Making the Case for Marine Spatial Planning in the Maltese Islands

Marine spatial planning (MSP) has been gaining in stature recently as an ecosystem-based tool for the management of marine space that promotes the sustainable and optimal use of resources with minimal stakeholder conflicts. Malta is the quintessential maritime nation, with a disproportionately large marine area compared to its terrestrial area. Nonetheless, its limited coastline, a considerable portion of which is inaccessible, poses inevitable conflicts between multiple marine activities and designations, including aquaculture, fishing, bunkering, coastal tourism, navigation, renewable energy installations, conservation of biological diversity and protected areas (on ecological criteria). This article makes the case to implement MSP-based policies and an applicable legal framework in the Maltese Islands.     

生态系统修复国内外研究进展与展望

气候变化和人类活动的增加不仅导致生态系统退化、生物多样性丧失、生物圈资源供给能力降低, 而且极大地制约了社会经济的可持续发展。尽管在全世界范围内已实施了大量的保护工作, 但全球生态系统退化仍在继续, 逐渐成为备受关注的全球性问题。文章首先厘清生态系统修复的发展历程、相关概念与理论。其次, 归纳生态系统修复的全球议题, 涉及生态系统服务及其价值评估、生物多样性保护、应对气候变化与碳储存、自然保护地、监测体系与适应性管理、公平性与多主体参与等方面。然后, 总结我国森林、草原、河流与湿地、海洋与海岸带的生态系统退化问题与修复进展, 梳理生态保护红线、自然保护地生态系统修复和国土空间生态保护修复3种措施的进展与不足。最后, 对山水林田湖草沙一体化保护与系统治理、生态系统修复的多元融资政策与渠道、荒野生态保护修复的探索与实践、城镇生态系统修复的研究与应用以及生态系统修复对生物多样性的保护与维持等五个方面进行展望, 以期为我国进一步开展生态系统保护修复的相关研究与实践提供指导。     

Land use and land cover change analysis in predominantly man-made coastal wetlands: towards a methodological framework

In areas with a long history of human occupation, coastal wetlands have undergone extensive modification to accommodate extractive activities as salt-extraction and aquaculture. These man-made wetlands maintain some of the ecological functions of natural wetlands in spite of their artificial character: their suitability as complimentary waterbird habitat is well documented. In cases of wetlands composed of mixed natural and man-made areas, similarities in substrate-vegetation-water compositions may pose challenges in the applicability of remote sensing and GIS techniques for the study of landscape changes, requiring tailor-made, case-specific methods. We explored this supposition by testing these techniques for the study of the Bahia de Cadiz Nature Park (Spain). Using Landsat imagery spanning the 1985–2011 period, natural and man-made marsh areas were classified separately and results merged to produce land cover classification maps. Different change dynamics were observed for the natural and man-made areas, the latter exhibiting prominent changes, including widespread vegetative succession. Further, through the overlay of ancillary land use data for 2011, an integrated land use and cover map was produced for this year. Different scenarios arising from the abandonment of extractive activity and structural negligence were highlighted. Furthermore, a methodological framework for the classification of predominantly man-made wetlands was designed. The method is cost-effective and open for integration of additional datasets, and is considered a beneficial input to conservation and land use management. Its applicability for monitoring of landscape change not only pertains to the study area, but also extends to other coastal wetland areas of a similar nature.     

Current Status and Future Prospects for the Assessment of Marine and Coastal Ecosystem Services: A Systematic Review

Background

Research on ecosystem services has grown exponentially during the last decade. Most of the studies have focused on assessing and mapping terrestrial ecosystem services highlighting a knowledge gap on marine and coastal ecosystem services (MCES) and an urgent need to assess them.

