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Genista scorpius. Under a dense shrub cover both runoff and sediment yield are strongly controlled. As the shrub cover becomes open, sediment yield and runoff increase greatly. A dense herbaceous cover yields high runoff coefficients but moderate soil losses. From the results obtained, the possibility of abandoned field reclamation by means of selective clearing of scrub is discussed.  相似文献   
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Regional Environmental Change - The montane and subalpine belts in European mountains were affected by intense land use/land cover changes during the twentieth century. In the case of the subalpine...  相似文献   
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A vegetation cover increase has been identified at global scales using satellite images and vegetation indices. This fact is usually explained by global climatic change processes such as CO2 and temperature increases. Nevertheless, although these causes can be important, the role of socioeconomic transformations must be considered in some places, since in several areas of Northern Hemisphere an important change in management practices has been detected. Rural depopulation and land abandonment have reactivated the natural vegetation regeneration processes. This work analyses the vegetation evolution in the central Spanish Pyrenees from 1982 to 2000. The analysis has been done by using calibrated-NDVI temporal series from NOAA-AVHRR images. A positive and significant trend in NDVI data has been identified from 1982 to 2000 coinciding with a temperature increase in the study area. However, the spatial differences in magnitude and the sign of NDVI trends are significant. The role of land management changes in the 20th century is considered as a hypothesis to explain the spatial differences in NDVI trends. The role of land-cover and human land-uses on this process has been analyzed. The highest increment of NDVI is detected in lands affected by abandonment and human extensification. The importance of management changes in vegetation growth is discussed, and we indicate that although climate has great importance in vegetal evolution, land-management changes can not be neglected in our study area.  相似文献   
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Mediterranean mountain biomes are considered endangered due to climate change that affects directly or indirectly different key features (biodiversity, snow cover, glaciers, run-off processes, and water availability). Here, we provide an assessment of temperature, precipitation, and spring precipitation changes in Mediterranean mountains under different emission scenarios (Special Report on Emission Scenarios) and Atmosphere-Ocean-Coupled General Circulation Models for two periods: 2055 (2040-2069 period) and 2085 (2070-2099). Finally, the future climate trends projected for Mediterranean mountains are compared with those trends projected for non-Mediterranean European mountain ranges. The range of projected warming varies between +1.4 degrees C and 5.1 degrees C for 2055 (+1.6 degrees C and +8.3 degrees C for 2085). Climate models also project a reduction of precipitation, mainly during spring (-17% under Alfi and -4.8% under B1 for 2085). On the contrary, non-Mediterranean European mountains will not experience a reduction of annual and spring precipitation. Implications of predicted climate change for both human and physical features are coupled in an integrated framework to gain a broad perspective on future trends and their consequences.  相似文献   
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