New Article in Science of the Total Environment: “Multiple urban stressors drive fish-based ecological networks in streams of Columbus, Ohio, USA”

Using one of our long-term datasets on stream water quality and fish assemblages in and around the metropolitan area of Columbus, OH, we examined the additive, synergistic, and antagonistic effects of multiple urban stressors on fish-based ecological networks. Both unweighted (simple node-link network topology) and bio-mass weighted (species links are weighted by biomass) networks were employed to generate the network indices: linkage density (average number of links per species), connectance (fraction of all possible links realized in a network), and compartmentalization (degree to which networks contain discrete sub-webs), mean link weight (the magnitude of trophic interactions among species in a network), and strength standard deviation (the distribution of total magnitude of all trophic interactions per species in a network). Urban stressors (sedimentation, percent impervious surface, and nutrient concentrations) and stream size (covariate) were used to predict variation network indices. While stream size was an important covariate, sedimentation had strong negative relationships with all network indices. Synergistic effects on network topology were realized through decreased sedimentation and increased stream size, while antagonistic effects emerged from interactions between sedimentation and percent impervious surface and between percent impervious surface and nutrient concentrations on mean link weight. Our results highlight the importance of studying multiple urban stressors simultaneously as they can and do interact in nature.

For access to the full article, please see the Publications page.

New article in Science: “Distorting science, putting water at risk”

Our policy piece tackles a pressing environmental issue: water protection. We examine the science and the law behind the recently finalized Navigable Waters Protection Rule, which removes protections for millions of miles of streams and acres of wetlands in the US. These streams and wetlands are vital ecosystems that both directly and indirectly provide a range of ecosystem services, including providing drinking water, reducing floods, and generating billions of dollars to the US economy. This new rule is based on questionable legal choices and is highly inconsistent with the best available science on water and watersheds, and in particular on how connections between waters are critical for their function. The result: a major rollback in environmental protections that has the potential to cause widespread and long-lasting harm to US waters.

For access to the full article, please see the Publications page.

See below for some of the media coverage on this:

A watershed moment for U.S. water quality

New Rule Threatens Environment, Puts U.S. Waters at Risk

Working with Couer d’Alene Tribe on Water Resources and Water Rights

Indigenous peoples that live in the area now known as the Northwestern US have relied on water resources for physical, cultural, and spiritual sustenance since time immemorial. Hunting, gathering, and fishing are central subsistence activities of the Couer d’Alene Tribe (Schitsu’umsh), whose homeland spanned ~3.5 million acres in present-day northern Idaho, eastern Washington and western Montana. The Lake Couer d’Alene Basin was at the heart of their homeland. Today, the CdA Reservation is a fraction of that their homeland.

Having recently returned from over a month on the CdA Reservation – working with the CdA Tribe on issues related to water quantity and water rights – I have a renewed appreciation for the history of the CdA people, their intimate relationship with the landscape, and the role science can play in environmental-justice issues.

Non-floodplain Wetland

Working in an off-channel wetland.

Floodplain Wetland

Fish Weir on Stream

Fringing Wetland, Lake Couer d’Alene

Freshwater Science’s BRIDGES features aquatic-terrestrial linkages

It’s been a while since our last post. We have a lot of news to report, so please tune-in for upcoming updates!

To start, I’d like highlight the recent Freshwater Science BRIDGES cluster of papers (Volume 38 • Issue 4 • 917-954, December 2019) that featured our work on how ecological networks can enhance understanding of aquatic-terrestrial linkages and inform conservation and management of linked aquatic-riparian ecosystems. Also check out neat companion papers by our colleagues Johanna Kraus (USGS), Jeff Wesner (USD) and Jeff Muehlbauer (USGS).

See the 1-page fact sheet summarizing the papers here:

Kraus et al 2019 BRIDGES 1-pager

Congrats to Leslie Rieck, Ph.D.!

A big congratulations to Leslie Rieck, who successfully defended her dissertation: “Associations Between Hydrogeomorphic Characteristics and Biotic Community Dynamics in Urban Streams of Columbus, Ohio, USA” earlier today (June 27, 2019). Leslie’s research addresses urbanization of watersheds and how altered fluvial geomorphic processes and channel structure relate to macroinvertebrate drift, fish assemblages and stream-riparian food webs. Leslie will start a post-doc at Lycoming College in PA later this summer.

Society for Freshwater Science hosts special webinar on proposed WOTUS Rule

REMINDER: Please join us for the SFS-sponsored webinar:

Waters of the US (WOTUS) Proposed Rule: Overview and Action Steps

Efforts by the Trump administration are underway to roll back our nation’s Clean Water Act protections. The newly proposed rule revises the definition of Waters of the United States (WOTUS) and aims to exclude thousands of miles of streams and millions of acres of wetlands that are critical
to freshwater resources.

