Public perceptions of ecosystem services and preferences for design scenarios of the flooded bank along the Three Gorges Reservoir: Implications for sustainable management of novel ecosystems

The newly formed extensive flooded land associated with the Three Gorges Reservoir hold great potentials to provide ecosystem services (ESs) for surrounding cities and communities. Conflicting values and conventional management strategies may complicate and inhibit broad-scale decision-making for this novel ecosystem. Public attitudes are a crucial influence in the way this process plays out. This study was conducted to assess how the reservoir bank is perceived by the general public of Chongqing Municipality in terms of importance of riparian ESs, and preference for corresponding landscape design styles through photo-questionnaire interviewing. Although Chongqing citizens know little of the “ecosystem services” concept, they do recognise riparian environmental and ecological benefits especially the bank protection and pollution interception functions, while benefits of habitats for wildlife and flood attenuation were of less concern. Recreational values were least appreciated, which is inconsistent with other studies. This may be attributed to a wider, intensive environmental education in various social media in today’s China. But publicity has been dominated by toxic air, water and soil pollution control rather than the benefits of nature conservation and personal contact with nature. In line with recognition of ESs, there is quite strong preference for the forested design scenario and particularly vegetation components across the socio-demographic spectrum. Overall, socio-demographic variables have very low explanatory power for the perceptual responses. Our study also revealed misunderstandings around riparian functions and a gap between public expectations and special abiotic and biotic prerequisites in restoring novel ecosystems. Finally, we discuss the relevance of this research to urban novel ecosystems in general, and implications for raising public awareness, engaging appropriate public values in sustainable design and management of such ecosystems.     

Agroforestry in the interior highlands

The USDA Agricultural Research Service, headquartered at the South Central Family Farm Research Center, Booneville, Arkansas, recently initiated an agroforestry research program for the interior highlands and the southeastern United States. The purpose of the agroforestry program is to develop a research and technology transfer program in agroforestry that will provide additional alternative income opportunities for family farms of this region. The objectives of the program are: 1) to develop new information on the establishment, maintenance, and utilization of conifer and hardwood tree stands in open pastures, 2) to develop new knowledge in multiple-use management and their environmental impacts, and 3) to facilitate multidisciplinary networks and partnerships of farmers, technical specialists, scientists, and managers for accomplishing agroforestry research and technology transfer.     

A mathematical model for generating land-use allocation alternatives for agroforestry systems

Agroforestry has been considered a viable land-use system particularly in the tropical regions. In developing or designing agroforestry systems, various concerns have to be addressed namely: (1) economic; (2) biological and physical; and (3) silvicultural and ecological considerations. This paper addresses these concerns from an interdisciplinary perspective. A land-use allocation model which ensures the simultaneous consideration of these concerns is proposed.     

上海宝山区城市表土重金属累积的空间分布规律

检测了上海宝山区127个表土样点的重金属含量。宝山区表土Zn、Cr、Cd、Pb、Cu、Ni、Mn的平均含量分别为228.6、127.6、0.56、118.5、55.2、55.7、718.7mg/kg。其中Pb、Zn、Cd的含量分别是上海土壤背景值的5.6、3.0、2.8倍,受污染较明显。宝山区地表的重金属含量呈现出明显的空间分布规律:工业区地表,如吴淞、大场等地,多种重金属污染均很重,Zn、Cr、Cd、Pb、Cu的平均含量分别高达407.6、319.0、0.75、101.2、76.2mg/kg;马路绿地土壤Pb的累积较显著,平均为180.2mg/kg;远郊菜地土壤重金属污染不明显。     

不同土地利用对表层土壤有机碳密度的影响

采用第二次土壤普查资料,研究了安徽省不同土地类型表层土壤的有机碳密度和碳库的特点。结果表明,安徽省平均有机碳密度为(31.64±16.39)tC/hm2,林地土壤表层有机碳密度高于全省表层土壤平均有机碳密度,旱作土壤表层有机碳密度则低于全省平均值。有机碳密度的大小顺序为:林地>水稻土耕层>旱地。安徽省表层土壤有机碳储量分布也表现为:林地>水稻土>旱地。表层土壤有机碳总量达0.28 Pg,其中林地占50%,水稻土占23%,而旱地只占18%。因此,人为利用特点是区域土壤碳库和碳密度的主要影响因素。分析表明:林地、水稻土和旱作土壤表层有机碳量与总氮之间的相关系数(R2)均大于0.78,农田土壤粘粒含量与土壤有机碳固定也有一定关系。     

A laboratory investigation of the release of a conservative tracer and herbicide from topsoil aggregates under varying rainfall intensities

Abstract. This paper describes the results of laboratory-based research which investigated the losses of the herbicide, isoproturon, and a non-adsorbing solute, bromide, from topsoil aggregates under high (7 mm h⁻¹ and low 2.7 mm h⁻¹) intensity simulated rainfall. The structures of the micro- and macro-aggregates from a clay soil of the Denchworth Series (from Wytham, Oxfordshire, UK) were observed using a scanning electron microscope, and the slaking of the topsoil aggregates was also investigated in order to provide a context for interpreting the experimental results. The topsoil at Wytham was found to have a bimodal structure with small microaggregates of 0.71 to 1 mm diameter clustered together to form larger macroaggregates of up to several centimetres diameter. Selected aggregates were air dried and then repacked in Buchner funnels to several centimetres depth in order to remove variability in the experimental results due to the effects of surface microrelief. Under saturated surface conditions high intensity simulated rainfall was less efficient at removing both non-adsorbing and adsorbing solutes from the repacked topsoil aggregates than low intensity rainfall. The observed decrease in the concentration of isoproturon and bromide in the leachate with time could be explained by a transport non-equilibrium effect.     

