Revegetation in Dead Dicranopteris (Gleicheniaceae) Fern Patches Associated with Hawaiian Rain Forests

Abstract

Dieback of Dicranopteris linearis (Burm. f.) Underwood on wet, open valley slopes and ridgelines of Maui, O'ahu, and Kaua'i has been attributed to feeding by the introduced leafhopper Sophonia rufofascia Kuoh & Kuoh. We studied early plant succession at a variety of low-elevation D. lineans dieback sites to assess the vulnerability of these disturbances to invasion by nonnative weeds. Dead patches of D. linearis were colonized by both native and alien plant species; the number and assemblage of colonizing plant species was site specific. Clidemia hirta (L.) D. Don and Nephrolepis multiflora (Roxb.) Jarrett ex C. Morton were the most common invasive species colonizing and spreading in dieback patches. Recolonization of dead patches by live D. linearis spreading from the margins was also common. In a simulated fern decomposition study, seedling germination increased as the depth of the thicket decreased. Fern dieback may enhance regeneration of the native tree Acacia koa A. Gray.