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Hilly Areas (hilly + area)
Selected AbstractsDiversification of rural livelihood strategies and its effect on local landscape restoration in the semiarid hilly area of the Loess Plateau, ChinaLAND DEGRADATION AND DEVELOPMENT, Issue 5 2010L. Wang Abstract This study is about the diversification of livelihood strategies and the interaction of farmers' livelihood with landscape change in Zhongzhuang small watershed, Pengyang County in Ningxia Autonomous region located in the Loess Plateau, western China. Farmers' livelihoods and landscape patterns during 1978,2007 in Zhongzhuang were analysed. In different stages, diverse limiting factors were discovered behind the diversification process of livelihood strategies. Before 1978, ,planned economy', ,production team organization', strict ,household registration system' and the scarcity of livelihood assets were the main factors restricting the diversification of livelihood strategies. From 1978 to 1993, the reform and open policy provided opportunities for local people to diversify their livelihood strategies, but livelihood strategies based on crop production still took an important role in their life. From 2000 to 2007, national policies brought assistance to help local farmers diversify their agricultural activities. However, the insufficient and incomplete credit and insurance market and lack of skill were the main factors constraining non-farm activity diversification. Meanwhile, through analysis of the links between livelihood strategies diversification and landscape pattern change, we found that diversification of farmers' livelihoods contributed to the recovery of the landscape. Finally, using this relationship, steps for future landscape restoration is proposed, which provide a new view of landscape restoration research in the Loess Plateau. Copyright © 2010 John Wiley & Sons, Ltd. [source] Factors Affecting the Distribution and Abundance of Asplenium nidus L. in a Tropical Lowland Rain Forest in Peninsular MalaysiaBIOTROPICA, Issue 4 2010Liwen Zhang ABSTRACT Asplenium nidus is an abundant epiphytic fern of tropical rain forests in the Old World, where it plays an important ecological role in the forest canopy as host to diverse arthropod communities. We investigated the factors that determine the distribution and abundance of A. nidus in the canopy of an aseasonal lowland dipterocarp forest at Pasoh Forest Reserve, Malaysia. We found that A. nidus was more abundant in the understory, and on hosts with smooth bark and relatively flat branch angles. Ferns were found on a wide diversity and size range of host taxa. However, both host taxa and host diameter at breast height had a significant effect on A. nidus occupancy. Asplenium nidus had an aggregated spatial distribution at all scales within the study area. Spatial aggregation at larger scales appears to be driven by habitat preference, as A. nidus abundance was positively associated with swampy areas and negatively associated with hilly areas. At smaller scales, limited dispersal of their wind-dispersed spores most likely explains the aggregated distribution. Larger individuals occurred higher in the canopy and were more common in the hilly area. Thus, the distribution of A. nidus may represent a trade-off between the availability of suitable microsites for establishment in the understory and better growth conditions higher in the canopy. However, A. nidus is known to comprise a complex of cryptic species, and future studies should incorporate molecular techniques to elucidate the potential role of speciation in explaining these patterns. Abstract in Malaysian is available at http://www.blackwell-synergy.com/loi/btp [source] Stocks and dynamics of SOC in relation to soil redistribution by water and tillage erosionGLOBAL CHANGE BIOLOGY, Issue 10 2006JIANHUI ZHANG Abstract Soil organic carbon (SOC) displaced by soil erosion is the subject of much current research and the fundamental question, whether accelerated soil erosion is a source or sink of atmospheric CO2, remains unresolved. A toposequence of terraced fields as well as a long slope was selected from hilly areas of the Sichuan Basin, China to determine effects of soil redistribution rates and processes on SOC stocks and dynamics. Soil samples for the determination of caesium-137 (137Cs), SOC, total N and soil particle size fractions were collected at 5 m intervals along a transect down the two toposequences. 137Cs data showed that along the long slope transect soil erosion occurred in upper and middle slope positions and soil deposition appeared in the lower part of the slope. Along the terraced transect, soil was lost over the upper parts of the slopes and deposition occurred towards the downslope boundary on each terrace, resulting in very abrupt changes in soil redistribution over short distances either side of terrace boundaries that run parallel with the contour on the steep slopes. These data reflect a difference in erosion process; along the long slope transect, water erosion is the dominant process, while in the terraced landscape soil distribution is mainly the result of tillage erosion. SOC inventories (mass per unit area) show a similar pattern to the 137Cs inventory, with relatively low SOC content in the erosional sites and high SOC content in depositional areas. However, in the terraced field landscape C/N ratios were highest in the depositional areas, while along the long slope transect, C/N ratios were highest in the erosional areas. When the samples are subdivided