Methodology/Principal Findings

We reviewed and summarized existing scientific literature related to MCES with the aim of extracting and classifying indicators used to assess and map them. We found 145 papers that specifically assessed marine and coastal ecosystem services from which we extracted 476 indicators. Food provision, in particular fisheries, was the most extensively analyzed MCES while water purification and coastal protection were the most frequently studied regulating and maintenance services. Also recreation and tourism under the cultural services was relatively well assessed. We highlight knowledge gaps regarding the availability of indicators that measure the capacity, flow or benefit derived from each ecosystem service. The majority of the case studies was found in mangroves and coastal wetlands and was mainly concentrated in Europe and North America. Our systematic review highlighted the need of an improved ecosystem service classification for marine and coastal systems, which is herein proposed with definitions and links to previous classifications.

Conclusions/Significance

This review summarizes the state of available information related to ecosystem services associated with marine and coastal ecosystems. The cataloging of MCES indicators and the integrated classification of MCES provided in this paper establish a background that can facilitate the planning and integration of future assessments. The final goal is to establish a consistent structure and populate it with information able to support the implementation of biodiversity conservation policies.     

海洋可持续发展目标与海洋和滨海生态系统管理

海洋和海岸带可以为人类提供多种生态系统服务,保护与持续利用海洋资源以促进海洋和海岸带可持续发展已被正式纳入联合国可持续发展目标。实施海洋可持续发展目标面临几大挑战,包括如何减小陆基人类活动的影响、加强海岸带的综合管理、提高海洋资源效率、适应气候变化和提高沿海居民的人类福祉等。为应对这些挑战,需要将海洋和海岸带融合为一个大型生态系统,利用基于生态系统的管理方法,综合考虑各个部门和多种胁迫因素的累积影响,通过建立综合的海洋观测体系,合理划分海洋功能区,按照海洋环境承载力限制陆基人类活动,合理配置并有效利用海洋资源,提升海洋和海岸带生态系统的整体服务功能,从而进一步推进实施海洋可持续发展目标。     

Ethnobiology, socio-economics and management of mangrove forests: A review

There is growing research interest in the ethnobiology, socio-economics and management of mangrove forests. Coastal residents who use mangroves and their resources may have considerable botanical and ecological knowledgeable about these forests. A wide variety of forest products are harvested in mangroves, especially wood for fuel and construction, tannins and medicines. Although there are exceptions, mangrove forest products are typically harvested in a small-scale and selective manner, with harvesting efforts and impacts concentrated in stands that are closer to settlements and easiest to access (by land or by sea). Mangroves support diverse, local fisheries, and also provide critical nursery habitat and marine productivity which support wider commercial fisheries. These forests also provide valuable ecosystem services that benefit coastal communities, including coastal land stabilization and storm protection. The overlapping of marine and terrestrial resources in mangroves creates tenure ambiguities that complicate management and may induce conflict between competing interests. Mangroves have been cut and cleared extensively to make way for brackish water aquaculture and infrastructure development. More attention is now given to managing remaining forests sustainably and to restoring those degraded from past use. Recent advances in remotely sensed, geo-spatial monitoring provide opportunities for researchers and planners to better understand and improve the management of these unique forested wetlands.     

论生态保护红线的类型划分与管控

生态保护红线划定的目的是为了保护支撑人类经济社会可持续发展的自然生态系统, 实施最为严格的管控措施, 不断改善生态系统服务功能。本文根据《环境保护法》规定和国内相关研究与实践积累, 明确了生态保护红线的概念, 提出了以重点生态功能区保护红线、生态敏感区/脆弱区保护红线、禁止开发区保护红线为核心的生态保护红线体系构成。并进一步将重点生态功能区保护红线区分为陆地重点功能区(包括水源涵养区、水土保持区、防风固沙区和生物多样性维护区)和海洋重点功能区(包括海洋水产种质资源保护区、重要滨海湿地、特殊保护海岛、珍稀濒危物种集中分布区、重要渔业水域等); 将生态敏感区/脆弱区保护红线区分为陆地生态敏感区/脆弱区(土地沙化区、水土流失区、石漠化区、盐渍化区)和海洋生态敏感/脆弱区(海岸带自然岸线、红树林、重要河口、重要砂质岸线、沙源保护海域、珊瑚礁及海草床等); 禁止开发区则包含了自然保护区、世界自然文化遗产地、风景名胜区、森林公园、地质公园、湿地公园、饮用水水源地等类型。基于国家关于生态保护红线管控的最新要求, 提出了分级划定、分类管理的生态保护红线基本管控思路与措施, 按照管理分级和围绕生态功能保护来确定具体管控措施, 旨在为增强生态保护效果, 优化国土空间开发格局, 促进生态文明建设提供理论依据。     

