Random placement and the distribution of fishes among coral patch reefs

Abstract

On the basis of repeated censuses of unmanipulated assemblages of fish on 20 lagoonal patch reefs. Sale & Douglas (1984) proposed a simple random placement model to account for the structure of such reef fish assemblages. The present paper uses their data augmented by additional censuses and a series of simulation models to explore the adequacy of their proposal. The distributions of a small proportion (about 8 species) of the 143 species recorded on the reefs, but including some of the most abundant species, could not be explained by a process of random colonization. These species vary greatly in abundance among censuses, and tend consistently to prefer certain reefs. The remaining species, while clearly possessing some microhabitat requirements, and perhaps responding to each other's presence, show distribution across patch reefs which are satisfactorily explained by a model of random placement of juveniles from a pool of potential colonists.

Temporal variability in patterns of association among fish species on coral patch reefs

“…Our studies of assemblages of reef fish on small patch reefs have largely failed to find such rules (Sale & Dybdahl 1975, 1978, Sale 1980b, Sale & Steel 1986. Others have had similar difficulty (Talbot et al 1978) or have drawn conclusions which we believe go beyond their data ( see discussion in Sale 1980a, Sale & Williams 1982.…”

“…Note the different scale in the last graph habitat , Sale & Steel 1986). Another explanation is that the species associate with each other but do not necessarily show affinity for any particular patch reefs.…”

“…The random placement model developed by Sale & Steel (1986) demonstrated that chance settlement alone could account for a surprising proportion of the pattern seen in distribution of species among these 20 patch reefs. This model was used to generate the tests of associations found among groups of the 25 most common species examined in this paper.…”

“…The N X N matrix (N = number of species) of similartotally, accounted for by a null model of random ity values forms the raw material for the cluster analysis recruitment of fish to reefs (Sale & Steel 1986). In that which is agglomerative and stepwise (e.g.…”

Total volume of 3D small patch reefs reflected in aerial photographs can predict total species richness of coral reef damselfish assemblages on a shallow back reef

“…Coral reefs form patchy habitats for sedentary marine animals on various scales, and coral reef fish communities are among the richest animal communities in nature (Lowe-McConnell 1987;Sale 1991Sale , 2002Bostro¨m et al 2011;Pittman et al 2011). Although patterns of reef connectivity and patch dynamics are not well understood for reef fish (Christie et al 2010;Mumby et al 2011), evidence suggests that larval connectivity between habitat patches within a coral reef area is high (e.g., Almany et al 2007;Planes et al 2009;Pinsky et al 2012).…”