Fast restore of the structure and composition of hemiepiphytes after a heavy-snowfall event in a subtropical forest

Abstract

Since epiphytes mainly obtain water and nutrients from surrounding air, they are extremely sensitive to environmental changes, making them reliable bio-indicators for monitoring climate change. Hemiepiphytes are one common form of epiphytic plants, consisting of primary and secondary hemiepiphytes. It is thus reasonable to suppose that the hemiepiphytes should respond strongly to an extreme change in local climatic conditions. Based on survey data of hemiepiphytes (all the investigated species are primary hemiepiphytes) on trees before (2014) and after (2018) a heavy snowfall event (2015, depth of 50 cm), we examined differences in the distribution and abundance of individuals, population structure, and the general network structure of hemiepiphyte–host associations in a subtropical forest in the Ailao Mountains (Yunnan Province, in southwest China). Contrary to our hypothesis, the results revealed no significant changes for the distribution and abundance of this hemiepiphyte community before and after the heavy-snowfall event. The population structure of all hemiepiphytes (pooled) shifted from a dynamic to a stable state, but did not change on a per species basis. According to the constructed network's parameters, no significant differences were found between years, except for changed web asymmetry, linkage density, and interaction evenness. Our results suggest hemiepiphytes are highly resilient to extreme weather perturbations: within just four years after the snowfall, the community was nearly fully restored to its prior composition and structure. We propose this resilience capability is linked to their ecophysiological characteristics and distributions on host trees.