17 research outputs found
Critical Habitats and Biodiversity: Inventory, Thresholds and Governance
The High Level Panel for Sustainable Ocean Economy (https://oceanpanel.org/) has commissioned a series of “Blue Papers” to explore pressing challenges at the nexus of the ocean and the economy. This paper is part of a series of 16 papers to be published between November 2019 and October 2020. It addresses how multiple human impacts will impact biodiversity underpinning ecosystem services such as marine fisheries, aquaculture, coastal protection and tourism. The paper examines the distribution of marine species and critical marine habitats around the world; analyses trends in drivers, pressures, impacts and response; and establishes thresholds for protecting biodiversity hot spots, and indicators to monitor change. From this scientific base, it assesses the current legal framework and available tools for biodiversity protection, current gaps in ocean governance and management and the implications for achieving a sustainable ocean economy tailored to individual coastal states grouped by social indicators
4SM: A Novel Self-Calibrated Algebraic Ratio Method for Satellite-Derived Bathymetry and Water Column Correction
All empirical water column correction methods have consistently been reported to require existing depth sounding data for the purpose of calibrating a simple depth retrieval model; they yield poor results over very bright or very dark bottoms. In contrast, we set out to (i) use only the relative radiance data in the image along with published data, and several new assumptions; (ii) in order to specify and operate the simplified radiative transfer equation (RTE); (iii) for the purpose of retrieving both the satellite derived bathymetry (SDB) and the water column corrected spectral reflectance over shallow seabeds. Sea truth regressions show that SDB depths retrieved by the method only need tide correction. Therefore it shall be demonstrated that, under such new assumptions, there is no need for (i) formal atmospheric correction; (ii) conversion of relative radiance into calibrated reflectance; or (iii) existing depth sounding data, to specify the simplified RTE and produce both SDB and spectral water column corrected radiance ready for bottom typing. Moreover, the use of the panchromatic band for that purpose is introduced. Altogether, we named this process the Self-Calibrated Supervised Spectral Shallow-sea Modeler (4SM). This approach requires a trained practitioner, though, to produce its results within hours of downloading the raw image. The ideal raw image should be a “near-nadir” view, exhibit homogeneous atmosphere and water column, include some coverage of optically deep waters and bare land, and lend itself to quality removal of haze, atmospheric adjacency effect, and sun/sky glint
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ATLAS AQUATICA EMPOWERING SCUBA DIVING INDUSTRY FOR MARINE CONSERVATION AND THE BLUE ECONOMY
Healthy oceans are essential for life, but a mere 2.9% are fully protected. The question then arises why is ocean protection so challenging? Among the many reasons is the economic allure of extractive activities which poses a barrier to alleviating human pressure on ocean areas. Marine protected areas (MPAs), primarily designed to preserve biodiversity, are often rationalized through a business lens and are expected to yield revenue by increasing tourists’ willingness to pay. However, MPAs are not business entities and require a set of enabling conditions to successfully reach their goals. In a successful marine protected area, a unit increase in natural capital results in a rise in tourist revenue. We developed a bioeconomic model to show how fully protecting diving sites can significantly enhance nature’s recovery and lead to larger revenues for the scuba diving industry. In Mexico, scuba diving generates as much revenue as the fishing industry, yet only 7% of the country’s diving sites are fully protected. Globally, the scuba diving industry generates up to $20 billion dollars per year, even though about half of the diving sites worldwide lack protection. Using global experiences, we designed a five-step bottom-up approach that scuba diving operators can use to amplify marine protection. This approach could catalyze the creation of stricter or new fullyprotected areas designed to incorporate existing businesses a significant departure from the traditional business framework. The Atlas Aquatica initiative advocates for a significant shift in narrative to stimulate broader acceptance of marine protection worldwide. We aim to contribute to a sustainable blue economic growth and the 30x30 conservation target by promoting the protection of diving sites globally
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The largest fully protected marine area in North America does not harm industrial fishing.
Marine protected areas (MPAs) that ban fishing restore marine life within their boundaries and can also replenish nearby fisheries. However, some argue that after large MPAs are established, fishing effort is displaced to unprotected areas and economic loss is incurred by the fishing industry. We tested these assumptions by assessing the behavior and productivity of the Mexican industrial fishing fleet before and after the implementation of the largest fully protected MPA in North America (the 147,000-square kilometer Revillagigedo National Park). We found no decrease in catches and no causal link between the variation of the spatial footprint of the industrial fleet and the implementation of the MPA. Our findings add to growing evidence that well-designed MPAs benefit marine ecosystems and, in the long term, can also benefit the fisheries they support
O Gerenciamento de Resultados Contábeis e o Controle de Provisões
A convergência às normas internacionais de contabilidade e relatórios financeiros (International Financial Reporting Standards ou IFRS) exige maior julgamento por parte dos gestores e flexibilidade na interpretação de normas e regulamentos contábeis, traduzindo-se muitas vezes em divergentes alternativas de contabilização de um mesmo evento contábil. Assim, neste artigo, o intuito é verificar possíveis indicativos da existência de manipulação com suavização dos resultados por meio do controle de provisões, com base na teoria da agência. Foi utilizada uma abordagem quantitativa com modelo de regressão com dados em painel em uma amostra de 49 companhias abertas brasileiras no período de 2007 a 2016. Os resultados dos testes sugerem que há evidencias de suavização de resultados por meio do controle de provisões, em virtude da influência da variação de lucro como fator explicativo da variação na provisão
Driven by Drones: Improving Mangrove Extent Maps Using High-Resolution Remote Sensing
This study investigated how different remote sensing techniques can be combined to accurately monitor mangroves. In this paper, we present a framework to use drone imagery to calculate correction factors which can improve the accuracy of satellite-based mangrove extent. We focus on semi-arid dwarf mangroves of Baja California Sur, Mexico, where the mangroves tend to be stunted in height and found in small patches, as well as larger forests. Using a DJI Phantom 4 Pro, we imaged mangroves and labeled the extent by manual classification in QGIS. Using ArcGIS, we compared satellite-based mangrove extent maps from Global Mangrove Watch (GMW) in 2016 and Mexico’s national government agency (National Commission for the Knowledge and Use of Biodiversity, CONABIO) in 2015, with extent maps generated from in situ drone studies in 2018 and 2019. We found that satellite-based extent maps generally overestimated mangrove coverage compared to that of drone-based maps. To correct this overestimation, we developed a method to derive correction factors for GMW mangrove extent. These correction factors correspond to specific pixel patterns generated from a convolution analysis and mangrove coverage defined from drone imagery. We validated our model by using repeated k-fold cross-validation, producing an accuracy of 98.3% ± 2.1%. Overall, drones and satellites are complementary tools, and the rise of machine learning can help stakeholders further leverage the strengths of the two tools, to better monitor mangroves for local, national, and international management