Structure of the Epiphyte Community in a Tropical Montane Forest in SW China

Abstract

Vascular epiphytes are an understudied and particularly important component of tropical forest ecosystems. However, owing to the difficulties of access, little is known about the properties of epiphyte-host tree communities and the factors structuring them, especially in Asia. We investigated factors structuring the vascular epiphyte-host community and its network properties in a tropical montane forest in Xishuangbanna, SW China. Vascular epiphytes were surveyed in six plots located in mature forests. Six host and four micro-site environmental factors were investigated. Epiphyte diversity was strongly correlated with host size (DBH, diameter at breast height), while within hosts the highest epiphyte diversity was in the middle canopy and epiphyte diversity was significantly higher in sites with canopy soil or a moss mat than on bare bark. DBH, elevation and stem height explained 22% of the total variation in the epiphyte species assemblage among hosts, and DBH was the most important factor which alone explained 6% of the variation. Within hosts, 51% of the variation in epiphyte assemblage composition was explained by canopy position and substrate, and the most important single factor was substrate which accounted for 16% of the variation. Analysis of network properties indicated that the epiphyte host community was highly nested, with a low level of epiphyte specialization, and an almost even interaction strength between epiphytes and host trees. Together, these results indicate that large trees harbor a substantial proportion of the epiphyte community in this forest.

Composition patterns and network structure of epiphyte–host interactions in Chilean and New Zealand temperate forests

“…For one, Burns (2007) suggested that specialist epiphyte species are only found on the largest host trees, so producing nested assemblages. Alternatively, nestedness may occur when epiphyte assemblages on small-diameter trees form perfect subsets of epiphyte assemblages on large-diameter trees (Zhao et al 2015). In this study, there was no marked difference in host tree diameter distributions; however, sites with a higher percentage of larger diameter trees were on average significantly nested.…”

“…Here, the most conservative metric to measure nestedness, NODF (Almeida-Neto et al 2008), still suggests nestedness in New Zealand networks. Although this may be attributed to network size (Nielsen & Bascompte 2007), tree diameter distributions (Zhao et al 2015), or branching architecture, we hypothesise that the abundance of nest epiphytes is the main determinant of nestedness in this study. However, further fine-grained analyses are needed to tease apart specific factors that produce a nested structure in epiphyte-host networks.…”

Tropical mountain passes are out of reach – but not for arboreal species

“…Additionally, plant communities vertically stratify within forests (Zhao et al . ), and plant traits might vary within this height–climate gradient. For example, geographic gradients in plant size were observed in epiphytic Asplenium bird's nest ferns in Malaysia, where individual fern biomass increases with height in the forest canopy (Fayle et al .…”

“…) as do plant communities (eg Zhao et al . ). For example, frog communities in the rainforests of the Philippines vertically stratify with some species living only on the ground and some only in the canopy (Scheffers et al .…”

Vascular epiphytes in the Grumari restinga, RJ: floristic and similarities between restingas in Eastern Brazil

“…These areas present greater availability of niches provided by forest stratification (from shrubs, treelets and trees in the understory to large trees in the upper canopy), thus offering greater heterogeneity of micro-habitats used for epiphyte colonization. The occurrence of large trees and favorable climatic factors (high humidity and mild temperatures) have been reported as the main factors related to the high diversity of epiphytes in the tropical region (Woods et al 2015;Zhao et al 2015;Ding et al 2016).…”