Comparing vascular epiphyte diversity hosted by the native Cedrela dugesii and the exotic Annona cherimola species in a cloud forest in central Mexico

Abstract Exotic species can significantly affect native species communities. However, there is a lack of studies comparing the communities of vascular epiphytes and their vertical stratification on native and exotic phorophytes coexisting within natural ecosystems. This study compares these aspects between the native phorophyte Cedrela dugesii and the exotic Annona cherimola within a fragment of cloud forest in central Mexico. We recorded all the epiphyte species present on every individual of each phorophyte species within 0.25 ha. We estimated and compared true diversities, relative abundance, and species composition, both total and per stratum: trunk (ZI), inner branches (ZII), and outer branches (ZIII) between phorophyte species. The association between epiphytes and phorophyte traits (branch diameter, inclination, and height; vegetation cover; and diameter at breast height) was also analyzed. The native phorophyte hosted a higher total ( 0 D:19) and per stratum ( 0 D ZI :10; 1 D ZI :5.1; 0 D ZIII :15) diversity than the exotic one ( 0 D:10; 0 D ZI :3, 1 D ZI :3; 0 D ZIII :7), except in ZII. In both phorophytes, the most abundant species were Pecluma ferruginea in ZI (native:34 stands; exotic:15 stands) and Tillandsia capitata in ZII and ZIII (native:71, 168 stands; exotic:27, 25 stands). Species composition was similar between phorophytes, but different between ZI (associated with high vegetation cover and thick branches) and ZIII (associated with tall branches). Although both phorophytes host epiphytes, a higher diversity is hosted by the native species than the exotic one. To conserve and maintain this diversity of epiphytes and their functionality within the locality, continuous monitoring of both phorophyte species is necessary.