Towards a framework for assessment and management of cumulative human impacts on marine food webs

Effective ecosystem‐based management requires understanding ecosystem responses to multiple human threats, rather than focusing on single threats. To understand ecosystem responses to anthropogenic threats holistically, it is necessary to know how threats affect different components within ecosystems and ultimately alter ecosystem functioning. We used a case study of a Mediterranean seagrass (Posidonia oceanica) food web and expert knowledge elicitation in an application of the initial steps of a framework for assessment of cumulative human impacts on food webs. We produced a conceptual seagrass food web model, determined the main trophic relationships, identified the main threats to the food web components, and assessed the components’ vulnerability to those threats. Some threats had high (e.g., coastal infrastructure) or low impacts (e.g., agricultural runoff) on all food web components, whereas others (e.g., introduced carnivores) had very different impacts on each component. Partitioning the ecosystem into its components enabled us to identify threats previously overlooked and to reevaluate the importance of threats commonly perceived as major. By incorporating this understanding of system vulnerability with data on changes in the state of each threat (e.g., decreasing domestic pollution and increasing fishing) into a food web model, managers may be better able to estimate and predict cumulative human impacts on ecosystems and to prioritize conservation actions.     

污泥活性炭深度处理焦化废水的试验研究

以污水处理厂剩余污泥为原料、氯化锌为活化剂,制备得到污泥活性炭AC-Z。借助比表面积测定和红外光谱分析表征污泥活性炭的物理化学性质。采用瓶点法静态吸附实验和动态柱吸附实验研究AC-Z对焦化废水生化尾水中COD和色度的去除效果。瓶点法静态试验表明:AC-Z对COD和色度的去除率随着pH的增大而减小,随投加量的增加而增大;AC-Z对COD和色度的吸附为吸热过程,COD的吸附数据符合Langmuir吸附等温方程,303 K时单层最大吸附量为117.65 mg/g;准二级动力学方程可以很好的描述303 K时AC-Z对COD的动力学吸附行为,吸附速率常数为2.55×10-3g(/mg.min)。动态试验表明:吸附流速10 BV/h,污泥吸附剂对COD和色度的去除效果较好,可以达到国家污水综合排放标准一级标准;选择质量分数5%NaOH为脱附剂时,脱附流速为5 BV/h,COD和色度的脱附率分别可以达到94.1%和91.1%以上。     

秸秆生物质炭DOM光谱特征及其与Cu2+的相互作用

通过荧光猝灭滴定法探究玉米秸秆炭（MSB）、水稻秸秆炭（RSB）和花生秸秆炭（PSB）中DOM的光谱特征及其与Cu²⁺的络合机理.结果表明：三种生物质炭的DOM均具有较高的亲水性和较低的芳香性,其中RSB-DOM的芳香性相对较强、分子量较大,但DOM含量低,PSB-DOM含量最高,芳香结构中含氧官能团较多.MSB和RSB-DOM中均含类富里酸组分C1和类腐殖酸组分C3、C4,RSB-DOM中还有类色氨酸组分C5,PSB-DOM则由两种类富里酸组分C1、C2和较长波长类腐殖酸组分C4组成,3种DOM均以类富里酸组分为主,占比达54.93%~86.29%.Cu²⁺与类腐殖酸组分的稳定常数（logK_M）高于类富里酸组分,且类腐殖酸组分C4的络合能力（f）最强,类腐殖酸组分的logK_M和f值总体上表现为：PSB-DOM> MSB-DOM>RSB-DOM.二维相关光谱分析发现,类富里酸组分对Cu²⁺最敏感,而Cu²⁺优先与类腐殖酸组分结合.研究结果有助于进一步揭示生物质炭的DOM对Cu²⁺环境行为的影响机制.     

煤矿社区居民的资源开发态度及其影响因素分析

居民对资源开发的态度是资源开发管理的重要社会与公众基础。基于对煤矿社区居民的调研数据,实证分析了居民资源开发态度的特征及其影响因素差异。结果显示：煤矿社区居民对资源开发总体呈现比较反对的态度。居民社会人口属性方面,受教育水平越高其对资源开发态度的支持程度越高;女性比男性更支持煤矿开采。在社会文化层面,就业机会和社会个人利益正向、显著影响居民资源开发态度;煤矿开采对居民生活和健康的不利影响负向、显著影响居民资源开发态度。在经济交通层面,资源开发的配套设施建设正向、显著影响居民资源开发态度;土地破坏和粮食减产负向、显著影响居民资源开发态度。在生态环境层面,自然灾害和地质灾害发生情况以及水质和水量的下降情况负向、显著影响居民资源开发态度。建议未来应制定针对性政策,改善居民资源开发态度,并着眼于资源开发沟通机制的完善、居民参与资源开发规划的制定和外部管理制度建设能力的提升。     

Market‐based conservation: Aligning static theory with dynamic systems

This paper provides a broad evaluation of the implications of market‐based conservation (MBC) strategies from economic, social and ecological perspectives. After reviewing the economic theory that underlies MBC initiatives, we develop a list of approaches that have been labeled as “market‐based”, and categorize them according to the degree to which they are free‐standing markets or require the intervention of the state. A multidisciplinary critique reveals the potential problems and pitfalls of MBC are due to a lack of ability to deal with dynamic systems in the real world. The dynamics of these three systems can undermine the intended goals of MBC.     

