Crustaceans as ecological indicators of metropolitan sandy beaches health

We have investigated how indices of beach health perform in predicting the abundances of the crustaceans Emerita brasiliensis and Atlantorchestoidea brasiliensis from 22 metropolitan beaches in the cities of Rio de Janeiro and Niterói. Urbanization, Recreation and Conservation indices were used to assess sandy beaches health. Grain size and beach slope were used as morphodynamics indicators. Diagram from the principal component analysis clearly separated beaches with different urbanization and conservation levels. Generalized additive models (GAM's) were adjusted for species abundance using the indices and morphodynamic parameters as explanatory variables. Lower abundances were predicted for beaches with high levels of urbanization, whereas predictions of higher abundances occurred on beaches with high conservation levels. Using theoretic inference we showed that the urbanization index was the most important predictor for abundance of A. brasiliensis and the conservation index was the most important predictor for E. brasiliensis, reflecting different responses by upper tidal and intertidal species. A. brasiliensis occupies the intermediate and upper beach zones and E. brasiliensis is a swash zone filter-feeder that is more abundant in pristine beaches. Both species are highly subject to the impact of bathers and coastal modification. Unexpected, the recreation index did not show a negative effect on abundance predictions. Urbanization and conservation indices can be suitable metrics to measure anthropogenic effects on macrobenthic species. Moreover, mole crabs and sandhoppers species can be easily monitored. Coastal urbanization is a global phenomenon and we used the diagram of urbanization and conservation levels to expose possible directions for management strategies of metropolitan sandy beaches.     

Effects of trawling on the diets of common demersal fish by‐catch of a tropical prawn trawl fishery

The ecological effect of prawn trawling on the benthos of the Gulf of Carpentaria, northern Australia, was investigated by examining stomach contents of common demersal fishes incidentally caught as by‐catch in the fishery. Fishes were collected from high and low fishing intensity sites in three regions based on vessel monitoring system data. The diets of eight species of benthic fish predators were compared between regions and fishing intensities. A regional effect on diet was evident for seven species. Only one generalist species had no significant difference in diet among the three regions. For the comparisons within each region, five predator species had significantly different diet between high and low fishing intensities in at least one region. Across the three regions, high fishing intensity sites had predators that consumed a greater biomass of crustaceans, molluscs and echinoderms. At low fishing intensity sites, predators had diets comprising a greater biomass of cnidarians and teleosts, and a different assemblage of molluscs, crustaceans and fishes. These changes in diet suggest that there may have been a shift in the structure of the benthic community following intensive fishing. Analysis of predator diets is a useful tool to help identify changes in the benthic community composition after exposure to fishing. This study also provided valuable diet information on a range of abundant generalist benthic predators to improve the ecosystem modelling tools needed to support ecosystem‐based fisheries management.     

中国沿海地区海洋渔业产业生态系统适应性循环过程及驱动机制

以中国沿海地区海洋渔业产业生态系统为研究对象,采用适应性循环理论将中国海洋渔业产业生态系统划分三个适应性循环圈,一个贫穷陷阱及构成适应性循环圈所需的若干个适应性循环,揭示中国海洋渔业产业生态系统适应性循环问题。结果表明：（1）1949年以来中国海洋渔业产业生态系统依次经历了第一个适应性循环的前环中环阶段（1949-1965年）、贫穷陷阱（1966-1976年）、第二个完整的适应性循环（1977-1985年）以及第三个适应性循环的前环阶段（1986年至今）;（2）海洋渔业产业、海洋渔业生态环境、海洋渔业社会环境是触发整个系统由开发到保护到释放再到更新转变的关键要素;（3）市场需求、政策制度响应和资源限制分别是推动中国海洋渔业产业生态系统适应性循环的外部扰沌力和内部驱动力。     

Multi-level assessment of ecological coastal restoration in South Texas

Adaptive management can be a very useful tool for assessing and improving coastal ecological engineering restoration projects. A shoreline restoration project using ecological engineering approaches to mitigate coastal erosion was developed and implemented in 2003 at Loyola Beach, Baffin Bay, TX. The project incorporated riprap, fiber matting, geotextile, and vegetation as an alternative to conventional hard structures for erosion control. As part of the restoration expansion, a detailed evaluation of the previous project was completed at several levels, including the landscape, geotechnical design, environmental and ecological considerations, and social and economic factors. The findings indicated that the vegetation and its underlying geotechnical integrity have played an important role in erosion mitigation. Overall the project was successful in the protection of the shoreline and was shown to be more ecologically beneficial than other hard structures. Based on the preliminary success of the initial project, the restoration techniques were adapted for another beach extension to the west. The assessment did reveal some weaknesses in the original project design including the need for more substantial toe protection and periodic maintenance requirements. Based on these assessments, some additional new methods for the restoration extension were proposed and implemented. The broader applicability of this restoration approach outside the local region has been presented through several outreach activities and delivered to coastal planners and land owners throughout the Texas Coastal Bend and Northern Mexico.     

