Regional Ecosystems Research

Introduced rats are notorious predators of birds and their nests worldwide, but especially on remote islands. Rats ( Rattus exulans ) first arrived in Hawai‘i with Polynesian colonists about 1,000 years ago, resulting in deleterious consequences for native birds and ecosystems. Since Western contact in 1778, two additional rat species have become established in Hawai‘i, including the highly...

Recent studies show that past and ongoing environmental changes have been substantial and have likely already affected conservation efforts in Hawai‘i. Much of the state has experienced substantial drying, including decreases in mean annual precipitation since the 1920s, longer rainless periods, and decreasing stream flow. Temperatures have been increasing in Hawai‘i for the last 40 years...

Hawai‘i's precipitation is greatest in upland areas that are typically forested. This precipitation provides water for both people and ecosystems. Precipitation can either run off and contribute to streamflow, or infiltrate into the ground and provide water for plants, base flow to streams, or recharge to aquifers. The exact routing that water takes is controlled by many factors, including the...

Rapid ‘Ōhi‘a Death (ROD) is an emerging and rapidly spreading disease of ‘ōhi‘a ( Metrosideros polymorpha ), a keystone native forest tree in the Hawaiian Islands. The disease is highly pathogenic in native ‘ōhi‘a and can lead to significant mortality once symptoms become evident. This emerging pathogen is a significant threat to native forests throughout the state because of its potential impacts...

Remote locations, rugged topography, extreme weather conditions, high numbers of threatened and endangered taxa, and widespread degradation of native ecosystems by invasive species makes routine monitoring to determine status and trends of ecosystems and native and invasive taxa difficult and expensive in the Hawaiian Islands. There is a need to supplement existing monitoring protocols with more...

While the Hawaiian avian disease system has been well-studied in the forests of the older section of Hawai‘i Volcanoes National Park (HAVO), and in many other locations throughout the state, nothing was known about avian disease in the new Kahuku Unit of Hawai‘i Volcanoes National Park and the adjacent Kau Forest Reserve. The high elevation forests of Kahuku are the only habitat located on...

This study focuses on assessing changes in vegetation cover and composition inside and outside a fenced exclosure within the USGS Ridge-to-Reef study area on the island of Moloka‘i. This information will be delivered to federal, state, and private land managers who are trying to determine best management practices to reduce erosion and sediment runoff from this dry habitat which has been heavily...

Small mammals (including three species of rats and one species of mongoose) and social Hymenoptera (order of insects including ants and yellowjacket wasps) form two groups of alien predators in Hawaiian ecosystems. The combined impact of these predators has resulted in substantial loss or reduction of native biota in the Pacific. Furthermore, given the past successes of managing or excluding feral...

Within a context of human-mediated land cover change, invasive competitors, predators and disease, conservation biologists and practitioners are now concerned that climate change will further impact the beleaguered flora and fauna of the Pacific Islands. Across the region and elsewhere, to determine these potential impacts of climate change on species and ecosystems, research efforts have focused...

Initial studies suggest terrestrial Hawaiian plant species may be vulnerable to climate change. However, these models lack information on species-specific traits that affect ecological and evolutionary responses of species to climate change. Research is needed to refine current vulnerability models and apply these to Pacific Islands outside Hawai‘i.

Montane plant communities in widely separated intact natural environments of the world have responded to changes in precipitation and temperature regimes by shifting both margins and core distributional ranges upward in elevation. Reduced evapotranspiration rates in cooler climate zones at higher elevation may compensate for less precipitation and higher temperatures within species’ former ranges...

Feral pigs ( Sus scrofa ) have been identified as a significant problem in 120 U.S. National Wildlife Refuges. Pigs cause substantial degradation to natural ecosystems through rooting, digging, and browsing, but they are particularly destructive in Hawai‘I, which has no native terrestrial large mammals.