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Titolo:
Effects of herbivore exclusion and nutrient enrichment on coral reef macroalgae and cyanobacteria
Autore:
Thacker, RW; Ginsburg, DW; Paul, VJ;
Indirizzi:
Univ Guam, Marine Lab, Mangilao, GU 96923 USA Univ Guam Mangilao GU USA 96923 Guam, Marine Lab, Mangilao, GU 96923 USA
Titolo Testata:
CORAL REEFS
fascicolo: 4, volume: 19, anno: 2001,
pagine: 318 - 329
SICI:
0722-4028(200105)19:4<318:EOHEAN>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
HARE STYLOCHEILUS-LONGICAUDA; SECONDARY METABOLITES; CHEMICAL DEFENSES; PHASE-SHIFTS; COMMUNITY STRUCTURE; ALGAL SUCCESSION; EPILITHIC FORMS; LYNGBYA-WOLLEI; KANEOHE BAY; TOP-DOWN;
Keywords:
eutrophication; herbivory; algae; community ecology;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
76
Recensione:
Indirizzi per estratti:
Indirizzo: Thacker, RW Univ Alabama, CH 267,1530 3rd Ave S, Birmingham, AL 35294 USA Univ Alabama CH 267,1530 3rd Ave S Birmingham AL USA 35294 USA
Citazione:
R.W. Thacker et al., "Effects of herbivore exclusion and nutrient enrichment on coral reef macroalgae and cyanobacteria", CORAL REEF, 19(4), 2001, pp. 318-329

Abstract

Although phase shifts on coral reefs from coral-dominated to algal-dominated communities have been attributed to the effects of increased nutrient availability due to eutrophication and reduced herbivore abundance due to overfishing and disease, these factors have rarely been manipulated simultaneously. In addition, few studies have considered the effects of these factorson benthic, filamentous cyanobacteria (blue-green algae) as well as macroalgae. We used a combination of herbivore-exclusion cages and nutrient enrichment to manipulate herbivore abundance and nutrient availability, and measured the impacts of these treatments on macroalgal and cyanobacterial community structure. In the absence of cages, surface cover of the cyanobacterium Tolypothrix sp. decreased, while surface cover of the cyanobacteria Oscillatoria spp. increased. Cyanobacterial cover decreased in partial cages, and Tolypothrix sp. cover decreased further in full cages. Lower cyanobacterial cover and biomass were correlated with higher macroalgal cover and biomass. Dictyota bartayresiana dominated the partial cages, while Padina tenuisand Tolypiocladia glomerulata recruited into the full cages. Palatability assays demonstrated that herbivore-exclusion shifted macroalgal species composition from relatively unpalatable to relatively palatable species. Nutrient enrichment interacted with herbivore exclusion to increase the change in cover of D. bartayresiana in the uncaged and fully caged plots, but did not affect the final biomass of D. bartayresiana among treatments. Nutrient enrichment did not significantly affect the cover or biomass of any other taxa. These results stress the critical role of herbivory in determining coral reef community structure and suggest that the relative palatabilities ofdominant algae, as well as algal growth responses to nutrient enrichment, will determine the potential for phase shifts to algal-dominated communities.

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Documento generato il 27/09/20 alle ore 11:09:37