Linking fish consumption patterns and health risk assessment of mercury exposure in a coastal community of NW Mexico

We aimed at characterizing the methylmercury (MeHg) exposure through fish consumption in two populations (common general and fishing-related population (FRP)) using a probabilistic health risk assessment in children, women of childbearing age, and adults in Mazatlán. The hazard quotients (HQs) were obtained from fish consumption, defined through a survey, and the levels of mercury in fishery products, obtained from published information. The average fish ingestion rate (IR_food) was higher in the FRP (167.85 g d^?1) than in the general population (GP) (140.9 g d^?1). However, HQs were significantly (p < 0.05) higher in the GP (ranging from 0.18 to 10.91) compared to the FRP (0.20 to 2.48); significant differences were also found among groups of both populations. Remarkably, children in both populations exhibited the highest proportions of risk, reaching up to 97% in GP. For all populations, fish consumption was the most important variable influencing MeHg exposure. Overall, for MeHg exposure, there is no safe level of fish consumption without risk, and actions should be taken to mitigate possible risk; further research with current data is needed to assess potential health risks associated with MeHg exposure, particularly in children.     

Using multiple indicators to evaluate the ecological integrity of a coastal plain stream system

We demonstrate the use of multiple indicators to characterize the ecological integrity of a coastal plain stream system in the New Jersey Pinelands in relation to human-induced watershed alterations. The individual indicators include pH, specific conductance, stream vegetation and stream-fish, impoundment-fish, and anuran assemblages. We evaluate and compare the utility of the individual and multiple environmental and biological indicators and present a relatively straightforward method for ranking sites. Specific conductance and pH measured at 88 monitoring sites varied in relation to the percentage of altered land (developed land and upland agriculture) within the associated watersheds. All three environmental variables were associated with variations in the composition of stream vegetation and stream fish, impoundment fish, and anuran assemblages. With the exception of impoundment fish, the association between altered land and the multiple-indicator scores based on the two water-quality indicators and the four biological indicators was stronger than that displayed by any of the individual variables.     

Impact of glass eel fishery on by-catch fish species: a quantitative assessment

The present study evaluated the effect of the glass eel fishery on by-catch ichthyofauna in the Ebro River delta by investigating the primary responsible factors of discard mortality, in order to assess the adequacy of fishing and sorting procedures, and assess the ecological impact of this traditional activity. Results revealed that glass eel fishery had a negative impact on by-catch ichthyofauna mainly composed of mugilid fry and small-size estuarine species. Data showed that between 10 and 69% of incidental species died as a consequence of glass eel capture and sorting procedures. Differences in by-catch fish mortality rates depended on the glass eel sorting time, the total weight of catch, the discard ratio, by-catch fish size, and by-catch fish species composition. The total weight of the catch and the discard ratio were two of the main parameters affecting discarded fish mortality, since both had a direct effect on the period of time required for glass eel sorting during which by-catch fish were exposed to air and suffered from very aggressive sorting procedures that caused severe external and internal injuries. By-catch fish measuring less than 40 mm L _T were more susceptible to glass eel fishery procedures than those larger (>60 mm L _T), independent of the species considered or their stage of development. This fishery, similar to other ones, should strive to minimization the amount of discards and the mortality of discarded fish, by improving the selectivity of the fish trap and developing new sorting and selection procedures. E. Gisbert and M. A. López have contributed equally to this study. Guest editors: S. Dufour, E. Prévost, E. Rochard & P. Williot Fish and diadromy in Europe (ecology, management, conservation)     

Towards a sounder interpretation of entropy-based indicators in ecological network analysis

