A study led by biologists at the University of Hawai‘i at Hilo documents the loss of bird song complexity and the convergence of the songs of three species of Hawaiian honeycreepers on the island of Kaua‘i.
The three species of Hawaiian honeycreepers, ‘akeke‘e (Loxops cauruleirostris), ‘anianiau (Magumma parvus), and Kaua‘i ‘amakihi (Chlorodrepanis stejnegeri), have seen rapid declines in their population numbers in the wild due most likely to avian malaria and habitat loss. The honeycreepers forage on insects and help to pollinate plants and disperse seeds in the forests of Kaua‘i, their natural habitat.
“We did this study specifically in Kaua‘i because it is in a real crisis mode,” says Kristina Paxton, an ecologist and post-doctoral researcher at UH Hilo, who was the lead author of the study. “Their populations are crashing and malaria is probably the largest driving factor of the declines. But we are not only losing the individuals, we are losing their songs. When you go into the forest in Kaua‘i it is now quieter, and that’s losing a part of what makes the Hawaiian forest what it is. The quietness of the forest is a sign that the forest is facing challenges.”
Paxton is affiliated with the LOHE lab, a bioacoustics laboratory at UH Hilo led by Patrick Hart, professor of biology, and Adam Pack, professor of psychology. The lab goes by the Hawaiian name LOHE, which means “to perceive with the ear” and is an acronym for Listening Observatory for Hawaiian Ecosystems.
In January 2019, Dr. Cam Muir, along with 20 students and faculty members from the University of Mississippi, conducted research on the fungal recruitment by tea plants and soil ecosystems. Fungi are well known to play key roles in plant growth and can benefit plants by acting as a both mutualists and decomposers. The diversity of fungi and the impact of their species diversity on soil ecosystems is still poorly understood.
This collaboration between UH Hilo and Ole Miss has led to the recent submission of a $3.5 M grant proposal: Establishing Foundations for Ecosystem Steering. The proposal team is composed of faculty from University of Surrey (UK), Waseda University (Japan), Georgia Institute of Technology (USA), Earth-Life Science (Japan), University of Mississippi, and University f Hawai`I at Hilo (USA).
Students and faculty in lab conducting research on tissue sampling
Dr. Cam Muir teaching in "living lab"
Students from University of Mississippi at "living lab"
Faculty from "Ole Miss" conducting research on tea plants
Matthew Knope, assistant professor of biology, received the Frances Davis award for Excellence in Teaching. Assistant Prof. Knope joined UH Hilo in fall 2017 and quickly became known for putting teaching and his students as his highest priorities. Colleagues praise him for demonstrating his commitment and strong ability to integrate research and teaching and to directly involve students in his research. He is considered a natural and effective teacher and a rising star in the field of ecology and evolution.
The gift from Hawaii Forest & Trail will support research and technologies to reduce mosquito populations that spread avian disease in Hawai‘i.
A local tour company with a strong conservation mission has donated $25,000 to the biology department at the University of Hawai‘i at Hilo. The gift from Hawaii Forest & Trail will support research and technologies to reduce mosquito populations that spread avian disease in Hawai‘i.
“It’s our hope that through this donation, important research work will continue to make strides in protecting Hawaiian forest birds, including our much-loved ‘i‘iwi,” says Rob Pacheco, founder and president of the tour company.
The primary reason for the continued decline of native honeycreepers is mosquito-transmitted diseases such as avian malaria and avian pox. Climate change is exacerbating the problem, and mosquitoes are beginning to move up in elevation to the last disease-free habitats on all Hawai‘i islands.
Research shows mosquito suppression can be achieved by introducing different strains of Wolbachia bacteria into mosquitoes, which drops reproduction rates. Wolbachia male-based insect control programs have been highly successful for reducing local mosquito populations around the world.
