Lakes - Classification & Monitoring: a strategy for the classification of lakes

This is the report on Lakes – Classification and Monitoring, a strategy for the classification of lakes by the National Rivers Authority. This report describes a scheme for the assessment and monitoring of water and ecological quality in standing waters, greater than about 1ha in area, in England and Wales although it is generally relevant to Northwest Europe. Thirteen hydrological, chemical and biological variables are used to characterize the standing water body in any current sampling. Statistical testing on the chemical variables showed that at least six samples during a year would be needed to produce a representative sampling mean; but in this scheme the choice of variables minimizes logistic cost by not using boat sampling and time costs by not demanding extensive taxonomic work. Standing waters are classified in a state-changed system in which the contemporary values of the variables are compared with a reference baseline state and then placed in categories of percentage change from this baseline. The scheme is presently designed for use at about five year intervals on all lakes greater than 2ha area plus additional lakes of significant amenity or conservation interest.

Wetland resource evaluation and the NRA's role in its conservation. Classification of British wetlands

This is the Wetland resource evaluation and the NRA's role in its conservation: Classification of British wetlands report produced by the National Rivers Authority in 1995. This R&D document provides a clear classification for wetlands in England and Wales. The classification incorporates many of the existing ideas on the subject but avoids some of the problems associated with other classifications. A two-layered 'hydrotopographical' classification is proposed. The first layer identifies situation-types, i.e. the position the wetland occupies in the landscape, with special emphasis upon the principal sources of water. The second layer identifies hydrotopographical elements, i.e. units with distinctive water supply and, sometimes, distinctive topography in response to this. This system is seen as an independent, basic, classification upon which it is possible to superimpose additional, independent classifications based on other features (e.g. base-status, fertility, vegetation, management etc.). Some proposals for such additional classifications are provided.

Avaliação da influência do manejo agrícola no uso e cobertura das terras através de ferramentas de geoprocessamento e indicadores de qualidade dos solos na bacia hidrográfica do Córrego da Caçada - Paraty/RJ

A avaliação da qualidade dos solos e a redução da Mata Atlântica tem sido alvo de diversas pesquisas no Brasil e no mundo, principalmente quando estes estão atrelados ao recorte espacial de Unidades de Conservação. No entanto, tem sido difícil para os gestores dessas unidades a avaliação dos impactos ambientais gerados ao longo dos anos nas bacias hidrográficas, principalmente pela falta de investimentos. Esta dissertação teve por objetivo geral avaliar o atual estágio de degradação da bacia hidrográfica do Córrego da Caçada pertencente à Área de Proteção Ambiental Federal de Cairuçu, no município de Paraty RJ, analisando quantitativamente e qualitativamente a redução dos fragmentos de Mata Atlântica e estabelecendo relações com a degradação física e química dos solos dentro e fora dos fragmentos florestais. A metodologia utilizada para a redução ou avanço dos fragmentos de Mata Atlântica baseou-se no uso de fotografias aéreas do ano de 1956 e imagens de satélite de 2012, onde possibilitou a avaliação espaço-temporal do uso e cobertura das terras, através da produção de um mapa temático final. Além disso, foram elaborados mapas temáticos de reconhecimento da área de estudo, como o de hipsometria, de declividade, de orientação e forma das encostas, além da geração de perfis topográficos. Para a avaliação da qualidade física, química e biológica dos solos foram determinadas as curvas de distribuição granulométrica, a densidade relativa dos grãos sólidos e a densidade aparente, porosidade total, os limites de liquidez e plasticidade, a estabilidade dos agregados em água, análises morfológicas, a saturação de bases, a capacidade de troca catiônica (CTC), a saturação por alumínio, fósforo, pH e o carbono orgânico. Para tal, foi realizada a abertura de três perfis, sendo um em área de fragmento florestal e dois em áreas de pasto. O resultado das análises permitiu, segundo a Sociedade Brasileira de Ciência do solo, a classificação de dois tipos de solos na bacia, sendo: Cambissolo Háplico Tb Distrófico Típico em área fragmento florestal e em área de pasto, e um Latossolo Amarelo Tb Distrófico Típico em área de pasto. Os resultados de laboratório mostraram que os solos avaliados têm baixa fertilidade e valores variados nos resultados de física do solo. No entanto, além do histórico de uso do solo caracterizado pelas práticas rudimentares do manejo empregado pelos Caiçaras, o clima predominante na região possibilita um regime pluviométrico anual que passa dos 2.000mm de chuva/ano, caracterizando solos muito lixiviados e pobres quimicamente. Portanto, conclui-se que a relação das propriedades físicas e químicas avaliadas junto ao manejo inadequado ao longo dos anos tem apresentado um cenário de grandes dificuldades para a recuperação florestal na bacia hidrográfica do Córrego da Caçada, o que mostra a importância da avaliação dos impactos ambientais não só pelo recorte de bacias hidrográficas, como contextualizar seu posicionamento dentro de Unidades de Conservação, com legislações e objetivos específicos.