Various indicators rooted in the concepts of information and entropy have been proposed to be used for ecological network analysis. They are theoretically well grounded and widely used in the literature, but have always been difficult to interpret due to an apparent lack of strict relations with node and link weight. We generated several sets of 10,000 networks in order to explore such relations and work towards a sounder interpretation. The indices we explored are based on network composition (i.e., type and importance of network compartments), or network flows (i.e., type and importance of flows among compartments), including Structural Information (SI), Total System Throughput (TST), Average Mutual Information (AMI), Flow Diversity (H), and Ascendency (ASC). A correlation analysis revealed a lack of strict relationships among the responses of the investigated indicators within the simulated space of variability of the networks. However, fairly coherent patterns of response were revealed when networks were sorted by following a “bottom-up” criterion, i.e. by increasing the dominance of the large-sized top predator in the network. This ranking is reminiscent of ecosystem succession, along which the prominence of higher trophic level organisms progressively increases. In particular, the results show that a simple increase in organisms having large size and low consumption rates is potentially able to simultaneously lead to an increase of different types of information (as SI, H and AMI), thus also emphasizing the importance of bionomic traits related to body size in affecting information-related properties in a trophically connected community. The observed trends suffer from a certain dispersion of data, which was diminished by imposing specific and ecologically meaningful constraints, such as mass balancing and restriction to certain range of the ratio A/C, an index related to the viability of ecological networks. These results suggest that the identification of a set of effective constraints may help to identify improved conditions for applicability of the investigated flow-based indicators, and also provide indication on how to normalise them with respect to meaningful network properties or reference states. Thus, in order to increase confidence in the derived network metrics describing a particular ecosystem state, and thus increase their applicability, it is advisable to construct replicate networks by taking the variability of input data into account, and by applying uncertainty and sensitivity analyses.     

基于物质流和生态足迹的可持续发展指标体系构建——以安徽省铜陵市为例

将物质流分析方法和生态足迹模型相结合,构建可持续发展指标体系,利用因子分析法对安徽省铜陵市2000—2010年间的可持续发展状况进行了评价。结果表明:(1)铜陵市直接物质输入(DMI)总体呈增长趋势,2010年相比2000年增长2.65倍,进口比重有所下降,区域资源开采活动有所增强,但直接物质输入仍主要依赖于进口,区内加工排放(DPO)总体呈上升趋势,区域内隐藏流(DHF)成为环境压力的主要来源;(2)铜陵市物质生产力数据显示其在物质利用效益方面有了改善,但与同期国内平均水平相比,仍存在一定差距;(3)铜陵市人均生态足迹持续上升,2010年达到7 hm2/人,生态足迹与生态承载力之间的矛盾逐渐加大;(4)可持续发展指标体系评价表明,铜陵市可持续发展状况呈现下降趋势。铜陵市应从调整三次产业关系、转变经济运行方式等角度出发,实现真正意义上的可持续发展。     

海岸带城市生态承载力综合评价——以连云港市为例

海岸带是人类聚居和海洋资源开发利用的重点区域。海岸带城市综合生态承载力体现了海岸带生态系统对人类社会经济活动的承受能力,是判断海岸带城市生态系统健康程度和制定海岸带环境管理政策的重要依据。基于"压力(P)-状态(S)-响应(R)"概念模型,以连云港市为例,构建海岸带综合生态承载力评价指标体系,并对2005—2014年间连云港市的综合生态承载力进行评价。结果显示:连云港市海岸带综合生态承载力呈现逻辑斯蒂式波动上升趋势,2005—2007年处于超载状态,2008—2011年基本处于平衡状态,2012年后处于可载状态。对影响承载力的主要因素进行贡献度分析的结果表明:负向指标中,海岸带环境压力大于人口压力;正向指标中,海岸带经济发展水平及科技支撑条件的贡献呈上升趋势,海岸带可利用资源波动下降。结合相关分析和因子分析,得出海岸带环境压力、科技支撑条件及经济发展水平是制约综合承载力的关键因素。研究结果对海岸带地区环境管理及可持续发展政策制定具有重要意义。     

Dragonfly communities in coastal habitats of Kenya: indication of biotope quality and the need of conservation measures

This study highlights the species diversity of Odonata from coastal forests in southern Kenya, identifying indicator species for certain habitat types and emphasising the importance of conserving the last remaining coastal forest areas. A total of 78 species were recorded from coastal habitats in southern Kenya in this study; five species for the first time in eastern Africa. Dragonfly communities relative to different habitat types from indigenous forest to cultivated landscapes are described and compared. The forest species are often confined to coastal forests of East Africa. They are stenotopic and highly sensitive to disturbance. With increasing habitat disturbance the species richness increases at first, but most of the colonisers are eurytopic species that are common and widely distributed in Africa. The species assemblages between different habitat types in the disturbed landscape are more or less the same; the -diversity is much lower than in different habitat types of the natural coastal landscape. In the end, management implications are briefly discussed.     

