Rare Plants in Hawai'i Volcanoes National Park
The USGS is conducting an experiment to see if the extirmination of invasive rats will benefit native birds in two kipuka in Hawaii Volcanoes National Park. A kipuka is a patch of old growth forest surrounded by more recent lava flows.
While the USGS is studying native birds, they've asked me to monitor the response of rare endemic plants that are believed to be most threatened by the same rats that are reducing bird populations. I've been watching for changes in the fruiting, flowering and recruitment of these plants, especially Hibiscadelphus giffardianus (right image). Our findings, which suggest that invasive rats are one of numerous factors preventing the plant from maintaining a sustainable population size, are published in PLOS ONE.
Invasive black rats have been preying not only on the eggs of native birds, but also on the fruit and flowers of rare endemic plants
I've also started working with NPS scientists to monitor the status of Portulaca sclerocarpa (above), a Hawaiian plant that has been in steep population decline for the past several decades. I'll be monitoring the
Hibiscadelphus giffardianus has been on the brink of extinction since its discovery in 1911.
plants and using species distribution modeling to identify potential locations for successful outplantings after we better understand the factors that are most limiting its survival and reproduction. Possible factors include mice preying on seeds, climate change, and high soil temperatures from magma flowing very near the surface in its native range.