Résultats de la recherche | Land Portal

Résultats de la recherche

Showing items 1 through 9 of 105.
  1. Library Resource
    Articles et Livres
    décembre, 2010
    Australie

    The expansion of the artificial water-point network and livestock grazing in arid and semi-arid Australia has significantly increased access to water by water limited herbivores and thus has potential to seriously negatively affect the unique endemic flora and fauna. We examined the effects of the expansion of the water-point network on the arid and semi-arid zone bird community, using data from the Atlas of Australia bird surveys of 1977-1981 and 1996-2001. We examined whether traits of species could be used to uncover the critical ecological processes altered by this land use change.

  2. Library Resource
    Articles et Livres
    décembre, 2011
    Oman

    The productivity of semi-arid rangelands on the Arabian Peninsula is spatially and temporally highly variable, and increasing grazing pressure as well as the likely effects of climatic change further threatens vegetation resources. Using the Al Jabal al Akhdar mountains in northern Oman as an example, our objectives were to analyse the availability and spatial distribution of aboveground net primary production (ANPP) and the extent and causes of vegetation changes during the last decades with a remote sensing approach.

  3. Library Resource
    Articles et Livres
    décembre, 2013
    Australie

    Chemical and sediment losses from agricultural lands are threatening coastal marine and aquatic ecosystems in many parts of the world. This is an acute problem in Australia, where the condition of Great Barrier Reef (GBR) ecosystems is threatened by increased pollutant loads from agricultural lands, and Governments have enacted policies to reduce pollutant exports. These policies raise the question of how to identify changes in land management that will effectively reduce exports.

  4. Library Resource
    Articles et Livres
    décembre, 2013
    Australie

    The effects of agricultural practices on runoff water quality are a major concern worldwide, particularly where there is the potential to cause harm to aquatic ecosystems receiving the runoff. Cropping land has been identified as a major source of pollutants in the Fitzroy Basin, the largest catchment discharging into the Great Barrier Reef (GBR) lagoon. However, knowledge of pollutant generation rates in runoff from the dryland cropping (grains) industry's best management practices (BMPs) on Vertisol soils is limited, partly due to the scarce distribution of these soils worldwide.

  5. Library Resource
    Articles et Livres
    décembre, 2013
    Australie

    Concerns about excessive sediment loads entering the Great Barrier Reef (GBR) lagoon in Australia have led to a focus on improving ground cover in grazing lands. Ground cover has been identified as an important factor in reducing sediment loads, but improving ground cover has been difficult for reef stakeholders in major catchments of the GBR. To provide better information an optimising linear programming model based on paddock scale information in conjunction with land type mapping was developed for the Fitzroy, the largest of the GBR catchments.

  6. Library Resource
    Articles et Livres
    décembre, 2013
    Espagne

    Soil water repellency reduces infiltration capacity, enhancing overland flow and even runoff production, and may produce patchiness in water infiltration at the hillslope scale. Knowledge about hydrophobicity in rangelands of Mediterranean type climate and its relation with vegetation cover and land management is sparse. The objectives of the present work are to determine the degree and spatial occurrence of soil water repellency and to define its relationship with site characteristics, such as soil, vegetation and land management in rangelands of SW Spain.

  7. Library Resource
    Articles et Livres
    décembre, 2012
    Argentine

    We assessed the extension of natural habitat conversion into croplands and grazing lands in subtropical NW Argentina and its impact on two key ecosystem functional attributes. We quantified changes in remotely sensed surrogates of aboveground net primary production (ANPP) and seasonality of carbon gains. Both functional attributes are associated with intermediate ecosystem services sensuFisher et al. (2009). Deforestation was estimated based on photointerpretation of Landsat imagery.

  8. Library Resource
    Articles et Livres
    décembre, 2013
    Mongolie

    Mongolia, a vast and sparsely populated semi-arid country, has very little formal road infrastructure. Since the 1990s, private ownership and usage of vehicles has been increasing, which has created a web of dirt track corridors due to the communal land tenure and unobstructed terrain, with some of these corridors reaching over 4 km in width. This practice aids wind- and water-aided erosion and desertification, causing enormous negative environmental effects.

  9. Library Resource
    Articles et Livres
    décembre, 2012
    États-Unis d'Amérique

    Over half of the United States is privately owned. Improving environmental sustainability requires that the scientific and management communities provide effective outreach to the many landowners making decisions about land use and management practices on these lands. We surveyed California forest and rangeland owners in ten counties throughout the state to assess the impact of existing outreach and identify gaps in information distribution and content.

  10. Library Resource
    Articles et Livres
    décembre, 2011

    The relative magnitudes of, and factors controlling, denitrification and dissimilatory nitrate reduction to ammonium (DNRA) were measured in the soil of a re-connected temperate floodplain divided into four different land management zones (grazing grassland, hay meadow, fritillary meadow and a buffer zone). Soil samples were collected from each zone to measure their respective potentials for nitrate attenuation using ¹⁵N both at the surface and at depth in the soil column and additional samples were collected to measure the lability of the organic carbon.

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