexistence and community based conservation

Directory of Open Access Journals (Sweden)

Peter Tyrrell

2017-10-01

Full Text Available Rangelands across the world are home to millions of pastoral people and vast wildlife populations, which create a complex landscape for conservation. Community based conservation has been used to promote human-wildlife coexistence on pastoral lands, protecting wildlife outside of official protected areas. With the spread of community based conservation within the rangelands there is a need for more information on successful management practices. This study provides an example of this in the South Rift, Kenya, where seasonal movements of pastoralists aid coexistence. We used Density Surface Modelling (DSM, a novel tool for conservation managers in the rangelands, to predict wildlife and livestock abundance across the landscape and seasons. Wildlife grazers, zebra (Equus burchelli and wildebeest (Connochaetes taurinus, follow expected metabolic patterns, feeding on short grass outside the conservation area in the wet season, before returning to the taller-lower quality grazing in the conservation areas during the drought. Browsing wildlife, impala (Aepyceros melampus and Grant’s gazelle (Nanger granti, move from open grassland and bushland areas into thicker, denser browse as the seasons progress towards the drought. Livestock, both shoats (Ovis aries, and Capra aegagrus hircus and cattle (Bos indicus, are managed by community grazing committees, who enforce a grazing plan that creates spatial–temporal separation between wildlife and livestock. They exploit the high-quality grazing in the livestock area during the wet season while conserving pasture in the conservation area, which is utilized only as forage is depleted. This ensures that wildlife has access to a diverse resource base across all seasons and potentially reduces competition, allowing for a diverse and abundant wildlife community to coexist with livestock. This highlights the importance of the presence and maintenance of spatial and temporal heterogeneity of forage resources

Revolutionary land use change in the 21st century: Is (rangeland) science relevant?

Science.gov (United States)

Herrick, J.E.; Brown, J.R.; Bestelmeyer, B.T.; Andrews, S.S.; Baldi, G.; Davies, J.; Duniway, M.; Havstad, K.M.; Karl, J.W.; Karlen, D.L.; Peters, Debra P.C.; Quinton, J.N.; Riginos, C.; Shaver, P.L.; Steinaker, D.; Twomlow, S.

2012-01-01

Rapidly increasing demand for food, fiber, and fuel together with new technologies and the mobility of global capital are driving revolutionary changes in land use throughout the world. Efforts to increase land productivity include conversion of millions of hectares of rangelands to crop production, including many marginal lands with low resistance and resilience to degradation. Sustaining the productivity of these lands requires careful land use planning and innovative management systems. Historically, this responsibility has been left to agronomists and others with expertise in crop production. In this article, we argue that the revolutionary land use changes necessary to support national and global food security potentially make rangeland science more relevant now than ever. Maintaining and increasing relevance will require a revolutionary change in range science from a discipline that focuses on a particular land use or land cover to one that addresses the challenge of managing all lands that, at one time, were considered to be marginal for crop production. We propose four strategies to increase the relevance of rangeland science to global land management: 1) expand our awareness and understanding of local to global economic, social, and technological trends in order to anticipate and identify drivers and patterns of conversion; 2) emphasize empirical studies and modeling that anticipate the biophysical (ecosystem services) and societal consequences of large-scale changes in land cover and use; 3) significantly increase communication and collaboration with the disciplines and sectors of society currently responsible for managing the new land uses; and 4) develop and adopt a dynamic and flexible resilience-based land classification system and data-supported conceptual models (e.g., state-and-transition models) that represent all lands, regardless of use and the consequences of land conversion to various uses instead of changes in state or condition that are

[Effects of alien species Robinia pseudoacacia on plant community functional structure in hilly-gully region of Loess Plateau, China.

Science.gov (United States)

Zhu, Duo Ju; Wen, Zhong Ming; Zhang, Jing; Tao, Yu; Zeng, Hong Wen; Tang, Yang

2018-02-01

To investigate the effects of the introduction of Robinia pseudoacacia on the functional structure of plant communities, we selected paired-plots of R. pseudoacacia communities and native plant communities across different vegetation zones, i.e., steppe zone, forest-steppe zone, forest zone in hilly-gully region of Loess Plateau, China. We measured several functional characteristics and then compared the functional structures of R. pseudoacacia and native plant communities in different vegetation zones. The results showed that the variation of the functional traits across different vegetation zones were consistent in R. pseudoacacia community and native plant community, including leaf carbon concentration, leaf nitrogen concentration, leaf phosphorus concentration, specific leaf area, and leaf tissue density. The leaf carbon concentration, leaf nitrogen concentration, and specific leaf area of the R. pseudoacacia community were significantly higher than those of the native plant community. The trend of change that the functional diversity indices, i.e., FR ic , FE ve , FD iv , FD is , Rao of the R. pseudoacacia community and the native plant community with vegetation zones were different. The introduction of R. pseudoacacia enhanced the plant community functional diversity in the forest zone but reduced community functional diversity in the steppe zone.

Spectral identification of plant communities for mapping of semi-natural grasslands

DEFF Research Database (Denmark)

Jacobsen, Anne; Nielsen, Allan Aasbjerg; Ejrnæs, Rasmus

2000-01-01

identification of plant communities was based on a hierarchical approach relating the test sites to i) management (Ma) and ii) flora (Fl) using spectral consistency and separability as the main criteria. Evaluation of spectral consistency was based on unsupervised clustering of test sites of Ma classes 1 to 7...... as a measure of plant community heterogeneity within management classes. The spectral analysis as well as the maximum likelihood classification indicated that the source of spectral variation within management classes might be related to vegetation composition....

Interspecific Plant Interactions Reflected in Soil Bacterial Community Structure and Nitrogen Cycling in Primary Succession

Directory of Open Access Journals (Sweden)

Joseph E. Knelman

2018-02-01

Full Text Available Past research demonstrating the importance plant–microbe interactions as drivers of ecosystem succession has focused on how plants condition soil microbial communities, impacting subsequent plant performance and plant community assembly. These studies, however, largely treat microbial communities as a black box. In this study, we sought to examine how emblematic shifts from early successional Alnus viridus ssp. sinuata (Sitka alder to late successional Picea sitchensis (Sitka spruce in primary succession may be reflected in specific belowground changes in bacterial community structure and nitrogen cycling related to the interaction of these two plants. We examined early successional alder-conditioned soils in a glacial forefield to delineate how alders alter the soil microbial community with increasing dominance. Further, we assessed the impact of late-successional spruce plants on these early successional alder-conditioned microbiomes and related nitrogen cycling through a leachate addition microcosm experiment. We show how increasingly abundant alder select for particular bacterial taxa. Additionally, we found that spruce leachate significantly alters the composition of these microbial communities in large part by driving declines in taxa that are enriched by alder, including bacterial symbionts. We found these effects to be spruce specific, beyond a general leachate effect. Our work also demonstrates a unique influence of spruce on ammonium availability. Such insights bolster theory relating the importance of plant–microbe interactions with late-successional plants and interspecific plant interactions more generally.

Independent Effects of Invasive Shrubs and Deer Herbivory on Plant Community Dynamics

Directory of Open Access Journals (Sweden)

Jeffrey S. Ward

2016-12-01

Full Text Available Both invasive species and deer herbivory are recognized as locally important drivers of plant community dynamics. However, few studies have examined whether their effects are synergistic, additive, or antagonistic. At three study areas in southern New England, we examined the interaction of white-tailed deer (Odocoileus virginianus Zimmermann herbivory and three levels of invasive shrub control over seven growing seasons on the dynamics of nine herbaceous and shrub guilds. Although evidence of synergistic interactions was minimal, the separate effects of invasive shrub control and deer herbivory on plant community composition and dynamics were profound. Plant communities remained relatively unchanged where invasive shrubs were not treated, regardless if deer herbivory was excluded or not. With increasing intensity of invasive shrub control, native shrubs and forbs became more dominant where deer herbivory was excluded, and native graminoids became progressively more dominant where deer herbivory remained severe. While deer exclusion and intensive invasive shrub control increased native shrubs and forbs, it also increased invasive vines. Restoring native plant communities in areas with both established invasive shrub thickets and severe deer browsing will require an integrated management plan to eliminate recalcitrant invasive shrubs, reduce deer browsing intensity, and quickly treat other opportunistic invasive species.

Mother-Offspring Interactions in Raramuri Criollo Cattle on New Mexico and Chihuahua (Mexico) Rangelands

Science.gov (United States)

Rangeland beef cows spend approximately six months of a typical year raising their calf. This endeavor is known to significantly alter a dam’s grazing behavior and spatial distribution patterns. The objective of this study was to characterize cow-calf contact events in two herds of Raramuri Criollo ...

Deforestation of "degraded" rangelands: The Argentine Chaco enters the next stage of the Anthropocene

Science.gov (United States)

Twenty years ago I completed my Master’s work in the Chaco forests of northern Argentina. The native forests are, in fact, rangelands. In addition to livestock grazing, there is timber extraction, wildlife harvest (think tegu lizard cowboy boots), and charcoal production. I took part in a project co...

Mapping Erosion and Salinity Risk Categories Using GIS and the Rangeland Hydrology Erosion Model

Science.gov (United States)

Up to fifteen percent of rangelands in the state of Utah in the United States are classified as being in severely eroding condition. Some of these degraded lands are located on saline, erodible soils of the Mancos Shale formation. This results in a disproportionate contribution of sediment, salinity...

The Communities' research and development programme on decommissioning of nuclear power plants

International Nuclear Information System (INIS)

1981-01-01

This is the first progress report of the European Community's programme (1979-1983) of research on the decommissioning of nuclear power plants. It shows the status of the programme on 31 December 1980. The programme seeks to promote a number of research and development projects as well as the identification of guiding principles. The projects concern the following subjects: long-term integrity of buildings and systems; decontamination for decommissioning purposes; dismantling techniques; treatment of specific waste materials: steel, concrete and graphite; large transport containers for radioactive was produced in the dismantling of nuclear power plants; estimation of the quantities of radioactive wastes arising from decommissioning of nuclear power plants in the Community; influence of nuclear power plant design features on decommissioning

[A phylogenetic analysis of plant communities of Teberda Biosphere Reserve].

Science.gov (United States)

Shulakov, A A; Egorov, A V; Onipchenko, V G

2016-01-01

Phylogenetic analysis of communities is based on the comparison of distances on the phylogenetic tree between species of a community under study and those distances in random samples taken out of local flora. It makes it possible to determine to what extent a community composition is formed by more closely related species (i.e., "clustered") or, on the opposite, it is more even and includes species that are less related with each other. The first case is usually interpreted as a result of strong influence caused by abiotic factors, due to which species with similar ecology, a priori more closely related, would remain: In the second case, biotic factors, such as competition, may come to the fore and lead to forming a community out of distant clades due to divergence of their ecological niches: The aim of this' study Was Ad explore the phylogenetic structure in communities of the northwestern Caucasus at two spatial scales - the scale of area from 4 to 100 m2 and the smaller scale within a community. The list of local flora of the alpine belt has been composed using the database of geobotanic descriptions carried out in Teberda Biosphere Reserve at true altitudes exceeding.1800 m. It includes 585 species of flowering plants belonging to 57 families. Basal groups of flowering plants are.not represented in the list. At the scale of communities of three classes, namely Thlaspietea rotundifolii - commumties formed on screes and pebbles, Calluno-Ulicetea - alpine meadow, and Mulgedio-Aconitetea subalpine meadows, have not demonstrated significant distinction of phylogenetic structure. At intra level, for alpine meadows the larger share of closely related species. (clustered community) is detected. Significantly clustered happen to be those communities developing on rocks (class Asplenietea trichomanis) and alpine (class Juncetea trifidi). At the same time, alpine lichen proved to have even phylogenetic structure at the small scale. Alpine (class Salicetea herbaceae) that

Plants used for treatment of dysentery and diarrhoea by the Bhoxa community of district Dehradun, Uttarakhand, India.

