Wednesday, August 5, 2009
Exhibit Hall NE & SE, Albuquerque Convention Center
Cesar Manrique-Ascencio, Centro de Investigaciones en Ecosistemas, Universidad Nacional Autónoma de México, Morelia, Mexico, Karina Boege, Ecología evolutiva, Instituto de Ecología, UNAM, México, Mexico and Ek del-Val, Centro de Investigaciones en Ecosistemas, Morelia, Mexico
Background/Question/Methods Beetles (Coleoptera) are the most diverse group on Earth for this reason they are good indicators of general biodiversity and conservation status of a particular ecosystem. Plant succession in tropical forests has been well-studied, nevertheless we do not have the same information for insect-communities, we do not know the assemblage rules and the expected insect community associated with plant succession. This investigation evaluated the composition and abundance of the Coleoptera community associated with the vegetational succession of the tropical dry forest in Mexico. We set up 12 permanent plots of tropical dry forest corresponding to grasslands, 3-5 years of abandonment, 8-12 years of abandonment and mature forest, with 3 replicates per successional stage. During the 2007 rainy season we sampled the beetle community associated with all the plants present in 4 transects of 2x25m per plot, up to 3m height, once per month. Results/Conclusions
Total beetle species richness was higher in the grasslands (128) and in forests of 3-5 years (141) in comparison with mature forests (56) and forests of 8-12 years (50) in all samplings (P=0.03). The two most common families (accounting for 50% of species) across sampled plots were: Chrysomelidae and Curculionidae. Abundance was also higher in the grasslands (50 individuals / sample) and it decreased with sucessional age. Mature forest had the lowest abundance per transect (10 individuals / sample) (P <0.001). Rarefaction curves comparing the four succesional stages showed that grasslands are the best sampled stage while mature forests need further sampling to complete the assemblage. Regarding trophic guilds, not surprising most beetle species are herbivorous followed by predators and saprophagous, this trend was consistent in the four successional stages. We discuss the implications of these beetle community patterns for ecosystem functioning.