“The ultimate goal is to be able to release male mosquitoes with a different Wolbachia strain into the wild to mate with wild females, to suppress mosquito populations,” says Jolene Sutton, assistant professor of biology and top researcher into native avian disease via mosquitoes. None of the mosquitoes here are native to Hawai‘i. If we can reduce or even eliminate mosquito populations in Hawai‘i, we have a good change of saving many iconic bird species. Our research focuses on evaluating and developing novel strategies for mosquito control, including Wolbachia-based strategies and genetic ones. We want to ensure that new technologies are safe and effective.”
She adds, “This donation will go a long way to help further this work. We are very grateful to have this kind of local interest and support.”
Researchers at the University of Hawai‘i at Hilo were recently awarded a Bradshaw Medal for their provocative paper questioning a fundamental assumption of the field of restoration ecology, which is the science of restoring natural habitats that have been subject to anthropogenic disturbances.
The Bradshaw Medal, named after British ecologist and restoration pioneer Tony Bradshaw, is given by the Society for Ecological Restoration, in recognition of a scientific paper published in the Society’s major journal, Restoration Ecology, which advances the field of restoration ecology.
Cordell is also an affiliate faculty member at UH Hilo who serves in an advisory role for the tropical conservation biology and environmental sciences graduate program. Coauthors Ostertag, an ecologist, and Michaud, a hydrologist, are both professors and researchers at UH Hilo. Warman is a plant ecologist with the USDA forestry institute who also teaches at UH Hilo.
A provocative approach to native forest restoration
The provocative aspect of the paper is in its relatively accepting attitude towards nonnative, noninvasive plant species, often the traditional nemesis of ecologists. The authors argue that in some cases it is better to “give up” on the traditional goal of restoring disturbed ecosystems to their pristine native state, and instead pursue a “hybrid” approach that incorporates both native plant species and nonnative (but noninvasive) plants.
“Our perspective is that in many cases we cannot keep these areas all native,” says Ostertag. “It is just not feasible or pragmatic.”
The focus of the paper is a multiyear, multistudy restoration project called Liko Nā Pilina, which in Hawaiian means roughly “growing or budding novel relationships.” The project is an ongoing effort to restore an area of Hawaiian lowland wet forest, an ecosystem found on the northeastern sides of the Hawaiian islands and that is particularly susceptible to loss of native plant species biodiversity and domination of invasive plant species. Hawaii’s native lowland wet forests were first altered by the arrival of the Polynesians and later exploited by Western colonists for agricultural and housing purposes. The result was an altered ecosystem and loss of biodiversity. Today, remnants of the forests remain on Hawai‘i Island in patchy forest reserves in Puna and East Hawai‘i, but they remain threatened by development.
In practice, ecologists want to restore ecosystems back to their original state because the native species evolved over time to fill certain niches or functions in the overall system. This was the original goal of the research team in the Liko Nā Pilina project.
“We had originally done an experiment where we removed all the invasives from our ten-by-ten meter plots,” explains Ostertag. “We thought by removing the highly invasive species we would able to improve the germination of the native species and get them to regenerate. However, that is not really what we got. And the amount of weeding we had to do to keep out the invasives was really really intense. We estimated about 40 person hours per meter squared to do all the weeding to keep it native.”
“Weeding will kill you!” agrees Michaud, the hydrologist whose primary role was studying water flow in the study area. She and Ostertag, along with rest of the team, started to realize that the ecosystem would never return to an-all native state, and even if this were possible, the cost would be too high and payoff too low.
“We realized we needed a different strategy,” Ostertag says. “Just removing the invasives, just doing a passive restoration, was not going to work, the effort was too great. We decided that we needed to do a more active restoration that involved planting the specific species we wanted. This led us to this idea of planting a hybrid forest, making hybrid ecosystems of the native and nonnative species grow together, using nonnative species that were not invasive but that could fill important functional roles. This hypothesis led us to collecting really important data that showed that one problem is that the native community is missing certain functional roles. Therefore, by including nonnative, noninvasive species that can fill these functional roles that are currently missing, we might have more success.”
An example of a functional role that can be filled by a nonnative species is providing shade.
“We found that we were missing fast-growing species with large leaves that create a lot of shade,” explains Ostertag. “We need the shade in the environment because that’s what keeps out the highly invasive seedlings. We need to manipulate the light environment to the goldilocks level where it is just right. We needed species that closed the canopy faster and helped produce shade to keep out the undesirable invasive species but that still allowed native species’ seedlings to regenerate.”
