The Experts below are selected from a list of 26529 Experts worldwide ranked by ideXlab platform
Y W Yang - One of the best experts on this subject based on the ideXlab platform.
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rangeland degradation on the qinghai tibet plateau implications for rehabilitation
Land Degradation & Development, 2013Co-Authors: X L Li, Y M Qiao, Gary Brierley, Jing Zhang, Y W YangAbstract:With ever intensifying land use, land degradation is becoming an increasingly important issue around the world, especially in China. This paper evaluates the extent and underlying causes of rangeland degradation on the Qinghai-Tibet Plateau in China through a comprehensive review of the literature. Diverse forms and differing intensities of rangeland degradation have been reported in several regions of the Plateau. Rangeland degradation is particularly severe in South Qinghai, North Tibet and the Qaidam Basin. Anthropogenic activities, especially changing land use practices, are identified as the primary force driving rangeland degradation. Dissimilar to climate change-induced degradation, such anthropogenic degradation is a rather short-term process altering the abiotic properties of the underlying soil. On the basis of these findings, we assessed the prospects of rehabilitating degraded rangeland to productive uses. Different measures are proposed to rehabilitate Rangelands that have been degraded by different mechanisms. Reduction in grazing intensity is prescribed to rehabilitate reversibly degraded Rangelands. Targeted human intervention in the forms of selective planting of grasses and artificial seeding, in conjunction with ecological and biological control of the plateau rodent population, is recommended to rehabilitate ‘irreversibly’ degraded Rangelands. Our studies suggest it is very difficult or even impossible to rehabilitate new assemblage of species which appear as a result of climate change. Copyright © 2011 John Wiley & Sons, Ltd.
Andrew J Dougill - One of the best experts on this subject based on the ideXlab platform.
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using participatory mapping and a participatory geographic information system in pastoral land use investigation impacts of rangeland policy in botswana
Land Use Policy, 2017Co-Authors: Lenyeletse Vincent Basupi, Claire H Quinn, Andrew J DougillAbstract:Since the 1980s, the spatial extent of communal grazing lands in Botswana has been diminishing due to rangeland privatisation and fencing associated with animal health policies. Spatial comparisons of pastoral land use transformations are particularly important where accessibility to grazing and water resources remains at the core of sustainable pastoralism policies. Achieving success in pastoral development research requires a sound understanding of traditional pastoralists’ information systems, including the nature of local spatial knowledge. This study explores local spatial knowledge through participatory mapping and a Participatory Geographic Information System to understand and analyse pastoralists’ grazing patterns, spatial mobility and the impacts of subdivisions and privatisation policies in Botswana’s Ngamiland Rangelands. The study uses focus group discussions, historical analysis through key informant interviews, and participatory mapping exercises along with community guided transect walks. The resulting maps provide insights into the traditional tenure patterns of land use and the impacts of rangeland policy on traditional livestock spatial mobility and access to grazing lands. Privatisation and rangeland enclosures have resulted in the restricted movement of livestock and overstocking of floodplains and riparian Rangelands, with some natural water pans becoming inaccessible to local communities. We conclude that the integration of local spatial knowledge can be used to foster better articulation and understanding of pastoralists’ tenures, which are often lacking in communal land administration systems. Such integrated analysis can contribute to sustainable pastoral land management policy toolkits in semi-arid rangeland environments and enable better land tenure and management decision making for sustainable land management.
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reorienting land degradation towards sustainable land management linking sustainable livelihoods with ecosystem services in rangeland systems
Journal of Environmental Management, 2015Co-Authors: Mark Reed, Andrew J Dougill, J S Perkins, Julius Atlhopheng, K Mulale, Lindsay C. Stringer, Nicola FavrettoAbstract:This paper identifies new ways of moving from land degradation towards sustainable land management through the development of economic mechanisms. It identifies new mechanisms to tackle land degradation based on retaining critical levels of natural capital whilst basing livelihoods on a wider range of ecosystem services. This is achieved through a case study analysis of the Kalahari Rangelands in southwest Botswana. The paper first describes the socio-economic and ecological characteristics of the Kalahari Rangelands and the types of land degradation taking place. It then focuses on bush encroachment as a way of exploring new economic instruments (e.g. Payments for Ecosystem Services) designed to enhance the flow of ecosystem services that support livelihoods in rangeland systems. It does this by evaluating the likely impacts of bush encroachment, one of the key forms of rangeland degradation, on a range of ecosystem services in three land tenure types (private fenced ranches, communal grazing areas and Wildlife Management Areas), before considering options for more sustainable land management in these systems. We argue that with adequate policy support, economic mechanisms could help reorient degraded Rangelands towards more sustainable land management.
Nicola Favretto - One of the best experts on this subject based on the ideXlab platform.
