Functional traits of planted trees and facilitation of natural regeneration in riparian forest restoration

Abstract

The structure and composition of a plant community being restored change over time and facilitation is amongst the mechanisms involved in the successional process. By facilitation, some species can provide the arrival and establishment of others. Facilitation processes can help to restore degraded areas and the contribution of different functional groups of plants can be distinct. Understanding the contribution of different plant groups may provide guidelines for the design and management of restoration projects to maximize structural results, and to recover floristic and functional diversity. This research will be developed in a riparian forest restoration project started 10 years ago, at Assis State Forest (municipality of Assis, SP, Brazil), in order to verify the possible occurrence of facilitation processes related to functional traits of the species planted. One hundred trees of different species will be considered as sampling units. As functional traits of the species the following will be included: deciduousness, the symbiosis with nitrogen fixing bacteria and dispersal syndrome. Size and shape of individuals (diameter at breast height, crown diameter, and canopy size), abiotic variables under the canopies (light and soil moisture) and degree of occupation by invasive grasses will be recorded and analyzed as explanatory variables. The success of natural regeneration will be evaluated by the density and richness of woody species regenerating (response variables), measuring and identifying all the plants with a minimum height of 50 cm within a radius of 1.26 m from the trunk of the planted tree (area 5 m2). Facilitation of natural regeneration by the trees planted will be investigated by comparing mean values between functional groups or species and by correlations analysis between explanatory and response variables. (AU)