Join us for an informative and timely overview of the proposed WOTUS rule, the science that contradicts it, and how to submit an effective regulatory comment.

Dr. Mažeika Sullivan will lead this SFS-sponsored webinar open to the first 500 interested attendees at 2 P.M. ET on Monday, April 1st.

Click to Join the Webinar at 2 PM ET on April 1st
Dr. Mažeika Sullivan is an Associate Professor in the School of Environment and Natural Resources at The Ohio State University (OSU) and the Director of the Ramsar-designated Shiermeier Olentangy River Wetland Research Park. He received a B.A. in Anthropology from Dartmouth College, and earned his M.S. in Biology and Ph.D. in Natural Resources from the University of Vermont. Subsequently, he was a Postdoctoral Research Fellow at the University of Idaho before joining the OSU faculty in 2008. Dr. Sullivan’s research focuses on water quality and aquatic ecosystems, where his work integrates community and ecosystem ecology, fluvial geomorphology, and biogeochemistry. He is particularly interested in understanding natural and human drivers of biodiversity, community organization, and ecosystem function, and in using basic science to inform conservation and restoration efforts. Dr. Sullivan has published >50 peer-reviewed scientific publications. Dr. Sullivan also served as a member of the US EPA’s Science Advisory Board “Connectivity of Streams and Wetlands to Downstream Waters” Panel (2013-2014), has reviewed for over 30 ecological and environmental journals, and is an active member of the Society for Freshwater Science, American Fisheries Society, and the Ecological Society of America. Dr. Sullivan is a Distinguished University Teacher and served as a Fulbright Distinguished Chair of Biodiversity and Sustainable Development (Colombia, 2014-2015). His research has been funded by several sources, including the NSF, CDC, US Fish & Wildlife Service, Bureau of Land Management, US EPA, Ohio Department of Transportation, and the Ohio Division of Natural Resources.

Aquatic macroinvertebrate communities respond to riparian insect invader

Check out our new article about how a terrestrial invasive species shifts aquatic macroinvertebrate communities! You can read it here


Diesburg KM, SMP Sullivan, DWP Manning. 2018. Changes in benthic invertebrate communities of central Appalachian streams attributed to hemlock woolly adelgid invasion. Aquatic Sciences 81:11


Eastern hemlock trees (Tsuga canadensis [L.] Carr.) often dominate riparian vegetation of central Appalachian headwater streams, and the invasive hemlock woolly adelgid (Adelges tsugae Annand; HWA) has decimated hemlock stands in this region. Although research concerning HWA impacts on soil, hydrology, and forest structure is emerging, associated changes in stream structure and function are not as well documented. We quantified HWA-invasion effects on benthic macroinvertebrate communities in 21 headwater streams across Ohio, West Virginia, and Virginia (USA) representing unimpacted, moderate invasion, and severe invasion, respectively. We observed differences in benthic macroinvertebrate community composition; severely invaded sites exhibited the highest diversity, whereas moderate sites had the lowest diversity. The composition of macroinvertebrate functional feeding groups exhibited shifts as well. For example, the relative abundance of herbivorous invertebrates increased from 4% (± 3%) at unimpacted sites to 23% (± 14%) at severely impacted sites. Changes in macroinvertebrate density, diversity, and functional-group composition were associated with sediment grainsize distribution (proportion bedrock and D84), large-wood characteristics (volume and density), and nutrient concentrations (PO4 and NH4). Our results suggest that in-stream physical and chemical alterations associated with HWA-invasion and subsequent hemlock decline are associated with changes in stream invertebrate diversity and trophic relationships. We demonstrate how a pervasive terrestrial invader can influence in-stream biotic communities.

Joe Corra defends MSc thesis on aerial insectivorous birds, climate, and water quality in urbanizing landscapes

STRIVE Lab MSc candidate Joe Corra presented his research the relationships among water quality, climate, and aerial insectivorous birds, and how urbanization shapes those relationships. Aerial insectivorous birds – swallows, swifts, nightjars, and flycatchers – have experienced alarming declines in North America in recent decades. Declines have occurred across this diverse guild, suggesting that the availability and quality of insect prey is a common factor. Emergent aquatic insects constitute an important prey resource for many aerial insectivorous birds, and thereby connect riparian aerial insectivores to aquatic ecosystems. For his research, Joe used the Tree Swallow (Tachycineta bicolor) to investigate the associations between aerial insectivorous birds and urbanization, climate, and water quality. Building on the research launched by the STRIVE lab in 2014, he evaluated Tree Swallow reproductive success, body condition, and trophic dynamics at seven river-riparian sites representing urban and natural/protected land use in greater Columbus, Ohio over four consecutive breeding seasons (2014-2017).