based on 137Cs-derived erosion and deposition data, it is found that the erosional areas have similar C/N ratios for both toposequences, while the C/N ratios in depositional areas are significantly different from each other. These differences are attributed to the difference in soil erosion processes; tillage erosion is mainly responsible for high-SOC inventories at depositional positions on terraced fields, whereas water erosion plays a primary role in SOC storage at depositional positions on the long slope. These data support the theory that water erosion may cause a loss of SOC due to selective removal of the most labile fraction of SOC, while on the other hand tillage erosion only transports the soil over short distances with less effect on the total SOC stock. [source] Effects of topography on the spatial distribution of evapotranspiration over a complex terrain using two-source energy balance model with ASTER dataHYDROLOGICAL PROCESSES, Issue 16 2009H. K. Kafle Abstract Spatial distribution of evapotranspiration (ET) over a complex terrain is estimated using a new approach of the conventional two-source energy balance (TSEB) model by considering the effect of topography (difference in slope and aspect). We name this approach topography considered two-source energy balance (T2SEB) model. The novelty of this model is the estimation of incoming shortwave solar radiation considering slope, aspect, altitude, latitude, longitude, and the day of calculation in the TSEB model, so that the new model should have wider applicability than existing models over topographically complex areas. In this study, high spatial resolution Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data and meteorological data are used. ET over a complex terrain of Nagoya, Japan, on three different dates, 4 November 2005, 25 May 2004 and 30 October 2003, is estimated using both TSEB and T2SEB models. To validate both models, estimated results are compared with ground observation data at the flux tower site. Moreover, estimated results from TSEB and T2SEB models are compared in five different locations of different topography within the study area. Variation of net radiation absorbed by the surface (Rn) with topographical variables is also studied with the help of scatter plots. Estimated results for all three dates agreed within ±75 W m,2 with calculated values from both models at the flux tower site. TSEB underestimated/overestimated ET in sunlit/shaded areas in hilly areas. The T2SEB model estimated ET in hilly areas better than the TSEB model. Copyright © 2009 John Wiley & Sons, Ltd. [source] Factors Affecting the Distribution and Abundance of Asplenium nidus L. in a Tropical Lowland Rain Forest in Peninsular MalaysiaBIOTROPICA, Issue 4 2010Liwen Zhang ABSTRACT Asplenium nidus is an abundant epiphytic fern of tropical rain forests in the Old World, where it plays an important ecological role in the forest canopy as host to diverse arthropod communities. We investigated the factors that determine the distribution and abundance of A. nidus in the canopy of an aseasonal lowland dipterocarp forest at Pasoh Forest Reserve, Malaysia. We found that A. nidus was more abundant in the understory, and on hosts with smooth bark and relatively flat branch angles. Ferns were found on a wide diversity and size range of host taxa. However, both host taxa and host diameter at breast height had a significant effect on A. nidus occupancy. Asplenium nidus had an aggregated spatial distribution at all scales within the study area. Spatial aggregation at larger scales appears to be driven by habitat preference, as A. nidus abundance was positively associated with swampy areas and negatively associated with hilly areas. At smaller scales, limited dispersal of their wind-dispersed spores most likely explains the aggregated distribution. Larger individuals occurred higher in the canopy and were more common in the hilly area. Thus, the distribution of A. nidus may represent a trade-off between the availability of suitable microsites for establishment in the understory and better growth conditions higher in the canopy. However, A. nidus is known to comprise a complex of cryptic species, and future studies should incorporate molecular techniques to elucidate the potential role of speciation in explaining these patterns. Abstract in Malaysian is available at http://www.blackwell-synergy.com/loi/btp [source] Analysis of the Geomorphology and Environmental Geological Problems of Huzhou on the Yangtze River DeltaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 3 2004JIANG Yuehua Abstract, Geomorphically, Huzhou, which is on the Yangtze River delta is characterized mainly by plains, with small hills. This paper presents a detailed analysis of the environmental geological hazards both natural and those incurred by human activities in different morphologic units. The authors point out that most of the regional environmental geological problems in the natural geologic-morphologic conditions, such as crustal stability, foundation of soft soil, soil waterlogging and soil erosion, have insignificant effects to the society, or related countermeasures of prevention and control have been adopted. But environmental geological problems incurred by human being's economic activities become more and more severe, for example, water and soil pollution and land subsidence in plain areas resulting from overexploitation of groundwater, and landslides, karst collapses and water and soil loss etc. caused by quarrying in hilly areas. [source] | |||||||||||||