Mass mortality of coral reef ascidians following the 1997/1998 El Niño event
Kelmo, F.; Attrill, M.J.; Jones, M.B. (2006). Mass mortality of coral reef ascidians following the 1997/1998 El Niño event, in: Queiroga, H. et al. (Ed.) Marine biodiversity: patterns and processes, assessment, threats, management and conservation: Proceedings of the 38th European Marine Biology Symposium, held in Aveiro, Portugal, 8-12 September 2003. Developments in Hydrobiology, 183: pp. 231-240. dx.doi.org/10.1007/s10750-005-1119-z In: Queiroga, H. et al. (2006). Marine biodiversity - Patterns and processes, assessment, threats, management and conservation: Proceedings of the 38th European Marine Biology Symposium, held in Aveiro, Portugal, 8-12 September 2003. European Marine Biology Symposia, 38. Developments in Hydrobiology, 183. ISBN 1-4020-4321-X. XV, 353 pp. https://dx.doi.org/10.1007/1-4020-4697-9, more In: European Marine Biology Symposia., more |
| Available in | Authors | | Document type: Conference paper
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| Keywords | Accidents > Collisions
Climatic changes
Composition > Community composition
Erosion
Taxa > Species
Ascidiacea [WoRMS]
ASW, Brazil, Bahia [Marine Regions]; ASW, Brazil, Praia Rasa [Marine Regions]
Marine/Coastal | | Author keywords | ENSO; climate; Ascidiacea; community; bioerosion; Brazil |
| Authors | | Top | - Kelmo, F.
- Attrill, M.J., more
- Jones, M.B.
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| Abstract | In April/May each year from 1995 to 2000, ascidians were sampled randomly with 35 1m2 quadrats from three different reef habitats (intertidal reef tops, coastal reef walls and shallow-bank reefs) at four replicate localities (Praia do Forte, Itacimirim, Guarajuba and Abai) in northern Bahia (Brazil). As the sampling period included the 1997/1998 El Niño event, the most severe on record, for the first time these results allow a quantitative assessment of the impact of this major environmental stressor on the biodiversity of associated coral reef ascidians. Across all reef habitats, 22 ascidian species were recorded from three different orders (Aplousobranchia, Phlebobranchia and Stolidobranchia). After El Niño, all species showed significantly altered densities (ANOVA, F=602.90, p<0.0001); many species were absent from the reefs within 2 years of the El Niño period, but densities of Lissoclinum perforatum (all reefs) and Echinoclinum verrilli (subtidal reefs) increased significantly from 1998 onwards. Univariate and multivariate analyses confirmed that significant changes in assemblage composition had occurred. BIOENV analysis identified turbidity, mean temperature and cloud cover as the main factors best explaining these assemblage changes. Our results suggest that although the 1997/1998 El Niño had a differential effect on the species contributing to the ascidian assemblage of Brazilian coral reefs, most species disappeared and those remaining are likely to enhance reef degradation through their bioeroding activities. |
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