Science.gov (United States)

Gairola, Sumeet; Sharma, Jyotsana; Gaur, R D; Siddiqi, T O; Painuli, R M

2013-12-12

Dysentery and diarrhoea are major causes of morbidity and mortality in rural communities of developing world. The Bhoxa community is an important primitive indigenous community of Uttarakhand, India. In this paper we have tried to scientifically enumerate ethnomedicinal plants and herbal preparations used by Bhoxa community to treat dysentery and diarrhoea, and discuss their antidiarrhoeal properties in the light of previous ethnomedicinal, pharmacological, microbiological and phytochemical studies. To record plants and herbal preparations used by Bhoxa community of district Dehradun, Uttarakhand, India in treatment of dysentery and diarrhoea, and to discuss antidiarrhoeal and antimicrobial properties of the recorded plants. Ethnomedicinal survey was conducted in different villages of Bhoxa community located in district Dehradun, Uttarakhand, India. Thirty Bhoxa traditional healers were interviewed to collect information on plants used by them for treating dysentery and diarrhoea. For each of the recorded plant species the use value (UV) and fidelity level (FL) was calculated. Detailed literature survey was conducted to summarize ethnomedicinal, pharmacological, microbiological and phytochemical information on the medicinal plants listed in the present study. Fifty medicinal plants (45 genera and 30 families) were used by Bhoxa community to treat dysentery and diarrhoea, among which 27 species were used for dysentery, 41 for diarrhoea and 18 for both dysentery and diarrhoea. Three plants viz., Dioscorea bulbifera L., Euphorbia thymifolia L. and Prunus persica (L.) Stokes, recorded in the present survey have been reported for the first time in treatment of dysentery and diarrhoea by any indigenous communities in India. FL and UV values revealed that most preferred species for the treatment of dysentery and diarrhoea by Bhoxa community are Euphorbia hirta L. followed by Holarrhena pubescens Wall., Helicteres isora L. and Cassia fistula L. Earlier pharmacological

[Edge effect of the plant community structure on land-bridge islands in the Thousand Island Lake].

Science.gov (United States)

Su, Xiao-Fei; Yuan, Jin-Feng; Hu, Guang; Xu, Gao-Fu; Yu, Ming-Jian

2014-01-01

The research was conducted on 29 land-bridge islands in the Thousand Island Lake (TIL), where long-term monitoring plots were set up during 2009-2010. The community attributes including species richness, Shannon index, plant mean height, plant mean diameter at breast height (DBH) and plant density along the edge-interior gradient from edge to interior forest were calculated to investigate the edge effect. The results showed that the species richness and Shannon index were affected through the whole gradient (larger than 50 m), while the range of edge effect was 20-30 m on mean plant height, and 10 m on plant density and mean DBH. Community attributes differed significantly among the edge gradients. The species richness and Shannon index peaked at the intermediate edge gradient. Plant density decreased and plant mean height increased along the edge to interior gradient. All five community attributes were significantly associated with the edge gradient, also different functional groups, evergreen or deciduous species, trees or shrubs, shade tolerant or shade intolerant species, were differentially influenced by the edge effect. It was demonstrated the influence of edge effect on the fragmented forest community varied with community attributes and functional groups.

Temporal dynamics of soil nematode communities in a grassland plant diversity experiment.

NARCIS (Netherlands)

Viketoft, M.; Sohlenius, B.; Bostrom, S.; Palmborg, C.; Bengtsson, J.; Berg, M.P.; Kuss-Danell, K.

2011-01-01

We report here on an 8-year study examining links between plant and nematode communities in a grassland plant diversity experiment, located in the north of Sweden on previous agricultural soil. The examined plots contained 1, 4 and 12 common grassland plant species from three functional groups;

Phytosociology and plant community utilisation by vervet monkeys of the Blydeberg Conservancy, Limpopo Province

Directory of Open Access Journals (Sweden)

A.S. Barret

2006-12-01

Full Text Available The plant communities of the Blydeberg Conservancy were investigated as part of a research project on the foraging ecology of vervet monkeys Cercopithecus aethiops pygerythrus (senso lato in mixed lowveld bushveld and sour lowveld bushveld areas. To date there are no formal management plans for vervet monkeys. This is attributed to the limited knowledge of vervets and their utilisation of and impacts on ecosystems. From a TWINSPAN classification refined by Braun-Blanquet procedures, ten plant communities that can be placed into four major groups were identified. A classification and description of these communities, including a vegetation map are presented. Diagnostic species as well as prominent and less conspicuous species of tree, shrub, herb and grass strata are outlined. Of the ten available plant communities, the vervets utilised only six during the study period. There was an abundant supply of various food sources throughout the year, with movement patterns mostly coinciding with the fruiting times of several tree and other plant species.

Responses of Ammonia-Oxidising Bacterial Communities to Nitrogen, Lime, and Plant Species in Upland Grassland Soil

International Nuclear Information System (INIS)

Rooney, D.C.; Kennedy, N.M.; Clipson, N.J.W.; Rooney, D.C.; Kennedy, N.M.; Gleeson, D.B.

2010-01-01

Agricultural improvement of semi natural grasslands has been shown to result in changes to plant and microbial diversity, with consequences for ecosystem functioning. A microcosm approach was used to elucidate the effects of two key components of agricultural improvement (nitrogen addition and liming) on ammonia-oxidising bacterial (AOB) communities in an upland grassland soil. Plant species characteristic of unimproved and improved pastures (A. capillaries and L. perenne) were planted in microcosms, and lime, nitrogen (NH 4 NO 3 ), or lime plus nitrogen added. The AOB community was profiled using terminal restriction fragment length polymorphism (TRFLP) of the amoA gene. AOB community structure was largely altered by NH 4 NO 3 addition, rather than liming, although interactions between nitrogen addition and plant species were also evident. Results indicate that nitrogen addition drives shifts in the structure of key microbial communities in upland grassland soils, and that plant species may play a significant role in determining AOB community structure

Linking the development and functioning of a carnivorous pitcher plant's microbial digestive community.

Science.gov (United States)

Armitage, David W

2017-11-01

Ecosystem development theory predicts that successional turnover in community composition can influence ecosystem functioning. However, tests of this theory in natural systems are made difficult by a lack of replicable and tractable model systems. Using the microbial digestive associates of a carnivorous pitcher plant, I tested hypotheses linking host age-driven microbial community development to host functioning. Monitoring the yearlong development of independent microbial digestive communities in two pitcher plant populations revealed a number of trends in community succession matching theoretical predictions. These included mid-successional peaks in bacterial diversity and metabolic substrate use, predictable and parallel successional trajectories among microbial communities, and convergence giving way to divergence in community composition and carbon substrate use. Bacterial composition, biomass, and diversity positively influenced the rate of prey decomposition, which was in turn positively associated with a host leaf's nitrogen uptake efficiency. Overall digestive performance was greatest during late summer. These results highlight links between community succession and ecosystem functioning and extend succession theory to host-associated microbial communities.

Coal mining activities change plant community structure due to air pollution and soil degradation.

Science.gov (United States)

Pandey, Bhanu; Agrawal, Madhoolika; Singh, Siddharth

2014-10-01

The aim of this study was to investigate the effects of coal mining activities on the community structures of woody and herbaceous plants. The response of individual plants of community to defilement caused by coal mining was also assessed. Air monitoring, soil physico-chemical and phytosociological analyses were carried around Jharia coalfield (JCF) and Raniganj coalfield. The importance value index of sensitive species minified and those of tolerant species enhanced with increasing pollution load and altered soil quality around coal mining areas. Although the species richness of woody and herbaceous plants decreased with higher pollution load, a large number of species acclimatized to the stress caused by the coal mining activities. Woody plant community at JCF was more affected by coal mining than herbaceous community. Canonical correspondence analysis revealed that structure of herbaceous community was mainly driven by soil total organic carbon, soil nitrogen, whereas woody layer community was influenced by sulphur dioxide in ambient air, soil sulphate and soil phosphorus. The changes in species diversity observed at mining areas indicated an increase in the proportion of resistant herbs and grasses showing a tendency towards a definite selection strategy of ecosystem in response to air pollution and altered soil characteristics.

Threats to Mediterranean rangelands: a case study based on the views of citizens in the Viotia prefecture, Greece.

Science.gov (United States)

Kyriazopoulos, Apostolos P; Arabatzis, Garyfallos; Abraham, Eleni M; Parissi, Zoi M

2013-11-15

Rangelands in Greece constitute a very important natural resource as they occupy 40% of the total surface. Not only is their forage production essential for the development of extensive livestock farming, but also they play a key role in outdoor recreational activities, protection from erosion, provision of water supplies and biodiversity conservation. However, land use changes, inappropriate management and wildfires threaten their existence. The research was conducted among the citizens of Viotia prefecture, an area close to Athens, Greece, using personal interviews with a structured questionnaire in 2008. The aim was to record citizens' opinions regarding the threats to rangelands. The results suggest that the main threats as perceived by the respondents, are land use changes especially for urban development, and wildfires. The application of cluster analysis highlighted the differentiation among the respondents in ranking these threats. The more ecologically aware citizens recognised that mismanagement, abandonment and agriculture also threaten rangelands. These threats can have a considerable impact on the lives of the local people. Policy makers and managers should take the opinions of local citizens into consideration, and engage them in decision making so that sustainable management policies could be applied. Copyright © 2013 Elsevier Ltd. All rights reserved.

Habitat Fragmentation Drives Plant Community Assembly Processes across Life Stages

Science.gov (United States)

Hu, Guang; Feeley, Kenneth J.; Yu, Mingjian

2016-01-01

Habitat fragmentation is one of the principal causes of biodiversity loss and hence understanding its impacts on community assembly and disassembly is an important topic in ecology. We studied the relationships between fragmentation and community assembly processes in the land-bridge island system of Thousand Island Lake in East China. We focused on the changes in species diversity and phylogenetic diversity that occurred between life stages of woody plants growing on these islands. The observed diversities were compared with the expected diversities from random null models to characterize assembly processes. Regression tree analysis was used to illustrate the relationships between island attributes and community assembly processes. We found that different assembly processes predominate in the seedlings-to-saplings life-stage transition (SS) vs. the saplings-to-trees transition (ST). Island area was the main attribute driving the assembly process in SS. In ST, island isolation was more important. Within a fragmented landscape, the factors driving community assembly processes were found to differ between life stage transitions. Environmental filtering had a strong effect on the seedlings-to-saplings life-stage transition. Habitat isolation and dispersal limitation influenced all plant life stages, but had a weaker effect on communities than area. These findings add to our understanding of the processes driving community assembly and species coexistence in the context of pervasive and widespread habitat loss and fragmentation. PMID:27427960

Development of an improved compact package plant for small community waste-water treatment

CSIR Research Space (South Africa)

Hulsman, A

1993-01-01

Full Text Available The challenges facing the design and operation of small community wastewater treatment plants are discussed. The package plant concept is considered and the consequent development of a compact intermittently aerated activated sludge package plant...

Purple pitcher plant (Sarracenia rosea Dieback and partial community disassembly following experimental storm surge in a coastal pitcher plant bog.

Directory of Open Access Journals (Sweden)

Matthew J Abbott

Full Text Available Sea-level rise and frequent intense hurricanes associated with climate change will result in recurrent flooding of inland systems such as Gulf Coastal pitcher plant bogs by storm surges. These surges can transport salt water and sediment to freshwater bogs, greatly affecting their biological integrity. Purple pitcher plants (Sarracenia rosea are Gulf Coast pitcher plant bog inhabitants that could be at a disadvantage under this scenario because their pitcher morphology may leave them prone to collection of saline water and sediment after a surge. We investigated the effects of storm surge water salinity and sediment type on S. rosea vitality, plant community structure, and bog soil-water conductivity. Plots (containing ≥1 ramet of S. rosea were experimentally flooded with fresh or saline water crossed with one of three sediment types (local, foreign, or no sediment. There were no treatment effects on soil-water conductivity; nevertheless, direct exposure to saline water resulted in significantly lower S. rosea cover until the following season when a prescribed fire and regional drought contributed to the decline of all the S. rosea to near zero percent cover. There were also significant differences in plant community structure between treatments over time, reflecting how numerous species increased in abundance and a few species decreased in abundance. However, in contrast to S. rosea, most of the other species in the community appeared resilient to the effects of storm surge. Thus, although the community may be somewhat affected by storm surge, those few species that are particularly sensitive to the storm surge disturbance will likely drop out of the community and be replaced by more resilient species. Depending on the longevity of these biological legacies, Gulf Coastal pitcher plant bogs may be incapable of fully recovering if they become exposed to storm surge more frequently due to climate change.

Does the edge effect influence plant community structure in a tropical dry forest?

