Natalie Graham, Assistant Professor of Biology

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Assistant Professor Graham is a molecular ecologist whose most important contribution to the field is her research into the genetics of arthropod communities found in the Hawaiian archipelago.

Natalie in fern forest. She wears gloves and holds two labeled vials.
Natalie Graham holds vials used to collect samples of environmental DNA from water collected in fallen hapuʻu tree ferns. The water contains mosquito larva of the species Culex quinquefasciatus, which is a vector for the pathogen causing avian malaria, a major threat to Hawaiʻi’s native bird fauna. (Courtesy photo)

Posted Sept. 3, 2024

Natalie Graham is an assistant professor of biology at the University of Hawaiʻi at Hilo. A molecular ecologist, Graham’s primary research is in terrestrial arthropods found in the Hawaiian archipelago, which she studies to better understand what action should be taken to mitigate human impacts in the most vulnerable ecosystems. She does this through investigating how the structure of biological communities change over time, in particular, how anthropogenic changes are altering species interactions and potentially driving communities past ecological tipping points.

“I exploit the natural occurrence of age-structured terrains on the Hawaiian archipelago that represent communities in an assembly continuum at sites dating from 44 years to 5.5 million years in geological age,” says Graham about her work.

Logo with insects and trees: ʻElala Biodiversity Lab at UH Hilo.Graham received her master of science in biology from Sonoma State University, California, in 2014, and her doctor of philosophy in environmental science, policy, and management from University of California, Berkeley, in 2021. She arrived at UH Hilo in 2023, where she has founded the ʻElala Biodiversity Lab (ʻelala means insect in ʻōlelo Hawaiʻi, Hawaiian language). Graham also conducts research as an affiliate at Rausser College of Natural Resources at UC, Berkeley.

The research: Ecological and evolutionary dynamics

In a 2023 presentation, Graham explains the importance of researching ecological and evolutionary dynamics to understand how biodiversity accumulates through time. She says that interactions across space and time shape biodiversity, and while models have been developed to infer the dynamic processes shaping the evolution of communities, empirical data for understanding the interplay of ecology and evolution over long temporal scales are almost entirely lacking.

The Hawaiian archipelago provides an excellent backdrop for this research because each island is the result of the Pacific tectonic plate moving over a stationary “hot spot.” This means that each island began as a blank slate and represents a progressively longer amount of time that ecological and evolutionary processes have been able to shape present-day communities: younger islands tend to have communities with simpler networks and more generalized interactions (i.e., Hawaiʻi Island), while older islands have more established, complex, and specialized interactions (Kauaʻi).

Two women in a fern forest, peer into the foliage. The woman in foreground is wearing camo pants and has a large backpack on her back, she holds a camera trying to photograph the insect. The other researcher in the background is wearing a head lamp.
Natalie Graham (foreground) and research colleague Rosemary Gillespie, an entomologist at UC Berkeley, make their first sighting of an Orsonwelles spider at Kaiholena Nature Reserve on Hawaiʻi Island. Orsonwelles is a genus of American dwarf spiders native to the Hawaiian Islands, each species occurring on a single island, often at high elevations. (Photo: George Roderick)

Studying ecological genetics on islands with different geological development times has the potential to increase understanding of interactions between species, and how they have changed over time. Plant-arthropod interactions are an excellent model for this type of research because of the tremendous diversity in species and life histories, meaning scientists can find many more species and more specialized relationships between arthropods and plants.

Graham says that in her use of molecular tools to understand how biological communities are changing through time, her most significant contribution to the literature is the paper, Ecological network structure in response to community assembly processes over evolutionary time (Molecular Ecology, 2023). “This is a large, collaborative, empirical study using DNA metabarcoding (short sequences of DNA) which provides a profile of thousands of Hawaiian arthropods in communities across the geological time series,” she says. “There are more papers I am publishing soon about this research.”

  • Learn more about this National Science Foundation-funded research project, Dimensions in Biodiversity, to which Graham contributed while a graduate student and then doctoral candidate. It was Graham’s doctoral dissertation work to do the data collection, DNA metabarcoding (sequencing) and statistical analysis on that research.
  • See full list of Graham’s publications on her Google scholar page.

Current research

Since coming to UH Hilo, Assistant Professor Graham has wasted no time continuing her research.

Graham is a junior investigator for the Hawaiʻi IDeA Networks of Biomedical Research Excellence (HI INBRE) program, a statewide federal project aimed at expanding the biomedical research capacity in Hawaiʻi.