Findings: Urban sites were associated with earlier clutch initiation in the spring – urban Tree Swallows laid their eggs one week earlier than their non-urban counterparts. In addition, urban-breeding swallows had greater fledging success, with urban nests producing 1.4 more fledglings, on average, than sites in natural/protected landscapes. Body burdens of mercury were higher among nestlings at urban sites but exhibited strong interannual variability. A gradient of stream urbanization was related to greater dietary reliance by Tree Swallows on aquatic insects and aquatically-derived energy; further, urban swallows fed at higher trophic levels than did swallows at natural/protected sites.

Investigation of potential drivers suggested that multiple features of the urban environment, including higher mean temperatures, increased availability of high-quality aquatic insect prey, and fewer days of extreme cold may contribute to fledging success and influence the timing of Tree Swallow breeding in urban areas. Further, stream urbanization was related to increased reliance on aquatic resources and higher trophic position, highlighting the role of aquatic-terrestrial connectivity in urban areas. However, the potential risk from elevated aquatic contaminants in urban areas represents a potentially adverse impact for urban-breeding aerial insectivores. Overall, this research underscores the importance of water quality for terrestrial wildlife, and the results draw attention to the potential role for cities in the conservation of aerial insectivorous birds.

Adult Tree Swallow.

Joe banding a Tree Swallow.

Relationship between Urban Stream Index and Tree Swallow Trophic Position (nestlings: p < 0.0001; adults: p = 0.001).

This research was funded by the Ohio Division of Wildlife through the Ohio Biodiversity Conservation Partnership, The Columbus Zoo & Aquarium, and the National Science Foundation.

STRIVE Lab and GrayFishLab Recruiting Post-doc, Grad Students for ALAN Research

With new funding from the Ohio Department of Transportation, we’re looking for a motivated post-doc, as well as MSc, and PhD students to join our research groups. See below for details! Post-docs applicants apply by Jan. 04, 2019; Grad Student applicants apply by Jan. 01, 2019.

Aquatic Ecology – Artificial Lighting at Night: Closing date: Jan. 04, 2019. Start date: by March 1st if possible. Salary: $48-50K/annually, plus benefits. The Stream and River Ecology Laboratory at The Ohio State University is seeking a Post-Doctoral Research Associate. The incumbent will be expected to contribute to research on the ecological effects of artificial lighting at night (ALAN) in aquatic and riparian ecosystems (from individuals to ecosystems), including field, experimental (e.g., mesocosms), and lab work. In addition, the s/he will be expected to assist with the analysis of data as well as the preparation of reports, articles, and associated project deliverables. 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-PI Dr. Suzanne Gray. Strong statistical and programming skills, preferably with R, are required. Interest in gaining teaching experience 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 @

PhD position – ALAN 2018-final-ssfr2f

Also check out our previous and current work on ALAN under Projects.

Levon B. defends honor’s thesis on effects of urban stream temperatures on stream fish

After a couple years of hard field and lab work, STRIVE undergrad Levon Bajakian presented his honor’s research on the influences of urban stream temperatures on stream fish. Levon ran two lab trials to quantify the effects of both temperature variability (Trial 1) and consistently elevated temperatures (Trial 2) on Creek Chub, a common stream fish.

Creek Chub (Semotilus atromaculatus)
Photo: Brian Zimmerman

What did he find:
Creek Chub in the Trial 1 treatment group gained more weight and had lower blood plasma glucose concentrations (used as a measure of stress) than the control group, while Creek Chub in the Trial 2 treatment group showed no significant difference in weight compared to the control treatment, but the treatment group had significantly higher blood glucose concentrations. A stress response in a tolerant species like Creek Chub could potentially translate to severe impacts for more sensitive fish species as even minor increases in chronic stress caused by heat or other factors can have substantial consequences for wild fish. Altered temperature regimes are also likely to interact with other urban stressors on streams (e.g., pollution, altered hydrology and stream geomorphology, etc.), and will be an important area of future research.

Levon’s research complements ongoing research on the effects of urbanization on stream and wetland ecosystems. Here, Levon is working in the field filtering water samples, along with a little help from mi hijita Adela Lucía!

Levon shared a few thoughts on his research experience:
Completing my honors thesis has been one of the most challenging and rewarding experiences of my undergraduate career. I believe my time with Dr. Sullivan and the rest of STRIVE lab has helped me grow and develop both as a student and as a person, and I feel more prepared for life after graduation as a result. Needless to say, I am incredibly grateful to have been granted the opportunity to conduct research and explore my interests regarding urban stream temperatures and fish, and I would certainly recommend considering research to anyone else who might be interested!

Levon – thanks for all your great work and contributions to our research! Congrats on an excellent presentation, thesis, and your upcoming graduation. We all look forward to seeing where your talents take you in the coming years.