Erosion-reducing potential of Salix psammophila roots in the water–wind crisscrossed erosion region of the Chinese Loess Plateau: A simulated investigation

Laboratory-simulated experiments under a one-way wind erosion–rain erosion sequence were conducted to investigate the effect of S. psammophila roots on wind and water erosion processes and quantify its erosion-reducing potential. With the collected soil of sandy loam and planted shrub of S. psammophila, 16 soil boxes including bare and root-permeated soils were arranged in March 2017 and conducted in August 2017. With the wind speeds of 11 and 14 m s−1 and rainfall intensities of 60 and 100 mm h−1, two levels of interaction (11 m s−1 × 60 mm h−1 and 14 m s−1 × 100 mm h−1) were designed. The particle-size composition and sediment transport flux were examined in the former wind tunnel experiments, and the runoff hydrodynamic parameters and runoff and water erosion rates were determined in the following rainfall tests. The sediment reduction effect by roots (%) was used to quantify the erosion-reducing potential of roots. The results demonstrated that in the former wind tunnel experiments, compared with the bare soils, the root-permeated soils showed a slight coarsening of surface soil and had 18.03% and 35.71% less sediment transport flux at wind speeds of 11 and 14 m s−1, respectively. In the following rainfall tests, S. psammophila roots weakened the hydrodynamic intensity of overland flow and decreased runoff and water erosion rates by 13.34%, 30.70% and 4.44%, 43.72% at rainfall intensities of 60 and 100 mm h−1, respectively. Different from the water erosion process of bare soils, which showed an increased fluctuated trend, the root-permeated soils presented a steady increase in the early stage of rainfall and then a decrease-stable trend at the mid and end of rainfall. In the wind tunnel–rainfall experiments, the sediment reduction effect by Salix psammophila roots showed 24.37% and 39.72% at levels of 11 m s−1 × 60 mm h−1 and 14 m s−1 × 100 mm h−1, respectively. This kind of study may provide more insights into understanding ecological impacts of sandy vegetation construction on the water–wind crisscrossed erosion region of the Chinese Loess Plateau and also sandy land

Effects of gully topography on space-time patterns of soil moisture in a semiarid grassland

2009 Summer.Covers not scanned.Includes bibliographical references.Print version deaccessioned 2022.Gullies are pervasive topographic features in semiarid grasslands in North America. At the Army’s Piñon Canyon Maneuver Site (PCMS) in southeastern Colorado, gullies are important because they restrict the mobility of troops and vehicles in training exercises, and they represent areas that are potentially vulnerable to further erosion. Substantial research has examined the temporal evolution of gullies as well as the factors that initiate gullies and control their morphology. In particular, prolonged periods of low soil moisture (droughts), frequent flash floods, and human activity are thought to reduce vegetative cover and promote gully development. Much less is understood about the feedback of gully topography on space-time patterns of soil moisture. The presence of gullies may produce feedbacks to soil moisture that either enhance or diminish gully development. In this study, field observations from PCMS are used to study the effects of gullies on space-time patterns of soil moisture and to describe the interactions of soil moisture, soil texture, and vegetation around gullies. Three study sites at PCMS have been extensively instrumented. These sites are located in the same broad valley, but one site (~1500 m2) is ungullied while the other two sites (also ~1500 m2) each contain a gully. The gully sites are adjacent to each other and their two gullies are approximately parallel. Hourly soil moisture observations have been collected for 8 months at two sites and 4 months at one site using time domain reflectometry (TDR) probes installed along four transects within each site. Each transect contains 6-8 probes that are positioned at the mid-points between topographic breakpoints. Meteorological data are also collected at the ungullied site and between the two gullied sites. Overall, the occurrence of gullies was observed to not affect the spatial average soil moisture within the study sites, but the gullies do promote spatial variability in soil moisture. Gully bottoms tend to be wetter. Although the evidence here is not conclusive, this tendency may be due to gradual lateral inflows, thicker vegetation (which protects the soil against surface crusting and promotes infiltration), and the lower local elevations (which protect against higher wind speeds and evapotranspiration). The gully sidewalls tend to be drier because of rapid drainage during and after precipitation events and in some cases increased solar insolation