Directory of Open Access Journals (Sweden)

Diogo Gallo Oliveira

2013-04-01

Full Text Available Edge effects are considered a key factor in regulating the structure of plant communities in different ecosystems. However, regardless to few studies, edge influence does not seem to be decisive in semiarid regions such as the Brazilian tropical dry forest known as Caatinga but this issue remains inconclusive. The present study tests the null hypothesis that the plant community of shrubs and trees does not change in its structure due to edge effects. Twenty-four plots (20 x 20 m were set up in a fragment of Caatinga, in which 12 plots were in the forest edges and 12 plots were inside the fragment. Tree richness, abundance and species composition did not differ between edge and interior plots. The results of this study are in agreement with the pattern previously found for semiarid environments and contrasts with previous results obtained in different environments such as Rainforests, Savanna and Forest of Araucaria, which indicate abrupt differences between the border and interior of the plant communities in these ecosystems, and suggest that the community of woody plants of the Caatinga is not ecologically affected by the presence of edges.

Evapotranspiration over spatially extensive plant communities in the Big Cypress National Preserve, southern Florida, 2007-2010

Science.gov (United States)

Shoemaker, W. Barclay; Lopez, Christian D.; Duever, Michael J.

2011-01-01

Evapotranspiration (ET) was quantified over plant communities within the Big Cypress National Preserve (BCNP) using the eddy covariance method for a period of 3 years from October 2007 to September 2010. Plant communities selected for study included Pine Upland, Wet Prairie, Marsh, Cypress Swamp, and Dwarf Cypress. These plant communities are spatially extensive in southern Florida, and thus, the ET measurements described herein can be applied to other humid subtropical locations such as the Everglades.

Competition for light and nutrients in layered communities of aquatic plants

NARCIS (Netherlands)

Van Gerven, Luuk P.A.; de Klein, J.J.M; Gerla, Daan J.; Kooi, B.W.; Kuiper, Jan J.; Mooij, Wolf M.

2015-01-01

Dominance of free-floating plants poses a threat to biodiversity in many freshwater ecosystems. Here we propose a theoretical framework to understand this dominance, by modeling the competition for light and nutrients in a layered community of floating and submerged plants. The model shows that at

Competition for Light and Nutrients in Layered Communities of Aquatic Plants

NARCIS (Netherlands)

van Gerven, L.P.A.; de Klein, J.J.M.; Gerla, D.J.; Kooi, B.W.; Kuiper, J.J.; Mooij, W.M.

2015-01-01

Dominance of free-floating plants poses a threat to biodiversity in many freshwater ecosystems. Here we propose a theoretical framework to understand this dominance, by modeling the competition for light and nutrients in a layered community of floating and submerged plants. The model shows that at

Competition for light and nutrients in layered communities of aquatic plants

NARCIS (Netherlands)

Gerven, van Luuk P.A.; Klein, de Jeroen J.M.; Gerla, Daan J.; Kooi, Bob W.; Kuiper, Jan J.; Mooij, Wolf M.

2015-01-01

Dominance of free-floating plants poses a threat to biodiversity in many freshwater ecosystems. Here we propose a theoretical framework to understand this dominance, by modeling the competition for light and nutrients in a layered community of floating and submerged plants. The model shows that

A planning support system for rangeland allocation in Iran : case of Chadegan sub-region

NARCIS (Netherlands)

Farahpour, M.

2002-01-01

Rangelands, like other natural resources are subject to many changes. In Iran, one of the changes is the land tenure reform, that may have significant effects on both the land and the land user. Land tenure changes not only affect the life of the present, but also that of next generations,

Functional diversity in plant communities: Theory and analysis ...

African Journals Online (AJOL)

Plant functional diversity in community has become a key point in ecology studies recently. The development of species functional diversity was reviewed in the present work. Based on the former original research papers and reviews, we discussed the concept and connotation and put forward a new definition of functional ...

Plant communities as drivers of soil respiration: pathways, mechanisms, and significance for global change

Science.gov (United States)

Metcalfe, D. B.; Fisher, R. A.; Wardle, D. A.

2011-03-01

Understanding the impacts of plant community characteristics on soil carbon dioxide efflux (R) is a key prerequisite for accurate prediction of the future carbon balance of terrestrial ecosystems under climate change. In this review, we synthesize relevant information from a wide spectrum of sources to evaluate the current state of knowledge about plant community effects on R, examine how this information is incorporated into global climate models, and highlight priorities for future research. Plant species consistently exhibit cohesive suites of traits, linked to contrasting life history strategies, which exert a variety of impacts on R. As such, we propose that plant community shifts towards dominance by fast growing plants with nutrient rich litter could provide a major, though often neglected, positive feedback to climate change. Within vegetation types, belowground carbon flux will mainly be controlled by photosynthesis, while amongst vegetation types this flux will be more dependent upon the specific characteristics of the plant life form. We also make the case that community composition, rather than diversity, is usually the dominant control on ecosystem processes in natural systems. Individual species impacts on R may be largest where the species accounts for most of the biomass in the ecosystem, has very distinct traits to the rest of the community, or modulates the occurrence of major natural disturbances. We show that climate-vegetation models incorporate a number of pathways whereby plants can affect R, but that simplifications regarding allocation schemes and drivers of litter decomposition may limit model accuracy. This situation could, however, be relatively easily improved with targeted experimental and field studies. Finally, we identify key gaps in knowledge and recommend them as priorities for future work. These include the patterns of photosynthate partitioning amongst belowground components, ecosystem level effects of individual plant traits

Contrasting trait responses in plant communities to experimental and geographic variation in precipitation

DEFF Research Database (Denmark)

Sandel, Brody Steven; Goldstein, Leah; Kraft, Nathan

2010-01-01

Patterns of precipitation are likely to change significantly in the coming century, with important but poorly understood consequences for plant communities. Experimental and correlative studies may provide insight into expected changes, but little research has addressed the degree of concordance...... between these approaches. We synthesized results from four experimental water addition studies with a correlative analysis of community changes across a large natural precipitation gradient in the United States. We investigated whether community composition, summarized with plant functional traits......, responded similarly to increasing precipitation among studies and sites. In field experiments, increased precipitation favored species with small seed size,short leaf life span and high leaf nitrogen (N) concentration. However, with increasing precipitation along the natural gradient, community composition...

The Community's research and development programme on decommissioning of nuclear power plants

International Nuclear Information System (INIS)

1982-01-01

The programme, adopted by the Council of the European Communities, seeks to promote a number of research and development projects as well as the identification of guiding principles. The projects concern the following subjects: long-term integrity of buildings and systems; decontaminations for decommissioning purposes; dismantling techniques; treatment of specific waste materials (steel, concrete and graphite); large transport containers for radioactive waste arising from decommissioning of nuclear power plants in the Community; and influence of nuclear power plant design features on decommissioning

Soil-landform-plant communities relationships of a periglacial landscape at Potter Peninsula, Maritime Antarctica

Science.gov (United States)

Poelking, E. L.; Schaefer, C. E. R.; Fernandes Filho, E. I.; de Andrade, A. M.; Spielmann, A. A.

2014-08-01

Integrated studies on the interplay between soils, periglacial geomorphology and plant communities are crucial for the understanding of climate change effects on terrestrial ecosystems of Maritime Antarctica, one of the most sensitive areas to global warming. Knowledge on physical environmental factors that influence plant communities can greatly benefit studies on monitoring climate change in Maritime Antarctica, where new ice-free areas are being constantly exposed, allowing plant growth and organic carbon inputs. The relationship between topography, plant communities and soils was investigated in Potter Peninsula, King George Island, Maritime Antarctica. We mapped the occurrence and distribution of plant communities and identified soil-landform-vegetation relationships. The vegetation map was obtained by classification of a Quickbird image, coupled with detailed landform and characterization of 18 soil profiles. The sub-formations were identified and classified, and we also determined the total elemental composition of lichens, mosses and grasses. Plant communities at Potter Peninsula occupy 23% of the ice-free area, at different landscape positions, showing decreasing diversity and biomass from the coastal zone to inland areas where sub-desert conditions prevail. There is a clear dependency between landform and vegetated soils. Soils with greater moisture or poorly drained, and acid to neutral pH, are favourable for mosses subformations. Saline, organic-matter rich ornithogenic soils of former penguin rookeries have greater biomass and diversity, with mixed associations of mosses and grasses, while stable felseenmeers and flat rocky cryoplanation surfaces are the preferred sites for Usnea and Himantormia lugubris lichens, at the highest surface. Lichens subformations cover the largest vegetated area, showing varying associations with mosses.

Problems in implementing improved range management on ...

African Journals Online (AJOL)

Keywords: Africa; Australia; Livestock development; Pastoral communities; Rangeland development; Rangeland systems; Sustainability; development; ecology; holism; pastoralism; range management; strategies; environment; water; health; crop production; rangelands; resource management; north africa; holistic approach ...

Ecology of some mire and bog plant communities in the Western Italian Alps

Directory of Open Access Journals (Sweden)

Giorgio BUFFA

2003-02-01

Full Text Available During a mire vegetation study, conducted mainly in the subalpine-alpine sector of the Western Italian Alps, the ecology of several plant communities and numerous moss species of this kind of vegetation was evaluated. The study area covered the Piedmontese sector of the Graian Alps, the eastern sector of the Aosta Valley as well as certain localities of the Pennine Alps, the Canavese district and the Maritime Alps. They have a rocky substratum representative of the various regional lithologies and include the main sectors characterised by the highest precipitation. Three hundred and twenty two relevées were made using the phytosociological method and the pH and the conductivity of the water table and its depth were measured directly. Cluster Analysis allowed a classification of the samples and the identification of various groups of plant communities. Ordination performed by DCA and CCA allowed us to identify the ecological features of the various plant communities by using the values of the main environmental parameters, measured directly in the field, and certain climatic parameters (altitude and mean annual precipitation available. The use of climatic parameters is an important result for identifying communities which show greater oceanicity, something that is underlined also by the presence of indicator species such as Sphagnum papillosum and S. subnitens. Furthermore the communities are arranged in a "poor-rich" gradient, and are also profoundly influenced by depth to water table which is inversely correlated to the pH. Therefore we find certain kinds of communities all with a very low water table and which are little affected by its chemistry. Other groups share the fact that the water table is outcropping or near the surface and are distinguishable for their pH values and conductivity. We discuss the different response of the bryophytes and vascular plants of these communities to the environmental parameters considered, in light of their

How plants connect pollination and herbivory networks and their contribution to community stability.

Science.gov (United States)

Sauve, Alix M C; Thébault, Elisa; Pocock, Michael J O; Fontaine, Colin

2016-04-01

Pollination and herbivory networks have mainly been studied separately, highlighting their distinct structural characteristics and the related processes and dynamics. However, most plants interact with both pollinators and herbivores, and there is evidence that both types of interaction affect each other. Here we investigated the way plants connect these mutualistic and antagonistic networks together, and the consequences for community stability. Using an empirical data set, we show that the way plants connect pollination and herbivory networks is not random and promotes community stability. Analyses of the structure of binary and quantitative networks show different results: the plants' generalism with regard to pollinators is positively correlated to their generalism with regard to herbivores when considering binary interactions, but not when considering quantitative interactions. We also show that plants that share the same pollinators do not share the same herbivores. However, the way plants connect pollination and herbivory networks promotes stability for both binary and quantitative networks. Our results highlight the relevance of considering the diversity of interaction types in ecological communities, and stress the need to better quantify the costs and benefits of interactions, as well as to develop new metrics characterizing the way different interaction types are combined within ecological networks.

Environmental and community controls on plant canopy chemistry in a Mediterranean-type ecosystem.

Science.gov (United States)

Dahlin, Kyla M; Asner, Gregory P; Field, Christopher B

2013-04-23

Understanding how and why plant communities vary across space has long been a goal of ecology, yet parsing the relative importance of different influences has remained a challenge. Species-specific models are not generalizable, whereas broad plant functional type models lack important detail. Here we consider plant trait patterns at the local scale and ask whether plant chemical traits are more closely linked to environmental gradients or to changes in species composition. We used the visible-to-shortwave infrared (VSWIR) spectrometer of the Carnegie Airborne Observatory to develop maps of four plant chemical traits--leaf nitrogen per mass, leaf carbon per mass, leaf water concentration, and canopy water content--across a diverse Mediterranean-type ecosystem (Jasper Ridge Biological Preserve, CA). For all four traits, plant community alone was the strongest predictor of trait variation (explaining 46-61% of the heterogeneity), whereas environmental gradients accounted for just one fourth of the variation in the traits. This result emphasizes the critical role that species composition plays in mediating nutrient and carbon cycling within and among different communities. Environmental filtering and limits to similarity can act strongly, simultaneously, in a spatially heterogeneous environment, but the local-scale environmental gradients alone cannot account for the variation across this landscape.

Wastewater treatment plant effluent introduces recoverable shifts in microbial community composition in urban streams

Science.gov (United States)

Ledford, S. H.; Price, J. R.; Ryan, M. O.; Toran, L.; Sales, C. M.

