Evaluating factors that predict the structure of a commensalistic epiphyte–phorophyte network

Abstract

A central issue in ecology is the understanding of the establishment of biotic interactions. We studied the factors that affect the assembly of the commensalistic interactions between vascular epiphytes and their host plants. We used an analytical approach that considers all individuals and species of epiphytic bromeliads and woody hosts and non-hosts at study plots. We built models of interaction probabilities among species to assess if host traits and abundance and spatial overlap of species predict the quantitative epiphytehost network. Species abundance, species spatial overlap and host size largely predicted pairwise interactions and several network metrics. Wood density and bark texture of hosts also contributed to explain network structure. Epiphytes were more common on large hosts, on abundant woody species, with denser wood and/or rougher bark. The network had a low level of specialization, although several interactions were more frequent than expected by the models. We did not detect a phylogenetic signal on the network structure. The effect of host size on the establishment of epiphytes indicates that mature forests are necessary to preserve diverse bromeliad communities.

Experimental evidence of an increased leaf production in Prosopis after removal of epiphytes (Tillandsia)

“…All rights reserved. epiphytes and their hosts is considered a commensalistic relationship (Benzing and Seeman, 1978;Sáyago et al, 2013) or a facilitative interaction system (Callaway et al, 2002). Nevertheless, some epiphytic species can act as "structural parasites" (Stevens, 1987) because they can cause adverse effects in the host tree, such as defoliation and branch-death (Benzing and Seeman, 1978;Benzing, 2008;Caldiz and Beltrano, 1989;Johansson, 1974;Ruinen, 1953).…”

Processes entangling interactions in communities: forbidden links are more important than abundance in a hummingbird–plant network

“…Previous studies have found that species abundance has a major role in determining how interactions are structured in different ecological networks, including positive interactions such as plant-pollinators [9,14] and plant-plant facilitation [15], commensalistic interaction among epiphytes and phorophytes [16] or antagonisms between plant-herbivores and hosts-parasitoids [12,17]. These studies also showed that the observed interactions are better predicted by simulations when other factors are included together with the abundance, such as phenological overlap [9,11,12], morphological matches among species [14] or the phylogenetic relationship, which ultimately influences the traits of the species [15].…”

Diversity and distribution of epiphytic bromeliads in a Brazilian subtropical mangrove

“…Epiphyte colonization depends on the conditions and support provided by the host tree; therefore, epiphytes can be considered useful biological indicators of ecosystem health (Hayasaka et al 2012, Sáyago et al 2013. We can predict a rich bromeliad flora in mangroves with good development and conservation status, especially in mangrove forests with great abundance of mature specimens of L. racemosa.…”