Habitat selective factors influencing the distribution of larger benthic foraminiferal assemblages over the Kepulauan Seribu

Symbiont-bearing foraminifera are used to study the effects of habitat deterioration on benthic communities in coral reefs dominated by macroalgae. It is shown that, despite their preference for nutrient deprived conditions, some symbiont-bearing foraminifera occur on reefs heavily affected by nutrient stress and macro-algal dominance, thus highlighting the need for a better understanding of the autecology of species and assemblages in these conditions. Both diversity and habitat fractionation increases as terrestrial and nutrient influence decline. The assemblage structure in the most nearshore reefs are dominated by generalist species, while, additionally, more specialistic species occur at the more offshore reefs. Apart from larger scale gradients in ambient seawater quality, local scale variation in physical environmental conditions, such as habitat structure, are important for the assemblage structure as well.