Towards a model of a floodplain fish population and its fishery

Synopsis A model is developed which describes the way in which the fish populations of African rivers and their fisheries are influenced by the different types of flood Regime. Ichthyomass and fish catch are dependent on both the extent of flooding during high water and the amount of water remaining in the system during the dry season. The relative number and individual weight of fish are determined by the intensity of flooding, whereas the total number surviving to the next year depends more on the low water regime. Catch per unit effort falls with increasing difference between areas flooded at high and low water. A negative log-log relationship exists between catch and the ratio of maximum area flooded to minimum area of water remaining in the system. This relationship of catch to flood ratio may form the basis for a general index for the evaluation of both year-to-year variations within a floodplain, and differences between floodplains. Lines of equal catch are also derived for various combinations of high and low water areas; these might be used as guidelines for the hydrological management of tropical flood-plains.     

云南雨石得电站工程建设对巴江渔业资源及生态环境的影响

综述了巴江渔业资源状况和雨石得电站建设对资源和环境的影响。巴江共有鱼类60种,其中土著鱼类47种。有16个水生动物新种(其中鱼类新种14个),和国家二级保护动物红瘰疣螈。屯站建成后将对巴江急流鱼种及洄游鱼种的生存造成不利影响。当前应采取切实可行的生态措施,以保护巴江特有的生物资源。     

Diagnosis of complex coastal ecological systems: Environmental GIS analysis of a highly stressed Mediterranean lagoon through spatiotemporal indicators

This article explores the need for implementing spatiotemporal criteria in environmental planning of special protected areas, applying the analysis of reaction patterns in the case study of the Mar Menor, a Mediterranean coastal lagoon in South-Eastern Spain. To perform this, the Mar Menor environmental patterns suffering traditionally from intense coastal urbanization, and in recent years from important eutrophication problems, will be analyzed from an integrated approach and retrospectively assessed through territorial indicators. The evaluation will provide a clear example of a protected area regulated by multiple European Natura 2000 figures of protection that nevertheless is suffering from a strong and varied anthropic process over time. The results will show that paradoxically this process sometimes has little territorial linkage origin with the area concerned. This aspect will be addressed by using GIS indicators, to present the real correlation between coastal urbanization and agricultural land transformation with Mar Menor evolution over time (in which it is pointed out that the weight of the latter is much greater than the former) and how far it is necessary to establish an area of influence of the environmental impacts by proposing a new scope of application for the resolution of the current situation of eutrophication in its waters.     

Size-spectra as indicators of the effects of fishing on coral reef fish assemblages

The data requirements and resources needed to develop multispecies indicators of fishing impacts are often lacking and this is particularly true for coral reef fisheries. Size-spectra, relationships between abundance and body-size class, regardless of taxonomy, can be calculated from simple sizeabundance data. Both the slope and the mid-point height of the relationship can be compared at different fishing intensities. Here, we develop size-spectra for reef fish assemblages using body size- abundance data collected by underwater visual census in each of ten fishing grounds across a known gradient of fishing intensity in the Kadavu Island group, Fiji. Slopes of the size-spectra became steeper (F_9,69=3.20, p<0.01) and the height declined (F_9,69=15.78, p<0.001) with increasing fishing intensity. Regressions of numbers of individuals per size class across grounds were negative for all size classes, although the slope was almost zero for the smallest size class. Response to exploitation of each size class category was greatest for larger fish. Steepening of the slope with increasing fishing intensity largely resulted from reductions in the relative abundance of large fish and not from the ecological release of small fish following depletion of their predators. The slope and height of the size-spectrum appear to be good indicators of fishing effects on reef fish assemblages.     

