Plant diversity assessment in the Yaxchilan Natural Monument, Chiapas, México

Abstract

We assessed the diversity of vascular plains in the Yaxchilan Natural Monument, a nature protection area located in Chiapas State, southern Mexico. A checklist including 547 species (337 genera, 102 families) was produced by combining information derived from three sources: (1) an initial list derived from an ecological Study on forest structure; (2) a systematic survey conducted over an 18-month period; and (3) an extra visit to the site as part of,I more ambitious project covering the entire Lacandon rain forest region. February was the month in which the largest number of fertile vouchers was collected in two consecutive years. The families with greatest richness were Fabaceae (47 species), Orchidaceae (34), Rubiaceae (23), and Asteraceae (22). The most speciose genera were Piper (13 species), Psychotria (9), Adiantum and Peperomia (8). Trees were the largest growth form group (203 species), followed by terrestrial herbs (129). Most species (459) were encountered in primary, closed forest, but secondary vegetation contributed 125 species. An estimation of the total size of Yaxchilan flora obtained through the Chao 2 algorithm indicated that this protected area may host more than 850 plant species. Despite its relatively small area, the Yaxchilan Natural Monument hosts a considerable biodiversity, representing over 16.2% of the recorded flora in the entire Selva Lacandona region, and over 7.2% of the State flora.