2017-12-01

New technologies are allowing for intense scrutiny of the impact of land use on microbial communities in stream networks. We used a combination of analytical chemistry, real-time polymerase chain reaction (qPCR) and targeted amplicon sequencing for a preliminary study on the impact of wastewater treatment plant effluent discharge on urban streams. Samples were collected on two dates above and below treatment plants on the Wissahickon Creek, and its tributary, Sandy Run, in Montgomery County, PA, USA. As expected, effluent was observed to be a significant source of nutrients and human and non-specific fecal associated taxa. There was an observed increase in the alpha diversity at locations immediately below effluent outflows, which contributed many taxa involved in wastewater treatment processes and nutrient cycling to the stream's microbial community. Unexpectedly, modeling of microbial community shifts along the stream was not controlled by concentrations of measured nutrients. Furthermore, partial recovery, in the form of decreasing abundances of bacteria and nutrients associated with wastewater treatment plant processes, nutrient cycling bacteria, and taxa associated with fecal and sewage sources, was observed between effluent sources. Antecedent moisture conditions impacted overall microbial community diversity, with higher diversity occurring after rainfall. These findings hint at resilience in stream microbial communities to recover from wastewater treatment plant effluent and are vital to understanding the impacts of urbanization on microbial stream communities.

The Effects of Disturbance History on Ground-Layer Plant Community Composition in British Columbia

Directory of Open Access Journals (Sweden)

Michael Ton

2016-05-01

Full Text Available Plant communities are sensitive to perturbations and may display alternative recovery pathways depending on disturbance history. In sub-boreal lodgepole pine forests of central interior British Columbia, Canada, fire and logging are two widespread landscape disturbances that overlap in many regions. We asked whether cumulative, short-interval disturbance from logging and fire resulted in different ground-layer plant communities than resulted from fire alone. Using field-collected data, we compared the taxonomic composition and functional traits of 3-year old plant communities that were either harvested 6-to-13 years prior, or not harvested prior to being burned in a large stand-replacing fire. The taxonomic composition diverged between the two treatments, driven primarily by differences in a few key indicator species such as Petasites frigidus and Vaccinium membranaceum. Analysis of individual species’ morphological traits indicated that only a few species vary in size in relation to disturbance history. Our data suggest that a history of forest harvest leaves a subtle footprint on post-fire ground-layer plant communities at early stages of succession.

The impact of plant chemical diversity on plant-herbivore interactions at the community level.

Science.gov (United States)

Salazar, Diego; Jaramillo, Alejandra; Marquis, Robert J

2016-08-01

Understanding the role of diversity in ecosystem processes and species interactions is a central goal of ecology. For plant-herbivore interactions, it has been hypothesized that when plant species diversity is reduced, loss of plant biomass to herbivores increases. Although long-standing, this hypothesis has received mixed support. Increasing plant chemical diversity with increasing plant taxonomic diversity is likely to be important for plant-herbivore interactions at the community level, but the role of chemical diversity is unexplored. Here we assess the effect of volatile chemical diversity on patterns of herbivore damage in naturally occurring patches of Piper (Piperaceae) shrubs in a Costa Rican lowland wet forest. Volatile chemical diversity negatively affected total, specialist, and generalist herbivore damage. Furthermore, there were differences between the effects of high-volatility and low-volatility chemical diversity on herbivore damage. High-volatility diversity reduced specialist herbivory, while low-volatility diversity reduced generalist herbivory. Our data suggest that, although increased plant diversity is expected to reduce average herbivore damage, this pattern is likely mediated by the diversity of defensive compounds and general classes of anti-herbivore traits, as well as the degree of specialization of the herbivores attacking those plants.

Meat fatty acid and cholesterol level of free-range broilers fed on grasshoppers on alpine rangeland in the Tibetan Plateau.

Science.gov (United States)

Sun, Tao; Liu, Zhiyun; Qin, Liping; Long, Ruijun

2012-08-30

Meat safety and nutrition are major concerns of consumers. The development of distinctive poultry production methods based on locally available natural resources is important. Grasshoppers are rich in important nutrients and occur in dense concentrations in most rangelands of northern China. Foraging chickens could be used to suppress grasshopper infestations. However, knowledge of the fatty acid content of meat from free-range broilers reared on alpine rangeland is required. Rearing conditions and diet did not significantly (P > 0.05) affect concentrations of saturated fatty acid (SFA), arachidonic acid, docosahexaenoic acid or the ratio of total n-6 to total n-3 fatty acids. Breast muscle of chickens that had consumed grasshoppers contained significantly (P 0.05) higher than intensively reared birds. Compared with meat from intensively reared birds, meat from free-range broilers had less cholesterol and higher concentrations of total lipid and phospholipids. Chickens eating grasshoppers in rangeland produce superior quality meat and reduce the grasshopper populations that damage the pastures. This provides an economic system of enhanced poultry-meat production, which derives benefits from natural resources rather than artificial additives. Copyright © 2012 Society of Chemical Industry.

Weight gain and behavior of Raramuri Criollo versus Corriente steers developed on Chihuahuan Desert rangeland

Science.gov (United States)

Ranchers that raise Criollo cattle must overcome the challenge of lack of markets for weaned calves. Raramuri Criollo (RC) steers are commonly raised for beef and finished on rangelands, while Corriente (CR) are often raised for rodeo sports. No data exist on weight gains and grazing behavior of ran...

Weight gain and behavior of Raramuri Criollo versus crossbred steers developed on Chihuahuan Desert rangeland

Science.gov (United States)

Ranchers that raise Raramuri Criollo (RC) cattle must overcome the challenge of lack of markets for weaned calves. Growing and finishing RC or RC-crossbred steers on rangeland pastures is increasingly common; however, no data exist on their weight gains or grazing behavior. We tracked the weight a...

Comparative Assessment of Goods and Services Provided by Grazing Regulation and Reforestation in Degraded Mediterranean Rangelands

NARCIS (Netherlands)

Papanastasis, Vasilios P.; Bautista, Susana; Chouvardas, Dimitrios; Mantzanas, Konstantinos; Papadimitriou, Maria; Garcia Mayor, Angeles; Koukioumi, Polina; Papaioannou, Athanasios; Vallejo, Ramon V.

2017-01-01

Several management actions are applied to restore ecosystem services in degraded Mediterranean rangelands, which range from adjusting the grazing pressure to the removal of grazers and pine plantations. Four such actions were assessed in Quercus coccifera L. shrublands in northern Greece: (i)

Plant communities as drivers of soil respiration: pathways, mechanisms, and significance for global change

Science.gov (United States)

Metcalfe, D. B.; Fisher, R. A.; Wardle, D. A.

2011-08-01

Understanding the impacts of plant community characteristics on soil carbon dioxide efflux (R) is a key prerequisite for accurate prediction of the future carbon (C) balance of terrestrial ecosystems under climate change. However, developing a mechanistic understanding of the determinants of R is complicated by the presence of multiple different sources of respiratory C within soil - such as soil microbes, plant roots and their mycorrhizal symbionts - each with their distinct dynamics and drivers. In this review, we synthesize relevant information from a wide spectrum of sources to evaluate the current state of knowledge about plant community effects on R, examine how this information is incorporated into global climate models, and highlight priorities for future research. Despite often large variation amongst studies and methods, several general trends emerge. Mechanisms whereby plants affect R may be grouped into effects on belowground C allocation, aboveground litter properties and microclimate. Within vegetation types, the amount of C diverted belowground, and hence R, may be controlled mainly by the rate of photosynthetic C uptake, while amongst vegetation types this should be more dependent upon the specific C allocation strategies of the plant life form. We make the case that plant community composition, rather than diversity, is usually the dominant control on R in natural systems. Individual species impacts on R may be largest where the species accounts for most of the biomass in the ecosystem, has very distinct traits to the rest of the community and/or modulates the occurrence of major natural disturbances. We show that climate vegetation models incorporate a number of pathways whereby plants can affect R, but that simplifications regarding allocation schemes and drivers of litter decomposition may limit model accuracy. We also suggest that under a warmer future climate, many plant communities may shift towards dominance by fast growing plants which

Incorporating the soil environment and microbial community into plant competition theory.

Science.gov (United States)

Ke, Po-Ju; Miki, Takeshi

2015-01-01

Plants affect microbial communities and abiotic properties of nearby soils, which in turn influence plant growth and interspecific interaction, forming a plant-soil feedback (PSF). PSF is a key determinant influencing plant population dynamics, community structure, and ecosystem functions. Despite accumulating evidence for the importance of PSF and development of specific PSF models, different models are not yet fully integrated. Here, we review the theoretical progress in understanding PSF. When first proposed, PSF was integrated with various mathematical frameworks to discuss its influence on plant competition. Recent theoretical models have advanced PSF research at different levels of ecological organizations by considering multiple species, applying spatially explicit simulations to examine how local-scale predictions apply to larger scales, and assessing the effect of PSF on plant temporal dynamics over the course of succession. We then review two foundational models for microbial- and litter-mediated PSF. We present a theoretical framework to illustrate that although the two models are typically presented separately, their behavior can be understood together by invasibility analysis. We conclude with suggestions for future directions in PSF theoretical studies, which include specifically addressing microbial diversity to integrate litter- and microbial-mediated PSF, and apply PSF to general coexistence theory through a trait-based approach.

Incorporating the soil environment and microbial community into plant competition theory

Science.gov (United States)

Ke, Po-Ju; Miki, Takeshi

2015-01-01

Plants affect microbial communities and abiotic properties of nearby soils, which in turn influence plant growth and interspecific interaction, forming a plant-soil feedback (PSF). PSF is a key determinant influencing plant population dynamics, community structure, and ecosystem functions. Despite accumulating evidence for the importance of PSF and development of specific PSF models, different models are not yet fully integrated. Here, we review the theoretical progress in understanding PSF. When first proposed, PSF was integrated with various mathematical frameworks to discuss its influence on plant competition. Recent theoretical models have advanced PSF research at different levels of ecological organizations by considering multiple species, applying spatially explicit simulations to examine how local-scale predictions apply to larger scales, and assessing the effect of PSF on plant temporal dynamics over the course of succession. We then review two foundational models for microbial- and litter-mediated PSF. We present a theoretical framework to illustrate that although the two models are typically presented separately, their behavior can be understood together by invasibility analysis. We conclude with suggestions for future directions in PSF theoretical studies, which include specifically addressing microbial diversity to integrate litter- and microbial-mediated PSF, and apply PSF to general coexistence theory through a trait-based approach. PMID:26500621

Incorporating the soil environment and microbial community into plant competition theory

Directory of Open Access Journals (Sweden)

Po-Ju eKe

2015-10-01

Full Text Available Plants affect microbial communities and abiotic properties of nearby soils, which in turn influence plant growth and interspecific interaction, forming a plant-soil feedback (PSF. PSF is a key determinant influencing plant population dynamics, community structure, and ecosystem functions. Despite accumulating evidence for the importance of PSF and development of specific PSF models, different models are not yet fully integrated. Here, we review the theoretical progress in understanding PSF. When first proposed, PSF was integrated with various mathematical frameworks to discuss its influence on plant competition. Recent theoretical models have advanced PSF research at different levels of ecological organizations by considering multiple species, applying spatially explicit simulations to examine how local-scale predictions apply to larger scales, and assessing the effect of PSF on plant temporal dynamics over the course of succession. We then review two foundational models for microbial- and litter-mediated PSF. We present a theoretical framework to illustrate that although the two models are typically presented separately, their behavior can be understood together by invasibility analysis. We conclude with suggestions for future directions in PSF theoretical studies, which include specifically addressing microbial diversity to integrate litter- and microbial-mediated PSF, and apply PSF to general coexistence theory through a trait-based approach.

Lags in the response of mountain plant communities to climate change.

