Corey Tarwater, an associate professor, and Patrick Kelley, a research scientist,
both in UW’s Department of Zoology and Physiology, recently received a four-year Strategic
Environmental Research and Development Program (SERDP) grant to study the resilience
of the impacts of invasive species and climate change on Hawaii’s novel ecosystem.
This photo, from research conducted in Hawaii during 2019, includes, from left, Jeferson
Vizentin-Bugoni, an assistant professor of ecology at the Federal University of Pelotas
in Pelotas, Brazil; Sam Case, a previous UW Ph.D. student; Rene Tam, a field technician;
Jinelle Sperry, a wildlife biologist with the U.S. Army’s Research and Development
Center’s Construction Engineering Research Laboratory; Kelley; Tarwater; and Hannah
Horowitz, another field technician. (Jeff Foster Photo)
Two University of Wyoming researchers recently received a four-year Strategic Environmental
Research and Development Program (SERDP) grant to study the resilience of the impacts
of invasive species and climate change on Hawaii’s novel ecosystem.
Corey Tarwater, an associate professor, and Patrick Kelley, a research scientist,
both in UW’s Department of Zoology and Physiology, received the bulk of an SERDP grant
worth nearly $2 million for their project titled “Predicting Impacts of Species Loss
on Ecosystem Stability: An Experimental Test of a Novel Theoretical Framework.” Of
that grant total, UW will receive a shade over $1.38 million. The grant begins in
June 2024 and runs through May 2028.
The overall objective of this study is to understand and predict the impacts of multiple,
compounding threats on communities and ecosystem stability on O’ahu, an island of Hawaii, says Tarwater, who will serve as the principal investigator (PI) for the UW portion
of the grant.
“With this new project, we will experimentally remove invasive fruit and determine
if and how birds change their behavior as a result. From this work, we will be able
to tell resource managers in Hawaii how the removal of invasive species, gain of new
introduced species and gain of native species -- all scenarios that occur on the landscape
-- will impact seed dispersal of native plants and ecosystem stability,” Tarwater
says. “Further, we will be able to provide them with information on what suite of
plant species should be put into their managed areas, such that these areas will increase
seed dispersal of native species.”
“We want to see what happens when we do not allow important seed dispersers, such
as introduced birds, to access fruit of different invasive species,” adds Kelley,
co-PI on the grant. “We will be conducting a large-scale fruit manipulation experiment
at several sites on O’ahu and then examining what dispersers do in response. Do they remain in the area,
but simply switch their diets? Do they simply leave? Are these species replaced by
other bird species? All of this will help us understand how changes in invasive fruit availability impact
ecosystem stability.”
The proposed study will examine seed dispersal networks using a network analytic approach
to empirically test the researchers’ previously developed theoretical framework. Using data from this upcoming study and data the current grant team collected for
the Hawaii VINE (Vertebrate Introductions and Novel Ecosystems) Project over the last
10 years, the research team will use computer simulations to explore how adding or
removing species -- that play a crucial role in seed dispersal -- affects ecosystem
stability, Kelley says.
In Hawaii, most native plants require vertebrate dispersal; most native dispersers
are extinct (all are extinct on O’ahu); and invasive plants and dispersers are widespread,
Tarwater says. For example, the introduction of invasive birds brought avian malaria
to the islands. As a result of this introduction, native bird populations were decimated,
with the majority of those birds going extinct.
In the seed dispersal system the group studies, a combination of invasive plants outcompeting
native plants and invasive birds preferring to eat the fruits of invasive plant species
has resulted in population declines or extinction of many native plant species.
“Our previous work found that almost all seed dispersal was between invasive plants
and invasive birds and, while the invasive birds will eat some native plants, they
do so rarely,” she says. “In the heavily managed areas, where only native plants remain,
the invasive birds rarely go into these habitats because they are devoid of fruit.”
Climate change also will bring with it other types of challenges, such as fire. Given
that some of the native plant species only have 50-100 individuals left in the wild,
an increase in the number and severity of fires could have catastrophic impacts on
native populations, Tarwater says.
Other grant team members include Don Drake, a professor of botany at the University
of Hawaii-Mānoa; Jeff Foster, an associate professor of biological sciences at Northern
Arizona University; Jinelle Sperry, a wildlife biologist with the U.S. Army’s Research
and Development Center’s Construction Engineering Research Laboratory; and Jeferson
Vizentin-Bugoni, an assistant professor of ecology at the Federal University of Pelotas
in Pelotas, Brazil. The remainder of the grant is divided amongst these researchers.
The UW portion of the grant will support two UW Ph.D. students -- one in Tarwater’s
lab and one in Kelley’s lab. Additionally, Tarwater says “many undergraduates” will
be recruited to help with this project, and the UW grant team includes six field technicians
and one crew leader.
“By understanding the dynamics of these invaded ecosystems and how they’re impacted
by environmental variation, behavior or abundance of different species, we can begin
to gain valuable insights into managing ecosystems in an ever-changing world,” Kelley
says.
SERDP is the U.S. Department of Defense’s environmental and resilience science and
technology program, planned and executed in partnership with the Department of Energy
and the Environmental Protection Agency.