综合模型法评估黄河三角洲湿地景观连通性

景观连通性是区域生态系统功能完整的重要表征。连通性的评估对生态系统管理和保护规划有重要意义。综合常用的景观连通性评估模型,即最小耗费距离模型与电路理论模型,根据生态网络构建的一般范式,采取两种不同阻力面赋值方案,对黄河三角洲的湿地景观连通性进行评估,并对比分析了两种模型的基本原理、工作性能、分析尺度等。结果表明：最小耗费距离模型能够识别最优生态廊道,为景观连通性评估提供基本模式。电路理论则能扩展到潜在生态廊道和关键生态点的量化识别,能确定具有生态功能的“夹点”和障碍区的空间位置。综合两种模型,可以量化评估黄河三角洲湿地景观连通性,空间化三角洲湿地保护恢复的管理目标,即潜在廊道和关键生态节点,为区域生态系统功能评估和管理提供精准的数据支持。     

Fine-Scale Cartography of Human Impacts along French Mediterranean Coasts: A Relevant Map for the Management of Marine Ecosystems

Ecosystem services provided by oceans and seas support most human needs but are threatened by human activities. Despite existing maps illustrating human impacts on marine ecosystems, information remains either large-scale but rough and insufficient for stakeholders (1 km² grid, lack of data along the coast) or fine-scale but fragmentary and heterogeneous in methodology. The objectives of this study are to map and quantify the main pressures exerted on near-coast marine ecosystems, at a large spatial scale though in fine and relevant resolution for managers (one pixel = 20 x 20 m). It focuses on the French Mediterranean coast (1,700 km of coastline including Corsica) at a depth of 0 to 80 m. After completing and homogenizing data presently available under GIS on the bathymetry and anthropogenic pressures but also on the seabed nature and ecosystem vulnerability, we provide a fine modeling of the extent and impacts of 10 anthropogenic pressures on marine habitats. The considered pressures are man-made coastline, boat anchoring, aquaculture, urban effluents, industrial effluents, urbanization, agriculture, coastline erosion, coastal population and fishing. A 1:10 000 continuous habitat map is provided considering 11 habitat classes. The marine bottom is mostly covered by three habitats: infralittoral soft bottom, Posidonia oceanica meadows and circalittoral soft bottom. Around two thirds of the bottoms are found within medium and medium high cumulative impact categories. Seagrass meadows are the most impacted habitats. The most important pressures (in area and intensity) are urbanization, coastal population, coastal erosion and man-made coastline. We also identified areas in need of a special management interest. This work should contribute to prioritize environmental needs, as well as enhance the development of indicators for the assessment of the ecological status of coastal systems. It could also help better apply and coordinate management measures at a relevant scale for biodiversity conservation.     

