Broadcast Seeding as a Potential Tool to Reestablish Native Species in Degraded Dry Forest Ecosystems in Hawaii

Abstract

Hawaiian dry forests currently occupy a small fraction of their former range, and worldwide tropical dry forests are one of the most human-altered systems. Many small-scale projects have been successful in restoring native dry forests in abandoned pastures and degraded woodlands by outplanting after invasive species removal, but this is a costly approach. In this project, we tested forest restoration techniques involving broadcasting seeds pretreated to enhance germination and applying herbicide to reduce non-native grass competition. We compared three treatments: broadcast seeding, herbicide, and broadcast seeding combined with herbicide. After two years our study results suggest that broadcast seeding and the favorable microclimate created by eliminating invasive grasses through herbicide application may increase native seed germination and survival and promote higher species diversity.