Although studies dealing with aboveground organisms in the tropics have received great attention, few deal with the diversity of invertebrates in the soil, leaf litter or dead wood. For tropical dry forests, the status of information on soil animal diversity is limited particularly when compared to tropical wet forests, and considerably less than for other ecosystems such as temperate forests, grasslands and deserts. Given the high rate of forest conversion and persistence of deforestation in tropical dry forests, it is important to study the diversity of its fauna and assess how these global changes will affect the linkages of soil biota and ecosystem functioning. This presentation will focus on surveys and studies conducted in Puerto Rico, a tropical Caribbean island where a significant number of studies have focused on the characterization and relationship of soil organisms and ecosystem process in its dry forests.
In dry semitropical systems in Puerto Rico, faunal diversity was related to a gradient of higher tree diversity. Arthropod abundance was not related to litter quantity across sites, and was highest at the native plateau forest where arthropod predators were considerably lower. In decomposing logs of the same tree species, higher species diversity has been found in the tropical dry forest than the wet tropical forest. It is hypothesized that the presence of certain functional groups, rather than taxonomic identity, are important determinants of litter and wood decay in these tropical dry forests compared with other ecosystems examined.