Importance of dispersal routes that minimize open‐ocean movement to the genetic structure of island populations

Islands present a unique scenario in conservation biology, offering refuge yet imposing limitations on insular populations. The Kimberley region of northwestern Australia has more than 2500 islands that have recently come into focus as substantial conservation resources. It is therefore of great interest for managers to understand the driving forces of genetic structure of species within these island archipelagos. We used the ubiquitous bar‐shouldered skink (Ctenotus inornatus) as a model species to represent the influence of landscape factors on genetic structure across the Kimberley islands. On 41 islands and 4 mainland locations in a remote area of Australia, we genotyped individuals across 18 nuclear (microsatellite) markers. Measures of genetic differentiation and diversity were used in two complementary analyses. We used circuit theory and Mantel tests to examine the influence of the landscape matrix on population connectivity and linear regression and model selection based on Akaike's information criterion to investigate landscape controls on genetic diversity. Genetic differentiation between islands was best predicted with circuit‐theory models that accounted for the large difference in resistance to dispersal between land and ocean. In contrast, straight‐line distances were unrelated to either resistance distances or genetic differentiation. Instead, connectivity was determined by island‐hopping routes that allow organisms to minimize the distance of difficult ocean passages. Island populations of C. inornatus retained varying degrees of genetic diversity (N_A = 1.83 – 7.39), but it was greatest on islands closer to the mainland, in terms of resistance‐distance units. In contrast, genetic diversity was unrelated to island size. Our results highlight the potential for islands to contribute to both theoretical and applied conservation, provide strong evidence of the driving forces of population structure within undisturbed landscapes, and identify the islands most valuable for conservation based on their contributions to gene flow and genetic diversity.     

Assessing the population-level conservation effects of marine protected areas

Marine protected areas (MPAs) cover 3–7% of the world's ocean, and international organizations call for 30% coverage by 2030. Although numerous studies show that MPAs produce conservation benefits inside their borders, many MPAs are also justified on the grounds that they confer conservation benefits to the connected populations that span beyond their borders. A network of MPAs covering roughly 20% of the Channel Islands National Marine Sanctuary was established in 2003, with a goal of providing regional conservation and fishery benefits. We used a spatially explicit bioeconomic simulation model and a Bayesian difference-in-difference regression to examine the conditions under which MPAs can provide population-level conservation benefits inside and outside their borders and to assess evidence of those benefits in the Channel Islands. As of 2017, we estimated that biomass densities of targeted fin-fish had a median value 81% higher (90% credible interval: 23–148) inside the Channel Island MPAs than outside. However, we found no clear effect of these MPAs on mean total biomass densities at the population level: estimated median effect was –7% (90% credible interval: –31 to 23) from 2015 to 2017. Our simulation model showed that effect sizes of MPAs of <30% were likely to be difficult to detect (even when they were present); smaller effect sizes (which are likely to be common) were even harder to detect. Clearly, communicating expectations and uncertainties around MPAs is critical to ensuring that MPAs are effective. We provide a novel assessment of the population-level effects of a large MPA network across many different species of targeted fin-fish, and our results offer guidance for communities charged with monitoring and adapting MPAs.     

三峡生态屏障区农户退耕受偿意愿的调查分析

运用参与式农户评估方法,对三峡生态屏障区内农户退耕还林的受偿意愿进行了调查.分析表明,退耕还林的生态效益受到普遍认可,但其可持续性令人担忧.1355份有效问卷中,愿意接受补偿的占74%,对未来生计的预期与土地相关性低的农户更愿意退耕.受偿意愿的形成具有明显的社会异质性和区域差异性.受访者性别、耕地面积、家庭年收入、帮扶形式、是否移民对受偿意愿值具有显著影响.屏障区平均补偿意愿为1014元/(亩×a).万州、秭归、渝北的受偿意愿值高于平均水平.建立基于区域的生态补偿标准和多元化的生态补偿方式,可以弥补目前均一型生态补偿标准和方式的不足,促进退耕还林工程和区域的可持续发展.     

基于优先度的城市避难场所最优投资规划

由于地质条件、人口密度、救灾可达性和灾害风险等不同，需要对城市各个区域避难场所的投资建设进行优先度排序。如何利用有限资金既能保证优先投资区域的避难容量达到规定目标，又能实现整个城市防灾避难规模的最大化，是城市防灾规划建设的重要问题。运用最优化计算理论，给出了基于优先度的最优投资双层规划模型，并举例验证了该模型的可行性。     

数控机床的故障诊断

针对数控机床的故障特点，主要介绍了数控机床机械类故障和电气类故障的诊断程序和诊断方法。     

浅谈安全工程专业学历教育

从安全工程师应具备的知识结构出发，主要讨论了安全工程专业学历教育中的课程设置及办学过程中存在的一些的问题。     

广州市供水水源面临的问题和对策

通过分析广州市现有的水资源情况和饮用水的供水情况、地表水源和地下水水源概况等资料,针对广州市饮用水源面临的严峻形势,提出广州市应建设以地下水作为应急饮用水源,构建复合水源体系的规划。     

水污染控制管理方案优化研究——以胶州湾东北部为例

以水质目标和管理费用为约束条件,建立了水污染控制管理方案优化模型,并将其成功应用于胶州湾东北部的水污染控制管理,提出了有利于胶州湾东北部经济和水环境可持续发展的优化管理方案。实例研究表明,该优化模型可应用于水污染控制管理中,可为海岸带地区制定水污染控制方案提供科学依据。     

中药类制药工业污染物排放自行监测方案编制要点

分析了中药类制药工业企业自行监测方案的编制依据,以及中药制药生产工艺类型和污染排放特征,在此基础上确定了其污染物排放自行监测方案和周边环境质量影响监测方案的主要内容。针对废水、废气、噪声3类主要污染因子,明确了监测点位、监测指标、监测频次设定的注意事项,以及自行监测相关信息记录的内容要求。