Gonsiska, P. A. , Givnish, Thomas J. .
Phylogeny and a preliminary comparative analysis of leaf and environmental characteristics in the epiphytic bromeliad genus Catopsis.
Vascular epiphytes have received relatively little ecological and systematic study, even though they constitute up to 40% of plant species diversity in some tropical forests. Catopsis (Bromeliaceae: Tillandsioideae), with 15 spp., is an excellent model for studies of epiphyte ecology and evolution. Its species span a wide (but hitherto unquantified) range of light regimes from exposed treetops to shaded understories, and include carnivorous and non-carnivorous taxa, and tank-forming as well as non-tank-forming taxa, with a wide range in leaf morphology and gross plant form. Here we present a first report on an integrated study on speciation and adaptation in Catopsis. Plastid DNA sequences of rps16 and trnL-trnF were obtained for 1-3 accessions of 13 species of Catopsis and 15 outgroup taxa; the aligned data included 1536 characters, of which 88 were parsimony-informative. Maximum parsimony (MP) produced 16 shortest trees, each 198 steps long; maximum likelihood (ML) produced one most likely tree. MP and ML trees had almost identical topologies, involving a basal split in Catopsis, with no strongly supported differences. Canopy openness, specific leaf area, and leaf inclination were measured via tree-climbing for four representative Catopsis species in Veracruz, Mexico. We analyzed the need for phylogenetic correction in statistical analyses using CONTINUOUS; as a result of this study, uncorrected non-parametric statistics were used. Preliminary analyses confirm that Catopsis berteroniana experiences significantly greater light availability than the other three species, and has significantly more steeply inclined leaves than two of those species. However, it also has higher SLA (thinner leaves) than two species. This study is among the first to examine ecological and morphological traits of vascular epiphytes in a phylogenetic context; when completed – through extension to other Catopsis species and incorporation of photosynthetic data from common gardens – it should produce fundamental insights into the factors influencing habitat selection in bromeliads.
Log in to add this item to your schedule
1 - University of Wisconsin-Madison, Botany, 430 Lincoln Dr., Birge Hall, Madison, WI, 53706, U.S.A.
2 - University of Wisconsin-Madison, Department of Botany, Birge Hall, 430 Lincoln Dr., Madison, WI, 53706, U.S.A.
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM