Abstract
AbstractAimChronic anthropogenic stressors are increasing in intensity, making ecosystems more vulnerable to acute disturbances. Recovery processes are not always well understood due to the complexity of ecosystems and the lack of appropriate indicators. Temporal synchrony is a valuable metric for assessing whether fluctuations in abundance of different species are homogeneous or heterogeneous over time. Theoretically, a great diversity of responses by species facing disturbances is associated with a stable ecosystem, with species turnover guaranteeing the persistence of key ecological processes. We analysed the fluctuations of synchrony of a fish community to assess its resilience in an ecosystem exposed to various disturbances.LocationMoorea (French Polynesia).MethodsUsing one of the longest time series available for coral reefs (ca. 35 years), we examined the variations in substrate cover, and the abundance, synchrony and composition of different fish trophic guilds. Multivariate analyses involving synchrony were used to determine the stability of trophic guilds.ResultsChanges in fish community composition indicated incomplete taxonomic resilience. However, community synchrony was lower during periods of low coral cover, indicating greater response diversity, while total fish abundance remained fairly stable. Synchrony drop was due to relationships with coral cover that differed by trophic guild, or the differences in species responses within guilds. Some guilds such as sessile invertebrate feeders exhibited a strong homogeneity of response over time, indicating a greater vulnerability. We also highlighted that various types of disturbances had different effects on the synchrony of particular guilds.Main conclusionsThe fish community appeared functionally resilient, with stability of total abundance and most trophic guilds. This could be a factor explaining the rapid recovery of Moorea's coral reefs from disturbances. However, the homogeneous responses of some fish groups to disturbances may compromise the reef recovery potential on the long term if disturbances become more frequent.
Highlights
The capacity of an ecosystem to recover its main ecological functions after disturbances is known as ecological resilience (Holling, 1973)
After describing the changes in the fish community composition, we studied the variations of abundance and species synchrony for the whole community and its different trophic guilds
As we aimed at analysing the effect of acute disturbances on the fish community, we focused our analysis on the fore reef that has been strongly impacted during the last decades by acute environmental disturbances, especially cyclones and crown‐of‐thorns starfish (COTS) outbreaks (Adjeroud, 1997; Lamy et al, 2015, 2016)
Summary
The capacity of an ecosystem to recover its main ecological functions after disturbances is known as ecological resilience (Holling, 1973). The response diversity within functional groups has been increasingly studied in coral reef fish communities using spatial turnover (Lamy, Legendre, Chancerelle, Siu, & Claudet, 2015; Mellin, Bradshaw, Fordham, & Caley, 2014), cross‐scale redundancy (Nash, Graham, Jennings, Wilson, & Bellwood, 2016) or proportional changes in species abundances with coral cover (Pratchett, Hoey, Wilson, Messmer, & Graham, 2011) as indicators. Some of these studies showed high response diversity following acute disturbances (Pratchett et al, 2011; Wilson et al, 2008). We hypothesized that synchrony within trophic guilds would be higher, in particular in guilds that contain species with similar habitat requirements or that are strongly dependent on coral such as corallivores
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