Science.gov (United States)

Alexander, Jake M; Chalmandrier, Loïc; Lenoir, Jonathan; Burgess, Treena I; Essl, Franz; Haider, Sylvia; Kueffer, Christoph; McDougall, Keith; Milbau, Ann; Nuñez, Martin A; Pauchard, Aníbal; Rabitsch, Wolfgang; Rew, Lisa J; Sanders, Nathan J; Pellissier, Loïc

2018-02-01

Rapid climatic changes and increasing human influence at high elevations around the world will have profound impacts on mountain biodiversity. However, forecasts from statistical models (e.g. species distribution models) rarely consider that plant community changes could substantially lag behind climatic changes, hindering our ability to make temporally realistic projections for the coming century. Indeed, the magnitudes of lags, and the relative importance of the different factors giving rise to them, remain poorly understood. We review evidence for three types of lag: "dispersal lags" affecting plant species' spread along elevational gradients, "establishment lags" following their arrival in recipient communities, and "extinction lags" of resident species. Variation in lags is explained by variation among species in physiological and demographic responses, by effects of altered biotic interactions, and by aspects of the physical environment. Of these, altered biotic interactions could contribute substantially to establishment and extinction lags, yet impacts of biotic interactions on range dynamics are poorly understood. We develop a mechanistic community model to illustrate how species turnover in future communities might lag behind simple expectations based on species' range shifts with unlimited dispersal. The model shows a combined contribution of altered biotic interactions and dispersal lags to plant community turnover along an elevational gradient following climate warming. Our review and simulation support the view that accounting for disequilibrium range dynamics will be essential for realistic forecasts of patterns of biodiversity under climate change, with implications for the conservation of mountain species and the ecosystem functions they provide. © 2017 John Wiley & Sons Ltd.

Lags in the response of mountain plant communities to climate change

Science.gov (United States)

Alexander, Jake M.; Chalmandrier, Loïc; Lenoir, Jonathan; Burgess, Treena I.; Essl, Franz; Haider, Sylvia; Kueffer, Christoph; McDougall, Keith; Milbau, Ann; Nuñez, Martin A.; Pauchard, Aníbal; Rabitsch, Wolfgang; Rew, Lisa J.; Sanders, Nathan J.; Pellissier, Loïc

2018-01-01

Rapid climatic changes and increasing human influence at high elevations around the world will have profound impacts on mountain biodiversity. However, forecasts from statistical models (e.g. species distribution models) rarely consider that plant community changes could substantially lag behind climatic changes, hindering our ability to make temporally realistic projections for the coming century. Indeed, the magnitudes of lags, and the relative importance of the different factors giving rise to them, remain poorly understood. We review evidence for three types of lag: “dispersal lags” affecting plant species’ spread along elevational gradients, “establishment lags” following their arrival in recipient communities, and “extinction lags” of resident species. Variation in lags is explained by variation among species in physiological and demographic responses, by effects of altered biotic interactions, and by aspects of the physical environment. Of these, altered biotic interactions could contribute substantially to establishment and extinction lags, yet impacts of biotic interactions on range dynamics are poorly understood. We develop a mechanistic community model to illustrate how species turnover in future communities might lag behind simple expectations based on species’ range shifts with unlimited dispersal. The model shows a combined contribution of altered biotic interactions and dispersal lags to plant community turnover along an elevational gradient following climate warming. Our review and simulation support the view that accounting for disequilibrium range dynamics will be essential for realistic forecasts of patterns of biodiversity under climate change, with implications for the conservation of mountain species and the ecosystem functions they provide. PMID:29112781

Rangeland livestock production: Developing the concept of sustainability on the Santa Rita Experimental Range

Science.gov (United States)

George B. Ruyle

2003-01-01

The Santa Rita Experimental Range (SRER) was established in 1903 at the behest of concerned stockmen and researchers as the first facility in the United States set aside to study range livestock production. At the time, severe overgrazing of the public domain had seriously reduced carrying capacities of Southwestern rangelands. Researchers on the SRER developed and...

Vascular plant diversity and community Structure of nandi forests ...

African Journals Online (AJOL)

Abundance data of species was used for species diversity, similarity, species richness estimation and plant community analysis. PC-ORD, CANOCO and EstimateS were used to analyze the data. A total of 321 species ... Keywords: floristic composition, ordination, rarefaction, species accumulation, species richness.

Andean shrublands of Moquegua, South Peru: Prepuna plant communities

NARCIS (Netherlands)

Montesinos, D.B.; Cleef, A.M.; Sykora, K.V.

2012-01-01

A syntaxonomic overview of shrubland vegetation in the southern Andean regions of Peru is presented. For each plant community, information is given on physiognomy, floristic diversity, ecology and geographical distribution. The shrub vegetation on the slopes of the upper Tambo river valley includes

Evolution in plant populations as a driver of ecological changes in arthropod communities.

Science.gov (United States)

Johnson, Marc T J; Vellend, Mark; Stinchcombe, John R

2009-06-12

Heritable variation in traits can have wide-ranging impacts on species interactions, but the effects that ongoing evolution has on the temporal ecological dynamics of communities are not well understood. Here, we identify three conditions that, if experimentally satisfied, support the hypothesis that evolution by natural selection can drive ecological changes in communities. These conditions are: (i) a focal population exhibits genetic variation in a trait(s), (ii) there is measurable directional selection on the trait(s), and (iii) the trait(s) under selection affects variation in a community variable(s). When these conditions are met, we expect evolution by natural selection to cause ecological changes in the community. We tested these conditions in a field experiment examining the interactions between a native plant (Oenothera biennis) and its associated arthropod community (more than 90 spp.). Oenothera biennis exhibited genetic variation in several plant traits and there was directional selection on plant biomass, life-history strategy (annual versus biennial reproduction) and herbivore resistance. Genetically based variation in biomass and life-history strategy consistently affected the abundance of common arthropod species, total arthropod abundance and arthropod species richness. Using two modelling approaches, we show that evolution by natural selection in large O. biennis populations is predicted to cause changes in the abundance of individual arthropod species, increases in the total abundance of arthropods and a decline in the number of arthropod species. In small O. biennis populations, genetic drift is predicted to swamp out the effects of selection, making the evolution of plant populations unpredictable. In short, evolution by natural selection can play an important role in affecting the dynamics of communities, but these effects depend on several ecological factors. The framework presented here is general and can be applied to other systems to

Evolution in plant populations as a driver of ecological changes in arthropod communities

Science.gov (United States)

Johnson, Marc T.J.; Vellend, Mark; Stinchcombe, John R.

2009-01-01

Heritable variation in traits can have wide-ranging impacts on species interactions, but the effects that ongoing evolution has on the temporal ecological dynamics of communities are not well understood. Here, we identify three conditions that, if experimentally satisfied, support the hypothesis that evolution by natural selection can drive ecological changes in communities. These conditions are: (i) a focal population exhibits genetic variation in a trait(s), (ii) there is measurable directional selection on the trait(s), and (iii) the trait(s) under selection affects variation in a community variable(s). When these conditions are met, we expect evolution by natural selection to cause ecological changes in the community. We tested these conditions in a field experiment examining the interactions between a native plant (Oenothera biennis) and its associated arthropod community (more than 90 spp.). Oenothera biennis exhibited genetic variation in several plant traits and there was directional selection on plant biomass, life-history strategy (annual versus biennial reproduction) and herbivore resistance. Genetically based variation in biomass and life-history strategy consistently affected the abundance of common arthropod species, total arthropod abundance and arthropod species richness. Using two modelling approaches, we show that evolution by natural selection in large O. biennis populations is predicted to cause changes in the abundance of individual arthropod species, increases in the total abundance of arthropods and a decline in the number of arthropod species. In small O. biennis populations, genetic drift is predicted to swamp out the effects of selection, making the evolution of plant populations unpredictable. In short, evolution by natural selection can play an important role in affecting the dynamics of communities, but these effects depend on several ecological factors. The framework presented here is general and can be applied to other systems to

Linkage between bacterial and fungal rhizosphere communities in hydrocarbon-contaminated soils is related to plant phylogeny.

Science.gov (United States)

Bell, Terrence H; El-Din Hassan, Saad; Lauron-Moreau, Aurélien; Al-Otaibi, Fahad; Hijri, Mohamed; Yergeau, Etienne; St-Arnaud, Marc

2014-02-01

Phytoremediation is an attractive alternative to excavating and chemically treating contaminated soils. Certain plants can directly bioremediate by sequestering and/or transforming pollutants, but plants may also enhance bioremediation by promoting contaminant-degrading microorganisms in soils. In this study, we used high-throughput sequencing of bacterial 16S rRNA genes and the fungal internal transcribed spacer (ITS) region to compare the community composition of 66 soil samples from the rhizosphere of planted willows (Salix spp.) and six unplanted control samples at the site of a former petrochemical plant. The Bray-Curtis distance between bacterial communities across willow cultivars was significantly correlated with the distance between fungal communities in uncontaminated and moderately contaminated soils but not in highly contaminated (HC) soils (>2000 mg kg(-1) hydrocarbons). The mean dissimilarity between fungal, but not bacterial, communities from the rhizosphere of different cultivars increased substantially in the HC blocks. This divergence was partly related to high fungal sensitivity to hydrocarbon contaminants, as demonstrated by reduced Shannon diversity, but also to a stronger influence of willows on fungal communities. Abundance of the fungal class Pezizomycetes in HC soils was directly related to willow phylogeny, with Pezizomycetes dominating the rhizosphere of a monophyletic cluster of cultivars, while remaining in low relative abundance in other soils. This has implications for plant selection in phytoremediation, as fungal associations may affect the health of introduced plants and the success of co-inoculated microbial strains. An integrated understanding of the relationships between fungi, bacteria and plants will enable the design of treatments that specifically promote effective bioremediating communities.

Climate impacts on bird and plant communities from altered animal-plant interactions

Science.gov (United States)

Martin, Thomas E.; Maron, John L.

2012-01-01

The contribution of climate change to declining populations of organisms remains a question of outstanding concern. Much attention to declining populations has focused on how changing climate drives phenological mismatches between animals and their food. Effects of climate on plant communities may provide an alternative, but particularly powerful, influence on animal populations because plants provide their habitats. Here, we show that abundances of deciduous trees and associated songbirds have declined with decreasing snowfall over 22 years of study in montane Arizona, USA. We experimentally tested the hypothesis that declining snowfall indirectly influences plants and associated birds by allowing greater over-winter herbivory by elk (Cervus canadensis). We excluded elk from one of two paired snowmelt drainages (10 ha per drainage), and replicated this paired experiment across three distant canyons. Over six years, we reversed multi-decade declines in plant and bird populations by experimentally inhibiting heavy winter herbivory associated with declining snowfall. Moreover, predation rates on songbird nests decreased in exclosures, despite higher abundances of nest predators, demonstrating the over-riding importance of habitat quality to avian recruitment. Thus, our results suggest that climate impacts on plant–animal interactions can have forceful ramifying effects on plants, birds, and ecological interactions.

Soil-landform-plant-community relationships of a periglacial landscape on Potter Peninsula, maritime Antarctica

Science.gov (United States)

Poelking, E. L.; Schaefer, C. E. R.; Fernandes Filho, E. I.; de Andrade, A. M.; Spielmann, A. A.

2015-05-01

Integrated studies on the interplay between soils, periglacial geomorphology and plant communities are crucial for the understanding of climate change effects on terrestrial ecosystems of maritime Antarctica, one of the most sensitive areas to global warming. Knowledge on physical environmental factors that influence plant communities can greatly benefit studies on the monitoring of climate change in maritime Antarctica, where new ice-free areas are being constantly exposed, allowing plant growth and organic carbon inputs. The relationship between topography, plant communities and soils was investigated on Potter Peninsula, King George Island, maritime Antarctica. We mapped the occurrence and distribution of plant communities and identified soil-landform-vegetation relationships. The vegetation map was obtained by classification of a QuickBird image, coupled with detailed landform and characterization of 18 soil profiles. The sub-formations were identified and classified, and we also determined the total elemental composition of lichens, mosses and grasses. Plant communities on Potter Peninsula occupy 23% of the ice-free area, at different landscape positions, showing decreasing diversity and biomass from the coastal zone to inland areas where sub-desert conditions prevail. There is a clear dependency between landform and vegetated soils. Soils that have greater moisture or are poorly drained, and with acid to neutral pH, are favourable for moss sub-formations. Saline, organic-matter-rich ornithogenic soils of former penguin rookeries have greater biomass and diversity, with mixed associations of mosses and grasses, while stable felsenmeers and flat rocky cryoplanation surfaces are the preferred sites for Usnea and Himantormia lugubris lichens at the highest surface. Lichens sub-formations cover the largest vegetated area, showing varying associations with mosses.

Resistance and resilience of tundra plant communities to disturbance by winter seismic vehicles

International Nuclear Information System (INIS)

Felix, N.A.; Raynolds, M.K.; Jorgenson, J.C.; DuBois, K.E.

