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Located in the wild expanses of southeastern Alaska, the Tongass National Forest (TNF) is one of the largest old-growth temperate rainforests in the world. It stretches across more than 20,000 islands and is renowned for its natural beauty and rich biodiversity. The forest also features thousands of unexplored caves, that is, until today.
The U.S. Army Engineer Research Development Center's (ERDC) Construction Engineering Research Laboratory (CERL) is leading a study alongside the University of Alabama in Huntsville (UAH) and the U.S. Forest Service (USFS) to document cave biodiversity in the TNF and explore how these unique subterranean communities are connected using molecular genetic tools.
“The most exciting part of this project is how we are combining traditional cave surveys with molecular tools, including cutting-edge environmental DNA (eDNA) technology, to generate the first comprehensive assessment of TNF cave biodiversity,” said Dr. Aron Katz, a research biologist at CERL and lead principal investigator on this project. “We can characterize entire subterranean communities by analyzing eDNA - DNA shed by organisms into their environment - in water samples collected from caves and springs, allowing us to identify species that reside in habitats that are otherwise inaccessible to scientists.”
On the ERDC-CERL team, Katz collaborates with research biologist Dylan O'Hearn. Both Katz and O'Hearn work for CERL's Training Lands and Heritage branch. Their team, alongside their partners at UAH and USFS, began the annual surveys in the TNF in the summer of 2022. They have collected thousands of specimens and nearly 200 eDNA samples from 33 caves and numerous springs across seven islands.
“Doing these surveys is really interesting because we're operating at two scales- we're in Alaska, surrounded by huge mountains and forests, travelling long distances by boat, seaplane, or on foot to get to these sites, but then we get there and we're crawling around in this cramped underground environment searching for these really tiny organisms,” O’Hearn shared. “It's a unique experience and one of the best parts is the camaraderie we’ve built by working so hard as a team and hanging out in our off-hours."
The CERL team finds surveying the caves especially exciting because much of the invertebrate diversity remains unknown, and there are likely many species that could be new to science. In addition to these discoveries, the team is collecting genetic data generated from specimens and aquatic eDNA to map cave connections and assess how changes in connectivity can shape patterns of biodiversity in caves.
“These data will not only improve our understanding of present-day cave biodiversity, but also reveal factors influencing habitat connectivity and their impacts on the evolution of cave organisms." Katz said. "These findings, along with the development of new eDNA-based survey tools, will transform the USFS’s ability to survey, manage, and conserve vulnerable cave communities."
Dr. Matthew Niemiller, the principal investigator for UAH on this project, along with graduate students, Jared Higgs and Brendan Cramphorn, are currently working with CERL to identify cave invertebrates and create genetic profiles. These profiles will be used to compare patterns of diversity, infer evolutionary histories, and evaluate habitat connectivity across caves and islands.
“Cave and groundwater ecosystems have historically been poorly studied by biologists compared to ecosystems on the surface. We are discovering, even in more remote areas like TNF, that subterranean habitats are home to a diverse assemblage of organisms, many of which that are new to science or which we know little to nothing about their distributions, life histories, and ecologies,” Niemiller said. “We are beginning to address these knowledge gaps, which impact conservation and management of this unique biodiversity. Cave and groundwater species are ‘out of sight, out of mind’ for most people, yet they provide many important ecosystems services, such as nutrient cycling, biodegradation of contaminants, and water purification.”
Logging, climate change, and the effects of other human activities can have major impacts on subterranean ecosystems, so the USFS is interested in documenting cave biodiversity to inform and improve their karst and forest management efforts
“This research provides us the opportunity to reach some previously unexplored areas with a new objective, to catalog cave invertebrates endemic to the TNF’s vast karst landscapes. TNF is an archipelago of islands with complex geology and glacial history,” said Anna Harris, USFS Tongass Geologist and principal investigator for USFS. “Understanding the nature of these caves and invertebrates will help piece together the evolution of a fragile ecosystem, leading to informed management practices in a rapidly changing climate. For the Tongass Geology office, Christian DeCelle and myself, it has been a richly generative collaboration, and we feel fortunate to benefit from the expertise of this incredible team.”
The main goal of this project is to better understand the composition and connectivity of TNF cave communities, which will inform more effective conservation and management strategies. Additionally, the project aims to improve survey methods for cave biodiversity using eDNA analysis, enhancing the USFS’s and the Army’s ability to conduct more comprehensive, frequent and cost-effective assessments compared to traditional survey approaches.
| Date Taken: | 11.18.2024 |
| Date Posted: | 11.25.2024 13:42 |
| Story ID: | 486063 |
| Location: | ALASKA, US |
| Web Views: | 8 |
| Downloads: | 0 |
This work, ERDC researchers discovering hidden caves in Alaska, by Sophia Espinosa, identified by DVIDS, must comply with the restrictions shown on https://www.dvidshub.net/about/copyright.
