Résultats de la recherche | Land Portal

Résultats de la recherche

Showing items 1 through 9 of 64.
  1. Library Resource
    Articles et Livres
    décembre, 2015

    Projections of the response of crop yield to climate change at different spatial scales are known to vary. However, understanding of the causes of systematic differences across scale is limited. Here, we hypothesize that heterogeneous cropping intensity is one source of scale dependency. Analysis of observed global data and regional crop modelling demonstrate that areas of high vs. low cropping intensity can have systematically different yields, in both observations and simulations.

  2. Library Resource
    Articles et Livres
    décembre, 2015
    Chine

    Organic carbon (OC) sequestration in degraded semi‐arid environments by improved soil management is assumed to contribute substantially to climate change mitigation. However, information about the soil organic carbon (SOC) sequestration potential in steppe soils and their current saturation status remains unknown. In this study, we estimated the OC storage capacity of semi‐arid grassland soils on the basis of remote, natural steppe fragments in northern China. Based on the maximum OC saturation of silt and clay particles

  3. Library Resource
    Articles et Livres
    décembre, 2015
    Finlande

    Quantifying landscape‐scale methane (CH₄) fluxes from boreal and arctic regions, and determining how they are controlled, is critical for predicting the magnitude of any CH₄ emission feedback to climate change. Furthermore, there remains uncertainty regarding the relative importance of small areas of strong methanogenic activity, vs. larger areas with net CH₄ uptake, in controlling landscape‐level fluxes.

  4. Library Resource
    Articles et Livres
    décembre, 2015

    Land‐cover change and ecosystem degradation may lead to biotic homogenization, yet our understanding of this phenomenon over large spatial scales and different biotic groups remains weak. We used a multi‐taxa dataset from 335 sites and 36 heterogeneous landscapes in the Brazilian Amazon to examine the potential for landscape‐scale processes to modulate the cumulative effects of local disturbances.

  5. Library Resource
    Articles et Livres
    décembre, 2015

    This symposium introduction brings together two debates; the debate on global food prices and speculation, and the debate on so‐called global ‘land investment’ or ‘land grabbing’. Both debates are examining two sides of the same phenomenon – the growing role of private financial investors in the global agri‐food value chains and the myriad consequences of it. The symposium moves beyond the identification of finance as an exogenous factor to the trends in the sector.

  6. Library Resource
    Articles et Livres
    décembre, 2015

    The global rush for land has provoked diverse policy responses from host countries. While some governments are facilitating ‘land grabs’ within their borders, others have restricted land acquisitions by foreigners. Drawing from the Brazilian case, I argue that such restrictive regulations may be limited in their effectiveness because they apply a state‐centric geopolitical logic to a threat that is largely de‐territorialized and financialized.

  7. Library Resource
    Articles et Livres
    décembre, 2015
    Espagne

    AIM: Efforts to adapt conservation to climate change are hampered by a scarcity of studies of community‐level ecological responses. We examined temporal (40 years) and spatial (1700 m elevational gradient) variation in butterfly communities, aiming to test whether the composition of communities in terms of species' thermal envelopes tracked regional warming, and whether local habitat influenced community responses to climate variation. LOCATION: Sierra de Guadarrama (central Spain).

  8. Library Resource
    Articles et Livres
    décembre, 2015
    Australie

    AIM: Prescribed fire is a common land management for reducing risks from unplanned fires. However, the universality of such effectiveness remains uncertain due to biogeographical variation in fuel types, climatic influences and fire regimes. Here, we explore biogeographical patterns in the effectiveness of prescribed fire by calculating leverage (the reduction in unplanned area burnt resulting from recent previous area burnt) across south‐eastern Australia over a 25 year period. LOCATION: The 30 bioregions of south‐eastern Australia.

  9. Library Resource
    Articles et Livres
    décembre, 2015

    In the Mekong Delta, alluvial clay soils have been used intensively over many generations for rice monoculture. Currently, farmers are confronted by problems of declining land productivity. Rotations comprising rice and upland crops can increase soil quality, but appropriate cropping systems for paddy soils have received relatively little attention. We therefore established a multiyear field experiment to evaluate the long‐term effects of cropping systems with different rotations on soil chemical quality.

  10. Library Resource
    Articles et Livres
    décembre, 2015

    Fire regimes are changing throughout the world. Changed fire patterns across northern Australian savannas have been proposed as a factor contributing to recent declines of small‐ and medium‐sized mammals. Despite this, few studies have examined the mechanisms that underpin how species use habitat in fire‐affected landscapes. We determined the habitats and resources important to the declining golden‐backed tree‐rat (Mesembriomys macrurus) in landscapes partially burnt by recent intense fire.

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