Contribution of peeling host for epiphyte abundance in two tropical dry forests in the “El Cielo Biosphere Reserve”, Mexico

Abstract

Host traits partly determine the abundance and species richness of epiphytes in tropical forests. It has been proposed that older trees with rough bark and evergreens often house more individuals and more epiphytic species than those with thin, smooth, and peeling bark, which harbor few epiphytes. We hypothesize (i) that epiphytes are more abundant and species‐rich in the more shaded forest, which is related to bark roughness, and (ii) that epiphytes are distributed in the middle of the host, where microenvironmental conditions are more favorable to survival. We evaluated abundance, species richness, and vertical distribution of epiphytes in two tropical dry forests, according to the deciduousness and basal area of the trees. Moreover, we selected the most abundant epiphytes to test whether their distribution is related to a specific bark type and examine their vertical distribution in two dry forests. We distinguished a high abundance and species richness of epiphytes in the deciduous forest, although basal area and host species richness were higher in the semi‐deciduous forest. In both forests, we found a positive relationship between epiphyte abundance and basal area. Higher abundance of epiphytes was related to the predominance of Tillandsia schiedeana, a drought‐adapted species, in both forests. Unexpectedly, epiphytes abundantly colonized Bursera simaruba, a host with peeling bark and a very branched crown, where small individuals of T. schiedeana colonized abundantly toward the top of the crown. Our results show the importance of the tropical dry forest, particularly, B. simaruba, in maintaining epiphyte diversity in terms of T. schiedeana colonization.

Structuring Interaction Networks Between Epiphytic Bryophytes and Their Hosts in Yunnan, SW China

“…It has been repeatedly confirmed that epiphyte-host interactions correlate well with host size, because large tree size provides more surface areas, various microhabitats, and longer exposure time for the colonization of epiphytes (Agglael Vergara-Torres et al, 2010;Sayago et al, 2013;Zotarelli et al, 2019). For example, in a tropical montane forest, DBH alone explained 6% of the epiphyte community variation (Zhao et al, 2015), and a study conducted in two tropical dry forests found a positive relationship between epiphyte richness and host tree size (i.e., height and DBH) (Siaz-Torres et al, 2021). Some researchers treated the host tree individuals as isolated islands, and the epiphyte diversity is predicted by the theory of island biogeography which depicts that larger hosts are able to support a larger number of epiphytic species (Spruch et al, 2019).…”