Modeling and predicting the growth of the mussel,Mytilus edulis: implications for planning of aquaculture and eutrophication mitigation

The increased pressure on the marine ecosystems highlights the need for policies and integrated approaches for sustainable management of coastal areas. Spatial planning based on geographic information of human activities, ecological structures and functions, and their associated goods and services is a fundamental component in this context. Here, we evaluate the potential of predictive modeling to provide spatial data on one ecosystem function, mussel growth for use in such processes. We developed a methodology based on statistical modeling, spatial prediction, and mapping for the relative growth of the blue mussel, Mytilus edulis. We evaluated the performance of different modeling techniques and classification schemes using empirical measurements of growth from 144 sampling sites and data on biological, chemical, and physical predictors. Following comparisons of the different techniques and schemes, we developed random forest models to predict growth along the Swedish west coast. Implemented into GIS the best model produced in this study predicts that low, intermediate, and high growth rates can be expected in 53%, 32%, and 15% of modeled area, respectively. The results of this study also suggest that the nature and quality of predictor data hold the key to improving the predictive power of models. On a more general note, this study exemplifies a feasible approach based on measuring, modeling, and mapping for obtaining scientifically based spatial information on ecosystem functions and services affected by a complex set of factors. Such information is fundamental for maritime spatial planning and ecosystem‐based management and its importance is likely to increase in the future. Because of its close link to nutrient assimilation and production yield, site‐specific information of soft tissue growth such as the map of predicted growth rate developed in this study can be used as a tool for optimizing actions aimed at mitigating eutrophication and aquaculture operations and in maritime spatial planning processes of coastal areas.     

State and management of wetlands in Bangladesh

Wetlands are a vital link between land and water in Bangladesh. A majority of the people of Bangladesh are critically dependent on wetlands. In this paper, the values of wetlands, causes and effects of wetlands degradation, as well as the present wetlands management approach, are analyzed and recommendations for wetlands management are suggested based on participatory rural appraisal (PRA), field visit, personal experience, and existing literature and information. Wetlands play a crucial role in maintaining the ecological balance of ecosystems, but wetlands habitat of Bangladesh is under constant threat due to increase of population, intensive agriculture, overfishing, siltation, pollution, ill-planned infrastructures, lack of institutional coordination, lack of awareness, etc. As a result biodiversity is reducing, many species of flora and fauna are threatened, wetlands-based ecosystem is degenerating, and the living conditions of local people are deteriorating as livelihoods, socioeconomic institutions, and cultural values are affected. Wetlands management is not addressed separately in water management activities of Bangladesh. In order to balance human needs and wetlands conservation, a mainly community-based wetlands management approach has been taken in Bangladesh, but this is not enough to prevent the degradation of wetlands. Therefore, Bangladesh now needs a comprehensive strategy combining political, economic, social, and technological approaches to stop further degradation of wetlands. Therefore, wetlands management should be incorporated into a system of integrated land and water use and, indeed, into the socioeconomic system of the country. Policies, strategies, and management plans for sustainable use and conservation of wetlands of Bangladesh must be based on solid knowledge and understanding of their ecological and socioeconomic functions and processes.     

Ensuring the adaptive potential of Coastal wetlands of India- the need of the hour for sustainable management

India is endowed with a variety of coastal wetlands viz., mangroves, seagrasses, saltmarshes, coral reefs, lagoons and tidal flats, and the country is also a signatory to the Ramsar Convention on Wetlands and the Convention of Biological Diversity, besides having a robust framework of laws and policies, governing the wetland conservation. However, the conservation strategies can better be improved in the context of increasing pressures and threats and limited success of restoration/rehabilitation. Land conversion and ecological degradation of coastal wetlands are the stressors, associated with rapid coastal developmental activities and climate change. The coastal wetlands require desired habitat niche and hence, the conversion of coastal wetlands to other land uses (including agricultural and urban lands) may lead to permanent loss, whereas ecologically degraded coastal wetlands may be resilient if supported by effective protection measures. Preventing the habitat conversion and maximizing the adaptive potential (viz., the ability of populations or species to adapt to rapid environmental change with minimal disruption) by preserving the ecological health are the need of the hour to safeguard the existing coastal wetlands and sustain the provisional ecosystem services offered by them rather than short-term increase in area by unproductive restoration/rehabilitation efforts. Since coastal wetlands are flow through ecosystems, preserving the hydrological connectivity, facilitating the connectivity between adjacent ecosystems and protection of natural corridors are potential strategies that are required to enhance the adaptive potential of coastal wetlands. This analysis calls for site-specific, long-term and integrated ecosystem-based protection, management and rehabilitation strategies based on scientific principles and enforcing the effective legislative measures to regularize the coastal developmental activities in India.

