Navigating boundaries after dam removal

The theme for the 2018 Society for Freshwater Science meeting in Detroit, MI was “navigating boundaries in freshwater science”. A strong contingent of STRIVE lab members presented research that fit well within this theme, ranging from nutrient dynamics in linked reservoir-stream systems (K. Stefanik, R. Czaja), ecological networks (T. Kenly), upstream-downstream connections driven by aquatic insect drift (L. Rieck), urbanization effects on fish (L. Bajakian), cross-boundary effects of invasive species (K. Diesburg), and water quality and aerial insectivorous birds (J. Corra, D. Manning). Congrats to all for a successful and productive meeting! Check out the STRIVE lab twitter feed for action photos and more!

Speaking of navigating boundaries – we are continuing to learn more about the 5th Ave dam removal and how the Olentangy River ecosystem is responding to the removal of this conspicuous upstream-downstream boundary. Our work (and several other dam-removal studies) has previously focused on the importance of restoring upstream-downstream connections within the stream channel (see our blog post from last year, as well as recent article by Cook and Sullivan, below). But, we wanted to know more about how removing the dam could have effects that cross from the river to the riparian zones directly adjacent to the stream channel. To figure this out, we measured a few key responses: one was the number and biomass of aquatic insects that emerged from the river, and another was the spiders and birds (tree swallows) that live near the river and rely on aquatic insects for food. We also measured the chemical signatures (stable isotopes) of the algae and detritus in the river, the emergent insects, and spiders and swallows; these signatures allowed us to piece together the diets of spiders and swallows to understand how much of their food comes from the river, vs. terrestrial sources.

An orb-weaving spider of the family Tetragnathidae. These spiders often live in the margins of rivers, eating emerging aquatic insects. After dam removal, we observed a nearly 10-fold decline in their densities adjacent to the river. Photo: A. Kautza

So what happened to the river after dam removal that crossed aquatic-terrestrial boundaries? Well, mostly we found that the contraction of the river channel, and loss of vegetation at the edge of the river channel was bad news for the spiders (pictured left) – we saw close to a 10-fold decline in spider densities after the dam was removed, particularly where there was extensive floodplain restoration (pictured below).

The other responses we measured were less clear. By and large, spider and swallow diets were unchanged post-dam removal, and the variation we did observe was explained more by regional factors like annual temperatures, precipitation, and the river’s discharge. Nevertheless, we think that navigating across boundaries in this way could be an important aspect of future dam-removal monitoring and restoration efforts, particularly for larger dam-removal projects that prompt drastic changes to river morphology, and functioning.

Looking upstream toward Lane Avenue during extensive riparian restoration of the Olentangy River a few months after dam removal. Photo: SMP Sullivan

For more information, you can read the paper (open access) online:

Sullivan, S. M. P., D. W. P. Manning, and R. P. Davis. 2018. Do the ecological effects of dam removal extend across the aquatic-terrestrial boundary? Ecosphere 9(4):e02180 DOI:10.1002/ecs2.2180.

On the topic of dam removal, also check out another recent paper (also open access) from STRIVE on the ecological effects of dam removal:

Cook, D.R., and S.M.P. Sullivan. 2018. Associations between riffle development and benthic macroinvertebrate and fish assemblages following lowhead dam removal. Environmental Monitoring and Assessment 190: 339.


Looking for talented and motivated post-doctoral researcher – apply by April 27th:

Aquatic Ecology: Closing date: April 27th, 2018. Start date: by July 1st if possible. Salary: $46-48K/annually, plus benefits. The Stream and River Ecology Laboratory ( at The Ohio State University is seeking a Post-Doctoral Research Associate to contribute to an EPA-STAR-funded project on harmful algal blooms in the upper Ohio River Basin. The incumbent will be expected to contribute to studies of the ecological impacts of nutrient enrichment in streams, rivers, and reservoirs (from individuals to food webs to ecosystem functions), including field, experimental (e.g., mesocosms), and lab work. In addition, the incumbent will be expected to assist with the analysis of data as well as the preparation of reports, articles, and associated project deliverables. In addition to contributing to the project described above, the incumbent will be expected to pursue additional, complementary research. The incumbent will be based at the Schiermeier Olentangy River Wetland Research Park ( and will be mentored by Dr. Mažeika Sullivan, with opportunities to work with project co-PIs Dr. Lauren Pintor and Dr. Kaiguang Zhao. Strong statistical and programming skills, preferably with R, are required. Interest in teaching within the Aquatic Sciences curriculum is highly desirable. Applicants must have completed and defended their Ph.D. by the start of the appointment. Interested applicants should submit the following: (1) Cover letter, C.V., and the names and contact information for three references; (2) Unofficial transcripts; and (3) Examples of published work. Funding is available for two years. For more information or to apply, contact Dr. Sullivan @

