ite the potential importance of substratum type to the sessile assemblage developing, few field experiments have examined the effects of this factor in marine habitats. Three types of hardsubstrate are common in the shallow waters near Galeta Point on the Caribbean coast of Panama: coral, on intertidal reef-flats, rock, more common in lagoonal areas, and wood, most abundant in the nearby mangrove forest. There were significant differences in the number of alga species, and the abundances of some of these species, colonizing plates of these 3 natural substrata and of 2 artificial substrata(perspex and concrete) in 4 habitats (front and back reef-flat, lagoon and mangrove forest). Effects of substrata varied among habitats. In the lagoon, for example, plates of rock, concrete and perspex were colonized by more species than were plates of coral or wood. Further, at some times on the reef-flat.algae occupied less space on perspex plates than on plates of the other 4 types of substrata. In contrast, the coralline crust LUlothamn~on sp. was most abundant on perspex and concrete in the lagoon. Results demonstrate that type of substratum plays an important role in determining the abundance of sessile species in some marine habitats. Reasons for these effects are not clear but may include differential grazing by invertebrates or differential retention of spores, water or heat. Using artificial substrata to follow the development of sessile assemblages may give misleading results, particularly if comparisons are made among habitats.
|Number of pages||8|
|Journal||Marine Ecology - Progress Series|
|Publication status||Published - 2 Mar 1989|