Infrastructure expansion challenges sustainable development in Papua New Guinea

The island of New Guinea hosts the third largest expanse of tropical rainforest on the planet. Papua New Guinea—comprising the eastern half of the island—plans to nearly double its national road network (from 8,700 to 15,000 km) over the next three years, to spur economic growth. We assessed these plans using fine-scale biophysical and environmental data. We identified numerous environmental and socioeconomic risks associated with these projects, including the dissection of 54 critical biodiversity habitats and diminished forest connectivity across large expanses of the island. Key habitats of globally endangered species including Goodfellow's tree-kangaroo (Dendrolagus goodfellowi), Matchie's tree kangaroo (D. matschiei), and several birds of paradise would also be bisected by roads and opened up to logging, hunting, and habitat conversion. Many planned roads would traverse rainforests and carbon-rich peatlands, contradicting Papua New Guinea's international commitments to promote low-carbon development and forest conservation for climate-change mitigation. Planned roads would also create new deforestation hotspots via rapid expansion of logging, mining, and oil-palm plantations. Our study suggests that several planned road segments in steep and high-rainfall terrain would be extremely expensive in terms of construction and maintenance costs. This would create unanticipated economic challenges and public debt. The net environmental, social, and economic risks of several planned projects—such as the Epo-Kikori link, Madang-Baiyer link, Wau-Malalaua link, and some other planned projects in the Western and East Sepik Provinces—could easily outstrip their overall benefits. Such projects should be reconsidered under broader environmental, economic, and social grounds, rather than short-term economic considerations

Comparative assessment of the vulnerability and resilience of 10 deltas : work document

Background information about: Nile delta (Egypt), Incomati delta (Mozambique), Ganges-Brahmaputra-Meghna (Bangladesh), Yangtze (China), Ciliwung (Indonesia), Mekong (Vietnam), Rhine-Meuse (The Netherlands), Danube (Romania), California Bay-Delta, Mississippi River Delta (USA

Atlas of Ocean Wealth

The Atlas of Ocean Wealth is the largest collection to date of information about the economic, social and cultural values of coastal and marine habitats from all over the world. It is a synthesis of innovative science, led by The Nature Conservancy (TNC), with many partners around the world. Through these efforts, they've gathered vast new datasets from both traditional and less likely sources.The work includes more than 35 novel and critically important maps that show how nature's value to people varies widely from place to place. They also illustrate nature's potential. These maps show that one can accurately quantify the value of marine resources. Further, by enumerating such values, one can encourage their protection or enhancement for the benefit of people all around the world. In summary, it clearly articulates not just that we need nature, but how much we need it, and where

Projected Impact of Global Warming on West Africa: Case for Regional and Transnational Adaptive Measures

This paper explores the concept of Global Warming, the science behind it and signs of it in the region of West Africa. Then it attempts a look at how the countries of West Africa plan for life in a dramatically warmed world. It will conclude by making a case for Regional and Transnational Adaptation measures to cope with an increasingly warming and vulnerable world. The paper is based on a review of research projects, abstracts of international conferences, regional and international literature on climate change and policies, draft strategies, policies and action plans developed by countries of the region, as well as the Economic Community of West African States (ECOWAS), African Union (AU), New Economic Partnership for Africa’s Development (NEPAD) and other regional policies and schemes in response to climate change. Cite as: 20 Annl. Survey Int\u27l. Comp. L. 101 (2014)

Deserts and Desertification

A desert is an ecosystem in an arid zone in which sand dunes cover the land and sandstorms often occur. Although desert vegetation is sparse, it plays an important role in ecosystem structure and function. Desertification is one of the most severe environmental problems today. Land desertification can be controlled through many measures, such as eco-villages, eco-agriculture, biodiversity conservation, and the combination of engineering and biology. This edited volume provides new insights into the pattern of desert ecosystems and the progress of desertification control. It is a useful resource for researchers in ecology, forestry, and land desertification control