Newly-funded Project Investigates HABs in the Upper Ohio River Basin

We’re eager to get started on a newly funded, 3-year, ~$700K grant by the U.S. Environmental Protection Agency (EPA), as part of its Science to Achieve Results (STAR) program. Our project focuses on nutrient enrichment and harmful algal blooms (HABs) in Ohio River catchments of Ohio, Kentucky, and Indiana, with a particular focus on non-agricultural freshwaters. This research is in collaboration with Drs. Lauren Pintor and Kai Zhao.

Specifically, we propose to develop a watershed classification system to diagnose and manage harmful algal blooms (HABs) in the upper Ohio River basin. The goal is a multi-scale, hierarchical tool that links climate and land-use with river physicochemical gradients and ecological condition to predict and prevent HABs. The resulting classification system will be presented in a framework that can be used by managers as a regular part of watershed planning and risk assessment efforts to prevent and predict HABs. This management tool represents a novel application of theoretical knowledge of hierarchical processes in watersheds and an innovative approach to predicting and managing HABs.

Conceptual model of relationships to be tested and used to develop multi-scale, hierarchical management tool.

CDC Funds Research on Antibiotic-resistant Bacteria in Rivers

We’re excited to collaborate with project leads Dr. Tom Wittum (OSU Vet Preventative Med) and Dr. Jiyoung Lee (OSU Environmental Health Sciences) on CDC-funded research investigating sources and fates of antibiotic-resistant bacteria in rivers.

In particular, our focus in on carbapenem drugs, which are often the antimicrobial therapy of choice to treat life-threatening invasive gram negative infections. The emergence of carbapenem-resistant Enterobacteriaceae (CRE) represents a critically important threat to public health. CRE are known to emerge in healthcare settings in response to frequent antimicrobial use and disseminate through environments that provide appropriate selection pressure. Our working hypothesis is that waste from metropolitan medical centers regularly transports CRE to wastewater treatment plants where they are maintained and ultimately discharged into surface waters, which may then serve as a reservoir for widespread dissemination of these highly resistant organisms. Study systems include the Scioto and Olentangy Rivers of central and southern Ohio.

Katherine Harris Receives SENR Honors and Undergrad Research Award

The School of Environment & Natural Resources, Honors and Undergraduate Research Program has awarded Katherine Harris funding to support her undergraduate research project. Congrats Kate!

Kate, a member of the Stream and River Ecology (STRIVE) lab and undergraduate student majoring in Environmental Science, is studying stress responses of a common stream fish – Creek Chub (Semotilus atromachulatus; see photo below, by Brian Gratwicke) – to temperature variability of urban streams. Kate will be housing fish and running her experiment in aquatic habitat tanks (see below) in the STRIVE Wetlab at the Olentangy River Wetland Research Park.

Tracking seasonal responses of macroinvertebrate communities after dam removal

There are thousands of dams throughout the rivers of the U.S., and they affect two essential aspects of the way rivers work: the natural flow of the river is disrupted, and the connection of upstream-to-downstream habitats are severed, impeding the movement of fish, macroinvertebrates and other aquatic organisms. However, the number of dams that are being decommissioned and removed is accelerating, and once the dam is gone, river channels and their floodplains are being restored to improve water quality, reconnect upstream and downstream habitats, and return the river to a more natural flow regime. Here in Columbus, the 75-year-old 5th Avenue dam on the Olentangy River (pictured above left) was removed in the fall of 2012, clearing the way for the river channel and floodplain to be restored (right next to Ohio Stadium on the OSU campus, see pictures below). We have been following several ecological responses of the river and its restoration after dam removal. One aspect of the river we tracked was the macroinvertebrate community, which is often used as an indicator of water quality.

