Host tree traits in pasture areas affect forest and pasture specialist epiphyte species differently

Abstract

Premise Epiphytes have commensal relationships with their host trees. Besides the influence of tree traits, little has been discussed concerning the ecology of epiphytes in disturbed habitats (e.g., pasture). We herein tested whether the occurrences of pasture and forest specialist epiphytes in pastures are affected differently by tree traits. We hypothesized that (H1) the richness and abundance of generalist epiphytes would be positively associated with area availability; (H2) the richness and abundance of forest epiphyte species would be associated both with (H2.a) area availability and (H2.b) tree traits related to higher seed adherence, and/or (H2.c) less severe habitat (e.g., high humidity and more shade). Methods We sampled 9567 epiphyte individuals from 16 species on 759 scattered remnant trees. The epiphyte species were divided into two ecological groups: forest specialists and pasture specialists. We evaluated four host tree traits: two related to tree size (crown area and trunk diameter) and two related to habitat type (crown leaf density and bark rugosity). Results The richness and abundance of both pasture and forest specialists were positively related with tree size. However, the abundance of pasture specialists was negatively related with crown leaf density, whereas richness of forest epiphytes was positively related with bark rugosity. Conclusions Large scattered trees tend to present higher richness and abundance of both pasture and forest specialist epiphytes compared to the smaller trees. However, high crown leaf density limits abundance of pasture specialist epiphytes, whereas rugose bark increases the richness of forest epiphytes.

Host Tree and Geography Induce Metabolic Shifts in the Epiphytic Liverwort Radula complanata

“…We observed a significant phylogenetic relationship of host tree species with the metabolic constitution of R. complanata independent of geographic origin. It has been described before that different host trees possess specific bark chemistry with unique conditions, such as bark pH or the elemental (C, N, P, Mg, Ca, …) content per bark dry mass filter for specific epiphytic communities [ 34 , 35 ]. While R. complanata has been found to be not very selective regarding its substrate ( R. complanata can grow on many types of bark, mainly of deciduous trees, but also on rocks and even on bare soil), these unspecific and rather wide requirements are mirrored by its metabolome, which is regulated depending on the conditions of the host substrate.…”

The effect of habitat transformation on a twig epiphytic orchid: Evidence from population dynamics

“…However, in the present study, the populations of R. granadensis colonizing isolated fruit or shade trees within a transformed pasture matrix had a higher density of plants per phorophyte compared with the forest sub-sites (Supplement Table 1). This may be partly explained as isolated trees in open pastures tend to grow larger and wider crowns (Elias et al, 2021). In Andean human-transformed landscape, Köster et al (2011) found that tree traits explain 60% of the epiphytic community composition in an Ecuadorian cloud forest, where the isolated trees act as steppingstones that permit some persistence of epiphytes outside of the forest in a changing landscape mosaic (Köster et al, 2009;Elias et al, 2021).…”

Quantification and Variation of Microclimatic Variables Within Tree Canopies - Considerations for Epiphyte Research

“…For the epiphytes, tree height has been one of the key predictive variables of epiphyte richness in a local context (Flores-Palacios and García-Franco, 2006;Krömer et al, 2007). Taller trees often harbor a higher richness, biomass and abundance of epiphytes, compared to smaller trees (Flores-Palacios and García-Franco, 2006;Elias et al, 2021;Mitchell et al, 2021). The stratification of epiphytes along the vertical profile of trees has thus been the focus of several scientific studies in the past (see Johansson, 1974 andZotz, 2007).…”