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Publication
Trees as habitat islands: temporal variation in alpha and beta diversity in epiphytic laurel forest bryophyte communities
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Advisor(s)
Abstract(s)
Aim: Trees represent striking examples of habitat islands, with various degrees of
spatial isolation and evolving properties during their life cycle. Here, we investigate
whether changes in habitat conditions, dispersal limitations or competition cause
variation in patterns of epiphytic species richness and turnover.
Location: Madeira island.
Taxon: Bryophytes.
Methods: Using linear mixed effect models, we test whether species richness exhi bits a monotonic or hump-shaped relationship with time. Two groups of host-tree
species, late- and early-successional, were considered. We further identify the
mechanisms explaining the observed variation in species composition by dividing
beta diversity into its nestedness (bsne) and turnover (bsim) components and correlat ing them with tree age and geographical distance among trees.
Results: The best-fit models all included tree age (T), but its quadratic term (T2
) and
tree height (H, here a surrogate of area) were not systematically included. bsim, but
not bsne, correlated with host-tree age, and both bsim and bsne correlated with geo graphical distance.
Main conclusions: Tree age was consistently included in all of the best-fit models,
reflecting the progressive increase in epiphyte bryophyte species richness through
time. The limited contribution of T2 and H to the best models suggests that compe tition for space is not a key factor on mature trees. The correlation of bsim, but not
bsne, with host-tree age, and of bsim and bsne with distance among trees, suggests
that variation in species composition is caused by (1) temporal community shifts
due to allogenic drivers and (2) dispersal limitations, which are reflected by the
higher similarity of the epiphyte communities on clustered trees rather than by an
increasing probability of colonization with tree age. Since actual ancient laurel for ests may no longer exist in Madeira, the conservation of clusters of late-succes sional trees, enhancing connectivity at small spatial scales, is of utmost importance
for the conservation and recovery of the unique laurel forest epiphytic flora.
Description
Keywords
Beta diversity Dispersal Epiphytes Laurel forest Macaronesia Nestedness Species turnover . Faculdade de Ciências da Vida
Citation
Patino, J., Gómez‐Rodríguez, C., Pupo‐Correia, A., Sequeira, M., & Vanderpoorten, A. (2018). Trees as habitat islands: temporal variation in alpha and beta diversity in epiphytic laurel forest bryophyte communities. Journal of Biogeography, 45(8), 1727-1738. DOI: 10.1111/jbi.13359
Publisher
Wiley