998 resultados para Typological Classification


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The National Marine Fisheries Service is required by law to conduct social impact assessments of communities impacted by fishery management plans. To facilitate this process, we developed a technique for grouping communities based on common sociocultural attributes. Multivariate data reduction techniques (e.g. principal component analyses, cluster analyses) were used to classify Northeast U.S. fishing communities based on census and fisheries data. The comparisons indicate that the clusters represent real groupings that can be verified with the profiles. We then selected communities representative of different values on these multivariate dimensions for in-depth analysis. The derived clusters are then compared based on more detailed data from fishing community profiles. Ground-truthing (e.g. visiting the communities and collecting primary information) a sample of communities from three clusters (two overlapping geographically) indicates that the more remote techniques are sufficient for typing the communities for further in-depth analyses. The in-depth analyses provide additional important information which we contend is representative of all communities within the cluster.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

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.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

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.