Descripción: |
There is a lack of knowledge on the factors driving epiphytic community assemblage along water-limited environments. Epiphytic bromeliad
and host communities were analyzed in a range of vegetation types, following a precipitation gradient from 500 to 1500 mm y
-1
. Plots were
set up in scrub mangrove, coastal sand dune scrub, deciduous, semi-deciduous and sub-perennial forests within the Yucatan Peninsula in
Mexico. Identity and abundance of hosts and epiphytes, as well as host height and seasonal microenvironmental variables, were recorded at
each vegetation type. The study found epiphytic bromeliads to be mainly located in the lower canopy strata of all but the wettest site (subperennial
forest). Total epiphyte richness (estimated using species accumulation curves) increased with annual precipitation. Bromeliad
species density decreased with vapor pressure deficit and increased with host species density. Semi-variograms and kriging analysis showed a
high spatial correlation in bromeliad and host species density. The species composition, however, was unrelated to space, according to a
Mantel test, but related to host species composition. The current study shows that diversity and structural integrity of the canopy may be as
important as climate in the conservation of epiphytic composition in water-limited environments, where epiphytes are found in sheltered,
lower canopy strata.
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