Insects are important participants in many ecosystem processes, but the effects of anthropogenic and natural disturbances on insect communities have been poorly studied. To describe how disturbances affect insect communities, we addressed two questions: Do insect communities return to a pre-hurricane composition? And how do insect communities change during succession? To answer these questions, we studied insect communities in a chronosequence of two abandoned pastures (5 yr and 32 yr) and a mature forest (>80 yr) that were recently disturbed by two hurricanes (Hurricane Hugo, 1989; Hurricane Georges, 1998). Although insect abundance and richness fluctuated during the study, all sites returned to pre-hurricane (Hurricane Georges) abundance and richness in less than one year. All trophic categories present before Hurricane Georges were present after the hurricane, but richness within categories fluctuated greatly. Insect richness did not increase during succession; the 5 yr site had the highest richness, the >80 yr site had an intermediate richness, and the 32 yr site the lowest. Nevertheless, the species composition of the two forested sites was different in comparison to the 5 yr site. These results suggest that trophic structure varies little in time and space, but the species composition within each trophic category is highly variable.
RESUMENLos insectos participan en muchos de 10s procesos de 10s ecosistemas, sin embargo pocos estudios se han investigado el efecto que tienen las perturbaciones naturdes y antropogknicas sobre las comunidades de insectos. Para describir cbmo estas perturbaciones afectan a las comunidades de insectos, nos planteamos dos preguntas: regresan las comunidades de insectos a la composicibn previa desphes de un huracin? Y cbmo cambian las comunidades de insectos durante la sucesibn? Para contestar estas preguntas, estudiamos las comunidades de insectos en una cronosecuencia de dos pastides abandonados (5 afios y 32 aiios) y un bosque maduro (>80 aiios) que heron recientemente perturbados por dos huracanes (Huradn Hugo, 1989; Huracin Georges, 1998). Aunque la abundancia y riqueza de insectos fluctub durante el estudio, todos 10s sitios recuperaron 10s niveles prehuracin (Huracin Georges) en menos de un afio. Todas las categorias trbficas presences antes del Huracin Georges siguieron presences despub del huracin, pero la riqueza dentro de las categorias fluctub ampliamente. La riqueza de insectos no aumentb durante la sucesibn; el sitio de 5 af~os tuvo la riqueza m h alta, el sitio de >80 aiios tuvo una riquaa intermedia, y el sitio de 32 aiios t w o la riqueza m h baja. Sin embargo, la composicibn de especies de 10s dos sitios de bosque h e diferente en comparacibn al sitio de 5 aiios. Estos resultados sugieren que la estructura trbfica varia poco en tiempo y espacio, pero la composicibn de especies de las categorias trbficas es muy variable.
Plant functional traits influence the decomposition of their own residues occurring underneath individual plant species. Arthropods associated to litter are critical components influencing decomposition. Nevertheless, few studies have established a direct relation between plant traits and belowground arthropods. To address this relation at the individual plant species scale, this study was conducted in the Guánica dry forest, Puerto Rico, by selecting five tree species and ten isolated trees/species where variations due to neighbor trees are reduced. Mature green leaves, litter, and associated arthropods were sampled from November 2004 through September 2005. Collected arthropods were counted and classified, and abundances were standardized to ind/m 2 . Arthropod abundance did not differ among plant species, but richness, and species and trophic composition were different among the plant species. Predators, omnivores, and sucking herbivores showed a similar species composition among plant species, while detritivore was the only trophic groups with a different species composition among plants. These results are further supported by canonical correspondence analysis results showing that detritivore arthropod species composition covaries with the physicochemical characteristics of mature green leaves of plants. These findings support that the plant idiosyncratic characteristics affect the structure of litter/humus arthropods up to the first consumer level.
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