     

陆源人类活动对近海生态系统的影响

随着海岸带快速城市化和经济发展,人类活动对近海生态系统的影响日益增加。通过对国内外大量相关文献的分析和与国际专家的研讨,分别从海洋资源开发、海岸带城市化和环境变化等几个方面概述了陆源人类活动对近海生态系统的影响。目前陆源人类活动导致近海生态系统出现的主要问题有:海洋生物资源过度捕捞、海岸带富营养化、海洋酸化、珊瑚礁退化、海洋垃圾、以及海岸带矿产开采等高强度开发活动引发的重金属和持久性有机污染物污染等。这些问题会直接导致海洋生物群落结构变化、影响水质、降低海洋生物多样性,最终影响海洋生态系统服务功能,威胁海洋生态系统健康。这些问题的根源多来自陆地,必须将海洋和陆地作为一个有机整体,整合海陆系统相互作用的科学计划,推进海洋资源和近海生态系统的可持续管理。     

Ecological impacts of non-native Pacific oysters (<Emphasis Type="Italic">Crassostrea gigas</Emphasis>) and management measures for protected areas in Europe

Pacific oysters are now one of the most ‘globalised’ marine invertebrates. They dominate bivalve aquaculture production in many regions and wild populations are increasingly becoming established, with potential to displace native species and modify habitats and ecosystems. While some fishing communities may benefit from wild populations, there is now a tension between the continued production of Pacific oysters and risk to biodiversity, which is of particular concern within protected sites. The issue of the Pacific oyster therefore locates at the intersection between two policy areas: one concerning the conservation of protected habitats, the other relating to livelihoods and the socio-economics of coastal aquaculture and fishing communities. To help provide an informed basis for management decisions, we first summarise evidence for ecological impacts of wild Pacific oysters in representative coastal habitats. At local scales, it is clear that establishment of Pacific oysters can significantly alter diversity, community structure and ecosystem processes, with effects varying among habitats and locations and with the density of oysters. Less evidence is available to evaluate regional-scale impacts. A range of management measures have been applied to mitigate negative impacts of wild Pacific oysters and we develop recommendations which are consistent with the scientific evidence and believe compatible with multiple interests. We conclude that all stakeholders must engage in regional decision making to help minimise negative environmental impacts, and promote sustainable industry development.     

气候变化条件下全氟化合物对海岸带可持续发展的影响及管控策略

海岸带生态系统为人类提供了食物、水等丰富的物质以及文化、休闲等生态系统服务。但由于全氟化合物等污染物的排放和气候变化的影响,海岸带地区环境日益恶化、资源枯竭、极端气候灾害加剧。这些问题直接导致了海岸带水质下降、近海生物多样性减少、生物群落结构变化,海岸带生态系统可持续发展受到影响。全氟化合物在自然环境中难以降解,会沿食物链在生物体内累积和放大进而对人类健康造成风险。随着氟化工产业在我国的快速发展、新型全氟化合物的不断更替以及气候变化的加剧,全氟化合物对海岸带生态的影响面临着极大的不确定性。为了更好地服务海岸带生态系统的可持续发展,目前仍需要加快完善立法保障,在全国范围内对全氟化合物进行监测;将海洋与陆地作为一个有机整体,统筹陆地影响和海岸带管控,严格控制污染物的排放。     

Evaluation of ecosystem health for the coastal wetlands at the Yangtze Estuary, Shanghai

