“Paleoartists” attempt to hone their craft and captivate the public even as they grapple with emerging data that alter how we see dinosaurs.
Image credit: Mark Witton.
New Research In
Physical Sciences
Featured Portals
Articles by Topic
Biological Sciences
Featured Portals
Articles by Topic
Edited by David W. Schindler, University of Alberta, Edmonton, Canada, and approved December 12, 2019 (received for review August 6, 2019)
Significance
The annual appearance of massive mayfly swarms is a source of public fascination and spectacular natural phenomenon that plays a key role in regional food webs. Alarming reports of insect declines motivate efforts to uncover long-term and large-scale invertebrate population trends. Monitoring aquatic insect abundance across ecosystems continues to be logistically infeasible, leaving the vulnerability of these communities to intensifying anthropogenic impacts unknown. We apply radar remote sensing to quantify aquatic insect abundance at scales that have been previously impossible, revealing persistent declines in biomass flux from aquatic to terrestrial habitats. As ecological indicators, these losses may signal deterioration in water quality and, if current population trends continue, could cascade to widespread disappearance from some of North America’s largest waterways.
Abstract
Seasonal animal movement among disparate habitats is a fundamental mechanism by which energy, nutrients, and biomass are transported across ecotones. A dramatic example of such exchange is the annual emergence of mayfly swarms from freshwater benthic habitats, but their characterization at macroscales has remained impossible. We analyzed radar observations of mayfly emergence flights to quantify long-term changes in annual biomass transport along the Upper Mississippi River and Western Lake Erie Basin. A single emergence event can produce 87.9 billion mayflies, releasing 3,078.6 tons of biomass into the airspace over several hours, but in recent years, production across both waterways has declined by over 50%. As a primary prey source in aquatic and terrestrial ecosystems, these declines will impact higher trophic levels and environmental nutrient cycling.
Footnotes
- ↵1To whom correspondence may be addressed. Email: p.step{at}nd.edu.
Author contributions: P.M.S. and C.E.W. designed research; P.M.S. performed research; D.M. contributed new reagents/analytic tools; P.M.S. analyzed data; and P.M.S., S.A.E., C.E.W., J.L.T., and J.F.K. wrote the paper.
The authors declare no competing interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.1913598117/-/DCSupplemental.
Published under the PNAS license.
Log in using your username and password
Purchase access
You may purchase access to this article. This will require you to create an account if you don't already have one.
Declines in an abundant aquatic insect, the burrowing mayfly, across major North American waterways
Sign up for Article Alerts
Article Classifications
- Biological Sciences
- Ecology
- Physical Sciences
- Environmental Sciences
Jump to section
You May Also be Interested in
Coral reef bleaching frequently makes headlines, but researchers are still trying to sort out the cellular mechanisms at work.
Image credit: The Ocean Agency/XL Catlin Seaview Survey.
Greenhouse gas emissions in the first decades of the 21st century are likely to affect global sea level for centuries, and limiting long-term sea-level rise might require stringent near-term emission reductions.
Image courtesy of Lucy Reading-Ikkanda (artist).
A single formulation combining two gene therapies treated an array of age-related disorders in mice.
Image courtesy of Pixabay/Sipa.
Many ecosystems in the United States may be vulnerable to increased fire occurrence and frequency caused by invasive grasses.
Image courtesy of Pixabay/Stevepb.