GIS-based integrated evaluation of environmentally sensitive areas (ESAs) for land use planning in Langkawi,Malaysia

Extensive economic growth, tourism activities and over-exploitation of resources have become the common causes of environmental degradation in Langkawi. The sudden development leap resulting from UNESCO's recognition of Langkawi Archipelago as a Global Geopark in 2007, leads to continuous conflicts between enhancing environmental protection and meeting tourism and development needs. Environmental sensitivity evaluation is a basis upon which the concept of environmentally sensitive areas (ESAs) can be practised in order to protect the environment, regulate development activities and promote sustainable land use planning. This study embarks on evaluating and classifying environmental sensitivity as well as comparing different ESA approaches applicable for land use planning in Langkawi. A GIS-based integrated evaluation model was performed on two assessment sets (Set A and Set B) using a standard grading system and weights determined with analytic hierarchy process (AHP) method. Of these sets, the former consists of selected indicators from the Malaysian integrated ESA instrument while the latter are derived from previous eco-environmental studies conducted in China. The projected final ESA maps of Langkawi indicate spatial distribution of four environmental sensitivity classes. More highly and moderately sensitive areas are observed in Set A, accounting for 339.15 km² or 72.24% of the total land area compared to Set B with only 259.04 km² or 55.18% respectively. The results also reveal large proportion of low sensitivity areas in Set A, covering areas of 117.42 km² (25.01%). In contrast, more areas with non-sensitivity are widely distributed in Set B, occupying areas of 123.02 km² (26.20%). Taking into consideration the natural and cultural characteristics of the islands, it is suggested that Set A is a better approach to portray current environmental concerns and to coordinate future land use planning as well as fits Langkawi's aspiration in becoming a sustainable, world-class Global Geopark. This study provides beneficial information and opportunity for reasonable rearrangement of zoning and development guidelines and strategies within sensitivity areas. It promotes effective utilization of the natural resources, minimizes negative tourism impacts and adequately highlights ecosystem functions to prosper local socio-economic growth. It also represents an early step for the design of universal ESA instruments to regulate local development activities and promote sustainable land use planning in vulnerable areas at global levels.     

Sexual differences in survival rates of adult pipistrelle bats (Pipistrellus pipistrellus) in South Sweden

Summary A pipistrelle bat (Pipistrellus pipistrellus) population in southernmost Sweden was studied for eight consecutive breeding seasons by means of bat boxes. Survival rates were calculated using Cormack's stochastic technique. The mean survival rate of adult females exceeded that of territorial males. Annual variations in survival rates were most evident in males, low rates being observed in years following wet autumns. Energy constraints imposed on territorial males by the mating system, a resource defence polygyny, were assumed to account for the differences obtained in survival rates between the sexes.     

美国对入侵种的管理对策

外来种入侵是产生当前世界生物多样性危机的重要原因之一。目前外来种入侵问题已经引起人们的普遍关注。1999年2月美国联邦政府发布总统令,号召联邦政府机构执行人员防止外来入侵种所造成的严重环境威胁,指示有关职能部门行使职权阻止引入入侵种并且恢复本地种。总统令指示建立一个入侵物种理事会,并就理事会、联邦机构的职责做了相应界定。美国农业部等部门支持的入侵植物管理国家策略项目,提出了针对入侵种的三项国家目标一入侵种的预防、控制和本地种的恢复。国家管理策略的制定不同层次的人们提供了合作、教育和研究的机遇。美国政府部门以及有关社会团体已经就外来种入侵危害防范积极展开行动,包括制定标准防止入侵种进入,控制、根除入侵种,向民众进行有关外来种入侵的教育,增加财政年度预算等等。     

兼性甲烷氧化菌的发现历程

兼性甲烷氧化菌在新陈代谢上具有独一无二的特性:它们能够利用甲烷或一些含碳碳键的有机物作为唯一碳源和能源.甲基细胞菌属(Methylocella)、甲基孢囊菌属(Methylocystis)和甲基帽菌属(Methylocapsa)的一些菌株已经被确定为兼性甲烷氧化菌.它们都属于a-变形菌纲,能够像利用甲烷一样在大分子有机酸或乙醇里生长.本文全面系统地总结了兼性甲烷氧化菌的研究发展历史,推断出兼性甲烷氧化菌易在酸性环境富集生长;介绍了与之有相近功能的兼性甲烷氧化生物;浅析了其对多碳化合物的代谢机理;最后讨论了兼性甲烷氧化菌研究的现存问题和工程应用前景.     

