Résultats de la recherche | Land Portal

Résultats de la recherche

Showing items 1 through 9 of 21.
  1. Library Resource
    Articles et Livres
    décembre, 2016

    Increasing community dissimilarity across geographic distance has been described for a wide variety of organisms and understanding its underlying causes is key to understanding mechanisms driving patterns of biodiversity. Both niche‐based and neutral processes may produce a distance decay relationship; however, disentangling their relative influence requires simultaneous examination of multiple potential drivers.

  2. Library Resource
    Articles et Livres
    décembre, 2016

    Although agriculture is amongst the world's most widespread land uses, studies of its effects on stream ecosystems are often limited in spatial extent. National monitoring data could extend spatial coverage and increase statistical power, but present analytical challenges where covarying environmental variables confound relationships of interest. Propensity modelling is used widely outside ecology to control for confounding variables in observational data.

  3. Library Resource
    Articles et Livres
    décembre, 2016
    Chili, Mexique, Uruguay

    Co‐management (Co‐M), defined as the sharing of management tasks and responsibilities between governments and local users, is emerging as a powerful institutional arrangement to redress fisheries paradigm failures, yet long‐term assessments of its performance are lacking. A comparative analysis of five small‐scale Latin American shellfisheries was conducted to identify factors suggesting success and failure.

  4. Library Resource
    Articles et Livres
    décembre, 2016

    Caught between ongoing habitat destruction and funding shortfalls, conservation organizations are using systematic planning approaches to identify places that offer the highest biodiversity return per dollar invested. However, available tools do not account for the landscape of funding for conservation or quantify the constraints this landscape imposes on conservation outcomes.

  5. Library Resource
    Articles et Livres
    décembre, 2016

    Population ecology, the discipline that studies the dynamics of species’ populations and how they interact with the environment, has been one of the most prolific fields of ecology and evolution. Demographic research is central to quantifying population‐level processes and their underlying mechanisms and has provided critical contributions to a diversity of research fields. Examples include the spread of infectious diseases, eco‐evolutionary dynamics and rapid evolution, mechanisms underlying invasions and extinctions, and forest productivity.

  6. Library Resource
    Articles et Livres
    décembre, 2016

    Desert biological soil crusts (BSCs) are formed by adhesion of soil particles to polysaccharides excreted by filamentous cyanobacteria, the pioneers and main producers in this habitat. Biological soil crust destruction is a central factor leading to land degradation and desertification. We study the effect of BSC structure on cyanobacterial activity. Micro‐scale structural analysis using X‐ray microtomography revealed a vesiculated layer 1.5–2.5 mm beneath the surface in close proximity to the cyanobacterial location.

  7. Library Resource
    Articles et Livres
    décembre, 2016
    États-Unis d'Amérique

    There are several alternative hypotheses about the effects of territoriality, kinship and prey availability on individual carnivore distributions within populations. The first is the land‐tenure hypothesis, which predicts that carnivores regulate their density through territoriality and temporal avoidance.

  8. Library Resource
    Articles et Livres
    décembre, 2016

    Bumble bee (Bombus) species are ecologically and economically important pollinators, and many species are in decline. In this article, we develop a mechanistic model to analyse growth trajectories of Bombus vosnesenskii colonies in relation to floral resources and land use. Queen production increased with floral resources and was higher in semi‐natural areas than on conventional farms. However, the most important parameter for queen production was the colony growth rate per flower, as opposed to the average number of available flowers.

  9. Library Resource
    Articles et Livres
    décembre, 2016
    Viet Nam

    Dam‐induced resettlers in Vietnam manifest their responses and resistances in many different ways. This is a multiple response that expresses itself at many different levels and is spatio‐temporally contingent. These actors can be individuals, families, groups of people or communities. Drawing on fieldwork in resettlement sites of the Sơn La hydropower dam in the north‐west of Vietnam, this paper explores how political responses and resistance among Sơn La's resettlers were produced through resettlement conditions.

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