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reorienting land degradation towards sustainable land management linking sustainable livelihoods with ecosystem services in rangeland systems
Journal of Environmental Management, 2015Co-Authors: Mark Reed, Andrew J Dougill, J S Perkins, Julius Atlhopheng, K Mulale, Lindsay C. Stringer, Nicola FavrettoAbstract:This paper identifies new ways of moving from land degradation towards sustainable land management through the development of economic mechanisms. It identifies new mechanisms to tackle land degradation based on retaining critical levels of natural capital whilst basing livelihoods on a wider range of ecosystem services. This is achieved through a case study analysis of the Kalahari Rangelands in southwest Botswana. The paper first describes the socio-economic and ecological characteristics of the Kalahari Rangelands and the types of land degradation taking place. It then focuses on bush encroachment as a way of exploring new economic instruments (e.g. Payments for Ecosystem Services) designed to enhance the flow of ecosystem services that support livelihoods in rangeland systems. It does this by evaluating the likely impacts of bush encroachment, one of the key forms of rangeland degradation, on a range of ecosystem services in three land tenure types (private fenced ranches, communal grazing areas and Wildlife Management Areas), before considering options for more sustainable land management in these systems. We argue that with adequate policy support, economic mechanisms could help reorient degraded Rangelands towards more sustainable land management.
Osama Z Alhamdan - One of the best experts on this subject based on the ideXlab platform.
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incorporating hydrologic data and ecohydrologic relationships into ecological site descriptions
Rangeland Ecology & Management, 2016Co-Authors: Jason C Williams, Frederick B Pierson, Kenneth E Spaeth, Joel R Brown, Osama Z Alhamdan, Mark A Weltz, M A Nearing, Jeffrey E Herrick, Jan BollAbstract:The purpose of this paper is to recommend a framework and methodology for incorporating hydrologic data and ecohydrologic relationships in Ecological Site Descriptions (ESDs) and thereby enhance the utility of ESDs for assessing Rangelands and guiding resilience-based management strategies. Resilience-based strategies assess and manage ecological state dynamics that affect state vulnerability and, therefore, provide opportunities to adapt management. Many Rangelands are spatially heterogeneous or sparsely vegetated where the vegetation structure strongly influences infiltration and soil retention. Infiltration and soil retention further influence soil water recharge, nutrient availability, and overall plant productivity. These key ecohydrologic relationships govern the ecologic resilience of the various states and community phases on many rangeland ecological sites (ESs) and are strongly affected by management practices, land use, and disturbances. However, ecohydrologic data and relationships are often missing in ESDs and state-and-transition models (STMs). To address this void, we used literature to determine the data required for inclusion of key ecohydrologic feedbacks into ESDs, developed a framework and methodology for data integration within the current ESD structure, and applied the framework to a select ES for demonstrative purposes. We also evaluated the utility of the Rangeland Hydrology and Erosion Model (RHEM) for assessment and enhancement of ESDs based in part on hydrologic function. We present the framework as a broadly applicable methodology for integrating ecohydrologic relationships and feedbacks into ESDs and resilience-based management strategies. Our proposed framework increases the utility of ESDs to assess Rangelands, target conservation and restoration practices, and predict ecosystem responses to management. The integration of RHEM technology and our suggested framework on ecohydrologic relations expands the ecological foundation of the overall ESD concept for rangeland management and is well aligned with resilience-based, adaptive management of US Rangelands. The proposed enhancement of ESDs will improve communication between private land owners and resource managers and researchers across multiple disciplines in the field of rangeland management.
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risk assessment of erosion from concentrated flow on Rangelands using overland flow distribution and shear stress partitioning
Transactions of the ASABE, 2013Co-Authors: Osama Z Alhamdan, Frederick B Pierson, M A Nearing, Jan Boll, J J Stone, C J Williams, Patrick R Kormos, Mark A WeltzAbstract:Abstract. Erosion rates of overland flow on Rangelands tend to be relatively low, but under certain conditions where flow is concentrated, soil loss can be significant. Therefore, a rangeland site can be highly vulnerable to soil erosion where overland flow is likely to concentrate and exert high shear stress on soil grains. This concept is commonly applied in cropland and wildland soil erosion modeling using predictions of flow effective shear stress (shear stress applied on soil grains). However, historical approaches to partition shear stress in erosion models are computationally complex and require extensive parameterization. Furthermore, most models are not capable of predicting the conditions in which concentrated flow occurs on Rangelands. In this study, we investigated the Rangelands conditions at which overland flow is more likely to become concentrated and developed equations for partitioning the shear stress of concentrated flow on Rangelands. A logistic equation was developed to estimate the probability of overland flow to become concentrated. Total shear stress of rangeland overland flow was partitioned into components exerted on soil, vegetation, and rock cover using field experimental data. In addition, we investigated the vegetation cover limit at which the effective shear stress component is substantially reduced, limiting the erosion rate. The results from the partitioning equations show that shear stress exerted on soil grains was relatively small in sheet flow. Shear stress exerted on soil grains in concentrated flow was significantly higher when bare soil exceeded 60% of the total surface area but decreased significantly when the bare soil area was less than 25% or when the plant base cover exceeded 20%. These percentages could be used as relative measures of hydrologic recovery for disturbed Rangelands or as triggers that indicate a site is crossing a threshold beyond which soil erosion might accelerate due to the high effective shear stress.
