Redundancy in metrics describing the composition, structure, and functioning of the North Sea demersal fish community
|Author(s)||Greenstreet Simon P. R.1, Fraser Helen M.1, Rogers Stuart I.2, Trenkel Verena3, Simpson Stephen4, Pinnegar John K.2|
|Affiliation(s)||1 : Marine Scotland, Marine Lab, Aberdeen AB11 9DB, Scotland.
2 : Ctr Environm Fisheries & Aquaculture Sci, Lowestoft NR33 0HT, Suffolk, England.
3 : IFREMER, F-44311 Nantes 03, France.
4 : Univ Bristol, Sch Biol Sci, Bristol BS8 1UG, Avon, England.
|Source||Ices Journal Of Marine Science (1054-3139) (Oxford Univ Press), 2012-01 , Vol. 69 , N. 1 , P. 8-22|
|WOS© Times Cited||23|
|Keyword(s)||community health, community size structure, ecosystem approach to management, life-history-trait metrics, metric suites, species diversity, state indicators|
|Abstract||Broader ecosystem management objectives for North Sea demersal fish currently focus on restoring community size structure. However, most policy drivers explicitly concentrate on restoring and conserving biodiversity, and it has not yet been established that simply restoring demersal fish size composition will be sufficient to reverse declines in biodiversity and ensure a generally healthy community. If different aspects of community composition, structure, and function vary independently, then to monitor all aspects of community general health will require application of a suite of metrics. This assumes low redundancy among the metrics used in any such suite and implies that addressing biodiversity issues specifically will require explicit management objectives for particular biodiversity metrics. This issue of metric redundancy is addressed, and 15 metrics covering five main attributes of community composition, structure, and function are applied to groundfish survey data. Factor analysis suggested a new interpretation of the metric information and indicated that a minimum suite of seven metrics was necessary to ensure that all changes in the general health of the North Sea demersal fish community were monitored properly. Covariance among size-based and species-diversity metrics was low, implying that restoration of community size structure would not necessarily reverse declines in species diversity.|