海南岛甘什岭低地次生雨林土壤有机碳及影响因素

热带雨林是世界上最复杂的森林生态系统,在全球碳循环中发挥着重要作用。热带低地次生雨林是受人类干扰较为严重的雨林类型,而关于其土壤有机碳库的研究甚少。以海南岛甘什岭热带低地次生雨林为研究对象,通过野外调查采样与室内分析相结合等方法,研究了经人为采伐干扰后自然更新恢复形成的3种林分类型(Ⅰ为较大采伐强度下恢复的灌丛与低矮乔木,Ⅱ为经中等采伐强度恢复成林分密度较大的次生雨林,Ⅲ为因交通条件不便,受采伐干扰较小的次生雨林)的土壤有机碳含量、碳密度的垂直分布特征及其影响因素,旨在为热带低地次生雨林恢复与土壤固碳能力研究提供科学依据。研究结果表明:(1)3种类型低地次生雨林的土壤有机碳含量均随土层深度的增加而降低,垂直分布特征为0—20 cm土层有机碳含量最高(3.07—4.49 g·kg^?1),在类型Ⅲ的变异系数最大为5.60%;(2)土壤有机碳密度的分布特征与有机碳含量基本一致,0—100 cm土层土壤有机碳密度为4.14—6.42 kg·m^?2,仅为全国平均水平的50.8%;(3)土壤有机碳与土壤全氮、碱解氮、有效磷均呈极显著正相关性(P<0.01),与林分凋落物厚度和物种丰富度呈显著正相关性(P<0.05)。热带雨林特有的水热条件、物种丰富度、土壤质地和极度缺磷现象的综合作用是形成其土壤有机碳积累特征的主要因素,加强受干扰破坏热带雨林的保护与修复,有助于土壤有机碳的积累。     

Landsenses pattern design to mitigate gale conditions in the coastal city – a case study of Pingtan,China

ABSTRACT

Due to the special geographic locations and multiple typhoons a year, the frequent strong winds bring great discomfort and danger to the daily lives of the urban residents in southeast coast of China. The strategic design of landsenses pattern on different scales can help reduce gale days in urban areas while delivering diverse additional benefits such as pollution control and biodiversity habitat protection. Although the greatest gale days are observed in cold and damp winters, there is comparatively little information available for land managers to determine an appropriate strategy for landsenses pattern design under these climatic conditions. We present a framework for prioritization and selection of landsenses pattern for gale day reductions. The framework is supported by examining the relationships between urban landsenses pattern evolution and gale day mitigation in the past, with which we used to develop implementation guidelines that maximize reductions of urban surface gale days. We focus particularly on quantifying the benefits of four types of landsenses: land-use patterns, urban road network, architectural patterns, and vertical greening systems (green walls and facades) and demonstrate how to apply the framework with a case study from Pingtan Island, China.     

Intraguild predation and mesopredator release effect on long-lived prey

Complete extirpation of a species can generate cascading effects throughout an ecosystem, yet are precisely the goal of island eradications of pest species. “Mesopredator release effect”, an asymmetrical special case of intraguild predation, has been hypothesised as a possible indirect effect from eradications, where superpredator removal can generate a mesopredator increase which may increase the impact on their shared prey. Theoretically this suggests that for intraguild predators, the superpredator may protect the shared prey from mesopredation, and removal of superpredators alone is not recommended. We create a model of long-lived age-structured shared prey and explore the non-equilibrium dynamics of this system. The superpredator can impact all prey life-stages (adult survival and reproductive success) whereas the smaller mesopredator can only impact early life-stages (reproductive success). This model is independently tested with data from a closed oceanic island system where eradication of introduced intraguild predators is possible for conservation of threatened birds. Mesopredator release only occurs in strongly top-down moderated (resource-abundant) systems. Even when mesopredator release can occur, the negative impact of more mesopredators is outweighed by the benefit of superpredator removal, allowing recovery of the prey population. Results are robust to 10% variation in model parameters. The consideration of age-structured prey contradicts previous theoretical results for mesopredator release effect and intraguild predation. Superpredator eradication is vital for population recovery of long-lived insular species. Nonetheless island conservation must retain a whole-ecosystem perspective given the complex trophic relationships among multiple species on islands.     

上海崇明岛农田土壤中多氯联苯的残留特征

在上海崇明岛采集了101个耕层土壤样品,利用GC-μECD测定了8种多氯联苯(PCBs)浓度,并对其进行多元统计分析,探讨了其可能的污染来源.结果表明,样品PCBs浓度范围为n.d.~261ng/g,均值为56.0ng/g,低氯联苯含量和检出率均较高.不同土壤利用方式对PCBs残留量有一定影响,表现为水稻田土壤>大棚蔬菜西瓜田土壤>露天蔬菜西瓜田土壤.主成分分析和相关性研究结果显示,土壤中低氯联苯同系物间相关性较好,污染来源可能为同一类.     