“The research focus is the human, animal, and environmental health consequences of introduced arthropod pest species,” she says. “The methods include environmental DNA surveys for biosecurity and long-read sequencing for building genomic resources in Hawaiʻi.”

Graham also is working with a UH Hilo SEED Money Grant of intramural funding awarded in the spring of 2024 to investigate how arthropod and plant communities are shifting when the forest is hit with high rates of the pathogen that causes Rapid ʻŌhiʻa Death, a fungal disease that has killed hundreds of thousands of mature ʻōhiʻa trees (Metrosideros polymorpha) throughout the Hawaiian Islands. ROD is caused by two invasive fungi, Ceratocystis huliohia and Ceratocystis lukuohia, and has the potential to irreversibly change some native Hawaiian ecosystems.

“I will use the SEED grant and my INBRE research data to apply for additional funds to continue to understand forest ecosystems in Hawaiʻi and how they are changing over time,” she says.

Graham is currently working on building a DNA barcode reference library for arthropods of the Hawaiian Islands. This would generate DNA sequences for the major endemic insects and also the major pest species.

Diagram shows photos of the different spiders, Araneae Diversity: Tetragnathidae, Linyphiidae, Araneidae, Theridiidae, Salticidae, Philodromidae, Thomisidae. The diagram is laid out in a circular progression with the photos of the spiders and the the DNA sequencing in a spiraling color-coded wheel.
Phylogeny of spiders: This diagram shows DNA sequences of spiders sampled from the Pihea trail at Kokeʻe State Park on Kauaʻi. The spider photos, which are representative of Hawaiian Araneae diversity, are from the Hawaiʻi Dimensions in Biodiversity research project, in which Natalie Graham was a contributing researcher when she was a graduate student and then doctoral candidate. (Courtesy of Natalie Graham)

“This DNA reference library will help with my community level analyses as well as ongoing work of others to understand bird and bat diets, and other species interactions,” explains Graham. “For example, I am using DNA sequencing of arthropod communities to capture their biotic associations (species interactions) with plants across spatial, temporal, and disturbance gradients. I am also using environmental DNA (eDNA) sampling as a means to quickly determine species interactions, for example, molecular spider gut content analysis or pollination studies from washing flowers for eDNA.”

Graham is also currently experimenting with how eDNA can be used for rapid assessment of ecosystem health to keep up with fast changing community composition such as invasive species or species turnover, or rapidly changing abiotic (climate) variables.

Research opportunities for students

While actively pursuing her research interests, Graham also teaches genetics (class and lab) for the undergraduate biology program; insect systematics and ecology for both the biology department and the tropical conservation biology and environmental graduate program; and quantitative ecology for the graduate program.

She’s also actively involved in creating research opportunities for her students, mentoring and inspiring them every step of the way.

Natalie and three female students in a forest of trees, one holds a measuring device.
Natalie Graham and students on an excursion collecting data. (Courtesy photo)

While doing her INBRE research on introduced arthropod pest species, she also is creating year-round training opportunities for student interns, a mission of the statewide federally-funded program. “This is a really great way for students to get involved in biomedical and biotechnology projects,” says Graham.

In the summer of 2024, Graham had five student interns working on research projects. Two were visiting students from the University of Trier in Germany, and three were UH Hilo students. Two of the UH Hilo students were paid by the SEED grant to work on that forestry project. One student was from UH Hilo’s Pacific Internship Programs for Exploring Science (PIPES) who investigated eDNA detection of Hylaeus bees in high ultraviolet conditions at Keauhou Bay on the west side of Hawaiʻi Island; the Hylaeus genus is the only native bee genus in Hawaiʻi.

Assistant Professor Graham encourages students who are interested in learning molecular ecology methods to contact her about current research opportunities. She also encourages high school students interested in genetics or entomology to contact her for a tour of the lab “if they want to see a cutting edge facility for genetic research into the biological communities in our backyards.”

Upcoming projects

Graham is planning to expand the DNA reference library to include arthropod taxa on islands across the Indo-Pacific. “I’m working on a Oxford Nanopore Technologies handheld sequencing device pipeline for rapid DNA identification of emerging pest species,” she explains.

She’d also like to start a research entomological collection, a small entomology museum for UH Hilo’s College of Natural and Health Sciences where she is based, that would serve students, the entomology community, and anyone in the public interested in insects and other arthropods, particularly the local fauna from Hawaiʻi Island.

By Susan Enright, a public information specialist for the Office of the Chancellor and editor of Keaohou and UH Hilo Stories. She received her bachelor of arts in English and certificate in women’s studies from UH Hilo.