Across a range of spatial scales, and for a wide spectre of taxonomic groups, it has been documented that average AP26113 ic50 species richness within a sampling

area of a given size increase when moving from high to low latitudes (Stevens 1989; Gaston 1996, 2000; Witman et al. 2004). Many hypotheses have been put forward to explain the observed patterns but few causal relationships have been identified (Pianka 1966; Gaston 2000; Hillebrand 2004; Jablonski et al. 2006; Harrison and Cornell 2007; Buckley et al. 2010). selleck inhibitor These patterns also exist in the marine benthos (Sanders 1968; Roy et al. 1998; Gray 2001; Witman et al. 2004), with diversity culminating on tropical coral reefs. Exceptions are however found within some taxa (Hillebrand 2004; Krug et al. 2007) and at some high latitude

biodiversity hotspots like those created by deep coldwater coral reefs (Jensen and Fredriksen 1992; Freiwald et al. 2004). Generally, structural complexity provides shelter against predation and physical disturbance (Menge et al. 1983; Mattila 1995; Walters and Wethey 1996) and introduces additional habitats and higher species diversity (Menge and Sutherland 1976; Sebens 1991). Encrusting organisms with hard exoskeletons build secondary substrate and may increase Selleckchem LY3039478 substrate complexity with crevices and cavities (Dean 1981; Senn and Glasstetter 1989; Sebens 1991). A species rich and diverse fauna is thus often associated Immune system with aggregated calcareous-building species and non-tropical shallow-water examples are found in aggregations of red algae (Sneli 1968; Salas and Hergueta

1986; Sintes 1987; Sintes et al. 1987) and serpulid polychaetes (Haines and Maurer 1980a, b; Kirkwood and Burton 1988; Moore et al. 1998). Especially in canals and tidal inlets with high current velocities, reef-like structures of encrusting animals may develop (Odum et al. 1974). Serpulid polychaetes cement their tubes to firm substrates and occur throughout the world, often aggregating in unstable environments. Their growth is fast and some species can develop reefs that are several meters thick and kilometres long (ten Hove 1979), which provide habitats, feeding grounds, refuge, and reproduction areas for an abundant and diverse fauna (Moore et al. 1998). The genus Filograna is widely distributed, but due to the smallness of the tubes their aggregations are not spectacular (ten Hove 1979). Unlike most other genera, Filograna aggregations grow by asexual budding (Faulkner 1930; Kupriyanova and Jirkov 1997), possibly in addition to larval gregariousness, at a pace that on settlement panels can reach 4500 individuals per month (ten Hove 1979).