Food-web traits of the North Aegean Sea ecosystem (Eastern Mediterranean) and comparison with other Mediterranean ecosystems

A mass-balance trophic model was built to describe the food-web traits of the North Aegean Sea (Strymonikos Gulf and Thracian Sea, Greece, Eastern Mediterranean) during the mid-2000s and to explore the impacts of fishing. This is the first food-web model representing the Aegean Sea, and results were presented and discussed in comparison to other previous ecosystems modelled from the western and the central areas of the basin (South Catalan and North-Central Adriatic Seas).     

Investigation of forest-resources potential of Selenge River Basin on transboundary territory of the Republic of Buryatia and Mongolia

The author studied the issues of the present-day status of forest resources and forest management of the Selenge River Basin on the transboundary territory of the Buryat Republic and Mongolia. It is necessary to establish a good policy for wood cutting of the main and secondary use and reforestation.     

生态系统服务功能动态区划方法与应用

开展区域生态系统服务功能动态区划,对生态系统服务功能的分区管理具有重要的指导价值。本文介绍了生态系统服务功能区划的方法--生态系统服务功能动态区划系统(SIZES)。该方法包括生态系统服务功能多层次表征、位序矩阵生成、核心生态系统服务功能空间辨识和动态区划边界生成四个模块,它们能实现生态系统服务功能动态区划边界的生成。其中,生态系统服务功能多层次表征模块和动态区划边界生成模块是主要模块,而构建生态系统服务功能表征指标体系和生成区划单元是该方法的关键所在。利用SIZES将锡林郭勒盟划分为6个生态系统服务功能区,科学合理地解释了该区生态系统服务功能空间分异规律,为指导该区生态系统服务功能分区管理,提供了具有时空特性的决策参考信息。     

Sensitivity and uncertainty analysis of regional marine ecosystem services value

Marine ecosystem services are the benefits which people obtain from the marine ecosystem, including provisioning ser-vices, regulating services, cultural services and supporting services. The human species, while buffered against environmental changes by culture and technology, is fundamentally dependent on the flow of ecosystem services. Marine ecosystem services be-come increasingly valuable as the terrestrial resources become scarce. The value of marine ecosystem services is the monetary flow of ecosystem services on specific temporal and spatial scales, which often changes due to the variation of the goods prices, yields and the status of marine exploitation. Sensitivity analysis is to study the relationship between the value of marine ecosystem services and the main factors which affect it. Uncertainty analysis based on varying prices, yields and status of marine exploitation was carried out. Through uncertainty analysis, a more credible value range instead of a fixed value of marine ecosystem services was obtained in this study. Moreover, sensitivity analysis of the marine ecosystem services value revealed the relative importance of different factors.     

Sediment segregation by biodiffusing bivalves

The selective processing of sediment fractions (sand and mud; >63 μm and ≤63 μm median grain size) by macrofauna was assessed using two size classes of inert, UV-fluorescent sediment fraction tracers (luminophores). The luminophores were applied to the sediment surface in 16 m² replicated plots, defaunated and control, and left to be reworked by infauna for 32 days. As the macrofaunal assemblage in the ambient sediment and the control plots was dominated by the common cockle Cerastoderma edule, this species was used in an additional mesocosm experiment. The diversity, abundance and biomass of the defaunated macrobenthic assemblage did not return to control values within the experimental period. Both erosion threshold and bed elevation increased in the defaunated plots as a response to the absence of macrofauna and an increase in microphytobenthos growth. In the absence of macrobenthos, we observed an accretion of 7 mm sediment, containing ca. 60% mud. Image analysis of the vertical distribution of the different luminophore size classes showed that the cockles preferentially mobilised fine material from the sediment, thereby rendering it less muddy and effectively increasing the sand:mud ratio. Luminophore profiles and budgets of the mesocosm experiment under “no waves–no current” conditions support the field data very well.     

Changes of coral communities over 35 years: Integrating in situ and remote-sensing data on Saint-Leu Reef (la Réunion, Indian Ocean)

