Policy challenges and approaches for the conservation of mangrove forests in Southeast Asia

Many drivers of mangrove forest loss operate over large scales and are most effectively addressed by policy interventions. However, conflicting or unclear policy objectives exist at multiple tiers of government, resulting in contradictory management decisions. To address this, we considered four approaches that are being used increasingly or could be deployed in Southeast Asia to ensure sustainable livelihoods and biodiversity conservation. First, a stronger incorporation of mangroves into marine protected areas (that currently focus largely on reefs and fisheries) could resolve some policy conflicts and ensure that mangroves do not fall through a policy gap. Second, examples of community and government comanagement exist, but achieving comanagement at scale will be important in reconciling stakeholders and addressing conflicting policy objectives. Third, private‐sector initiatives could protect mangroves through existing and novel mechanisms in degraded areas and areas under future threat. Finally, payments for ecosystem services (PES) hold great promise for mangrove conservation, with carbon PES schemes (known as blue carbon) attracting attention. Although barriers remain to the implementation of PES, the potential to implement them at multiple scales exists. Closing the gap between mangrove conservation policies and action is crucial to the improved protection and management of this imperiled coastal ecosystem and to the livelihoods that depend on them.     

A spatial-temporal optimization approach to watershed management: Acid mine drainage treatment in the Cheat River watershed, WV, USA

Most water management studies concentrate on the inter-temporal allocation problem or, more recently, spatial dynamics - but not both. While early spatial-temporal studies focused on the allocation of water quantity, this paper presents an approach to water quality analysis that incorporates both spatial and temporal dynamics in a watershed framework. The acid mine drainage (AMD) problem in the Cheat River watershed of West Virginia, USA, serves as a case study and provides an opportunity to test the modeling approach developed. The empirical models are written in General Algebraic Modeling System (GAMS) and solved using the CPLEX mixed integer programming package. The results suggest that available investments should be concentrated in heavily impaired stream segments. The model can be used to assess the economic implications of alternative watershed Total Maximum Daily Load (TMDL) implementation or other management strategies.     

Fuel derived pollutants and boating activity patterns in the Sea of Galilee

MTBE (Methyl tert-Butyl Ether) is a fuel additive that replaced lead as an antiknock compound in internal combustion motors. Few years after its introduction, detectable levels of MTBE were found in various water bodies. MTBE has a very low taste and odor threshold and is a potential carcinogen. Another group of fuel derived toxic compounds that has been detected in water bodies is BTEX (Benzene, Toluene, Ethylbenzene and Xylene). Boating activity and allochthonous contributions from watersheds are the major sources of fuel derived pollutants in lakes. Their concentrations in lakes thus vary as a function of boating activity intensity, lake surface area and depth, weather and wind regime, land-use in the watershed, etc. The Sea of Galilee (Lake Kinneret) is the only recreational lake in Israel and an important freshwater source. In the current study, a sampling campaign was conducted in order to quantify MTBE and BTEX concentrations in Lake Kinneret, its marinas and its main contributing streams. In addition, a boating-use survey was performed in order to estimate MTBE and BTEX contribution of recreational boating. The sampling campaign revealed that, as expected, MTBE concentrations were higher than BTEX, and that near shore (i.e., marina) concentrations were higher than in-lake concentrations. Despite the clear contribution from boating, high MTBE concentrations were found following a major inflow event in winter, indicating the importance of the allochthonous contribution. The contribution from boating during summer, as measured indirectly by in-lake concentrations, is likely underestimated due to enhanced MTBE volatilization due to strong winds and high temperatures. May–September was found to be the main recreational boating season, with continued boating year round. On average, a single boat is active 23 d/y, with 84% of the watercrafts being active only during weekends and holidays. The survey further indicated that boats stay in the lake for 4.5 h on average, which conforms to the unique winds regime that limits afternoon activity due to high winds, and have an average fuel consumption of 14 L/h. The annual load of MTBE and BTEX from recreational boating in Lake Kinneret was estimated at 4430 and 6220 kg/y respectively.     

