Neutral Plant-Plant Associations Predominate in the Community of Vascular Epiphytes in a Cloud Forest in Central Mexico.

Premise of research. In ecosystems where they are common, vascular epiphytes usually interact positively with both their hosts and other epiphytes. However, there are no integrative studies simultaneously analyzing both host-epiphyte and epiphyte-epiphyte associations in ecosystems with a high abundance of vascular epiphytes, such as cloud forests. Most studies have described host-epiphyte associations, but there is a lack of studies evaluating the type of associations established between vascular epiphytes with different growth forms, reproductive states, and taxonomic identities. The goal of this study was to describe the host-epiphyte and epiphyte-epiphyte associations in a cloud forest in central Mexico. Moreover, we evaluated the effect of vascular epiphyte reproductive state, growth form, and taxonomic identity on those associations. Methodology. We first described the host and vascular epiphyte species in the community. Then all host-epiphyte and epiphyte-epiphyte associations were recorded. Pivotal results. All types of associations were recorded among both host-epiphyte (random: 44%; positive: 29%; negative: 27%) and epiphyte-epiphyte (random: 69%; positive: 15%; negative: 16%) associations. Most epiphytes were hosted by four phorophyte species; however, the most abundant phorophytes hosted few or no epiphytes. Epiphyte-epiphyte conspecific associations were mostly positive, whereas the heterospecific associations were predominantly random. At the community level, this pattern did not vary between reproductive states. Associations between heterospecific epiphytes with different growth forms were predominantly random but were positive between conspecifics. Epiphytes with creeping and rosette growth forms established negative associations with their neighbors. Conclusions. Our results show the importance and complexity of the host-epiphyte and epiphyte-epiphyte associations established. To our knowledge, this is the first study in which the epiphyte-epiphyte and host-epiphyte associations and the effect of epiphyte growth form and reproductive state are evaluated. [ABSTRACT FROM AUTHOR]