Effects of microhabitat characteristics and spatial scale on recruitment and adult abundance in Caribbean reef fishes.

Patchiness and scale are essential components in the study of ecology. An important question for ecologists is how these two factors interact to influence the distribution and abundance of species and the structure of assemblages or communities. Specifically, do processes that function at small spatial scales within patches influence population distribution among patches at larger spatial scales? In Chapter 2, I examined recruitment in 14 species of Caribbean reef fish. I determine that not all sites (patches of habitat) were equally likely to be replenished (receive recruitment), but that the effect was species specific. Six of the 14 species of fish had spatial patterns of recruitment that were consistent through time, demonstrating that some locations were better supplied with new individuals than other sites. However, not all species recruited well to the same sites, demonstrating that no general recruitment pattern existed for all species. The other 8 species demonstrated highly variable recruitment both in both space and time. In Chapter 3, I focused on a single species, the stoplight parrotfish Sparisoma viride, and determined whether large scale recruitment patterns could be explained by small scale microhabitat use. I found that stoplight recruits associate with the coral Porites porites at small spatial scales. In Chapter 4, I examined the influence of pre- and post-settlement processes on recruitment in the stoplight parrotfish more closely. Specifically, I determined the effects of substratum type, conspecific presence, and damselfish presence on settlement and recruitment to 2.0 m$\sp2$ patch reefs. Although stoplights recruited in greater numbers to the coral Porites than to the coral Montastrea, I found no evidence to suggest that this difference was established by microhabitat choice during settlement. Contrary to these results, stoplights settled in higher numbers to reef that supported resident conspecifics than to empty patch reefs. Persistence was also higher in the presence of conspecifics. Damselfish had no effect on settlement, but they did decrease recruitment. In Chapter 5, I determined whether microhabitat use by 11 species of adult reef fish at small spatial scales predicts their abundance among patches (reefs) at larger spatial scales. Most species showed non-random microhabitat use at small spatial scales. (Abstract shortened by UMI.)Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1997 .T64. Source: Dissertation Abstracts International, Volume: 59-08, Section: B, page: 3852. Adviser: Peter F. Sale. Thesis (Ph.D.)--University of Windsor (Canada), 1997