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Along the world's (sub) tropics mangroves are important coastal ecosystems supporting small-scale fisheries and human populations, highlighting the need to consider participatory approaches in this ecosystem management. We carried out a socio-ecological assessment to characterize the use and perceptions of local populations at Northeastern Brazil (São Francisco River Estuary) on mangrove fisheries and local development, and pointed out strategies for environmental planning. The questionnaire-based results show that the locals are economically dependent on mangrove fisheries, exploring 12 types of fish, 4 types of crabs, 3 types of mollusks and shrimps. All populations indicated a decrease in the fishery yield, mainly due to a high fishery pressure and shrimp farming. We conclude that strategies pointed out by the locals as creation of an protected area of sustainable use (Extractive Reserve), aided by government support to create a local small-scale fishery processing industry, to cultivate oysters and fish and ecotourism are sustainable alternatives for poverty alleviation and mangrove conservation. These alternatives and the socio-ecological assessment should be a guideline for other mangroves areas worldwide with similar environmental problems and where fishery is the base of economic subsistence, in order to guarantees the long term sustainability of mangrove socio-ecological systems.

No litoral Norte e na Baixada Santista as análises espaço-temporais revelaram importantes alterações de origem antrópica na paisagem ao longo do tempo. No litoral Norte destaca-se o incremento de casas de veraneio instaladas sobre a vegetação de manguezal e de restinga, ambas áreas de preservação permanente. Na Baixada Santista, trecho sul do Canal da Bertioga, observou-se que a expansão da mancha urbana e introdução de estruturas náuticas geraram redução e fragmentação da área inicial da vegetação. Ainda na Baixada Santista, Ilha Barnabé, observou-se a construção de rodovia e ferrovia, expansão portuária e retificação de canal provocando perda de extensas áreas de manguezal por aterros, alagamentos, cortes de vegetação e alterações da hidrodinâmica local. No Litoral Sul, encontram-se os manguezais mais conservados do Estado de São Paulo. Nesse segmento do litoral as diferentes ferramentas de escalas espaço-temporais mostraram que os bosques de mangue respondem positivamente à importante deposição sedimentar nas faces convexas dos canais lagunares, característica desse segmento. Novos bosques de mangue foram identificados e monitorados, em parcelas fixas, ao longo do tempo. Conclui-se que os manguezais do Estado de São Paulo sofreram distintas alterações ao longo do tempo, em função de cada trecho de segmento de costa. Os diversos estudos de caso analisados fornecem informações das alterações espaçotemporais na paisagem e nos bosques de mangue. A aplicação das ferramentas utilizadas no presente estudo contribuiu para a obtenção de grande número de informações sobre dinâmica e as alterações antrópicas dos manguezais, as quais são imprescindíveis para a elaboração de planos de gestão e conservação da zona costeira do Estado de São Paulo (Brasil), com vistas à conservação da paisagem e dos recursos naturais.

Oil spills are potential threats to the integrity of highly productive coastal wetlands, such as mangrove forests. In October 1983, a mangrove area of nearly 300 ha located on the southeastern coast of Brazil was impacted by a 3.5 million liter crude oil spill released by a broken pipeline. In order to assess the long-term effects of oil pollution on mangrove vegetation, we carried out a GIS-based multitemporal analysis of aerial photographs of the years 1962, 1994, 2000 and 2003. Photointerpretation, visual classification, class quantification, ground-truth and vegetation structure data were combined to evaluate the oil impact. Before the spill, the mangroves exhibited a homogeneous canopy and well-developed stands. More than ten years after the spill, the mangrove vegetation exhibited three distinct zones reflecting the long-term effects of the oil pollution. The most impacted zone (10.5 ha) presented dead trees, exposed substrate and recovering stands with reduced structural development. We suggest that the distinct impact and recovery zones reflect the spatial variability of oil removal rates in the mangrove forest. This study identifies the multitemporal analysis of aerial photographs as a useful tool for assessing a system's capacity for recovery and monitoring the long-term residual effects of pollutants on vegetation dynamics, thus giving support to mangrove forest management and conservation.

