Commonness, rarity, and oligarchies of woody plants in the tropical dry forests of Mexico
Por:
Williams, John N., Trejo, Irma, Schwartz, Mark W.
Publicada:
1 jul 2017
Categoría:
Ecology, evolution, behavior and systematics
Resumen:
We assessed woody plant communities in two widely separated forests in
the tropical dry forest (TDF) biome of Mexico for evidence of similar
patterns of species commonness and rarity. We used belt transects laid
out along contour lines (i.e., constant elevation) and stratified across
elevation gradients at sites in Jalisco and Oaxaca to sample woody plant
species diversity, abundance, relative frequency and basal area. We
assembled a combined species list and compared species found in both
sites (shared) to species found in only one site, assessing whether the
most and least common species at a site tended to be shared or unshared.
Of the 8242 individuals sampled, 370 species or morpho-species were
identified, with 222 species recorded at the Jalisco site and 270 at the
Oaxaca site-122 (33%) species were shared across sites. Abundance,
frequency and basal area of shared species were greater on average than
for unshared species, and were positively correlated across sites. A
subset of 68 shared species (18%) accounted for over half of all
individuals encountered at the two sites. Species in the most common
quartile were more likely to be shared than expected by chance, while
species in the least common quartile were less likely. A genus-level
analysis found similar patterns. Our findings suggest that the TDF of
Pacific coast Mexico shows evidence of widespread dominance by a small
subset of species. These findings have potentially important
implications for predicting species composition, understanding the role
of oligarchic species in ecological processes, and conserving rare
species.
Filiaciones:
Inst Politecn Nacl, CIIDIR Unidad Oaxaca, Xoxocotlan 68130, Oaxaca, Mexico
Univ Nacl Autonoma Mexico, Inst Geog, Mexico City 04510, DF, Mexico
Univ Calif Davis, John Muir Inst Environm, Davis, CA 95616 USA
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