نتایج جستجو برای: vegetation degradation
تعداد نتایج: 196873 فیلتر نتایج به سال:
Livestock grazing practices in rangelands are being recognized as management tool for environmental protection and increased livestock productivity. Continuous grazing has been largely reported to reduce pasture productivity and increase environmental degradation. Rotational grazing is an alternative to continuous grazing and is considered to reduce negative environmental effects and provide qu...
The ‘rain use efficiency’ (RUE) may be defined as the ratio of above-ground net primary productivity (ANPP) to annual precipitation, and it is claimed to be a conservative property of the vegetation cover in drylands, if the vegetation cover is not subject to non-precipitation related land degradation. Consequently, RUE may be regarded as means of normalizing ANPP for the impact of annual preci...
Carbon release from thawing permafrost soils could significantly exacerbate global warming as the active-layer deepens, exposing more carbon to decay. Plant community and soil properties provide a major control on this by influencing the maximum depth of thaw each summer (active-layer thickness; ALT), but a quantitative understanding of the relative importance of plant and soil characteristics,...
Quantitatively distinguishing grassland degradation due to climatic variations from that due to human activities is of great significance to effectively governing degraded grassland and realizing sustainable utilization. The objective of this study was to differentiate these two types of drivers in the Liao River Basin during 1999-2009 using the residual trend (RESTREND) method and to evaluate ...
The Pantanal's biodiversity constitutes a valuable natural resource, in economic, cultural, recreational, aesthetic, scientific and educational terms. The vegetation plus the seasonal productivity support a diverse and abundant fauna. Many endangered species occur in the region, and waterfowl are exceptionally abundant during the dry season. Losses of biodiversity and its associated natural hab...
Fire is an effective management tool for reconstructed prairies. However, due to safety concerns, road departments and other prairie managers are sometimes reluctant to use fire. Therefore, alternative techniques to manage reconstructed prairie, such as mowing or haying, need to be considered. The goal of this study is to determine if mowing and/or haying can be used to manage vegetation in lie...
Contrary to wetlands or moderate climates, the understanding of carbon exchange between ecosystem and atmosphere in arid and semi-arid environments is more challenging due to the sensible feedback of terrestrial ecosystems to environmental variability. Especially in the savannah regions of South Africa the biomes are strongly affected on the one hand by low and sporadic precipitation and on the...
Degradation of communal grazing land vegetation is a widespread problem throughout sub Saharan Africa and its restoration is a challenge for the management of many semi-arid areas. This study assessed the effectiveness of different age (young versus old) exclosures on species composition and diversity, biomass production and woody structure in northern Ethiopia. The species composition and dive...
New Zealand Journal of Ecology (1997) 21(2): 129-140 ©New Zealand Ecological Society these conceptual extremes should be seen as being endpoints of a range of possible situations, and not as discrete alternatives. It is therefore unlikely that an observed field situation would be completely described by any one of the models alone. More recently developed models use the conceptual extremes as c...
Two Atlantic Forests and two Cerrado areas in Brazil were sampled for non-flying small mammal fauna. In each biome one area with altered and another with almost unaltered vegetation (national parks), were chosen to investigate these fauna. Species richness of Atlantic Forest and Cerrado was comparable in the conserved as well as in the altered areas. Data suggested that species could be divided...
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