Net-spinning caddisfly distribution in large regulated rivers
September 20, 2020
- Most of the world's large rivers are dammed for the purposes of water storage, flood control, and power production. Damming rivers fundamentally alters water temperature and flows in tailwater ecosystems, which in turn affects the presence and abundance of downstream biota.
- We collaborated with more than 200 citizen scientists to collect 2,194 light trap samples across 2 years and more than 2,000 river km. Samples contained 16,222 net‐spinning caddisfly (Hydropsyche) individuals across six species. We used these data to model the distribution of Hydropsyche throughout the Colorado River Basin in the western U.S.A. to identify the roles of water temperature, flows, and species‐specific morphology in determining aquatic species distributions throughout a large arid watershed that has been heavily altered by damming.
- We predicted that water temperatures would determine Hydropsyche presence and abundance to a greater extent than diel variation in river stage associated with hydropower production. Among many species, adult female Hydropsychids are morphologically adapted to swim to deep‐water oviposition sites. We predicted that the presence of this ability would negate the otherwise deleterious effects of high stage change on caddisfly egg mortality.
- We found that distributions of the two most widespread species, Hydropsyche occidentalis and Hydropsyche oslari (92% of total Hydropsyche captured), were both predicted by water temperatures. However, we also found that the abundance of H. oslari decreased by as much as 10‐fold as diel stage change increased, despite the presence of female morphological adaptations for deep‐water oviposition. We found sexual dimorphism and evidence for deep‐water swimming adaptations in 5/6 species.
- Our results show that net‐spinning caddisflies have species‐specific responses to environmental variation and suggest that environmental flows designed to reduce diel stage change and destabilise water temperatures may improve habitat quality for these ubiquitous and important aquatic insects.
Citation Information
| Publication Year | 2021 |
|---|---|
| Title | Net-spinning caddisfly distribution in large regulated rivers |
| DOI | 10.1111/fwb.13617 |
| Authors | Anya Metcalfe, Jeffrey Muehlbauer, Theodore Kennedy, Charles Yackulic, Kimberly L. Dibble, Jane C. Marks |
| Publication Type | Article |
| Publication Subtype | Journal Article |
| Series Title | Freshwater Biology |
| Index ID | 70214567 |
| Record Source | USGS Publications Warehouse |
| USGS Organization | Southwest Biological Science Center |
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Adult net-spinning caddisfly (Hydropsyche spp.) catch rates and morphology from large rivers of the southwestern United States, 2015-2016
These data describe the distribution and abundance of Hydropsyche, a widespread and diverse genus of net-spinning caddisflies, in the Colorado River Basin. Abundance data, measured as catch rates, were collected by citizen scientists using light traps. We subsampled Hydropsyche spp. from light trap samples collected throughout the Colorado River Basin and measured the lengths and widths of mesotho
Charles B Yackulic, Ph.D.
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Research Statistician
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Related Content
Adult net-spinning caddisfly (Hydropsyche spp.) catch rates and morphology from large rivers of the southwestern United States, 2015-2016
These data describe the distribution and abundance of Hydropsyche, a widespread and diverse genus of net-spinning caddisflies, in the Colorado River Basin. Abundance data, measured as catch rates, were collected by citizen scientists using light traps. We subsampled Hydropsyche spp. from light trap samples collected throughout the Colorado River Basin and measured the lengths and widths of mesotho
Charles B Yackulic, Ph.D.
Research Statistician
Research Statistician
Email
Phone