Monitoring coral reef communities at a decadal scale is necessary to understand and project their dynamics to provide a basis for reef management in light of disturbances and climate change. Complementing infrequent and localised in situ observations, time-series of aerial photographs and remotely sensed satellite images provide a means of monitoring the position and extent of reef-top coral communities, vegetation and abiotic substrata at the whole reef scale. The aim of the present study was to map such changes on Saint-Leu Reef (La Réunion) between 1973 and 2007. The period included two cyclones (1989, 2002) and one severe bleaching event (2002). Vertical images of the reef were recorded in five aerial photographs (1973, 1978, 1989, 1997, and 2003) and two Quickbird satellite images (2002, 2006) during that time. Quantitative in situ observations of parts of the reef-top were also available both to document ecological and substratum characteristics that produce the color and texture observable in the photos and satellite images. Coral communities were mapped on all images using manual delineation of polygons identified according to color and texture contrast. The 2006 Quickbird image was used as the mapping base and 15 types of coral communities were identified from a reef survey conducted in 2007. This hierarchical typology used coral growth forms, live and dead coral cover, macro-algae, substratum (sand, rubble and platform) and, to a lesser extent, coral taxonomy. The polygons at date t were over-laid onto image t − 1 across the whole series and their boundaries were manually edited to match the pattern on the earlier image. Labelling of polygons was guided by field-survey data and maps. For coral-dominated patches, six successive pairs of maps from 1973 to 2006 were compared to produce ‘coral community change maps’ for that period. Despite the multiple disturbance events, the coral community distribution and composition in 2006 on Saint-Leu Reef did not display major differences compared to 1973. This suggests a high degree of coral resilience at the site, led by rapid recovery of compact branching corals. The mapping techniques overcame challenges due to different image quality and the sparsity of in situ observations in time and space. Our results demonstrate the potential for further application of reef monitoring protocols based on complementary in situ and remote-sensing data to help understand the dynamics of reef-top coral reef communities and geomorphology over years to decades.     

Composition, structural characteristics and temporal patterns of fish assemblages in non-tidal Mediterranean lagoons: A case study

The importance of transitional water ecosystems as nursery habitats and feeding grounds for fish species is well-known. Detailed studies of colonization patterns of fish guilds in response to biotic and abiotic drivers are however unevenly distributed among ecosystem types. We address here the temporal variability of fish assemblages in small non-tidal lagoons in the Mediterranean basin. The study was carried out at the Acquatina lagoon (Lecce, Italy) where four stations, situated in two habitat types along a confinement gradient, were sampled twice per month for one year with fyke nets. Forty-five taxa ranging across 20 families were collected, with the most abundant species, Atherina boyeri, accounting for more than 95% of total abundance. Pooling all species together (excluding sand smelt), the structural features of the assemblage, relative abundance of families, and abundance of individual species all showed significant temporal patterns. Mean abundance peaked in Summer and Autumn and fell in Winter, whereas taxonomic richness and diversity were highest in Summer and lowest in Spring. Within the fish assemblage, multivariate ordination showed temporal segregation of species belonging to the same family or genus and expected to be functionally similar, suggesting that they avoid competition for space and resources by timing inward migration and peak occurrence differently. Of the environmental driving forces, which also showed temporal patterns of variation, salinity was the main factor affecting the distribution of individuals and species. The catch of young individuals of several marine species confirmed the role of this small lagoon as a nursery and feeding area, and emphasized the need for further studies.     

California Current Large Marine Ecosystem: Publicly available dataset of state and federal laws and regulations

Transitioning ocean governance into an ecosystem-based approach requires improved knowledge of ecosystems and existing management systems. While there has been increased effort to compile and synthesize ecological data, relatively little scholarship has been focused on improving and understanding ocean management systems. This paper presents a unique dataset that makes objective analyses of ocean management possible across multiple jurisdictions and sectors in the California Current. Following an explanation of the criteria used to compile relevant statutes and regulations, the paper suggests applications for the dataset including education and policy uses and ecosystem-based management tool development to identify and measure problems of fragmented management.     

海洋渔业对海洋生态系统的影响及其管理的探讨

海洋渔业对海洋生态系统的影响越来越受到人们的重视,考虑生态系统的管理已经成为海洋渔业管理的发展趋势.作者分析了海洋渔业对海洋生态系统产生的影响,包括捕捞活动对目标和非目标种产生的危害、渔业资源栖息地和环境破坏、生物多样性降低等;分析了国际上考虑生态系统的海洋渔业管理的法律框架、国际组织和有关国家的实践及其具体措施,指出了中国在此方面存在的问题:海洋生态系统的基础科学研究缺乏系统性和全面性;基于生态系统的海洋渔业管理的理论研究比较缺乏;相关的法律框架不够完善等.讨论了应用生态系统方法的海洋渔业管理与传统的海洋渔业管理间的关系,指出生态系统方法在其实践中将存在各种问题,认为生态系统方法应有选择地应用.对中国海洋渔业管理如何应用生态系统方法,建议:(1)加强海洋生态系统的基础科学研究;(2)开展基于生态系统的海洋渔业管理理论和方法研究;(3)逐步建立相关的法律和制度框架;(4)开展广泛的多部门合作和国际合作.     

海洋浮游生态系统模型的稳态非线性动力学研究

以Logistic模型为基础,考虑捕捞行为及其所造成的污染对浮游生物的削弱作用,并考虑浮游生态系统具有一定的自净能力,建立了一个新的海洋浮游生态系统非线性动力学模型。分析了模型的非线性动力学特性,并得出了模型的稳定性条件和发生Hopf分岔条件,在此基础上,深入分析了捕捞强度参数的变化对系统稳态的影响,并且用数值模拟验证了理论分析结果的正确性。