1992-01-01

Effects of winter seismic exploration on arctic tundra were evaluated on the coastal plain of the Arctic National Wildlife Refuge, four to five growing seasons after disturbance. Plant cover, active layer depths, and track depression were measured at plots representing major tundra plant communities and different levels of initial disturbance. Results are compared with the initial effects reported earlier. Little resilience was seen in any vegetation type, with no clearly decreasing trends in community dissimilarity. Active layer depths remained greater on plots in all nonriparian vegetation types, and most plots still had visible trails. Decreases in plant cover persisted on most plots, although a few species showed recovery or increases in cover above predisturbance level. Moist sedge-shrub tundra and dryas terraces had the largest community dissimilarities initially, showing the least resistance to high levels of winter vehicle disturbance. Community dissimilarity continued to increase for five seasons in moist sedge-shrub tundra, with species composition changing to higher sedge cover and lower shrub cover. The resilience amplitude may have been exceeded on four plots which had significant track depression

Legacy effects of no-analogue disturbances alter plant community diversity and composition in semi-arid sagebrush steppe

Science.gov (United States)

Ripplinger, Julie; Franklin, Janet; Edwards, Thomas C.

2015-01-01

Questions(i) What role does the type of managed disturbance play in structuring sagebrush steppe plant communities? (ii) How does the composition of post-disturbance plant communities change with time since disturbance? (iii) Does plant community diversity change over time following managed disturbance?LocationField study within the sagebrush steppe ecosystem. Rich County, Utah, USA.MethodsWe developed a chronosequence spanning up to 50 yrs post-treatment to study sagebrush steppe vegetation dynamics. Direct ordination was used to examine plant community composition by managed disturbance type and time since disturbance, and factorial analysis of covariance was used to examine diversity dynamics following disturbance. Indicator species values were calculated in order to identify characteristic species for each disturbance type.ResultsPlant communities experienced a shift toward distinct community composition for each of the three managed disturbance types, and gave no indication of returning to untreated community composition or diversity. Small post-disturbance increases in the number of non-native grass species were observed in the treatments relative to reference, with native forb species making the largest contribution to altered composition. On fire- and chemically-treated sites the proportional native forb species richness increased over time since disturbance, while the proportional contribution of non-native forbs to total species richness decreased. For all three treatment types, native grasses contributed less on average to total richness than on reference sites, while non-native grasses made up a higher proportion of total richness.ConclusionsCommon shrubland management techniques have legacy effects on the composition and diversity of sagebrush steppe plant communities, and no-analogue disturbances, such as chemical or mechanical treatments, have more pronounced legacy effects than treatments similar to natural disturbance regimes (fire). This study

Plant domestication and the assembly of bacterial and fungal communities associated with strains of the common sunflower, Helianthus annuus.

Science.gov (United States)

Leff, Jonathan W; Lynch, Ryan C; Kane, Nolan C; Fierer, Noah

2017-04-01

Root and rhizosphere microbial communities can affect plant health, but it remains undetermined how plant domestication may influence these bacterial and fungal communities. We grew 33 sunflower (Helianthus annuus) strains (n = 5) that varied in their extent of domestication and assessed rhizosphere and root endosphere bacterial and fungal communities. We also assessed fungal communities in the sunflower seeds to investigate the degree to which root and rhizosphere communities were influenced by vertical transmission of the microbiome through seeds. Neither root nor rhizosphere bacterial communities were affected by the extent of sunflower domestication, but domestication did affect the composition of rhizosphere fungal communities. In particular, more modern sunflower strains had lower relative abundances of putative fungal pathogens. Seed-associated fungal communities strongly differed across strains, but several lines of evidence suggest that there is minimal vertical transmission of fungi from seeds to the adult plants. Our results indicate that plant-associated fungal communities are more strongly influenced by host genetic factors and plant breeding than bacterial communities, a finding that could influence strategies for optimizing microbial communities to improve crop yields. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Using Plant Functional Traits and Phylogenies to Understand Patterns of Plant Community Assembly in a Seasonal Tropical Forest in Lao PDR.

Directory of Open Access Journals (Sweden)

Manichanh Satdichanh

Full Text Available Plant functional traits reflect different evolutionary responses to environmental variation, and among extant species determine the outcomes of interactions between plants and their environment, including other plant species. Thus, combining phylogenetic and trait-based information can be a powerful approach for understanding community assembly processes across a range of spatial scales. We used this approach to investigate tree community composition at Phou Khao Khouay National Park (18°14'-18°32'N; 102°38'- 102°59'E, Laos, where several distinct forest types occur in close proximity. The aim of our study was to examine patterns of plant community assembly across the strong environmental gradients evident at our site. We hypothesized that differences in tree community composition were being driven by an underlying gradient in soil conditions. Thus, we predicted that environmental filtering would predominate at the site and that the filtering would be strongest on sandier soil with low pH, as these are the conditions least favorable to plant growth. We surveyed eleven 0.25 ha (50x50 m plots for all trees above 10 cm dbh (1221 individual trees, including 47 families, 70 genera and 123 species and sampled soils in each plot. For each species in the community, we measured 11 commonly studied plant functional traits covering both the leaf and wood economic spectrum traits and we reconstructed a phylogenetic tree for 115 of the species in the community using rbcL and matK sequences downloaded from Genebank (other species were not available. Finally we compared the distribution of trait values and species at two scales (among plots and 10x10m subplots to examine trait and phylogenetic community structures. Although there was strong evidence that an underlying soil gradient was determining patterns of species composition at the site, our results did not support the hypothesis that the environmental filtering dominated community assembly processes

Hierarchical spatial point process analysis for a plant community with high biodiversity

DEFF Research Database (Denmark)

Illian, Janine B.; Møller, Jesper; Waagepetersen, Rasmus

2009-01-01

A complex multivariate spatial point pattern of a plant community with high biodiversity is modelled using a hierarchical multivariate point process model. In the model, interactions between plants with different post-fire regeneration strategies are of key interest. We consider initially a maxim...

Tracking fungal community responses to maize plants by DNA- and RNA-based pyrosequencing.

Directory of Open Access Journals (Sweden)

Eiko E Kuramae

Full Text Available We assessed soil fungal diversity and community structure at two sampling times (t1 = 47 days and t2 = 104 days of plant age in pots associated with four maize cultivars, including two genetically modified (GM cultivars by high-throughput pyrosequencing of the 18S rRNA gene using DNA and RNA templates. We detected no significant differences in soil fungal diversity and community structure associated with different plant cultivars. However, DNA-based analyses yielded lower fungal OTU richness as compared to RNA-based analyses. Clear differences in fungal community structure were also observed in relation to sampling time and the nucleic acid pool targeted (DNA versus RNA. The most abundant soil fungi, as recovered by DNA-based methods, did not necessary represent the most "active" fungi (as recovered via RNA. Interestingly, RNA-derived community compositions at t1 were highly similar to DNA-derived communities at t2, based on presence/absence measures of OTUs. We recovered large proportions of fungal sequences belonging to arbuscular mycorrhizal fungi and Basidiomycota, especially at the RNA level, suggesting that these important and potentially beneficial fungi are not affected by the plant cultivars nor by GM traits (Bt toxin production. Our results suggest that even though DNA- and RNA-derived soil fungal communities can be very different at a given time, RNA composition may have a predictive power of fungal community development through time.

Biomass, Leaf Area, and Resource Availability of Kudzu Dominated Plant Communities Following Herbicide Treatment

Energy Technology Data Exchange (ETDEWEB)

L.T. Rader

2001-10-01

Kudzu is an exotic vine that threatens the forests of the southern U.S. Five herbicides were tested with regard to their efficacy in controlling kudzu, community recover was monitored, and interactions with planted pines were studied. The sites selected were old farm sites dominated by kudzu.These were burned following herbicide treatment. The herbicides included triclopyr, clopyralid, metsulfuron, tebuthiuron, and picloram plus 2,4-D. Pine seedlings were planted the following year. Regression equations were developed for predicting biomass and leaf area. Four distinct plant communities resulted from the treatments. The untreated check continued to be kudzu dominated. Blackberry dominated the clopyradid treatment. Metsulfron, trychlopyr and picloram treated sites resulted in herbaceous dominated communities. The tebuthiuron treatment maintained all vegetation low.

Water and Nitrogen Limitations of Ecosystem Processes Across Three Dryland Plant Communities

Science.gov (United States)

Beltz, C.; Lauenroth, W. K.; Burke, I. C.

2017-12-01

The availability of water and nitrogen (N) play a major role in controlling the distribution of ecosystem types and the rates of ecosystem processes across the globe. Both these resources are being altered by human activity. Anthropogenic fixation of N has increased inputs into the biosphere from 0.5 kg N ha-1 yr-1 to upwards of 10 kg N ha-1 yr-1, while the amount and seasonality of precipitation are expected to continue to change. Within dryland environments, the relationships between increasingly available N and ecosystem processes are especially complex due to dryland's characteristic strong limitation by low and highly variable precipitation. Other experiments have shown that this interplay between N and water can cause temporally complex co-limitation and spatially complex responses with variable effects on ecosystems, such as those to net primary productivity, soil respiration, and plant community composition. Research spanning multiple dryland plant communities is critical for generalizing findings to the 40% of the Earth's terrestrial surface covered in dryland ecosystems. Given IPCC projections in which both N availability and precipitation are altered, examining their interactive effect across multiple plant communities is critical to increasing our understanding of the limitations to ecosystem process in drylands. We are studying a gradient of three plant communities representing a C4 grassland (shortgrass steppe), a C3/C4 grassland (mixed grass prairie), and a shrub-dominated ecosystem with C3 and C4 grasses (sagebrush steppe). We added two levels of N (10 kg N ha-1 and 100 kg N ha-1) and increased summer monthly precipitation by 20%. Sites responded differently to treatments, with the scale of effect varying by treatment. The high-level nitrogen increased soil N availability and soil respiration, while decreasing soil carbon in the labile pool in the upper soil layers. These results will allow for better understanding of increased N in combination with

Community-Weighted Mean Plant Traits Predict Small Scale Distribution of Insect Root Herbivore Abundance.

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Ilja Sonnemann

Full Text Available Small scale distribution of insect root herbivores may promote plant species diversity by creating patches of different herbivore pressure. However, determinants of small scale distribution of insect root herbivores, and impact of land use intensity on their small scale distribution are largely unknown. We sampled insect root herbivores and measured vegetation parameters and soil water content along transects in grasslands of different management intensity in three regions in Germany. We calculated community-weighted mean plant traits to test whether the functional plant community composition determines the small scale distribution of insect root herbivores. To analyze spatial patterns in plant species and trait composition and insect root herbivore abundance we computed Mantel correlograms. Insect root herbivores mainly comprised click beetle (Coleoptera, Elateridae larvae (43% in the investigated grasslands. Total insect root herbivore numbers were positively related to community-weighted mean traits indicating high plant growth rates and biomass (specific leaf area, reproductive- and vegetative plant height, and negatively related to plant traits indicating poor tissue quality (leaf C/N ratio. Generalist Elaterid larvae, when analyzed independently, were also positively related to high plant growth rates and furthermore to root dry mass, but were not related to tissue quality. Insect root herbivore numbers were not related to plant cover, plant species richness and soil water content. Plant species composition and to a lesser extent plant trait composition displayed spatial autocorrelation, which was not influenced by land use intensity. Insect root herbivore abundance was not spatially autocorrelated. We conclude that in semi-natural grasslands with a high share of generalist insect root herbivores, insect root herbivores affiliate with large, fast growing plants, presumably because of availability of high quantities of food. Affiliation of

Soils as a Solution: The Potential of Rangelands to Contribute to Climate Change Mitigation

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Silver, W. L.; Ryals, R.; DeLonge, M. S.; Owen, J. J.

