SFS Annual Meeting

5/22/2018  |   09:00 - 09:15   |  410 B

THE COMPLEX RESPONSE OF HIGHLY MODIFIED RIVERS TO ADDITIONAL DRIVERS OF CHANGE Large rivers and their floodplains are among the most productive ecosystems, globally, yet are the ecosystem most affected by humans. Few studies explicitly explore multiple anthropogenic drivers in large river systems. To improve our knowledge of the influence of anthropogenic drivers in large rivers, we need to investigate ecosystem response at broad spatial and temporal scales, whereas most studies focus on single drivers and small scales. Our study uses a nearly 60-year, river-wide dataset to determine if fish diversity in the Illinois River (ILR; Illinois, USA) changed in response to two major, system-wide anthropogenic drivers: policy-based water quality improvements (principally the Federal Water Pollution Control Act [FWPCA, ca. 1948] and the Clean Water Act [CWA, ca. 1972]) and invasion by bigheaded carps (BHC, ca. 2000; i.e., silver carp Hypophthalmichthys molitrix and bighead carp H. nobilis). We analyzed diversity changes for the entire river system, between distinct geomorphic zones, and among functional feeding guilds. Although the response was complex, overall, fish diversity increased substantially in the whole river, and the upper and lower river, and several FFGs displayed diversity increases more impressive than the combined group.

Jason DeBoer (Primary Presenter/Author), Illinois Natural History Survey, Illinois River Biological Station, jadeboer@illinois.edu;


Martin Thoms (Co-Presenter/Co-Author), University of New England, Armidale, NSW Australia, mthoms2@une.edu.au;


Michael Delong (Co-Presenter/Co-Author), Winnona State University, MDelong@winona.edu ;


Andrew Casper (Co-Presenter/Co-Author), Illinois Natural History Survey, afcasper@illinois.edu;


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5/22/2018  |   09:15 - 09:30   |  410 B

SHORT-TERM STREAM RESPONSES TO HURRICANE HARVEY ALONG AN ARIDITY GRADIENT Global change models predict that the frequency and intensity of weather driven disturbances will increase. At the same time, long-term average precipitation and temperature regimes are also shifting. We can use a space for time approach along natural climate gradients to enhance our understanding of how these simultaneous changes will affect the structure and function of stream ecosystems. Here we report on community and ecosystem responses of streams to Hurricane Harvey along a natural mean precipitation gradient. Ecosystem metabolism, water chemistry and nutrients, invertebrate and fish community composition and abundance were measured before and after the storm in streams receiving average annual precipitation ranging from 55 cm/yr to 110 cm/yr. Across the gradient, we observed a pattern of disturbance followed by rapid recovery, with metabolism returning to normal levels within weeks and communities recovering within several months. Long-term precipitation regime had the largest effect on mobilization of nutrients and dissolved organic carbon immediately after the storm, with the highest increases in concentration in the more arid streams.

Christopher Patrick (Primary Presenter/Author), Virginia Institute of Marine Science (VIMS), cpatrick@vims.edu;


James Hogan (Co-Presenter/Co-Author), Texas A&M University – Corpus Christi, james.hogan@tamucc.edu;


Brandi Kiel Reese (Co-Presenter/Co-Author), Texas A&M University Corpus Christi, Brandi.Reese@tamucc.edu ;


Fernando Carvallo (Co-Presenter/Co-Author), Texas A&M University–Corpus Christi, fcarvallo@islander.tamucc.edu ;


Darcy Gonzalez (Co-Presenter/Co-Author), Texas A&M University–Corpus Christi, marinescientist19@outlook.com ;


Sean Kinard (Co-Presenter/Co-Author), Virginia Institute of Marine Science, s2kinard@gmail.com;


Jacob Hosen (Co-Presenter/Co-Author), Purdue University, jhosen@purdue.edu;


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5/22/2018  |   09:30 - 09:45   |  410 B

THE EFFECTS OF ECOSYSTEM DISTURBANCE REGIMES ON COMMUNITY AND LANDSCAPE BIODIVERSITY IN SOUTHEASTERN MASSACHUSETTS HEADWATER STREAMS Streams are dynamic systems shaped by geographic location, hydrology, riparian vegetation, and in-stream habitat. Furthermore, ecosystem disturbance plays a major role in structuring stream communities and ecosystem processes. Disturbances include flooding, drought, and fire events as well as anthropogenic disturbances such as land use changes, damming, and pollution. Agricultural use constitutes a press disturbance regime, homogenizing the surrounding landscape and simplifying in-stream habitat, leaving legacy effects after farming ceases. Active restoration is intended to ameliorate these effects by reintroducing variation, with the goal of shifting the ecosystem into a more diverse and natural state, thereby acting as a pulse disturbance. In our study, we used a Before-After-Control-Impact (BACI) design to investigate the effects of disturbance regimes on structural, compositional, and functional attributes of macroinvertebrate and habitat/ecosystem biodiversity in a least-impacted stream system, an active flow-through cranberry bog system, and a restored flow-through cranberry bog system in Southeastern Massachusetts from 2014-2017. Overall, we expected a compositional shift in the restored treatment away from the active cranberry bog and towards the least disturbed system, however, the restored treatment is likely to achieve an alternative stable state, at least in the immediate future.