Abstract. This study has mapped mangrove habitat and assessed the protection of this environment across the coastal protected areas with the use of Landsat satellite images integrated with geographic information system (GIS) in the entire Brazilian coast. The results are important to satisfy a great number of needs, including scientific ones as well as planning and environmental managements in conservation efforts. A total of 1,071,083.74 hectares of mangrove forest was registered, with 86% of this value present in the macrotidal coast. Mangrove habitats have shown high level of protection with almost 83% of the area of mangrove cover located within protected areas if we consider three levels of governance -federal, state and municipality. 77% of protected mangroves are situated in protected areas of sustainable use. Focus on implementation efforts of these areas should be attempted as a way to ensure sustainable management of mangrove resources. Key words: Protected areas, GIS, remote sensing, conservationResumo. Mapeamento e avaliação da proteção dos hábitats de manguezais no Brasil. Este estudo mapeou os hábitats de mangue e avaliou a proteção deste ambiente pelas áreas protegidas costeiras através do uso de imagens de satélite Landsat integrado com o sistema de informação geográfica (SIG) em todo o litoral brasileiro. Os resultados são importantes para satisfazer um grande número de necessidades, incluindo as científicas, bem como ações de planejamento e de gestão ambiental nos esforços de conservação. Um total de 1.071.083,74 de hectares de mangue foi registrado, com 86% deste valor presente na costa de macromarés. Os manguezais mostraram um nível elevado de proteção com aproximadamente 83% de sua cobertura vegetal localizada dentro de áreas protegidas, se consideramos as áreas instituídas pelos três entes do governo -federal, estadual e municipal. 77% dos manguezais sob proteção estão situadas em áreas protegidas das categorias de uso sustentável. Esforços na implementação destas áreas devem ser atentados, como forma de garantir uma gestão sustentável dos recursos provenientes dos manguezais.

Ucides cordatus is a relevant fishery resource of Brazilian mangroves and requires legal normative to sustainable use based on stock assessment and management. This study evaluated some population parameters (structure, density, abundance, fishery potential and stock) of this crab species in Brazil Southeast (São Paulo, State), discussing the use of the results to delineate fishery management strategies. Density was monthly evaluated (September 1998 to August 1999), using five sample quadrats of 2x2 m. Density (ind.m-2) was indirectly estimated by counting the opened (with biogenic activity) and closed galleries, and contrasted with flooding level by tides using the vertical distribution of macroalgae in the base of trees. Density of U. cordatus ranges from 2 to 11 ind.m-2 (6±2 ind.m-2) and statistical difference occurred among monthly means (F=11.58; p=0.000). The relationship density vs. tidal flooding indicated a decrease of U. cordatus density in mangroves with higher levels of tidal flooding (r=-0.94; p=0.001). The total abundance of U. cordatus was estimated in 63.7 millions of crabs in 10.61 km2, with a reduction of 34.9% due to total mortality discount. Estimates like that are uncommon in literature, and could be used for fishery forecasts, allowing improvement by the introduction of new variables to be known in the future.

Ucides cordatusis a semi-terrestrial crab and key species endemic to mangrove areas of eastern Americas. In North-eastern Brazil this crab holds a major socio-economic function for artisanal fisheries, as in the São Francisco River Estuary (10°30′27″S 36°23′45″W). Nevertheless, decreases in this species’ stock have been reported since 2000, requiring assessments of the crab population for conservation and management purposes. This study aims at assessing the population status and the fishery potential of this species in the mangroves of this estuary and suggests strategies for its fishery and conservation, according to the guidelines of the National Management Plan forU. cordatusSustainable Use. Six different sites established in 30 km2of mangroves were sampled, with the density ofU. cordatusburrows estimated to evaluate the population structure using the measure of burrow diameters. Results show that the crab mean burrow size was 56.82 (±12.2) mm and that the medium-size crabs (40–70 mm) are the most abundant. The total mean crab density was 1.2 crabs m−2, from which the density of crabs in commercial size (0.85 ± 0.55 crabs m−2) was significantly higher than those in non-commercial size (0.35 ± 0.21 burrow m−2). These mangroves showed a high potential for the crab fishery, with an immediate extractive potential (IEP) of 71.2% and future extractive potential (FEP) of 28.8%. Nevertheless, a lower crab density, probably due to high crab mortality, mangrove deforestation for shrimp farming and high fishery pressure, is a limiting factor for local fishery. We conclude that mangrove areas more appropriate forU. cordatusfishery (extractive areas) show higher mean crab size, IEP and density of commercial crabs, wherein a fixed exploitation rate or/and a fixed escapement rule should be considered. Exclusion areas, intended for the conservation, show lower values of these population parameters and higher FEP, wherein the fishery should be prohibited. These management strategies should also be considered in other Brazilian mangrove areas showing similar crab population structure, thus contributing to the National Management Plan forU. cordatusSustainable Use.

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