Nom du corpus

Corpus Systématique Animale

Titre du document

Causes and consequences of sea urchin abundance and diversity in Kenyan coral reef lagoons

Lien vers le document
Éditeur
Springer (journals)
Langue(s) du document
Anglais
Type de document
Research-article
Mots-clés d'auteur
  • Community structure
  • Coral reefs
  • Predation
  • Sea urchins
  • Triggerfish
Nom du fichier dans la ressource
Echinodermes_v2b_0336, Eponges_v2b_0317
Auteur(s)
  • T. R. McClanahan 1,2
  • S. H. Shafir 3,4
Affiliation(s)
  • 1) Center for Wetlands, University of Florida, 32611, Gainesville, FL, USA
  • 2) Coral Reef Conservation Project, P.O. Box 99470, Mombasa, Kenya
  • 3) Program in Human Biology, Stanford University, 94305, Stanford, CA, USA
  • 4) Center for Conservation Biology, Stanford University, 94305, Stanford, CA, USA
Résumé

Large differences in community structure of sea urchins and finfish have been observed in Kenyan reef lagoons. Differences have been attributed to removal of finfish predators through human fishing activities. This study attempted to determine (i) the major sea urchin finfish predators, (ii) the effect of predation on sea-urchin community structure, and (iii) the possible effect of sea urchin increases and finfish decreases on the lagoonal substrate. Six reefs, two protected and four unprotected, were compared for differences in finfish abundance, sea urchin abundance and diversity and substrate cover, diversity and complexity. Comparisons between protected and unprotected reefs indicated that finfish populations were ca. 4 x denser in protected than unprotected reefs. Sea urchin populations were >100 x denser and predation rates on a sea urchin, Echinometra mathaei, were 4 x lower in unprotected than in protected reefs. The balistidae (triggerfish) was the single sea-urchin finfish predator family which had a higher population density in protected than in unprotected reefs. Balistid density was positively correlated with predation rates on tethered E. mathaei (r=0.88; p<0.025) and negatively correlated with total sea-urchin density (r=?0.89; p<0.025) on the six reefs. We conclude from observations that the balistids Balistaphus undulatus and Rhinecanthus aculeatus are the dominant sea-urchin predators. The sea-urchin assemblage had its greatest diversity and species richness at intermediate predation rates and low to intermediate sea-urchin densities. At low predation rates and high sea-urchin density E. mathaei dominated the assemblage's species composition. Preferential predation on the competitive dominant maintains the assemblage's diversity, supporting the compensatory mortality hypothesis (Connell 1978) of coral reef diversity. Protected reefs had greater cover of hard coral, calcareous and coralline algae, and greater substrate diversity and topographic complexity than unprotected reefs which had greater algal turf and sponge cover. Coral cover and topographic complexity were negatively correlated with total sea urchin density. Although experimentation is lacking, these substrate changes may be due to the switch from finfish to sea-urchins as consumers which results from overfishing of finfish. Removal of top invertebrate-eating carnivores appears to have cascading effects on the entire coral reef ecosystem.

Catégories Science-Metrix
  • 1 - natural sciences
  • 2 - biology
  • 3 - ecology
Catégories INIST
  • 1 - sciences appliquees, technologies et medecines
  • 2 - sciences biologiques et medicales
  • 3 - sciences biologiques fondamentales et appliquees. psychologie
  • 4 - ethologie animale
Catégories Scopus
  • 1 - Life Sciences ; 2 - Agricultural and Biological Sciences ; 3 - Ecology, Evolution, Behavior and Systematics
Catégories WoS
  • 1 - science ; 2 - ecology
Identifiant ISTEX
5EF9437AE9D66922D8DD7272E45792218CBA6FF3
Revue

Oecologia

Année de publication
1990
Présence de XML structuré
Non
Version PDF
1.3
Score qualité du texte
10
Sous-corpus
  • Echinodermes
  • Eponges
Type de publication
Journal
ark:/67375/1BB-0Q4ZTTX1-C
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