Seabed classification for trawlability determined with a multibeam echo sounder on Snakehead Bank in the Gulf of Alaska

Rockfishes (Sebastes spp.) tend to aggregate near rocky, cobble, or generally rugged areas that are difficult to survey with bottom trawls, and evidence indicates that assemblages of rockfish species may differ between areas accessible to trawling and those areas that are not. Consequently, it is important to determine grounds that are trawlable or untrawlable so that the areas where trawl survey results should be applied are accurately identified. To this end, we used multibeam echosounder data to generate metrics that describe the seafloor: backscatter strength at normal and oblique incidence angles, the variation of the angle-dependent backscatter strength within 10° of normal incidence, the scintillation of the acoustic intensity scattered from the seafloor, and the seafloor rugosity. We used these metrics to develop a binary classification scheme to estimate where the seafloor is expected to be trawlable. The multibeam echosounder data were verified through analyses of video and still images collected with a stereo drop camera and a remotely operated vehicle in a study at Snakehead Bank, ~100 km south of Kodiak Island in the Gulf of Alaska. Comparisons of different combinations of metrics derived from the multibeam data indicated that the oblique-incidence backscatter strength was the most accurate estimator of trawlability at Snakehead Bank and that the addition of other metrics provided only marginal improvements. If successful on a wider scale in the Gulf of Alaska, this acoustic remote-sensing technique, or a similar one, could help improve the accuracy of rockfish stock assessments.

Marine and estuarine ecosystem and habitat classification

The Ecological Society of America and NOAA's Offices of Habitat Conservation and Protected Resources sponsored a workshop to develop a national marine and estuarine ecosystem classification system. Among the 22 people involved were scientists who had developed various regional classification systems and managers from NOAA and other federal agencies who might ultimately use this system for conservation and management. The objectives were to: (1) review existing global and regional classification systems; (2) develop the framework of a national classification system; and (3) propose a plan to expand the framework into a comprehensive classification system. Although there has been progress in the development of marine classifications in recent years, these have been either regionally focused (e.g., Pacific islands) or restricted to specific habitats (e.g., wetlands; deep seafloor). Participants in the workshop looked for commonalties across existing classification systems and tried to link these using broad scale factors important to ecosystem structure and function.

An objective classification of climatic regions in the Pacific and Indian oceans

We have applied a number of objective statistical techniques to define homogeneous climatic regions for the Pacific Ocean, using COADS (Woodruff et al 1987) monthly sea surface temperature (SST) for 1950-1989 as the key variable. The basic data comprised all global 4°x4° latitude/longitude boxes with enough data available to yield reliable long-term means of monthly mean SST. An R-mode principal components analysis of these data, following a technique first used by Stidd (1967), yields information about harmonics of the annual cycles of SST. We used the spatial coefficients (one for each 4-degree box and eigenvector) as input to a K-means cluster analysis to classify the gridbox SST data into 34 global regions, in which 20 comprise the Pacific and Indian oceans. Seasonal time series were then produced for each of these regions. For comparison purposes, the variance spectrum of each regional anomaly time series was calculated. Most of the significant spectral peaks occur near the biennial (2.1-2.2 years) and ENSO (~3-6 years) time scales in the tropical regions. Decadal scale fluctuations are important in the mid-latitude ocean regions.