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Titolo:
THE RELATION BETWEEN COMMUNITY BIOMASS AND EVENNESS - WHAT DOES COMMUNITY THEORY PREDICT, AND CAN THESE PREDICTIONS BE TESTED
Autore:
DROBNER U; BIBBY J; SMITH B; WILSON JB;
Indirizzi:
LUND UNIV,DEPT ECOL,ECOL BLDG S-22362 LUND SWEDEN UNIV OTAGO,DEPT BOT DUNEDIN NEW ZEALAND
Titolo Testata:
Oikos
fascicolo: 2, volume: 82, anno: 1998,
pagine: 295 - 302
SICI:
0030-1299(1998)82:2<295:TRBCBA>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
NEW-ZEALAND; HERBACEOUS VEGETATION; SPECIES RICHNESS; DOMINANCE DIVERSITY; NULL MODEL; COMPETITION; ABUNDANCE; INDEXES; FOREST;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
27
Recensione:
Indirizzi per estratti:
Citazione:
U. Drobner et al., "THE RELATION BETWEEN COMMUNITY BIOMASS AND EVENNESS - WHAT DOES COMMUNITY THEORY PREDICT, AND CAN THESE PREDICTIONS BE TESTED", Oikos, 82(2), 1998, pp. 295-302

Abstract

Several theories of community structure make predictions of how the processes that control species diversity should change along a gradientoi decreasing stress and therefore, apart from disturbance effects, along a gradient of increasing biomass. These include the theories of 'Small species pool', 'Higher extinction rate', 'Small populations', 'Reduced patchiness and 'Competitive dominance'. This body of theory haspreviously been applied to species richness, giving the Humped-back model. It has not previously been applied to evenness. We do this, and show that the same theory predicts a monotonic decrease in evenness asstress decreases and biomass increases. We test this prediction, by sampling 10 distinct vegetation types in a temperate oceanic area of New Zealand, selected to cover the widest range of ecological conditionsin the region. In replicate quadrats, the photosynthetic biomass of all species was determined. Evenness was calculated by three recently recommended indices. Evenness was lower in sites with higher biomass, in superficial conformity with theory, However, a permutation test showed that this relation persisted when the biomass values were allocatedto sites and species at random. This artefact is shown to be related to the approximately geometric distribution of abundances in most plant communities. There is no tendency in the observed data for evenness to decrease more strongly than expected under this null model. Our results therefore fail to support the 'Higher extinction rate', 'Small populations', 'Reduced patchiness' and 'Cumulative competition' theorieson which the prediction was based.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 21/09/20 alle ore 18:41:50