2015-12-01

The majority of soil-related climate change research has focused on describing the problem - estimating rates of carbon (C) losses and greenhouse gas (GHG) emissions from natural and managed ecosystems. More research is needed to explore potential solutions to climate change through mitigation and adaptation. Here we report on an integrated set of studies aimed at critically evaluating the biogeochemical potential of rangeland soils to help mitigate climate change, while improving the sustainability and productivity of food production systems. We explored direct effects through enhanced net primary production (NPP) and soil C sequestration, and indirect effects through diversion of high emitting sources to lower emitting organic matter dynamics. We used a combination of long- and short-term field experiments, modeling, laboratory assays, life cycle assessment (LCA), and meta-analyses in consultation with a diverse group of stakeholders from both the private and public sectors. We found that organic matter amendments held particularly strong potential. Compost amendments increased soil C storage by 0.5-1.0 Mg C ha-1 y-1 in surface soils over 5 y, and increased NPP and water holding capacity. We measured 1.0 Mg of new C ha-1 y-1 over 3 y. Long-term amendment of cattle manure increased surface soil C by 19.0±7.3 Mg C ha-1 relative to unmanured fields. However, field and modeling experiments suggested that manure amendments lead to large nitrous oxide emissions that eventually eliminated CO2e benefits, whereas compost amendments continued to benefit climate for decades longer. An LCA identified a broader range of climate impacts. When scaled to an area of 25% of California's rangelands, new C sequestered following compost amendments (21 million Mg CO2e) exceeded emissions from cattle (15 million Mg CO2e); diverting organics from waste streams to amendments led to additional GHG savings. In collaboration with our partners, our research contributed to the development of

Concentration of petroleum-hydrocarbon contamination shapes fungal endophytic community structure in plant roots

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Guillaume eBourdel

2016-05-01

Full Text Available Plant-root inhabiting fungi are a universal phenomenon found in all ecosystems where plants are able to grow, even in harsh environments. Interactions between fungi and plant roots can vary widely from mutualism to parasitism depending on many parameters. The role of fungal endophytes in phytoremediation of polluted sites, and characterization of the endophytic diversity and community assemblages in contaminated areas remain largely unexplored. In this study, we investigated the composition of endophytic fungal communities in the roots of two plant species growing spontaneously in petroleum-contaminated sedimentation basins of a former petro-chemical plant. The three adjacent basins showed a highly heterogeneous patterns of pollutant concentrations. We combined a culture-based isolation approach with the pyrosequencing of fungal ITS ribosomal DNA. We selected two species, Eleocharis erythropoda Steud. and Populus balsamifera L., and sampled three individuals of each species from each of three adjacent basins, each with a different concentration of petroleum hydrocarbons. We found that contamination level significantly shaped endophytic fungal diversity and community composition in E. erythropoda, with only 9.9% of these fungal Operational Taxonomic Units (OTUs retrieved in all three basins. However, fungal community structure associated with P. balsamifera remained unaffected by the contamination level with 28.2% of fungal OTUs shared among all three basins. This could be explained by the smaller differences of pollutant concentrations in the soil around our set of P. balsamifera sampless compared to that around our set of E. erythropoda samples. Our culture-based approach allowed isolation of 11 and 30 fungal endophytic species from surface-sterilized roots of E. erythropoda and P. balsamifera, respectively. These isolates were ribotyped using ITS, and all were found in pyrosequensing datasets. Our results demonstrate that extreme levels of

THE CONCENTRATION OF PHOTOSINTHESIS PIGMENTS IN THE ANTHROPOGENIC PLANT COMMUNITIES IN TOBOLSK TOWN

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Еlena Ivanovna Popova

2016-10-01

Full Text Available Photosynthesis means a lot in the life of a plant body. For the normal photosynthesis process it is necessary to have certain external and internal conditions. The topic of the research is the study of photosynthesis pigments in anthropogenic plant communities. The aim of our work was to study the pigment composition plants of anthropogenic phytocenoses. Methods: we have used the spectrophotometric method to define the concentration of pigments. Results: the research has shown that the concentration of a – chlorophyll, b – chlorophyll and carotenoids changes depending on the site conditions. The maximal concentration of a and b chlorophyll is found on less polluted areas. High carotenoid concentration was found in stress anthropogenic conditions. On the one hand, this carotenoid concentration decreases the stress effect. On the other hand it fulfils the protection function, preventing the chlorophyll molecules and other organic substances from destruction. In the research you will find the species composition of vascular plants on the sites under research. Jaccard’s coefficient of community has been defined. Field of application of results: the data can be used to predict the dynamics of populations and communities of plants in the contaminated areas and monitor the status of natural ecosystems.

Plant communities as drivers of soil respiration: pathways, mechanisms, and significance for global change

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D. B. Metcalfe

2011-08-01

Full Text Available Understanding the impacts of plant community characteristics on soil carbon dioxide efflux (R is a key prerequisite for accurate prediction of the future carbon (C balance of terrestrial ecosystems under climate change. However, developing a mechanistic understanding of the determinants of R is complicated by the presence of multiple different sources of respiratory C within soil – such as soil microbes, plant roots and their mycorrhizal symbionts – each with their distinct dynamics and drivers. In this review, we synthesize relevant information from a wide spectrum of sources to evaluate the current state of knowledge about plant community effects on R, examine how this information is incorporated into global climate models, and highlight priorities for future research. Despite often large variation amongst studies and methods, several general trends emerge.

Mechanisms whereby plants affect R may be grouped into effects on belowground C allocation, aboveground litter properties and microclimate. Within vegetation types, the amount of C diverted belowground, and hence R, may be controlled mainly by the rate of photosynthetic C uptake, while amongst vegetation types this should be more dependent upon the specific C allocation strategies of the plant life form. We make the case that plant community composition, rather than diversity, is usually the dominant control on R in natural systems. Individual species impacts on R may be largest where the species accounts for most of the biomass in the ecosystem, has very distinct traits to the rest of the community and/or modulates the occurrence of major natural disturbances. We show that climate vegetation models incorporate a number of pathways whereby plants can affect R, but that simplifications regarding allocation schemes and drivers of litter decomposition may limit model accuracy. We also suggest that under a warmer future

Climate change drives a shift in peatland ecosystem plant community: implications for ecosystem function and stability.

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Dieleman, Catherine M; Branfireun, Brian A; McLaughlin, James W; Lindo, Zoë

2015-01-01

The composition of a peatland plant community has considerable effect on a range of ecosystem functions. Peatland plant community structure is predicted to change under future climate change, making the quantification of the direction and magnitude of this change a research priority. We subjected intact, replicated vegetated poor fen peat monoliths to elevated temperatures, increased atmospheric carbon dioxide (CO2 ), and two water table levels in a factorial design to determine the individual and synergistic effects of climate change factors on the poor fen plant community composition. We identify three indicators of a regime shift occurring in our experimental poor fen system under climate change: nonlinear decline of Sphagnum at temperatures 8 °C above ambient conditions, concomitant increases in Carex spp. at temperatures 4 °C above ambient conditions suggesting a weakening of Sphagnum feedbacks on peat accumulation, and increased variance of the plant community composition and pore water pH through time. A temperature increase of +4 °C appeared to be a threshold for increased vascular plant abundance; however the magnitude of change was species dependent. Elevated temperature combined with elevated CO2 had a synergistic effect on large graminoid species abundance, with a 15 times increase as compared to control conditions. Community analyses suggested that the balance between dominant plant species was tipped from Sphagnum to a graminoid-dominated system by the combination of climate change factors. Our findings indicate that changes in peatland plant community composition are likely under future climate change conditions, with a demonstrated shift toward a dominance of graminoid species in poor fens. © 2014 John Wiley & Sons Ltd.

Estimating climate change effects on net primary production of rangelands in the United States

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Matthew C. Reeves; Adam L. Moreno; Karen E. Bagne; Steven W. Running

2014-01-01

The potential effects of climate change on net primary productivity (NPP) of U.S. rangelands were evaluated using estimated climate regimes from the A1B, A2 and B2 global change scenarios imposed on the biogeochemical cycling model, Biome-BGC from 2001 to 2100. Temperature, precipitation, vapor pressure deficit, day length, solar radiation, CO2 enrichment and nitrogen...

Restructuring of endophytic bacterial communities in grapevine yellows-diseased and recovered Vitis vinifera L. plants.

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Bulgari, Daniela; Casati, Paola; Crepaldi, Paola; Daffonchio, Daniele; Quaglino, Fabio; Brusetti, Lorenzo; Bianco, Piero Attilio

2011-07-01

Length heterogeneity-PCR assays, combined with statistical analyses, highlighted that the endophytic bacterial community associated with healthy grapevines was characterized by a greater diversity than that present in diseased and recovered plants. The findings suggest that phytoplasmas can restructure the bacterial community by selecting endophytic strains that could elicit a plant defense response.

A Post Licensing Study of Community Effects at Two Operating Nuclear Power Plants. Final Report.

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Purdy, Bruce J.; And Others

In an effort to identify and assess the social, economic, and political effects of nuclear power plant construction and operation upon two host communities (Plymouth, Massachusetts and Waterford, Connecticut), a post-licensing review revealed that the primary impact of the nuclear power plants in both communities was an increase in the property…

Three-dimensional framework of vigor, organization, and resilience (VOR) for assessing rangeland health: a case study from the alpine meadow of the Qinghai-Tibetan Plateau, China.

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Li, Yuan-yuan; Dong, Shi-kui; Wen, Lu; Wang, Xue-xia; Wu, Yu

2013-12-01

Rangeland health assessments play an important role in providing qualitative and quantitative data about ecosystem attributes and rangeland management. The objective of this study is to test the feasible of a modified model and visualize the health in a three-dimensional model. A modified Costanza model was employed, and eight indicators, including the biomass, biodiversity, and carrying capacity [associated with the vigor, organization, and resilience (VOR)] were applied. An entropy method was also developed to calculate the weight of each indicator, and a three-dimensional framework was applied to visualize the indicators and health index. The conceptual model was demonstrated using data from a case study on the alpine rangeland of the Qinghai-Tibetan Plateau, one of the globally important grassland biomes being severely degraded by natural and human factors. The health indices of four grassland plots at different levels of degradation were calculated using a modified approach to measuring their VOR. The results indicated that the least disturbed plot was relatively healthy compared to the other plots. In addition, the health indices presented in the three-dimensional VOR framework decreased in a consistent manner across the four plots along the disturbance gradients. Such rangeland health assessments should be integrated with management efforts to insure their long-term sustainable use.

Summer freezing resistance: a critical filter for plant community assemblies in Mediterranean high mountains

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David Sánchez Pescador

2016-02-01

Full Text Available Assessing freezing community response and whether freezing resistance is related to other functional traits is essential for understanding alpine community assemblages, particularly in Mediterranean environments where plants are exposed to freezing temperatures and summer droughts. Thus, we characterized the leaf freezing resistance of 42 plant species in 38 plots at Sierra de Guadarrama (Spain by measuring their ice nucleation temperature, freezing point (FP, and low-temperature damage (LT50, as well as determining their freezing resistance mechanisms (i.e., tolerance or avoidance. The community response to freezing was estimated for each plot as community weighted means (CWMs and functional diversity, and we assessed their relative importance with altitude. We established the relationships between freezing resistance, growth forms, and four key plant functional traits (i.e., plant height, specific leaf area, leaf dry matter content, and seed mass. There was a wide range of freezing resistance responses and more than in other alpine habitats. At the community level, the CWMs of FP and LT50 responded negatively to altitude, whereas the functional diversity of both traits increased with altitude. The proportion of freezing-tolerant species also increased with altitude. The ranges of FP and LT50 varied among growth forms, and only the leaf dry matter content correlated negatively with freezing-resistance traits. Summer freezing events represent important abiotic filters for assemblies of Mediterranean high mountain communities, as suggested by the CWMs. However, a concomitant summer drought constraint may also explain the high freezing resistance of species that thrive in these areas and the lower functional diversity of freezing resistance traits at lower altitudes. Leaves with high dry matter contents may maintain turgor at lower water potential and enhance drought tolerance in parallel to freezing resistance. This adaptation to drought seems to

Conceptual hierarchical modeling to describe wetland plant community organization

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Little, A.M.; Guntenspergen, G.R.; Allen, T.F.H.

2010-01-01

Using multivariate analysis, we created a hierarchical modeling process that describes how differently-scaled environmental factors interact to affect wetland-scale plant community organization in a system of small, isolated wetlands on Mount Desert Island, Maine. We followed the procedure: 1) delineate wetland groups using cluster analysis, 2) identify differently scaled environmental gradients using non-metric multidimensional scaling, 3) order gradient hierarchical levels according to spatiotem-poral scale of fluctuation, and 4) assemble hierarchical model using group relationships with ordination axes and post-hoc tests of environmental differences. Using this process, we determined 1) large wetland size and poor surface water chemistry led to the development of shrub fen wetland vegetation, 2) Sphagnum and water chemistry differences affected fen vs. marsh / sedge meadows status within small wetlands, and 3) small-scale hydrologic differences explained transitions between forested vs. non-forested and marsh vs. sedge meadow vegetation. This hierarchical modeling process can help explain how upper level contextual processes constrain biotic community response to lower-level environmental changes. It creates models with more nuanced spatiotemporal complexity than classification and regression tree procedures. Using this process, wetland scientists will be able to generate more generalizable theories of plant community organization, and useful management models. ?? Society of Wetland Scientists 2009.

