AbstractsBiology & Animal Science

Hawaiian forest bird conservation and koa (acacia koa) forestry on Hawaii island

by Laurie E Strommer




Institution: University of Hawaii – Manoa
Department:
Year: 2016
Keywords: koa reforestation areas
Posted: 02/05/2017
Record ID: 2064786
Full text PDF: http://hdl.handle.net/10125/101776


Abstract

Ph.D. University of Hawaii at Manoa 2011. Biodiversity is threatened by habitat loss and degradation. In Hawaiʻi, species persistence will likely depend on varying degrees of habitat restoration. Efforts to restore habitats for Hawaiian forest birds include reforestation of degraded pasture with Acacia koa (koa), a valuable endemic hardwood. I investigated the ecological benefits of koa reforestation areas (KRAs) to forest bird conservation at two sites on Hawaiʻi Island. I compared vegetation characteristics of KRAs and native forests and found that koa forestry can facilitate native understory development in some cases. The 'Field of Dreams' hypothesis, which states that animals will colonize restored vegetation structure, was assessed by analyzing bird behavior in KRAs and native forest sites. Two endangered species in this community (Hawaii akepa (Loxops coccineus) and Hawaiʻi Creeper (Oreomystis mana)) are missing or uncommon in the KRAs. Four species have colonized the KRAs: Hawaiʻi 'Amakihi (Hemignathus virens), 'Elepaio (Chasiempis sandwichensis), 'Oma'o (Myadestes obscurus) and 'Akiapola'au (Hemignathus munroi). 'I'iwi (Vestiaria coccinea) and 'Apapane (Himatione sanguinea) allocate time differently in the KRAs and native forests. Sequential behavior analysis suggested that KRAs and intact forests may not be equivalent habitat for juveniles of four species. Six species of forest birds use the KRAs for foraging. I found that foraging microhabitat differs between KRAs and native forest sites for Hawaiʻi 'Amakihi. Foraging niche breadth and overlap for all species were similar across sites. I calculated indices of foraging effort and opportunity and found that !Apapane appear to forage differently in the KRAs and native forest sites. My results suggest that animal behavior can be informative in assessment of restoration success. I conclude that KRAs have ecological benefits: they provide some ecosystem services and can enhance native forest understory development. KRAs provide foraging habitat for Hawaiian forest birds. While four bird species have colonized the KRAs, we will not know if they have done so successfully until demographic studies can be completed. Finally, the conservation benefit of the KRAs exists only as long as they are standing: if these forests are to be harvested in the future, extreme care will be required if it is to be sustainable.