长兴岛邻近海域的沉积物粒度参数特征及物源分析

采用筛分法和吸液法分析长兴岛邻近海域11个表层沉积物样品,获得了1Φ间隔的粒度参数数据。分析结果表明,临港工业区附近海域的沉积物类型主要有G、S、S-T-Y、TS、YS、G-S-T、ST、YT共8种,S和ST是该区的优势和次优势组份。平均粒径在-1~2.623Φ,分选系数在0.221~3.213,偏态在0.311~1.311,峰态在0.828~3.978。基于沉积物各粒级的空间分布规律,对研究区域的物质来源情况,进行了分析讨论。     

崇明岛风景旅游区空气负离子监测评价方案研究

崇明岛作为上海市的未来生态岛屿,至今尚未开展过系统的空气负离子研究。依据该县相关规划,结合区域植被、地貌、人为影响等因素,在东滩国家级自然保护区、东平国家森林公园、前卫村、明珠湖和西沙湿地5个监测区域共选定了18个空气质量监测点进行研究。按崇明风景旅游区的具体情况,对国内外7种空气负离子监测评价方法进行了比较,最终确定选用安培空气质量评价系数、森林空气离子评价系数、空气负离子系数评价法、轻重离子比评价法来对该岛的空气质量进行评价。最后还对相关负离子监测仪器进行了分析及建议。     

强烈风化条件下玄武岩发育土壤的元素地球化学特征

海南岛地处热带,晚第三纪以来喷发的玄武岩上广泛发育铁铝土。土壤剖面的常量元素、微量元素、化学风化指标及元素迁移率的研究表明:(1)土壤Al2O3、Fe2O3、SiO2和TiO2元素富集,水溶型元素强烈淋失,高CIA值和低ba值均显示其经历强烈的化学风化作用;(2)元素含量和元素迁移率的计算结果显示,温带难迁移的Ti、Zr、Hf和Nb等元素在高温多雨的热带环境下也会发生强烈的淋失,究其原因主要受湿热环境下高有机质含量和强酸性条件影响;(3)Fe、Al、Cu和Ni等元素的迁移则反映了基岩发育土壤自下而上的风化渐进特征;(4)表层土壤K、Na和Sr元素的强烈富集则与大气沉降有关。     

Efficient thinning regimes for Eucalyptus fastigata: Multi-objective stand-level optimisation using the island model genetic algorithm

A stand-level optimisation problem formulated to determine a set of efficient thinning regimes satisfying two objectives, i.e. value production for sawlog harvesting and volume production for a pulpwood market, was demonstrated for a Eucalyptus fastigata trial in Kaingaroa Forest, New Zealand. Genetic algorithms were used to estimate the set of efficient thinning regimes (i.e. regimes that occur when it is not possible to increase the achievement of one objective without reducing another) known as a Pareto frontier. Each thinning regime specified a unique combination of initial planting density; frequency, timing and intensity of thinning; final crop number; and rotation length. Specifications for the “best” regime in the Pareto set (i.e. the one that satisfied a balanced trade-off between value and volume production) were similar to those recommended through professional judgment based on pooled long-term field observations from different eucalypt species grown throughout New Zealand. The advantage of Pareto optimality was the ability of not only identifying a unique thinning regime, but equally efficient regimes each providing a different combination of value and volume production. Research on this approach has the potential of being applied to other forest sites, providing there is sufficient re-measurement data to reflect stand growth dynamics.     

海岸带国土空间开发适宜性评价及功能空间配置——以海南岛为例

海岸带国土空间开发适宜性评价及功能空间布局优化是推进陆海统筹战略目标的科学基础。以海南岛为例,基于环境损益分析思想构建海岸带“潜力—限制”评价指标体系,综合运用多要素乘积及空间叠置等方法,对海南岛海岸带地区的国土空间开发建设适宜性进行集成评价,并依据功能空间判别条件识别“港—工—城”区、滨海旅游区、农林牧渔区以及自然保护区四类海岸带功能空间。研究表明：海南岛海岸带国土空间开发适宜区总体呈现“西岸多,东岸少”的空间分布格局,适宜、基本适宜、基本不适宜、不适宜建设区面积依次为1785.32 km²、1724.57 km²、812.86 km²、4051.67 km²,适宜区与不适宜区重叠交错,给海岸带国土空间开发带来巨大压力。海岸带地区四类功能空间面积依次为1813.39 km²、2138.26 km²、1831.62 km²和2591.15 km²,分别占海岸带面积的21.65%、25.53%、21.87%和30.94%,海岸带的功能空间呈现“一环”“两极”和“多点”的空间格局。依据归纳出的三类典型功能空间冲突,对功能空间进行了调整优化,增强了各类功能空间的集聚性和连通性,但仍存在海域与陆域的相同功能空间不连片,海陆经济联系不够通畅,相互支撑不足等问题,国土空间开发还存在较多的陆海矛盾和冲突。研究结果指明了各类适宜性等级区域的开发或保护模式,丰富了适宜性的应用条件,也是对国土空间开发适宜性评价的适当拔高。     

旅游区旅游环境容量研究

选择典型的海岛型旅游区——蜈支洲岛旅游区为研究对象,通过分析旅游容量体系,定量研究了该景区的旅游环境容量。研究结果表明,该旅游区的生态环境容量、功能设施容量、空间环境容量和社会环境容量分别为10 400、7 200、8 910和17 000人次/日。功能设施容量和空间环境容量成为制约景区接待规模的限制因子。提出新建和改建基础服务设施、建立淡旺季两套管理措施、新建景点和扩建游步道等措施,来提高蜈支洲岛景区的整体环境容量并缓解旅游旺季带来的环境容量超载问题。