Despite the growing awareness of the important ecological functions and values provided by coastal and estuarine wetlands, wetland degradation continues worldwide due to increasing anthropogenic disturbances. Chongming Dongtan wetlands, adjacent to Shanghai, the largest city and industrial and trading port in China in rapid urban expansion and socioeconomic development are currently threatened with biodiversity reduction, wetland loss, contamination, and invasion of exotic plant. Sustainable protection and management of Dongtan Nature Reserve necessitate research to develop diagnostic tools and indicators for a comprehensive and objective assessment of wetland ecosystem health condition. Based on the pressure-state-response framework and ecological and environmental surveys at the Dongtan wetlands, an indicator system was established for evaluating the coastal wetlands ecosystem health, using indicators detected from satellite imagery and current field surveys. Through the establishment of health assessment units and spatial quantification of the indicators, the spatial clustering analysis, integrated with remote sensing and geographic information system technique was applied to make an accurate diagnosis of ecosystem health for Chongming Dongtan wetlands and highlight the areas in subhealthy and unhealthy condition and urgent need of conservation and management. The results from this research indicated that the ecosystem health condition at the Dongtan wetlands showed spatial variation, to a certain extent, corresponding to the distributions of elevation and land cover types. More than 75 % of the total study area was at a relatively healthy level, with 34.19 km² for the very healthy zone and 41.08 km² for the healthy zone, while the subhealthy and unhealthy zones covered 18.23 and 4.76 km², respectively. This study demonstrated the potential for this integrated approach to give objective and effective evaluation of ecosystem health for the dynamic coastal and estuarine wetlands and provide up-to-date information to assist with early warning for ecological security and management decisions for Chongming Dongtan Nature Reserve.     

Characterizing mauka-to-makai connections for aquatic ecosystem conservation on Maui,Hawaiʻi

Mauka-to-makai (mountain to sea in the Hawaiian language) hydrologic connectivity – commonly referred to as ridge-to-reef – directly affects biogeochemical processes and socioecological functions across terrestrial, freshwater, and marine systems. The supply of freshwater to estuarine and nearshore environments in a ridge-to-reef system supports the food, water, and habitats utilized by marine fauna. In addition, the ecosystem services derived from this land-to-sea connectivity support social and cultural practices (hereafter referred to as socio-cultural) including fishing, aquaculture, wetland agriculture, religious ceremonies, and recreational activities. To effectively guide island resource management, a better understanding of the linkages from ridge-to-reef across natural and social usages is critical, particularly in the context of climate change, with anticipated increasing temperature and shifting precipitation patterns. The objective of this study was to identify spatial linkages that promote multiple and diverse uses, following the ridge-to-reef concept, at an island-wide scale to identify regions of high conservation importance for aquatic resources. We selected the Island of Maui as a study representative of many Pacific islands. Diverse datasets, including agricultural lands within watersheds, wetland locations, presence of stream species, indicators of freshwater input from streams, coral cover, nearshore fish biomass, socio-cultural data such as fishpond locations, wetland taro cultivation, beach recreation use, and lastly the dynamically downscaled Coupled Model Intercomparison Project Phase (CMIP5) future climate projections scenarios (Representative Concentration Pathway (RCP) 4.5 & 8.5) were used to examine the spatial linkages through hydrological connectivity from land to the sea. Zonation spatial planning software was used to prioritize areas of high management and conservation value and to help inform aquatic resources management. The resulting prioritized areas included many minimally disturbed watersheds in east Maui and western nearshore and coastal zones that are adjacent to diverse coral reefs. These results are driven by the importance of fish biomass and coral reef distribution as well as traditional wetland taro cultivation and coastal access points for recreation. These results underline the importance of examining ridge-to-reef systems for aquatic resource management and including important social and cultural values in resource management upon planning adaptation strategies for climate change. Improving our understanding of diverse natural and socio-cultural influences on habitat conditions and their values in these areas provides an opportunity to strategically plan future management and conservation actions.     

