Resultados de la búsqueda | Land Portal

Resultados de la búsqueda

Mostrando ítems 1 a 9 de 228.
  1. Library Resource
    Artículos de revistas y libros
    Abril, 2017

    Although REDD+ is approaching its 10th anniversary, major impacts in terms of reduced forest loss are hard to document. Conservation practitioners and scholars are therefore increasingly asking why REDD+ has not delivered more tangible results. A recent Comment in Conservation Biology by Fletcher et al. (2016) addresses this question. We agree with Fletcher et al. that REDD+ has been hyped in some circles, which has created unrealistic expectations among policy makers and forest dwellers alike. Yet, we argue that Fletcher et al.

  2. Library Resource
    Artículos de revistas y libros
    Diciembre, 2017

    Wetlands are important providers of ecosystem services and key regulators of climate change. They positively contribute to global warming through their greenhouse gas emissions, and negatively through the accumulation of organic material in histosols, particularly in peatlands. Our understanding of wetlands’ services is currently constrained by limited knowledge on their distribution, extent, volume, interannual flood variability and disturbance levels.

  3. Library Resource
    Artículos de revistas y libros
    Diciembre, 2010

    Estimates of the percent of Earth's land surface that has either been transformed or degraded by human activity range between 39 and 50 percent, with agriculture accounting for the vast majority of these changes. Although much of the focus of research on land use and cover change in the tropics has been on deforestation, ongoing socioeconomic changes both locally and globally have made land transitions in the tropics extremely fluid. In addition, feedbacks between land cover change and human behavior constrain the extent and trajectories of land transitions.

  4. Library Resource
    Artículos de revistas y libros
    Diciembre, 2012
    Estados Unidos de América

    1. Little is known about the diversity and land management response of native solitary bees in globally rare barrens restricted to the northeastern United States. Herein we assess solitary bee diversity in a scrub oak barrens 2 years after a mow and herbicide treatment. 2. Standard bowl‐trap and sweep‐net surveys were repeated six times during June–August in four treated scrub oak patches and a nearby untreated scrub oak patch. 3. Bee richness and total abundance (all specimens) did not differ appreciably between the treated and untreated scrub oak.

  5. Library Resource
    Artículos de revistas y libros
    Diciembre, 2012

    1. Arctic vegetation tends to be spatially heterogeneous and can have large areas of mixed ‘transition zone’ vegetation between stands dominated by a single or few species. If plant photosynthesis and growth within these transition zones differs significantly from main vegetation stands, and if transition zones are not considered when extrapolating stand‐level findings to larger scales in space, then transition zones will provide considerable error to landscape‐level estimates of gross primary productivity (GPP).

  6. Library Resource
    Artículos de revistas y libros
    Diciembre, 2014
    Estados Unidos de América, América Septentrional

    AIM: The geographical expansion of white‐winged doves (Zenaida asiatica) in North America has attracted the attention of biologists and sportsmen because of their recreational and aesthetic value; however, data on factors driving the spatial spread of this species are lacking. We examined spatial and temporal patterns of range expansion for white‐winged doves along the northern edge of their geographical range from 1979 to 2007 and used a dynamic occupancy model to estimate when and where doves would be found along an expansion gradient. LOCATION: Southern half of the USA.

  7. Library Resource
    Artículos de revistas y libros
    Diciembre, 2007
    Australia

    Offsets (also known as mitigation banks, compensatory habitat, set-asides) is a policy instrument recently introduced in several States in Australia to permit some land clearing while striving for no net loss in the extent and condition of native vegetation overall. Offsetting is criticized with respect to the amount of gain required to compensate for losses from clearing, the equivalence of losses and gains, the time lag between losses and gains and a poor record of compliance.

  8. Library Resource
    Artículos de revistas y libros
    Diciembre, 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.

  9. Library Resource
    Artículos de revistas y libros
    Diciembre, 2015
    China

    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

  10. Library Resource
    Artículos de revistas y libros
    Diciembre, 2015
    Finlandia

    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.

Búsqueda en la Biblioteca de Tierras

A través de nuestro sólido motor de búsqueda, puede explorar cualquier elemento de los más de 64.800 recursos rigurosamente seleccionados en la Biblioteca de la Tierra. Si desea obtener una visión general de lo que es posible, siéntase libre de examinar la  Guía de búsqueda

Comparta esta página