Check out our new article about how macroinvertebrate communities responded after the 5th Avenue dam was removed:

Sullivan SMP, Manning DWP. (2017) Seasonally distinct taxonomic and functional shifts in macroinvertebrate communities following dam removal. PeerJ 5:e3189

Abstract: Dam removal is an increasingly popular restoration tool, but our understanding of ecological responses to dam removal over time is still in the early stages. We quantified seasonal benthic macroinvertebrate density, taxonomic composition, and functional traits for three years after lowhead dam removal in three reaches of the Olentangy River (Ohio, USA): two upstream of former dam (one restored, one unrestored), and one downstream of former dam. Macroinvertebrate community density, generic richness, and Shannon–Wiener diversity decreased between ∼9 and ∼15 months after dam removal; all three variables consistently increased thereafter. These threshold responses were dependent on reach location: density and richness increased ∼15 months after removal in upstream reaches versus ∼19 months downstream of the former dam. Initial macroinvertebrate density declines were likely related to seasonality or life-history characteristics, but density increased up to 2.27× from year to year in three out of four seasons (late autumn, early spring, summer) across all reaches. Macroinvertebrate community composition was similar among the three reaches, but differed seasonally based on non-metric multidimensional scaling (NMDS) and analysis of similarity (ANOSIM). Seasonal differences among communities tended to decrease after dam removal. We detected community-wide shifts in functional traits such as multivoltinism, depositional habitat use, burrowing, and collector-gatherer feeding mode. We observed that these traits were expressed most strongly with Chironomidae, which was the most abundant family. Our results suggest that seasonal environmental conditions can play a role in the response and recovery of macroinvertebrate communities—often used to monitor ecosystem condition—following dam removal. In particular, macroinvertebrate density and diversity can show recovery after dam removal, especially in seasons when macroinvertebrate density is typically lowest, with concomitant changes to functional trait abundance. Thus, we recommend scientists and managers consider responses to dam removal throughout the year. Further, similar density, generic richness, and functional traits among reaches suggest that channel restoration after dam removal may initially have equivocal effects on invertebrate communities.

Congrats to Bobby Davis, MSc!

Congrats to Bobby Davis, who recently defended and submitted his MSc thesis: Monitoring fish-community contaminant body burdens following lowhead dam removal in an urban river system. Bobby is now located in Washington, D.C., where he has started his new position with the World Wildlife Fund (WWF) in the aquaculture division of the food team, where he’ll be working on markets-based incentives programs to minimize the environmental impacts of aquaculture operations. Best of luck!

SENR Welcomes Dr. Caryn Vaughn as Fall Seminar Speaker

We’re thrilled to host Dr. Caryn Vaughn, Presidential Professor of Biology and George Lynn Cross Research Professor at the University of Oklahoma.  Dr. Vaughn will be speaking this afternoon as part of our SENR Seminar Series. The title of her talk is: “Consumer Aggregations Act as Hotspots of Ecosystem Services in Rivers”. See announcement here: vaughn-flyer-2

Welcome Dr. Vaughn!

American Alligator in Olentangy River!

There was an American alligator sighted in the Olentangy River on campus yesterday (08/23) and again this morning (08/24). USDA has been notified and the alligator has now been captured (37″, 80 lbs) and will be sent to a sanctuary in South Carolina.
.gator image2 image3
 Photo credits: Kristen Diesburg and Anthony Ignozzi

Contaminant export from rivers regulated by riparian land cover and urban pollution

Check out our new article:

Alberts, J.M., and S.M.P. Sullivan. 2016. Factors influencing aquatic-to-terrestrial contaminant transport to terrestrial arthropod consumers in a mid-size river system. Environmental Pollution 213: 53-62

Research highlights:

  • River contamination decreased with downstream longitudinal distance from a large urban center (see Figure below).
  • Recipient consumer dynamics were influenced by riparian habitat complexity.
  • Contaminant flux via emergent insects was not a strong predictor of terrestrial arthropod body burdens.
  • Terrestrial consumer body burdens were best predicted by riparian land cover.
  • Riparian land cover regulated aquatic-to-terrestrial contaminant transport.

Figure 3b_Alberts and Sullivan_2016_STOTEN