Host preferences of low-trunk vascular epiphytes in a cloud forest of Veracruz, Mexico

Abstract

The diversity, abundance and frequency of vascular epiphytes on the lower trunk were compared between two host groups of a Mexican cloud forest: angiosperm trees (n = 72) and tree ferns (n = 28). The bark of the five most frequent host trees and the root mantle of the two tree ferns were analysed for their thickness, water content, water retention capacity and pH. A total of 55 epiphyte species and 910 individuals were found on the 27 host species. On hosts with a dbh range of 5–10 cm, epiphytes were significantly more diverse (4.3±0.9 species per host) and more abundant (12.5±2.2 individuals per host) on tree ferns than on angiosperm trees (1.9±0.2 species per host and 3.9±0.6 individuals per host). However, these differences were not significant for the dbh class of 10–20 cm, because epiphyte numbers increased on angiosperm trees with larger host size, but not in tree ferns. Most epiphyte species had no preference for any host group, but four species were significantly more frequent on tree ferns and two species on angiosperm trees. The higher epiphyte diversity and abundance on tree fern trunks of the smallest dbh class is attributed to their presumably greater age and to two stem characteristics, which differed significantly between host groups, the thicker root mantle and higher water retention capacity of tree ferns. These bark characteristics may favour germination and establishment of epiphytes.

Species Richness and Abundance of Low-Trunk Herb Epiphytes in Relation to Host Tree Size and Bark Type, Eastern Amazonia

“…Species richness of epiphytes is often lower on trunks than on the higher parts of the same phorophyte because of the reduced amount of surface available for attachment (TER STEEGE; CORNELISSEN, 1989). Mehltreter et al (2005) studied the low-trunk epiphyte assembly at a high altitude forest in Veracruz, Mexico and found around 20% more species (55 in total) than we found at CNF. According to Gentry and Dodson (1987b) the contribution of epiphytic species to the whole diversity of an area varies according to the different forest type and is usually smaller in lowland forests such as in the CNF.…”

“…The number of low-trunk epiphytic species and individuals may be correlated with the trunk diameter of their host trees (CALLAWAY et al, 2002;MORAN et al, 2003;VOLLRATH, 2003;MEHLTRETER et al, 2005). Larger trees are available as hosts for a longer period of time and usually have more surface area than smaller trees (FLORES-PALACIOS; GARCÍA-FRANCO, 2006;LAUBE;ZOTZ, 2006).…”

INFLUÊNCIA DOS FORÓFITOS Dicksonia sellowiana e Araucaria angustifolia SOBRE A COMUNIDADE DE EPÍFITOS VASCULARES EM FLORESTA COM ARAUCÁRIA

“…/ dez. 2015 no que se refere à arquitetura, diâmetro, rugosidade da superfície, potencial hidrogeniônico (pH) e umidade (JOHANSSON, 1974, MEHLTRETER et al, 2005. Segundo o Instituto Brasileiro de Geografia e Estatística (IBGE) (2012) a Floresta Ombrófila Mista, também conhecida como Floresta com Araucária, é uma unidade fitoecológica do bioma Floresta Atlântica e distribui-se no Planalto Sul-Brasileiro, em altitudes médias de 600 a 800 m, podendo atingir mais de 1000 m em algumas áreas.…”

“…Mehltreter et al (2005), no México, analisaram a influência do substrato em diferentes forófitos em Floresta Tropical Úmida Montana, obtendo as maiores médias de espécies em samambaias arborescentes, quando comparado às angiospermas arbóreas. Nesse estudo, apenas a umidade do forófito se relacionou com a abundância de epífitos.…”

“…/ dez. 2015 A diferença na riqueza vai de encontro ao registrado por Mehltreter et al (2005), no México, onde também foi registrado maior média em samambaias arborescentes (4,3) do que em troncos de árvores (2,9). Os autores observaram relação forte e positiva na abundância de indivíduos com o aumento da umidade dos substratos.…”