A new approach for designing disease intervention strategies in metapopulation models

We describe a new approach for investigating the control strategies of compartmental disease transmission models. The method rests on the construction of various alternative next-generation matrices, and makes use of the type reproduction number and the target reproduction number. A general metapopulation SIRS (susceptible–infected–recovered–susceptible) model is given to illustrate the application of the method. Such model is useful to study a wide variety of diseases where the population is distributed over geographically separated regions. Considering various control measures such as vaccination, social distancing, and travel restrictions, the procedure allows us to precisely describe in terms of the model parameters, how control methods should be implemented in the SIRS model to ensure disease elimination. In particular, we characterize cases where changing only the travel rates between the regions is sufficient to prevent an outbreak.     

西双版纳热带森林附生维管植物的物种多样性与区系特征

附生植物是山地森林生态系统中重要的结构性成分。因受林冠调查技术限制, 人们对林冠附生植物知之甚少。本文在前人有关西双版纳植物区系研究的基础上, 结合野外调查和标本资料, 对该地区附生植物的物种组成与分布进行了整理。结果表明, 西双版纳热带森林附生维管植物共有29科134属486种, 约占全部维管植物的11%。附生兰科是最丰富的类群(69属293种), 其中以石斛属(Dendrobium) (49种)和石豆兰属(Bulbophyllum) (48种)物种数最多。蕨类是仅次于兰科的附生类群(13科38属97种), 其中水龙骨科(51种)占附生蕨类总数的50%以上。基于生活史和养分来源的划分标准, 该地区48%的附生物种属于兼性附生, 其次是以兰科为主的专性附生(46%), 半附生仅占6%。从区系上看, 西双版纳附生植物属的分布具有明显的热带亚洲性质。附生植物主要分布于资源受限的林冠生境, 对环境变化极为敏感, 在人为干扰日益加剧的背景下, 这类植物正面临严重威胁。因此, 需要加强对西双版纳林冠亚系统的保护。     

Genetic mating patterns studied in pools with manipulated nest site availability in two populations of Pomatoschistus minutus

Pomatoschistus minutus show paternal care in a resource defence mating system. We investigated the effect of nest-site availability on parasitic spawning. Each experimental pool contained four potentially nest-building males, four females and nests-sites in shortage (2) or excess (6). Both treatments were conducted in two populations; one with natural nest-sites in excess, one with a nest-site shortage. Microsatellite-DNA revealed that all nest-holders had fertilized most of the eggs they tended. Yet, 35% of the nests contained eggs fertilized by another male and 14.4% of the males had performed parasitic spawning. There was no site or treatment effect. Several females spawned in two nests, which coincided with parasitic spawnings, suggesting a cost to the nest-holder in terms of lost mating success. Nest-holders with and without eggs and non-nesting males all spawned parasitically, generating a significantly lower opportunity for sexual selection compared to if there had been no parasitic spawning.     

The evolution of alternative mating strategies in variable environments

Summary We assessed the influence of phenotypic plasticity in age at maturity on the maintenance of alternative mating strategies in male Atlantic salmon,Salmo salar. We calculated the fitness,r, associated with the parr and the anadromous strategies, using age-specific survival data from the field and strategy-specific fertilization data from the laboratory. The fitness of each strategy depended largely on mate competition (numbers of parr per female, i.e. parr frequency) and on age at maturity. Fitness declined with increasing numbers of parr per female with equilibrium frequencies (at which the fitnesses of each strategy are equal) being within the range observed in the wild. Equilibrium parr frequencies declined with decreasing growth rate and increasing age at maturity. Within populations, the existence of multiple age-specific sets of fitness functions suggests that the fitnesses of alternative strategies are best represented as multidimensional surfaces. The points of intersection of these surfaces, whose boundaries encompass natural variation in age at maturity and mate competition, define an evolutionarily stable continuum (ESC) of strategy frequencies along which the fitnesses associated with each strategy are equal. We propose a simple model that incorporates polygenic thresholds of a largely environmentally-controlled trait (age at maturity) to provide a mechanism by which an ESC can be maintained within a population. An indirect test provides support for the prediction that growth-rate thresholds for parr maturation exist and are maintained by stabilizing selection. Evolutionarily stable continua, maintained by negative frequency-dependent selection on threshold traits, provide a theoretical basis for understanding how alternative life histories can evolve in variable environments.