宁德水产养殖区水质状况及驱动力分析

水产养殖对海岸带生态系统的水环境有显著影响,研究水产养殖地区的水质动态及其驱动力对海洋牧场建设和海岸带生态系统管理有着重要意义。以宁德为研究区域,基于2017年夏季和冬季水质监测和遥感影像等数据,通过地理信息系统技术和统计分析软件,分析了水产养殖区域的水质现状、水质变化和驱动力。结果表明,该海域水质处于重污染状态,富营养化水平较高。除了悬浮物和总磷之外,其他水质指标都呈现出显著的季节性差异,不同季节影响水质的因素也不相同。水质的季节性变化是初始水质状况、养殖活动和自然因素共同作用的结果。基于研究结果,笔者建议结合高分遥感技术对养殖区水面覆盖和利用进行监测,对养殖类型和行为(如饵料类型和投放方式)进行调控,开展水质长期监测和风险应急管理,保障海洋牧场社会经济效益的同时降低生态环境影响、防控生态和人体健康风险。     

Management strategies for sustainable invertebrate fisheries in coastal ecosystems of Galicia (NW Spain)

Artisanal coastal invertebrate fisheries in Galicia are socio-economically important and ecologically relevant. Their management, however, has been based on models of fish population dynamics appropriate for highly mobile demersal or pelagic resources and for industrial fisheries. These management systems focus on regulating fishing effort, but in coastal ecosystems activities that change or destruct key habitats may have a greater effect on population abundance than does fishing mortality. The Golfo Artabro was analysed as a representative example of a coastal ecosystem in Galicia, and the spider crab Maja squinado used as a model of an exploited coastal invertebrate, for which shallow coastal areas are key habitats for juvenile stages. The commercial legal gillnet fishery for the spider crab harvests adults during their reproductive migrations to deep waters and in their wintering habitats. Illegal fisheries operate in shallow waters. The annual rate of exploitation is >90%, and <10% of the primiparous females reproduce effectively at least once. A simple spatially-explicit cohort model was constructed to simulate the population dynamics of spider crab females. Yield- and egg-per-recruit analyses corresponding to different exploitation regimes were performed to compare management policies directed to control the fishing effort or to protect key habitats. It was found that the protection of juvenile habitats could allow increases in yield and reproductive effort higher than in the present system, with such protection based in the control of the fishing effort of the legal fishery. Additionally, there is an urgent need for alternative research and management strategies in artisanal coastal fisheries based on the implementation of a system of territorial use rights for fishers, the integration of the fishers into assessment and management processes, and the protection of key habitats (marine reserves) as a basic tool for the regulation of the fisheries.     

Modeling the trophic effects of marine protected area zoning policies: A case study

Marine protected areas (MPAs) are increasingly being recognized as an alternative management tool for conserving marine resources and ecosystems. By integrating organism dispersal rates, ecosystem interactions and fishing effort dynamics, ECOSPACE, a spatially explicit ecosystem-based modeling tool, allowed us to compare the ecological consequences of alternative MPA zoning policies within the proposed Gwaii Haanas National Marine Conservation Area, located off the west coast of British Columbia, Canada. The desired effects of MPAs include higher fishery yields, the conservation of biodiversity, and/or the preservation of intact ecosystems. However, ECOSPACE predicts that when MPAs are small, species interactions and movements may make these objectives difficult to achieve. ECOSPACE suggests that the effects of MPAs are reduced at their boundaries where fishing effort is predicted to concentrate. Furthermore, top predators may become more abundant within MPAs, which could lead to a depression of their prey species and a subsequent increase of species at even lower trophic levels. Trophic cascade patterns and density gradients across boundaries are nontrivial departures from our simple expectations of how MPAs protect areas and will force us to reconsider what constitutes effective conservation. Our ECOSPACE model indicates that the establishment of multi-use buffer zones may help alleviate these realistic but worrisome ecological predictions. When coupled with an overall reduction in harvest pressure, ECOSPACE suggests that a MPA with a large core `no-take' zone and large buffer will result in the greatest increase in organism biomass. The use of marine zoning may be an effective management tactic to reduce social conflict and conserve marine ecosystems.