Efectos de la diversidad forestal y disturbancia sobre la diversidad de epífitos en bosques secos tropicales

Abstract

Abstract:The dry forests of southern Ecuador present a great floristic variety and are known for their high degree of endemism from different taxonomic groups, however, these forests are disappearing at an alarming rate, due to anthropogenic disturbances. Epiphytic cryptogams (bryophytes and lichens) are important in seasonally dry tropical forests (SDTFs) due to their physiology being strongly coupled to humidity and solar radiation. We examined two types of forests according to a disturbance gradient (Natural and Semi-natural forests) where frequency and coverage of epiphytic cryptogams we registered on 182 trees. We recorded a total of 57 epiphytic cryptogams (51 lichens and 6 bryophytes). The highest number of species was observed in a natural forest with 51 species, followed by semi-natural forests (DF) with 45 species. Thus, lichens were dominant in seasonally dry tropical forests. We found that total richness tended to decrease when the range of the disturbance increased. The impoverishment was particularly due to the reduction of tree density and diversity (e.g. selective logging) in semi-natural compared to natural forests. However, the epiphytic composition did not differ significantly among the two types of forests. We conclude that epiphytic lichen richness in seasonally dry tropical forests of southern Ecuador is mainly limited by disturbance (selective logging)