Is facilitation a promising strategy for cloud forest restoration?

Abstract

The loss of primary cloud forest within the original range of this ecosystem is one of the highest worldwide. Facilitation is a process in the plant community dynamics that is potentially useful for the restoration of degraded ecosystems. Secondary cloud forest tree species possess attributes that make them suitable to be used as facilitator species for the establishment of tree species typical of intermediate and late successional stages. In this study we examined the facilitator potential of two early successional species, Alnus acuminata and Trema micrantha, both of which grow rapidly and are capable of gradually modifying physical micro-environmental conditions of open sites where forest was cleared. The aim was to assess the effects of these two species on the survival and growth of two intermediate successional species, Juglans pyriformis and Quercus insignis, and one late successional species, Oreomunnea mexicana. Open sites were used as control. Survivorship of the three target species was significantly higher under the canopies of A. acuminata and T. micrantha compared to open sites. Almost all annual growth rates (cover, diameter and height) were not different in both experiments (under the canopy of A. acuminata and T. micrantha), regarding treatment (under canopy vs. open areas) and species (target species). However, results for target species survival strongly suggest that plantations of early successional species can facilitate the establishment of intermediate and late successional trees, and thus represent a promising strategy for cloud forest restoration.