Dexter, Kyle , Terborgh, John , Cunningham, Cliff .
Tree plots, DNA barcoding, and tropical ecologists' contribution to species discovery.
The past 20 years has seen an upsurge in the number of tree plots and plant community surveys conducted by tropical ecologists. Ecologists generally identify individual trees in these plots and surveys using vegetative characters, or the morphology of leaves, twigs, bark, and trunks. However, the taxonomists whom delimit species generally use fertile characters, or the morphology of fruits, flowers, and their associated structures. Taxonomists prefer not to use vegetative characters because they consider them evolutionarily labile and potentially homoplastic. This disconnect begs the question of how often ecologists are wrong in their identifications and what impact this might have on the results and conclusions of their studies. I use information from two genetic markers, ITS 1 and 2 and the trnD-T chloroplast intergenic spacer, to assess the accuracy of identifications in a conventional ecological study of Inga species (Mimosoideae: Fabaceae) in tree plots in the Peruvian Amazon. I determine both the types and frequency of identification errors. The total error rates are significant (8.3% of all stems), but these errors do not seem to have a great effect on ecological analyses, at least at the community level. While the results show that identifications based on vegetative morphology alone can often be incorrect, I also demonstrate that using a purely DNA sequence based approach to species identification would not be entirely successful either. Finally, I argue that tropical ecologists, particularly if they incorporate information from genetic markers, stand to contribute substantially to species discovery in tropical rainforests.
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1 - Duke University, Biology Department, Biology Department, Duke University, Box 90338, Durham, NC, 27708, USA
Inga (Mimosoideae: Fabaceae).
Presentation Type: Oral Paper:Papers for Sections
Location: Council Chambers/SUB
Date: Monday, July 28th, 2008
Time: 3:45 PM