Abandoned floodplain plant communities along a regulated dryland river

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Reynolds, L. V.; Shafroth, Patrick B.; House, P. K.

2014-01-01

Rivers and their floodplains worldwide have changed dramatically over the last century because of regulation by dams, flow diversions and channel stabilization. Floodplains no longer inundated by river flows following dam-induced flood reduction comprise large areas of bottomland habitat, but the effects of abandonment on plant communities are not well understood. Using a hydraulic flow model, geomorphic mapping and field surveys, we addressed the following questions along the Bill Williams River, Arizona: (i) What per cent of the bottomland do abandoned floodplains comprise? and (ii) Are abandoned floodplains quantitatively different from adjacent xeric and riparian surfaces in terms of vegetation composition and surface sediment? We found that nearly 70% of active channel and floodplain area was abandoned following dam installation. Abandoned floodplains along the Bill Williams River tend to be similar to each other yet distinct from neighbouring habitats: they have been altered physically from their historic state, leading to distinct combinations of surface sediments, hydrology and plant communities. Abandoned floodplains may transition to xeric communities over time but are likely to retain some riparian qualities as long as there is access to relatively shallow ground water. With expected increases in water demand and drying climatic conditions in many regions, these surfaces and associated vegetation will continue to be extensive in riparian landscapes worldwide

[Species, functional, structural diversity of typical plant communities and their responses to environmental factors in Miao Archipelago, China.

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Zheng, Li Ting; Su, Tian; Liu, Xiang Yu; Yin, Fang; Guo, Chao; Tuo, Bin; Yan, En Rong

2018-02-01

Island vegetation plays an important role in biodiversity research across the world. The study of plant diversity in island is helpful for understanding the mechanism of plant diversity maintenance under land-sea interaction. Here, four typical plant communities (Quercus acutissima community, Robinia pseudoacacia community, Pinus thunbergii community and Vitex negundo community) in Miao Archipelago were selected to examine the species, functional and structural diversities and their responses to environmental factors at the community scale by using species diversity indices, functional diversity indices, as well as structural diversity indices. The results showed that the species richness and Rao index of P. thunbergii community was higher than that of Q. acutissima community and R. pseudoacacia community, but the structural diversity was lower. The species diversity and structural diversity of V. Negundo shrub were lower than that of forest community, but the functional diversity was higher than some forest communities. The relationship between the diversity of typical plant communities in island area illustrated a significant positive correlation between species richness with Rao index and tree height diversity, however the correlation with functional evenness was significantly negative. The structural diversity and functional evenness were determined by slope with negative and positive relationships, respectively. Functional heterogeneity, functional divergence and species diversity were affected largely by soil physical and chemical properties, displaying the positive relationship with soil bulk density and soil total carbon content, and a negative relationship with soil water content. In conclusion, diversity pattern of plant community in Miao Archipelago reflected not only the characteristics in mainland vegetation but also the special nature of the sea island.

Use of local pastoral species to increase fodder production of the saline rangelands in southern Tunisia

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Tlili, Abderrazak; Tarhouni, Mohamed; Cardà, Artemi; Neffati, Mohamed

2017-04-01

Climate changes associated with multiple destructive human activities accelerate the degradation process of the natural rangelands around the world and especially the vulnerable areas such as the dryland ecosystems (Anaya-Romero et al., 2015; Eskandari et al., 2016; Muños Rojas et al., 2016; Vicente-Serrano et al., 2016). The vegetation cover and the biomass production of these ecosystems are decreasing and this is resulting in land degradation due to the soil erosion and changes in soil quality due to the abuse and misuse of the soil resources (Cerdà et al., 2016; Prosdocimi et al., 2016; Keesstra et al., 2016). To cope with such threats, it is necessary to develop some management techniques (restoration, plantation…) to enhance the biomass production and the carbon sequestration of the degraded rangelands (Muñoz-Rojas et al., 2016; Tarhouni et al., 2016). The valorization of saline water by planting pastoral halophyte species in salt-affected soils as well as the marginal areas are considered among the valuable tools to increase the rangeland production in dry areas. In this work, the ability of four plants (Atriplex halimus L. (Amaranthaceae), Atriplex mollis Desf. (Amaranthaceae), Lotus creticus L. (Fabaceae) and Cenchrus ciliaris L. (Poaceae)) to grow and to produce are tested under a field saline conditions (water and soil). Non-destructive method (Vegmeasure) is used to estimate the biomass production of these species. Chemical (crude protein, moisture and ash contents) and biochemical analyses (sugars, tannins and polyphenols contents) are also undertaken. Two years after plantation, the obtained results showed the ability of the four species to survive and to grow under high salinity degree. A strong positive correlation was obtained between the canopy cover and the dry biomass of the four studied species. Hence, the restoration of saline soils can be ensured by planting local halophytes. Acknowledgements. The research leading to these results has

Interactions among predators and the cascading effects of vertebrate insectivores on arthropod communities and plants.

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Mooney, Kailen A; Gruner, Daniel S; Barber, Nicholas A; Van Bael, Sunshine A; Philpott, Stacy M; Greenberg, Russell

2010-04-20

Theory on trophic interactions predicts that predators increase plant biomass by feeding on herbivores, an indirect interaction called a trophic cascade. Theory also predicts that predators feeding on predators, or intraguild predation, will weaken trophic cascades. Although past syntheses have confirmed cascading effects of terrestrial arthropod predators, we lack a comprehensive analysis for vertebrate insectivores-which by virtue of their body size and feeding habits are often top predators in these systems-and of how intraguild predation mediates trophic cascade strength. We report here on a meta-analysis of 113 experiments documenting the effects of insectivorous birds, bats, or lizards on predaceous arthropods, herbivorous arthropods, and plants. Although vertebrate insectivores fed as intraguild predators, strongly reducing predaceous arthropods (38%), they nevertheless suppressed herbivores (39%), indirectly reduced plant damage (40%), and increased plant biomass (14%). Furthermore, effects of vertebrate insectivores on predatory and herbivorous arthropods were positively correlated. Effects were strongest on arthropods and plants in communities with abundant predaceous arthropods and strong intraguild predation, but weak in communities depauperate in arthropod predators and intraguild predation. The naturally occurring ratio of arthropod predators relative to herbivores varied tremendously among the studied communities, and the skew to predators increased with site primary productivity and in trees relative to shrubs. Although intraguild predation among arthropod predators has been shown to weaken herbivore suppression, we find this paradigm does not extend to vertebrate insectivores in these communities. Instead, vertebrate intraguild preda-tion is associated with strengthened trophic cascades, and insectivores function as dominant predators in terrestrial plant-arthropod communities.

A baseline classification of riparian woodland plant communities in ...

African Journals Online (AJOL)

The plots were placed along a gradient from the main water body to the drier fringe of the riparian zone. Plant species present in each plot were recorded with their estimated percentage cover using the Braun–Blanquet cover abundance scale. Hierarchical cluster analysis was used to determine vegetation communities.

Isolated and Community Contexts Produce Distinct Responses by Host Plants to the Presence of Ant-Aphid Interaction: Plant Productivity and Seed Viability

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Santiago, Graziele Silva; Zurlo, Luana Fonseca; Ribas, Carla Rodrigues; Carvalho, Rafaela Pereira; Alves, Guilherme Pereira; Carvalho, Mariana Comanucci Silva; Souza, Brígida

2017-01-01

Ant-aphid interactions may affect host plants in several ways, however, most studies measure only the amount of fruit and seed produced, and do not test seed viability. Therefore, the aim of this study was to assess the effects of the presence of ant-aphid interactions upon host plant productivity and seed viability in two different contexts: isolated and within an arthropod community. For this purpose we tested the hypothesis that in both isolated and community contexts, the presence of an ant-aphid interaction will have a positive effect on fruit and seed production, seed biomass and rate of seed germination, and a negative effect on abnormal seedling rates, in comparison to plants without ants. We performed a field mesocosm experiment containing five treatments: Ant-aphid, Aphid, Community, Ant-free community and Control. We counted fruits and seeds produced by each treatment, and conducted experiments for seed biomass and germinability. We found that in the community context the presence of an ant-aphid interaction negatively affected fruit and seed production. We think this may be because aphid attendance by tending-ants promotes aphid damage to the host plant, but without an affect on seed weight and viability. On the other hand, when isolated, the presence of an ant-aphid interaction positively affected fruit and seed production. These positive effects are related to the cleaning services offered to aphids by tending-ants, which prevent the development of saprophytic fungi on the surface of leaves, which would cause a decrease in photosynthetic rates. Our study is important because we evaluated some parameters of plant fitness that have not been addressed very well by other studies involving the effects of ant-aphid interactions mainly on plants with short life cycles. Lastly, our context dependent approach sheds new light on how ecological interactions can vary among different methods of crop management. PMID:28141849

Isolated and Community Contexts Produce Distinct Responses by Host Plants to the Presence of Ant-Aphid Interaction: Plant Productivity and Seed Viability.

Directory of Open Access Journals (Sweden)

Ernesto Oliveira Canedo-Júnior

Full Text Available Ant-aphid interactions may affect host plants in several ways, however, most studies measure only the amount of fruit and seed produced, and do not test seed viability. Therefore, the aim of this study was to assess the effects of the presence of ant-aphid interactions upon host plant productivity and seed viability in two different contexts: isolated and within an arthropod community. For this purpose we tested the hypothesis that in both isolated and community contexts, the presence of an ant-aphid interaction will have a positive effect on fruit and seed production, seed biomass and rate of seed germination, and a negative effect on abnormal seedling rates, in comparison to plants without ants. We performed a field mesocosm experiment containing five treatments: Ant-aphid, Aphid, Community, Ant-free community and Control. We counted fruits and seeds produced by each treatment, and conducted experiments for seed biomass and germinability. We found that in the community context the presence of an ant-aphid interaction negatively affected fruit and seed production. We think this may be because aphid attendance by tending-ants promotes aphid damage to the host plant, but without an affect on seed weight and viability. On the other hand, when isolated, the presence of an ant-aphid interaction positively affected fruit and seed production. These positive effects are related to the cleaning services offered to aphids by tending-ants, which prevent the development of saprophytic fungi on the surface of leaves, which would cause a decrease in photosynthetic rates. Our study is important because we evaluated some parameters of plant fitness that have not been addressed very well by other studies involving the effects of ant-aphid interactions mainly on plants with short life cycles. Lastly, our context dependent approach sheds new light on how ecological interactions can vary among different methods of crop management.

Ethnobotany of wild plants used for starting fermented beverages in Shui communities of southwest China.

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Hong, Liya; Zhuo, Jingxian; Lei, Qiyi; Zhou, Jiangju; Ahmed, Selena; Wang, Chaoying; Long, Yuxiao; Li, Feifei; Long, Chunlin

2015-05-28

Shui communities of southwest China have an extensive history of using wild plants as starters (Xiaoqu) to prepare fermented beverages that serve important roles in interpersonal relationships and cultural events. While the practice of using wild plants as starters for the preparation of fermented beverages was once prevalent throughout China, this tradition has seen a decline nationally since the 1930s. The traditional technique of preparing fermented beverages from wild plant starters remains well preserved in the Shui communities in southwest China and provides insight on local human-environment interactions and conservation of plant biodiversity for cultural purposes. The present study sought to examine the ethnobotany of wild plants used as starters for the preparation of fermented beverages including an inventory of plants used as a starter in liquor fermentation and associated knowledge and practices. Field surveys were carried out that consisted of semi-structured surveys and plant species inventories. One hundred forty-nine informants in twenty Shui villages were interviewed between July 2012 and October 2014 to document knowledge associated with wild plants used as a liquor fermentation starter. The inventories involved plant voucher specimens and taxonomic identification of plant collections. A total of 103 species in 57 botanical families of wild plants were inventoried and documented that are traditionally used as starters for preparing fermented beverages by Shui communities. The majority of the species (93.2%) have multiple uses in addition to being used as a starter with medicinal purposes being the most prevalent. Shui women are the major harvesters and users of wild plants used as starters for preparing fermented beverages and transfer knowledge orally from mother to daughter. Findings from this study can serve as a basis for future investigation on fermented beverages and foods and associated knowledge and cultural practices. However, with rapid

Development of the crop residue and rangeland burning in the 2014 National Emissions Inventory using information from multiple sources

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U.S. Environmental Protection Agency — This workbook contains all the activity data, emission factor data, and ancillary data used to compute crop residue burning and rangeland emissions for the 2014 NEI...

Interactions between plant and rhizosphere microbial communities in a metalliferous soil