Diversity in motion the influence of dispersal and metacommunity spatial structure on invertebrate communities in Heliconia phytotelmata /

by 1971- Guthrie, Carla Gabrielle

High rates of habitat fragmentation and modification are rapidly destroying existing neotropical forest ecosystems. Recognizing that it may be too difficult to preserve pristine landscapes, we need to consider how various land-use practices contribute to long-term patterns of diversity in regenerating forests. This study examines patterns of diversity for invertebrate communities in three secondary forest locations where prior land-use practices have affected forest regeneration and consequently the spatial structure of their host plant, Heliconia imbricata. The invertebrate communities reside within inflorescences, which are clustered into patches. In these forest locations, H. imbricata patches exhibit three levels of spatial isolation, ranging from highly isolated to somewhat isolated patches to a single location with no patch structure where many H. imbricata inflorescences cover a large area. Using the metacommunity framework, this study documented patterns of diversity for communities affected by three levels of spatial isolation. Additionally, the analysis was conducted at two spatial scales (inflorescencelevel and patch-level) to better understand the effects of isolation on diversity. Generally, decreasing spatial isolation increased local species richness and decreased the rate of compositional turnover among communities. This pattern was strongest when data were analyzed at the patch level. Regional species richness was not affected by spatial isolation. Overall, this study combines ideas of conservation biology and metacommunity theory to demonstrate the potential response of diversity in forests regenerating on lands with different land-use histories. The paradox in this system is that under present conditions the most intensely used land area, being slowest to regenerate, 1 best approximates the typical, primary forest metacommunity structure of these invertebrate communities. Less intensely used land tracts have resulted in an altered metacommunity structure.