Fern richness, tree species surrogacy, and fragment complementarity in a Mexican tropical montane cloud forest

We related pteridophytesversus tree species composition surrogate measures of diversity and complementarity of seven cloud forest fragments. Forest structure, and fern and tree composition were determined in 70 12 (.) 50 m transects. Fern density (10.150-25.080 individualy differed among sites. We recorded 83 fern species in the transects. Nonparametric richness estimates indicated that more sampling was needed to complete fern inventories (14 more species). However ferns recorded outside of the transects increased richness to 103 species (six more species than predicted). Twenty-eight species were unique and rare due to special habitat requirements. (Diplazium expansum. Hymenophyllum hirsutum. Melpoment leptostoma. Terpsichora asplenifolar or were at a geographical distrubution edge (Diplazium plantagunfoltum.Lncopodium thyoides. Peduma constraints Polypodrum puberulum). Correlations between fern richness and tree richness and density were not significant, but were significant between fern richness and fern density, between epiphytic fern density and tree richness and density. Tree richness is not a good surrogate for fern diversity. Only three species were recorded in all fragments (Polypadium leptdotruhum. P longepinnulatum. P. plebetuma) thus gragments pteridophytes compositions are highly complentary but more similar for ferns that for trees. A regional conversation approach which includes many small reserves needs to focus supplemenrity on patterns of tree and fern species richness.