Restoring Hawai‘i’s Wetlands and Investigating Potential Impacts from Climate Change
The James Campbell National Wildlife Refuge in Hawai’i provides important wetland habitats for four species of endangered waterbirds. However, due to invasive species and climate change impacts, these habitats are becoming unsuitable for the fledging and longevity of these birds. Researchers supported by this Pacific Islands CASC project will examine the effectiveness of adjusting the salinity of seven study ponds to control the invasive species that threaten these habitats to inform partner-based ecosystem-scale management plans.
Public Summary
James Campbell National Wildlife Refuge provides core wetland habitat for four species of endangered waterbirds: ae‘o (Hawaiian stilt) ,‘alae ke‘oke‘o (Hawaiian coot), ‘alae ‘ula (Hawaiian gallinule), and koloa maoli (Hawaiian duck). However, suitable habitat and successful fledging of chicks is threatened by invasive species as well as potential impacts from climate change. In particular, California bulrush is an aggressive plant that creates poor habitat for waterbirds, and the young chicks of Hawaiian waterbirds often become prey of American bullfrogs. However, the Refuge has the ability to increase the salinity of this wetland to help eradicate these invasive species, as California bulrush can only tolerate small amounts of salinity, and American bullfrogs’ eggs and tadpoles, up to 10 days old, are unable to survive in areas of high salinity.
During the Fall of 2022, the Refuge tested this strategy by turning on a saltwater pump from late September to late October. This short-term experiment was investigated by Dr. Carmella Vizza’s undergraduate lab classes at Hawaiʻi Pacific University, where students observed a temporary decrease in bulrush in areas where salinity was higher, encouraging the Refuge to invest in installing a longer-term pump as a management strategy.
To better examine the effectiveness of salinity to control invasive species, namely bulrush and bullfrogs, researchers will monitor seven study ponds consisting of four freshwater control ponds, two treatment ponds with varying salinities, and one naturally intertidal pond with the closest proximity to the ocean over a two-year period. In doing so, this project aims to implement an ecosystem-scale management experiment for endangered birds by forming a partnership between the U.S Fish and Wildlife Service and Hawai’i Pacific University that includes conservation, education, and outreach components. Additionally, the Refuge Visitor Services team will work with university students to engage local K-12 classes to aid in data collection, educate on potential implications of climate change, and expose students to the opportunities in STEM. Data will be presented at the U.S. Fish and Wildlife Service’s Science of the Service event, the Hawai‘i Conservation Conference, and through the University.
- Source: USGS Sciencebase (id: 683083c1d4be0269904c25b0)
The James Campbell National Wildlife Refuge in Hawai’i provides important wetland habitats for four species of endangered waterbirds. However, due to invasive species and climate change impacts, these habitats are becoming unsuitable for the fledging and longevity of these birds. Researchers supported by this Pacific Islands CASC project will examine the effectiveness of adjusting the salinity of seven study ponds to control the invasive species that threaten these habitats to inform partner-based ecosystem-scale management plans.
Public Summary
James Campbell National Wildlife Refuge provides core wetland habitat for four species of endangered waterbirds: ae‘o (Hawaiian stilt) ,‘alae ke‘oke‘o (Hawaiian coot), ‘alae ‘ula (Hawaiian gallinule), and koloa maoli (Hawaiian duck). However, suitable habitat and successful fledging of chicks is threatened by invasive species as well as potential impacts from climate change. In particular, California bulrush is an aggressive plant that creates poor habitat for waterbirds, and the young chicks of Hawaiian waterbirds often become prey of American bullfrogs. However, the Refuge has the ability to increase the salinity of this wetland to help eradicate these invasive species, as California bulrush can only tolerate small amounts of salinity, and American bullfrogs’ eggs and tadpoles, up to 10 days old, are unable to survive in areas of high salinity.
During the Fall of 2022, the Refuge tested this strategy by turning on a saltwater pump from late September to late October. This short-term experiment was investigated by Dr. Carmella Vizza’s undergraduate lab classes at Hawaiʻi Pacific University, where students observed a temporary decrease in bulrush in areas where salinity was higher, encouraging the Refuge to invest in installing a longer-term pump as a management strategy.
To better examine the effectiveness of salinity to control invasive species, namely bulrush and bullfrogs, researchers will monitor seven study ponds consisting of four freshwater control ponds, two treatment ponds with varying salinities, and one naturally intertidal pond with the closest proximity to the ocean over a two-year period. In doing so, this project aims to implement an ecosystem-scale management experiment for endangered birds by forming a partnership between the U.S Fish and Wildlife Service and Hawai’i Pacific University that includes conservation, education, and outreach components. Additionally, the Refuge Visitor Services team will work with university students to engage local K-12 classes to aid in data collection, educate on potential implications of climate change, and expose students to the opportunities in STEM. Data will be presented at the U.S. Fish and Wildlife Service’s Science of the Service event, the Hawai‘i Conservation Conference, and through the University.
- Source: USGS Sciencebase (id: 683083c1d4be0269904c25b0)