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characteristics of concentrated flow hydraulics for rangeland ecosystems implications for hydrologic modeling
Earth Surface Processes and Landforms, 2012Co-Authors: Frederick B Pierson, Osama Z Alhamdan, M A Nearing, Jan Boll, J J Stone, C J Williams, Corey A Moffet, Patrick R Kormos, Mark A WeltzAbstract:Concentrated flow is often the dominant source of water erosion following disturbance on Rangelands. Because of the lack of studies that explain the hydraulics of concentrated flow on Rangelands, cropland-based equations have typically been used for rangeland hydrology and erosion modeling, leading to less accurate predictions due to different soil and vegetation cover characteristics. This study investigates the hydraulics of concentrated flow using unconfined field experimental data over diverse rangeland landscapes within the Great Basin Region, United States. The results imply that the overall hydraulics of concentrated flow on Rangelands differ significantly from those of cropland rills. Concentrated flow hydraulics on Rangelands are largely controlled by the amount of cover or bare soil and hillslope angle. New predictive equations for concentrated flow velocity (R2 = 0·47), hydraulic friction (R2 = 0·52), and width (R2 = 0·4) representing a diverse set of rangeland environments were developed. The resulting equations are applicable across a wide span of ecological sites, soils, slopes, and vegetation and ground cover conditions and can be used by physically-based rangeland hydrology and erosion models to estimate rangeland concentrated flow hydraulic parameters. Published in 2011. This article is a US Government work and is in the public domain in the USA.
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new concentrated flow hydraulics equations for physically based Rangelands hydrology and erosion models
2012Co-Authors: Osama Z Alhamdan, Jason C Williams, Frederick B Pierson, M A Nearing, Jan Boll, Corey A Moffet, Patrick R Kormos, Jeff Stone, Mark A WeltzAbstract:We examined the hydraulics of concentrated flow using unconfined field experimental data over diverse rangeland landscapes, and developed new empirical prediction models of different rangeland concentrated flow hydraulic parameters, which can be applicable across a wide span of rangeland sites, ground cover, soil, and vegetation and ground cover conditions. The overall hydraulic characteristics in which concentrated flow forms on Rangelands differs significantly from that of cropland rills. The complexity of ground cover in rangeland landscapes relative to cropland adds more factors that control the hydraulics of concentrated flow. The shallowness of soil layers in Rangelands force the concentrated flow path to go wider rather than deeper as flow discharge increases. In such conditions, the increase of flow discharge would increase the ground and vegetation cover that the flow encounters and consequently would increase the hydraulic friction. Concentrated flow on Rangelands is also controlled by slope particularly in newly disturbed sites. These sites have high percentage of bare soil and little percentage of vegetation and rock cover sufficient to counteract the driving force of gravity for the flow. Moreover, slope has an effect on the rock and vegetation cover which are important controllers of concentrated flow. Multiple regression analysis (n=394) was used to develop the concentrated flow hydraulic parameters equations. The resulting predictive equations for concentrated flow velocity (R
X L Li - One of the best experts on this subject based on the ideXlab platform.
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rangeland degradation on the qinghai tibet plateau implications for rehabilitation
Land Degradation & Development, 2013Co-Authors: X L Li, Y M Qiao, Gary Brierley, Jing Zhang, Y W YangAbstract:With ever intensifying land use, land degradation is becoming an increasingly important issue around the world, especially in China. This paper evaluates the extent and underlying causes of rangeland degradation on the Qinghai-Tibet Plateau in China through a comprehensive review of the literature. Diverse forms and differing intensities of rangeland degradation have been reported in several regions of the Plateau. Rangeland degradation is particularly severe in South Qinghai, North Tibet and the Qaidam Basin. Anthropogenic activities, especially changing land use practices, are identified as the primary force driving rangeland degradation. Dissimilar to climate change-induced degradation, such anthropogenic degradation is a rather short-term process altering the abiotic properties of the underlying soil. On the basis of these findings, we assessed the prospects of rehabilitating degraded rangeland to productive uses. Different measures are proposed to rehabilitate Rangelands that have been degraded by different mechanisms. Reduction in grazing intensity is prescribed to rehabilitate reversibly degraded Rangelands. Targeted human intervention in the forms of selective planting of grasses and artificial seeding, in conjunction with ecological and biological control of the plateau rodent population, is recommended to rehabilitate ‘irreversibly’ degraded Rangelands. Our studies suggest it is very difficult or even impossible to rehabilitate new assemblage of species which appear as a result of climate change. Copyright © 2011 John Wiley & Sons, Ltd.