نتایج جستجو برای: term conservation
تعداد نتایج: 676103 فیلتر نتایج به سال:
Conservation biologists, restoration ecologists, and wildlife managers often select an ecological benchmark,1,2 ecological baseline,3 or historical landscape4,5 that they seek to recreate or maintain in an area. A benchmark is a goal toward which conservation activities are aimed; it is an ecological condition or process that is desired. Benchmarks vary in scale from a particular gene pool or r...
Site-based and cross-regional habitat and species conservation e!orts in Madagascar, such as proposed in the previous chapters of this Lemur Conservation Strategy, should always be the main focus of lemur conservation. However, with many wild lemur populations rapidly declining and their habitat being lost at constantly high rates, captive assurance colonies are becoming increasingly important,...
Aim Increasing threats to freshwater biodiversity are rapidly changing the distinctiveness of regional species pools and local assemblages. Biotic homogenization/differentiation processes are threatening the integrity and persistence of native biodiversity patterns at a range of spatial scales and pose a challenge for effective conservation planning. Here, we evaluate the extent and determinant...
In complex networks it is common to model a network or generate a surrogate network based on the conservation of the network’s degree distribution. We provide an alternative network model based on the conservation of connection density within a set of nodes. This density is measure by the rich–club coefficient. We present a method to generate surrogates networks with a given rich–club coefficie...
Populations of the marble trout (Salmo marmoratus) have declined critically due to introgression by brown trout (Salmo trutta) strains. In order to define strategies for long-term conservation, we examined the genetic structure of the 8 known pure populations using 15 microsatellite loci. The analyses reveal extraordinarily strong genetic differentiation among populations separated by < 15 km, ...
With an understudied amphibian fauna, the highest deforestation rate on the planet and high harvesting pressures, Southeast Asian amphibians are facing a conservation crisis. Owing to the overriding threat of habitat loss, the most critical conservation action required is the identification and strict protection of habitat assessed as having high amphibian species diversity and/or representing ...
Protected area management agencies are increasingly using management effectiveness evaluation (MEE) to better understand, learn from and improve conservation efforts around the globe. Outcome assessment is the final stage of MEE, where conservation outcomes are measured to determine whether management objectives are being achieved. When quantitative monitoring data are available, best-practice ...
We study a scalar integro-differential conservation law. The equation was first derived in [2] as the slow erosion limit of granular flow. Considering a set of more general erosion functions, we study the initial boundary value problem for which one can not adapt the standard theory of conservation laws. We construct approximate solutions with a fractional step method, by recomputing the integr...
Using the recent formulation of Noether’s theorem for the problems of the calculus of variations with fractional derivatives, the Lagrange multiplier technique, and the fractional Euler-Lagrange equations, we prove a Noetherlike theorem to the more general context of the fractional optimal control. As a corollary, it follows that in the fractional case the autonomous Hamiltonian does not define...
The advection equation is studied in a completely general two domain setting with different wave-speeds and a time-independent jump-condition at the interface separating the domains. Well-posedness and conservation criteria are derived for the initial-boundary-value problem. The equations are semidiscretized using a finite difference method on summation-by-parts (SBP) form. The stability and co...
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