Drs. Kristina Paxton and Patrick Hart were awarded a grant from the National Science Foundation (NSF) Grants for Rapid Response Research (RAPID) to assess the impact of Rapid ‘Ōhiʻa Death on Hawaiian forest birds. The project is entitled: “RAPID: Cascading effects of rapid and widespread mortality of a foundation tree species on animal communities in Hawaiʻi”
Rapid ‘Ōhiʻa Death or ROD, is a fungal pathogen causing rapid and widespread mortality of ‘Ōhiʻa (Metrosideros polymorpha), a foundation tree species in Hawaiian forests. ROD poses a serious threat to Hawaiʻi’s remaining native forests and the plants and animals that depend on ‘Ōhiʻa. Research focused on ROD to-date has been concentrated on understanding the pathology of the disease, how ROD is spread, and the impacts of ROD on ‘Ōhiʻa trees. However, there has not been an examination of how ROD is affecting animal communities reliant on ‘Ōhiʻa forests. ‘Ōhiʻa is an important nesting substrate and food resource for both insectivorous and nectarivorous Hawaiian forest birds, 57% of which are threatened or endangered, and there is no substitute for the volume, geographic spread, and year-round source of nectar provided by ‘Ōhiʻa. Given the foundational role of ‘Ōhiʻa in Hawaiian forest communities as the dominant tree in the canopy, the widespread or total loss of ‘Ōhiʻa would likely be catastrophic for endemic Hawaiian forest birds.
This project will use advances in recording technology to continuously record, over an extended period of time, the entire sound-producing animal community (i.e., biophony of a soundscape) within ‘Ōhiʻa forests across Hawaiʻi Island. By using soundscape analysis tools developed within the growing field of soundscape ecology the researchers will be able to rapidly assess changes in the biodiversity of audible birds, insects, and amphibian species associated with mortality of ʻŌhiʻa across the landscape. The research will also evaluate whether the diversity and composition of understory plant species moderates how reliant animal communities respond to the loss of a dominant forest tree species. The use of soundscape indices to model biodiversity following the loss of a foundation species represents a novel and relatively rapid method for assessing ecological change and would be applicable in a range of ecosystems outside Hawaiʻi.