Physiological indicators of fitness in benthic invertebrates: a useful measure for ecological health assessment and experimental ecology

Physiological indicators of fitness present a measure of an organism’s response to a changing environment. An analysis of how these organisms allocate and store their energy resources provides an understanding of how they cope with such environmental changes. Each individual has to balance the investment necessary to acquire a certain resource with the energy gained by it. This trade-off can be monitored by measuring several physiological indicators of fitness such as energy storage components, metabolic state or RNA/DNA ratio. Because environmental adaptations and ecological strategies of survival are best examined within the natural environment, our research has to rely on the physiological indicators that are easily accessible in the field. The physiological indicators presented here are significant for an individual’s fitness and in turn lead to reliable values in field-collected samples. Based on our own expertise and on a literature survey, the physiological relevance of the presented indicators is explained. Furthermore, some consideration to the analytical methods used to obtain the physiological indicators is given, and possible errors introduced at the sampling site and during the laboratory procedures are discussed. This work demonstrates that the integration of ecological and physiological expertise facilitates the identification of future ecological problems much earlier than separate approaches of both disciplines alone.     

近岸海域生态质量状况综合评价方法——以同安湾为例

基于国外近岸海域生态质量状况综合评价方法,结合我国海洋环境质量评价的研究现状,从生物要素以及水质和沉积物的物理化学要素中筛选出11个指标构成近岸海域生态质量状况综合评价指标体系;综合考虑国内外的评价标准,确定了优、良、中、差、劣5个生态质量状况等级的评价标准;采用层次分析和模糊数学的方法构建近岸海域生态质量状况综合评价方法,并通过同安湾生态质量状况等级与较大的人为扰动以及污染物浓度分布的相关分析对该评价方法进行验证.结果表明:同安湾生态质量状况综合评价等级为中级,处于向差过渡的状态,受人为扰动较大;该方法能够较好地反映主要的人为环境压力和风险因子,同时对未超标的污染因子有一定的预警作用.     

溢油事故中渔业资源损失的数值模拟评估模式

海洋溢油污染不仅关系到天然渔业资源、海鸟等生物、海域环境、海岸线生态的破坏,而且对渔业、捕捞业、旅游业都会造成巨大损失,甚至会直接或间接地危害人类的健康。短期来看,一方面石油、燃料油等进入海洋后,对海洋生物资源造成影响;另一方面会危害附近海区的海洋环境,侵害海洋生物以及海鸟赖以生存和栖息的环境。长期来看,持续的海洋污染会导致的生态环境失衡,海洋的生产力也随之下降。溢油事故中的渔业资源损失评估作为追究污染事故责任,尽快恢复海域资源与环境的重要一环需要不断改进创新。为了定量确定海洋溢油事故发生后渔业资源的损失程度,将传统的评估模式与现代科学技术相结合,通过海洋动力学、流体力学、海洋生物学、环境化学等多个学科交叉融合,将流场风场模型、溢油模型、海域调查监测、卫星遥感技术、毒性效应和渔业资源的损失评估方法相结合,形成一种渔业资源损失评估的数值模拟评估模式,以完善溢油事故中渔业资源损失评估体系。在溢油事故现场监测数据的基础上,运用数学计算理论选择相对应的溢油模型,结合具体溢油事故案例的潮流数据和风场数据,模拟海上溢油污染的时空分布情况。采用卫星遥感技术根据不同油品在海水中不同的亮度表现,处理得到溢油油膜信息,与模拟得到的油膜信息进行比对验证,并对模型进行修正,通过模拟得出污染海域油浓度分布与溢油污染范围信息,结合溢油污染对不同海洋生物的毒性效应,得到渔业资源的损失程度,为溢油事故的渔业资源损失评估提供一种思路,为溢油事故发生后的损失评估和事故处理起到一定的参考辅助作用。     

Kleptoparasitism in gulls Laridae at an urban and a coastal foraging environment: an assessment of ecological predictors

Capsule: Kleptoparasitism in gulls occurred at a greater rate at an urban compared with a coastal site. Population density and prey size predicted the rate of kleptoparasitism at the urban site.

Aims: To investigate and assess the ecological variables associated with kleptoparasitism among gulls at urban and rural sites.

Methods: Field observations were conducted at Brancaster (coastal rural) and Billingsgate Market (urban) to examine differences in the rate of kleptoparasitism in mixed-species flocks of gulls. Four key variables (prey size, population density, season and species) were assessed as predictors of kleptoparasitism.

Results: Generalized linear models revealed significant effects on kleptoparasitism rate of site, population density and prey size, and two-way interactions between these main terms. Population density and prey size differed significantly between sites, but population density appeared to predict the rate of kleptoparasitism.

Conclusion: Kleptoparasitism may well aid invasion and increase the range of environments a gull can tolerate by helping them meet their energy needs in novel environments where normal foraging behaviours are difficult to implement.