Enhancing Aboveground Carbon Storage and Invasion Resistance through Restoration: Early Results from a Functional Trait-Based Experiment

Abstract

One of many ecosystem services essential to land management is carbon regulation, but presence of invasive species can influence carbon (C) in undesirable ways. Here we discuss early results of C accumulation from the Liko Nā Pilina hybrid wet forest restoration experiment. The focus of our project is to deliberately increase C storage through a functional trait-based approach to restoration. By choosing plant species mixes with specific functional trait values, a novel ecosystem can be assembled that supports desired ecosystem services such as C regulation. We designed species mixtures based on species rate of C turnover (slow or moderate) and their position in trait space (complementary or redundant functional trait values). New species mixes were planted as four treatments (Slow Redundant, Slow Complementary, Moderate Redundant, and Moderate Complementary), with an additional unmanaged Reference treatment. Our objective was to compare C in aboveground woody biomass using allometric equations to determine which mixture had the greatest potential for site restoration, balancing carbon storage with the eventual goal of creating forests better able to resist establishment by invasion species. Initially, we predicted the Moderate Complementary treatment would have increased C storage. However, we found that the Moderate Redundant treatment had the greatest C storage, largely driven by a few fast-growing species during early development. Even though our short-term results did not support our experimental prediction, these data serve as an important benchmark for contrasting with later results when ecological succession might favor complementary species mixes for sustainable biomass productivity and decreased management efforts.