Estimation of pasture infectivity according to weather conditions through a fuzzy parametrized model for the free-living stage of Ostertagia ostertagi

Gastrointestinal parasitism is one of the diseases that has the highest economic impact on the Argentinian beef production system, rendering it inefficient. In the region of the Humid Pampas, it has been estimated that 22 million dollars are lost annually because of the death of calves and 170 million dollars are lost in sub-clinic costs. A mathematical model with fuzzy parameters was constructed for the analysis of the free-living stages of gastrointestinal parasites, with the purpose of estimating the pool of L3 larvae available for migration to pasture and the levels of infection in pasture at any time of the year under different climatic conditions. The model is formulated in terms of a system of three difference equations. These equations describe the abundance of parasites in each of the successive stages of the population development. The model was calibrated and tested with data gathered through fieldwork carried out in Tandil (37°19′S, 59°08′05″W), province of Buenos Aires (Argentina) and the corresponding weather data. A comparison between model simulations and fieldwork data obtained in other locations achieved satisfactory results.     

Impacts of Climate Change on Extreme Precipitation Events Over Flamingo Tropicana Watershed1

Abstract: Climate change, particularly the projected changes to precipitation patterns, is likely to affect runoff both regionally and temporally. Extreme rainfall events are expected to become more intense in the future in arid urban areas and this will likely lead to higher streamflow. Through hydrological modeling, this article simulates an urban basin response to the most intense storm under anthropogenic climate change conditions. This study performs an event‐based simulation for shorter duration storms in the Flamingo Tropicana (FT) watershed in Las Vegas, Nevada. An extreme storm, defined as a 100‐year return period storm, is selected from historical records and perturbed to future climatic conditions with respect to multimodel multiscenario (A1B, A2, B1) bias corrected and spatially disaggregated data from the World Climate Research Programme's (WCRP's) database. The cumulative annual precipitation for each 30‐year period shows a continuous decrease from 2011 to 2099; however, the summer convective storms, which are considered as extreme storms for the study area, are expected to be more intense in future. Extreme storm events show larger changes in streamflow under different climate scenarios and time periods. The simulated peak streamflow and total runoff volume shows an increase from 40% to more than 150% (during 2041‐2099) for different climate scenarios. This type of analysis can help evaluate the vulnerability of existing flood control system and flood control policies.     

Modeling Nutrient Export From Coastal California Watersheds

Nitrate and phosphate export coefficient models were developed for coastal watersheds along the Santa Barbara Channel in central California. One approach was based on measurements of nutrient fluxes in streams from specific land use classes and included a watershed response function that scaled export up or down depending on antecedent moisture conditions. The second approach for nutrient export coefficient modeling used anthropogenic nutrient loading for land use classes and atmospheric nutrient deposition to model export. In an application of the first approach to one watershed, the nitrate and phosphate models were within 20% of measured values for most storms. When applied to another year, both nitrate and phosphate models generally performed adequately with annual, storm‐flow, and base‐flow values within 20% of measured nutrient loadings. Less satisfactory results were found when applied to neighboring watersheds with difference percentages of land use and hydrologic conditions. Application of the second approach was less successful than the first approach.     

Individual based model of slug population and spatial dynamics

The slug, Deroceras reticulatum, is one of the most important pests of agricultural and horticultural crops in UK and Europe. In this paper, a spatially explicit individual based model (IbM) is developed to study the dynamics of a population of D. reticulatum. The IbM establishes a virtual field within which slug spatial dynamics and changes in abundance were simulated. The strong dependence of slug behaviour on environmental conditions is built into the model, which is based upon previous work on the environmental dependence of slug population dynamics. The simulation results show that the IbM described well changes in the slug population. The IbM proved capable of describing slug populations over 3.5 years, including the presence, magnitude and duration of D. reticulatum population crashes within this period. Moreover, the model was capable of reproducing slug population dynamics at two sites, with distinct weather and some 100 km apart, with minor changes in initialisation values but no change in model structure and parameter values. A study of field heterogeneity, which might simulate various field designs, indicated the importance of spatial structuring to slug population dynamics and the utility of the IbM for simulating a range of potential spatial management treatments for slug control to maximise crop yield. This IbM system performs well and is currently being used as part of an integrated approach to predict slug population dynamics and control in the UK.