Assessing the success of experimental rehabilitation on a coastal mineral sands mine in Namaqualand,South Africa§

The success of different rehabilitation treatments following surface mining on the arid west coast of South Africa was assessed. Treatments consisting of one or a combination of topsoil addition, plant translocation and seeding were applied to experimental rehabilitation sites in 2001, while the treatment of another site in 2008 combined all three techniques. Vegetation and species cover, species richness, diversity and evenness, and grazing capacity of rehabilitation sites were sampled during winter 2009 and summer 2010, and compared with a reference site. All rehabilitated sites achieved the objective to attain a minimum grazing capacity of 20 ha per small stock unit. Rehabilitation trials were successful in establishing a vegetation cover, but were unable to return species richness and diversity to reference levels and did not resemble the reference site in species composition. Common species in reference sites were absent or only occurred in low numbers. No treatment outperformed the others and further experimentation is needed to determine the most suitable combination. It is recommended that rehabilitation should be done in multiple stages in future to improve seedling survival and to return species that are unable to establish in the adverse conditions present at the onset of rehabilitation.     

Carbon Fluxes from Different Pools in a Mined Area under Reclamation in Minas Gerais State,Brazil

Despite the benefits of grass cultivation and organic fertilization in mining areas undergoing reclamation, these practices may be associated to CO₂ emissions and soil organic matter (SOM) losses by priming effect. In the present study, we evaluated the changes on SOM pools and C–CO₂ emissions in a bauxite‐mined area under reclamation fertilized with poultry litter (PL) (0, 10, 20, and 40 Mg ha⁻¹) and cultivated with Brachiaria brizantha . Increases of about 3·5 times in the soil labile C were observed 1 year after experiment establishment. High C–CO₂ fluxes and a significant positive priming effect were observed in the presence of B. brizantha , increasing native C mineralization by nearly 4·9 times. Nevertheless, no net soil C loss was detected, probably because of the C inputs derived from B. brizantha , which offset these losses. In fact, the grass increased total organic C by 45% when fertilized with 40 Mg PL ha⁻¹. The data obtained suggest that the cultivation of B. brizantha fertilized with PL can be a promising option for rapid recovery in SOM in areas under reclamation. Copyright © 2016 John Wiley & Sons, Ltd.     

土壤容许流失量研究的进展与趋势

概述了国内外土壤容许流失量（Ｔ值）研究的历史、目前研究的现状和未来的发展趋势,对Ｔ值研究的主要内容如成土速度、土壤养分流失、泥沙淤积损失、土壤流失与土地生产力的关系、保护沟道侵蚀的重要性等做了讲述。介绍了Ｔ值的数学表达和不同国家的Ｔ值标准,阐述了进行Ｔ值双值性研究的必要性,并对Ｔ值研究中存在的问题进行了分析。     

Variability in pattern and hydrogen isotope composition (δ2H) of long-chain n-alkanes of surface soils and its relations to climate and vegetation characteristics: A meta-analysis

The average chain length (ACL), carbon preference index (CPI), and hydrogen isotope composition (δ²H) of long-chain n-alkanes in sediments have been used to retrieve information about the paleoclimate. Despite their importance as in-between media from leaves to sediments, n-alkanes of surface soils have not been systematically analyzed at large scale. Such an investigation of the spatial variation of n-alkane properties in soil and their dependence on climatic and botanic (e.g., vegetation type) factors could provide a rationale for a better estimation of the past environment. We synthesized the patterns and δ²H of long-chain n-alkanes in soil (δ²H^n-alkanes) with regard to vegetation types (cropland, grassland, shrubland, and woodland) and environmental factors using data from peer-reviewed papers. Our results showed that the ACL and CPI of soil C₂₇–C₃₃ n-alkanes were not suitable indicators for differentiating vegetation types at large scale; instead, ACL significantly correlated with water conditions such as mean annual precipitation (MAP) and Palmer drought severity index (PDSI), and CPI significantly correlated with temperature without significant influence of vegetation type. The variation (i.e., standard deviation) of fractionation between the δ²H values in annual precipitation and in soil n-alkanes (ε_rain-soil) was smaller than that reported in leaves; therefore, soils were better suited to quantifying the general growing conditions of plants at a certain site. The fractionation ε_rain-soil correlated with climatic conditions as described by the PDSI and relative humidity (RH). This correlation agreed with the change in leaf water enrichment with changing RH taken from the literature and was independent of the vegetation type at large scale. This meta-analysis may provide useful information for the variations of the patterns and δ²H_n-alkanes values in surface soils.