Taxonomic turnover of corals, Kenya, 1991 to 2018

Coral reef communities exposed to rapid temperature rises and frequent thermal anomalies in marine reserves and fished reefs were evaluated for coral taxa turnover over 27 years. Temporal turnover within sites was consistently high (~40%) due to a combination of variable detection and episodic and directional changes. Temporal turnover displayed a rapid increase and slow return time after the 1996-98 period of cool and warm thermal anomalies. Marine reserves experienced high spatial turnover during this same period but fished reefs did not. Taxa were less broadly affected by subsequent warm temperature anomalies. Directional change in taxa for all sites combined indicated 3 overall losses and gains - Montipora being the only dominant taxa that declined. Despite similar mean turnover, there were more losses than gains in marine reserves (20 loses and 7 gains in 5 sites) than fished sites (16 gains and 15 losses in 7 sites). Turnover methods detect finer scale taxonomic change likely to be missed in evaluations of dominant taxa - especially in the higher diversity marine reserves. High spatial turnover, community change, and thermal acclimation in these shallow reef lagoons, rather than marine reserve management alone, is suggested to have prevented high net losses of taxa.