Ostertag adds that they plan to continue to manage the forest indefinitely to support the growth of native species and prohibit the spread of invasives under their new strategy of mixing native and nonnative species to fill functional roles.
“If you are in it for the long game you can start to see real changes,” she says. “After five years, we are starting to see the canopy getting darker and starting to close, and we are really reducing our weeding effort.”
Fine tuning the approach
Ostertag emphasizes that the researchers’ hybrid restoration strategy is not appropriate in every case.
“Our strategy for mixing native and nonnative is less palatable at higher elevations, which are more native-dominated,” she says. “And if there is already high native cover in an area you may not need this method. However, at the lower elevations, which are completely dominated by these highly invasive species, we think this is a realistic approach.”
Ostertag says that winning the Bradshaw Medal was a surprise considering that the team had originally written a completely different type of data-rich paper focusing on weeding and invasive species reoccurrence. The original idea was not reviewing well and instead a new paper emerged.
“We decided we would morph our study into a story format and a lessons learned paper,” says Ostertag. “It took on more of a narrative structure. I think people like the paper because we explain our experience over a decade of work, and the trials and tribulations of this lowland wet forest restoration project.”
Their mixing of native and nonnative species may raise the eyebrows of some conservation ecologists, but Ostertag says her colleagues in Hawai‘i have been very receptive to the hybrid approach.
“Ecologists who work in Hawai‘i were enthusiastic and encouraging because they understand the huge problem that we have with invasive species here,” says Ostertag. “Hawai‘i is like an endpoint on the conservation continuum. Half of our flora is nonnative, we have these highly disturbed systems in the low elevations, and if you go to most places you don’t see native species. They are completely altered, modified systems. Once people realize this, they understand that this is a potentially viable strategy that deserves to be tested.”
About the author of this story: Leah Sherwood is a graduate student in the tropical conservation biology and environmental science program at UH Hilo. She received her bachelor of science in biology and bachelor of arts in English from Boise State University.
The Society for Ecological Restoration recently presented the Bradshaw Medal to two outstanding papers published in its peer-reviewed journal, Restoration Ecology. Named for famed British ecologist and restoration pioneer Tony Bradshaw, the award honors scientific papers that advance the field of restoration ecology in a significant way. Susan Cordell, Rebecca Ostertag, Jené Michaud, and Laura Warman published “Quandaries of a decade‐long restoration experiment trying to reduce invasive species: beat them, join them, give up, or start over?” Their study investigated the most effective way to reforest native species in Hawai’i to recover biodiversity. Ostertag is a member of the Biology department and Michaud is a member of the Geology department at UH Hilo, while Cordell and Warman are affiliated with the USDA Forest Service Institute of Pacific Islands Forestry. Full article: https://www.ser.org/news/434318/
Read the article and watch the video to learn more about how UH Hilo graduate student, Jared Nishimoto, and undergraduates under the supervision of Dr. Jolene Sutton are developing genetic technologies that will help control invasive mosquitoes in Hawaiʻi.
CURE (Course-based Undergraduate Research Experiences) have proven effective for a wide-variety of student learning objectives and Matt Knope, along with his collaborators at Arizona State, are investigating which model of scientific inquiry results in better outcomes for students. Read the full article for more information.
Ms. Ashley Romero, a University of Hawai`i at Hilo Biology major,
has been awarded a $5,000 scholarship from the Fund for Education
Abroad for spring 2019. She will be participating in UH Hilo’s
direct international exchange program to the University of Waikato
in Hamilton, New Zealand.
The 22 spring 2019 FEA scholarship winners were selected from a
pool of over 1,250 applicants representing approximately 470
colleges and universities across the country.
Romero was also awarded the prestigious Benjamin A. Gilman
International Scholarship in the amount of $5,000 to be used
toward her study abroad program. The Gilman Scholarship supports
American undergraduate students of limited financial means to
study or intern abroad.