نتایج جستجو برای: forest and pastures
تعداد نتایج: 16850860 فیلتر نتایج به سال:
the growth of industries during the industrialization and after the industrial revolution has caused environmental problems all around the world; specifically in industrial countries. in spite of having high technology, industrial countries have not been able to solve the problem of environmental pollution. even meetings and conferences such as those held in stockholm and johannesburg have not ...
Land use change is a major threat to global biodiversity. Forest species face the dual threats of deforestation and intensification of forest management. In regions where forests are under threat, rural landscapes that retain structural components of mature forests potentially provide valuable additional habitat for some forest species. Here, we illustrate the habitat value of traditional wood ...
We studied the distribution of sandflies (Diptera: Phlebotominae)--insect vectors of several diseases, including leishmaniasis--at the interface between primary forest and cattle pasture and between primary forest and secondary forest (< 15 yr old) in Southern Brazilian Amazonia. Sandflies were collected by using a combination of light traps and traps having vertebrates as baits. Strong differe...
Understanding the response of species to anthropogenic landscape modification is essential to design effective conservation programs. Recently, insects have been used in empirical studies to evaluate the impact of habitat modification and landscape fragmentation on biological diversity because they are often affected rapidly by changes in land use. In this study, the use of the landscape matrix...
As Neotropical forests are increasingly converted to agriculture (especially pastures), little is known about the impacts on microbial biodiversity. To assess such impacts, I compared spore abundance and diversity of arbuscular mycorrhizal fungi (AMF) in soils from lowland evergreen forests and pastures in Nicaragua and Costa Rica. Species composition, dominance-diversity curves, and Simpson’s ...
We compared early plant succession in four abandoned pastures of differing age since abandonment and a nearby secondary forest site in northwestern Ecuador. Two "Open" pastures had no tree canopy covering, and two "Guava" pastures had a well-developed canopy cover of Psidium guajaua. No site had been seeded with pasture grasses. All pastures were compared in a chronological sequence; nvo were m...
Clearing tropical forests of the Amazon Basin for pasture alters rates of soil nitrogen cycling. Previous studies have shown that rates of soil net N mineralization and net nitri®cation are lower in established pastures than in forests. We compared soil inorganic N concentrations, rates of net and gross mineralization and net and gross nitri®cation in a chronosequence and an experimental slash-...
Conservation and restoration projects involving abandoned cattle pastures pose several challenges. Restoration ecologists recognize that natural restoration is possible, but few species can successfully colonize degraded pastures. The aim of the present study was to evaluate whether land colonized by the tree Myracrodruon urundeuva increase the amount of habitat available for bird communities i...
Many studies have identified drivers of deforestation throughout the tropics and, in most cases, have recognised differences in the level of threat. However, only a few have also looked at the temporal and spatial dynamics by which those drivers act, which is critical for assessing the conservation of biodiversity as well as for landscape planning. In this study, we analyse land cover change be...
[1] Our objective was to measure the stable carbon isotope composition of leaf tissue and CO2 released by respiration (dr), and to use this information as an estimate of changes in ecosystem isotopic discrimination that occur in response to seasonal and interannual changes in environmental conditions, and land-use change (forest-pasture conversion). We made measurements in primary forest and pa...
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