|Coral and algal response to the 1998 El Niño coral bleaching and mortality on Kenya’s southern reef lagoons - preprint|
McClanahan, T. (2001). Coral and algal response to the 1998 El Niño coral bleaching and mortality on Kenya’s southern reef lagoons - preprint. [S.n.]: [s.l.].
Algae; Coral reefs; Mortality; ISW, Kenyan Coast [Marine Regions]; Marine
|Author|| || Top |
The 1998 interaction between the El Niño and the Indian Ocean dipole produced one of the warmest years in recent records (McPhaden, 1999; Saji, 1999; Webster et al., 1999) and is reported to have caused extensive coral bleaching and mortality throughout the western Indian Ocean (Strong et al., 1998; Goreau et al., 1999; Wilkinson et al., 1999). Previous observations of coral bleaching in Kenya were recorded in 1987 and 1994 with the 1987 event causing significant mortality in corals and other benthic invertebrates (McClanahan, unpublished data and observations). The East African coast has a strong seasonal cycle and these bleaching events occurred at the end of the warm north-east monsoon, usually beginning in March, during the local annual peak of solar irradiance and water temperature (McClanahan, 1988). The recent 1998 coral bleaching event was the most severe in terms of the mortality of benthic organisms, particularly corals, and, therefore, efforts were made to document this event and to determine the sensitivity of coral genera to this disturbance, the role of reef management and in particular, the role of herbivory, on the ecological outcome of this coral mortality. Coral mortality from bleaching or other factors has been shown to produce a variety of responses in coral reef benthic communities (Brown, 1997). These range from quick recovery of coral cover and species composition (Brown, 1997), switches in coral species dominance (Aronson & Precht, 1997; Greenstein et al., 1998), overgrowth of bare substrate by erect fleshy algae (Shulman & Robertson, 1997; McClanahan et al., 1999), near extirpation of species (Glynn & Feingold, 1992), to the destruction of reef framework by bio-eroding organisms (Glynn, 1988; Eakin, 1996). The factors that determine reef changes by bleaching after mass mortalities are, therefore, of considerable interest to understanding reef ecology and for reef management. This study compares four un-fished coral reef parks of Kenya and a monitoring study of herbivorous sea urchins and fishes in and out of these marine parks to determine how these two factors influenced the mortality and the benthic response to this mortality approximately one year after the bleaching mortality. We hypothesised that coral mortality and herbivory would interact to influence the response of benthic algae and that management of herbivores would determine the response to this mortality.