1 March 2013 Spatial Distribution of Orchid Species in the Luquillo Mountains, Puerto Rico
Lauri B. Brewster, James D. Ackerman
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The remarkable diversity of the Orchidaceae has been attributed to specialized plantpollinator relationships. Limited gene flow among populations would enhance the probability of adaptation to local conditions, including the availability of different pollinator pools. Orchid populations are often viewed as small and hyperdispersed which is consistent with expected low levels of gene flow. Nonetheless, there are very few quantitative assessments of the dispersion of orchid populations. We describe the spatial distribution of orchids in the Caribbean National Forest of Puerto Rico along 2.05 km of transects covering 10250 m2. Thirteen species were encountered, eight of which were abundant enough for statistical analyses. The two most abundant species were Pleurothallis ruscifolia and P. pruinosa (respectively). Green's Index of Dispersion was used to categorize dispersion on hosts as being regular, random, or clumped. All eight species exhibited a random distribution. The distance between conspecific subpopulations was analyzed for each species, and the general distribution was what would be expected for orchids—hyperdispersal. The pattern of small, randomly dispersed subpopulations is consistent with an enhanced probability of local isolation, genetic drift and possibly differentiation. An assessment of effective population sizes and gene flow among subpopulations are needed to fully assess the effect of dispersion on these orchids.

Copyright 2013 College of Arts and Sciences University of Puerto Rico, Mayagü ez
Lauri B. Brewster and James D. Ackerman "Spatial Distribution of Orchid Species in the Luquillo Mountains, Puerto Rico," Caribbean Journal of Science 47(1), 50-56, (1 March 2013). https://doi.org/10.18475/cjos.v47i1.a6
Published: 1 March 2013
Caribbean forests
epiphyte ecology
index of dispersion
population dispersion
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