A conjoint analysis of landholder preferences for reward-based land-management contracts in Kapingazi watershed, Eastern Mount Kenya

Unsustainable land-use decisions and agricultural practices have become the key drivers of deteriorating watershed services in developing countries. However, landholders may have little or no incentives to take these impacts into account in their decision-making process. In recent years, reward-based provision of environmental services has emerged as an important market-based incentive for motivating landholders to adopt environmentally friendly land-use changes and agricultural practices. In this regard, for instance, the Pro-Poor Rewards for Environmental Services in Africa (PRESA) project has emerged as a large network to support and facilitate reward mechanisms in Africa. However, in many African rural settings, little is known about landholder attitudes and preferences related to the alternative land-management schemes. Using locally identified sets of six key land-management attributes, this paper applies conjoint methods to evaluate landholder preferences towards alternative land-management schemes aimed at enhancing the provision of watershed services in the River Kapingazi catchment in central Kenya. Data were collected from primary sources through focus groups and a questionnaire based conjoint survey. Three conjoint models were used; a traditional conjoint ratings model, a binary logit model, and an ordered logit model. Results from the focus groups indicated that shortage of water for both domestic use and irrigation was perceived as the most acute environmental problem in the area. Deforestation, poor river bank management and agricultural practices were identified as the major causes of the problem. Results from conjoint models show that the three principal attributes influencing landholder's ratings and probability of adopting the proposed land management options were 'size of land area to be committed', 'length of contract period', and 'granting or prohibiting rights to harvest environmental products from the committed land'. Thus, these attributes should be the focal points in designing land-management contract for watershed services in the study area.     

A hybrid scheme for comparing the effects of bird diversity conservation approaches on landscape patterns and biodiversity in the Shangan sub-watershed in Taiwan

This work utilizes bird survey data, regression modeling, land-use modeling and landscape metrics to evaluate the effects of various spatial bird diversity conservation approaches on land-use allocation, land-use patterns, and biodiversity in the Shangan sub-watershed in central Taiwan. A survey of the distribution of species revealed that bird species are concentrated in the central and western parts of the sub-watershed. The results obtained using a Shannon-Weaver diversity regression model suggest that diversity of land-use increases the diversity of bird species. Logistic regression results verify that socio-economic factors determine the potential advantages of designating a particular type of land-use in certain parts of the study area. The results of land-use simulation modeling indicate that the eastern and southwestern areas of the sub-watershed will change most frequently between 2007 and 2017. Additionally, increasing the areas to protect bird diversity will effectively increase the patch size, habitat core area, edge effect and habitat connectivity. The Shannon-Weaver diversity regression model shows that protecting bird species diversity in large areas increases bird diversity. The proposed modeling approach is an effective tool that provides useful information for ecological planning and policymaking related to watersheds.     

跨域治理理论比较与启示

我国幅员辽阔,有关公共事务的治理问题层出不穷,尤其在跨行政区域的公共事务治理上有效的治理手段捉襟见肘,这对我国的公共管理提出了严峻挑战.从跨域治理理论的兴起与发展人手,在详细分析三种跨域治理经典理论的基础上,比较了各种跨域治理理论的特征,总结出跨域治理理论对我国在此类问题上的几点启示.     

国际旅游组织介入背景下山岳型景区治理演化路径研究

景区治理是旅游研究的重要内容。伴随着全球一体化发展,国际旅游组织在景区治理中的地位和作用逐渐凸显。以路径创造理论为基础,综合运用文献分析、参与式观察和深度访谈等质性研究方法,以黄山风景区为例,构建了旅游发展的路径创造分析框架,探讨在国际旅游组织介入背景下,山岳型景区治理模式的演化过程及其影响。研究发现:（1）国际旅游组织介入改变了景区治理主体和治理结构,为黄山风景区治理创造了新的路径,也是推动其治理模式演化的重要力量。（2）从申报主体、作用路径、涉及范围、影响内容与介入成效等5个维度具体分析,黄山风景区加入国际旅游组织后经历了三次路径创造,并产生了明显的不同效应。（3）国际旅游组织介入对黄山风景区内部治理、毗邻社区参与治理经验输出三个方面均产生了显著的影响。     

县域国土空间主体功能区土地资源空间配置效率及管制策略——以江苏赣榆为例

从县域出发,深化主体功能区概念应用,探究土地资源空间配置效率及其管制策略对深化我国国土空间治理体系具有重要意义。通过梳理主体功能区与土地资源空间配置理论关系,借助C-D生产函数考察江苏赣榆主体功能区土地资源空间配置效率,并差别化提出管制策略。研究表明,主体功能区建设实质是“以地为本”,功能区划理念下土地资源空间配置应遵循边际净收益相等的转化度,具有增进用地效率、减少自发优势竞争效率损失的可能。对赣榆区研究发现,不同主体功能区农用地转为建设用地数量存在过量配置,具有帕累托改进空间,其根源在于现行土地计划管理缺乏弹性机制调节指标,造成实际落地中的空间错配。因此,赣榆区应从全区统筹主体功能定位,协调国土空间发展格局,其中优化开发区“革新土地空间结构,转变经济与产业发展方式”、重点开发区“助力城镇工业化进程,确保土地资源利用效益”、限制开发区“着力粮经产品安全,创新农业生产用地经营模式”、禁止开发区“划定生态空间红线,探索农旅生态用地结构布局”。     

洋河流域万全段重金属污染风险及控制对策

洋河流域是北京官厅水库重要的入库水源,通过对洋河流域万全段采集地表水和沉积物样品,研究重金属空间特征及其生态风险,结果表明,地表水中所监测的Cu、Ni、Cd、Zn、Cr、Pb、Hg、As含量分别为1.28~24.13、1.13~16.84、0.08~0.11、1.80~10.65、1.40~19.12、0.13~2.05、0.06~0.99、0.46~4.22μg·L-1,不同点位各重金属含量均低于国家Ⅳ类水质标准,仅满足一般工业用水和农业灌溉用水要求.沉积物中Cu、Ni、Cd、Zn、Cr、Pb、Hg、As含量分别为5.90~110.11、17.34~56.04、0.07~0.31、38.71~116.74、40.39~85.77、18.65~22.74、nd~0.047、0.85~9.98 mg·kg-1.沉积物中各重金属平均潜在生态风险均表现为轻微等级,但有部分点位Cd、Hg的潜在生态危害指数达到中等,危害指数由高到低分别为Cd>Cu>Hg>Ni>As>Pb>Cr>Zn.监测点重金属的累积生态风险由高到低分别为:YH-07>YH-03>YH-09>YH-02>YH-06>YH-04>YH-05>YH-01,平均潜在生态危害累积指数处于轻微级别,但点位YH-07潜在生态风险累积指数已达到中等级别.整个万全河段区域中,风险较高区域集中在农业耕作较密集的YH-02~YH-03点位和人工化程度较高的YH-07~YH-09点位.基于研究结果,提出了具体的重金属生态风险管理对策及建议,并明确了农业耕作控制区、河道改造控制区以及洋河水源保护缓冲区等3个污染风险调控功能区.     

首都水源地——洋河流域人为源多环芳烃(PAHs)排放清单估算及其影响分析

洋河流域位于京西北上风向,是北京重要水源地和生态保护屏障,我国北方典型的农牧交错带和生态脆弱敏感区,也是北京-张家口2022年冬奥会的申办地,具有极重要的战略地位.建立洋河流域大气PAHs排放清单,分析其可能来源及影响,通过气团后向轨迹辨识其区域PAHs传输途径,对于北京及张家口地区环境PAHs的污染控制具有重要的指导意义.本研究收集和分析了洋河流域大量工、农业生产和居民生活等相关数据资料,评估了流域各行业、各县市PAHs排放因子,单体排放量及其影响因素,通过气团后向轨迹模型分析了PAHs的传输轨迹.结果表明,洋河流域大气PAHs排放量为4.4×102t.从排放行业看,煤炭燃烧源、秸秆燃烧源是洋河流域大气PAHs的重要排放源,其贡献率分别为76%和16%.从排放地区看,宣化县的排放量最大,约49 t;其次分别为:兴和县、天镇县、怀来县、万全县,排放量分别约为:36、32、24和15 t.从排放谱看,低环(2~3环)与高环分子(4~6环)PAHs的排放量相差不大,分别约占PAHs排放总量的50%左右.洋河流域单位PAHs总排放量与各县市的工业生产总值(r=0.96,P<0.05)、居民收入(r=0.94,P<0.05)、人口密度呈正相关(r=0.92,P<0.05),与单位国土面积呈负相关(r=-0.9,P<0.05),与农业生产总值没有显著相关(r=0.026,P>0.01).流域内PAHs的较高排放与该地以煤炭为主的能源结构和较高的居民消费水平有关.基于气团后向轨迹模拟和洋河流域PAHs排放,可以推断洋河流域已成为PAHs的高污染风险区,通过西北气流可将流域高浓度的PAHs输送至北京,对北京的生态环境和人体健康造成潜在风险.