Alan Christian (Co-Presenter/Co-Author), University of Massachusetts Boston, alan.christian@umb.edu;


Sean McCanty (Primary Presenter/Author), University of Massachusetts Boston, seanmccanty@gmail.com;


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5/22/2018  |   09:45 - 10:00   |  410 B

SHORT-TERM IMPACTS OF HURRICANES IRMA AND MARIA ON TROPICAL STREAM CHEMISTRY AS MEASURED BY IN-SITU SENSORS High intensity hurricanes have been shown to alter topical forest productivity and stream chemistry at time scales of years to decades in the montane rain forest of Puerto Rico. Here we report the short-term impacts of Hurricanes Irma and Maria on the chemistry of Quebrada Sonadora using 15-minute sensor records and long-term weekly sampling that spans 34 years. Turbidity increased dramatically during Maria as expected. Contrary to our expectations, we found that solute-flow behavior changed with the advent of the storms. Specific conductance showed a dilution response to flow before the storms but changed to enrichment a month after Maria. Nitrate was unresponsive to flow before the hurricanes but large increases in concentration occurred at high flow for months after the hurricanes. The high frequency sensors are providing new insights into the response of this ecosystem in the days and weeks following two major disturbance events. The flipping of nitrate response to storms, from source limited to transport limited, suggests that these two severe hurricanes have fundamentally altered the nitrogen cycle at the site in ways that would not be evident without sensors.

William H McDowell (Primary Presenter/Author), University of New Hampshire, bill.mcdowell@unh.edu;


Jody Potter (Co-Presenter/Co-Author), University of New Hampshire, jody.potter@unh.edu;


Carla López-Lloreda (Co-Presenter/Co-Author), Virginia Tech, carla.lpez09@gmail.com;


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5/22/2018  |   10:00 - 10:15   |  410 B

URBAN STREAMS AND THEIR RESPONSE TO EXTREME WEATHER EVENTS: DROUGHT AND HURRICANE IMPACTS ON STREAM BIOTA, PUERTO RICO Global change is increasing the frequency of intense climatic events in the Caribbean. Puerto Rico experienced one major drought and two large hurricanes in the past years. The 2015 drought was the most severe drought in the last 50 years. Hurricanes Irma and Maria hit the island during 2017, both as major hurricanes. While hurricanes and tropical storms often affect Puerto Rico, direct hits by major hurricanes occur once every 21 years. Here we assess and contrast the effects of drought and hurricane disturbance on macroinvertebrate and fish assemblages in the Rio Piedras watershed, Metropolitan San Juan. Composition of both assemblages changed in response to drought. Exotic fishes were able to establish after the drought. In contrast, only macroinvertebrate abundance responded strongly to hurricane disturbance. Both disturbances have major effects on stream ecosystems. However, drought had more negative impacts on the ecosystem by allowing the establishment of introduced species. Hurricane impacts are large, but similar than more frequent storms and local fauna might be preadapted to those impacts. Thus, the predicted increase in drought frequency might be of larger concern for urban streams than hurricanes.

Alonso Ramírez (Primary Presenter/Author), North Carolina State University, alonso.ramirez@ncsu.edu;


Pablo Gutiérrez-Fonseca (Co-Presenter/Co-Author), University of Costa Rica, pabloe.gutierrezfonseca@gmail.com;


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5/22/2018  |   10:15 - 10:30   |  410 B

HURRICANE IMPACTS TO A TROPICAL STREAM ECOSYSTEM IN THE MOUNTAINS OF PUERTO RICO. Tropical ecosystems are subject to a variety of natural disturbances, with hurricanes among the most extreme. While the importance of hurricanes in structuring terrestrial environments is widely acknowledged, impacts on stream ecosystems are less understood. During 2017, Puerto Rico was impacted by two major Hurricanes (Irma and Maria, both category 4) resulting in major damage to forest and stream ecosystems. In this study, we use our ongoing research, as well as our long-term data sets (2009-2017), to assess hurricane impacts upon a second-order stream draining the El Yunque National Forest. Hurricanes significantly reduced canopy cover over the stream. Hurricanes caused a short-lived input of leaf-litter fall, 8-fold the long-term average. Organic biofilm (AFDM) and chlorophyll-a barely responded to post-hurricane increased light availability, suggesting that consumers or disturbance control primary productivity. Macroinvertebrate assemblages were severely impacted, with scrapers being favored by the limited response in algae after the hurricanes. Finally, shrimps showed only slight responses to the changes in the ecosystem. Our results highlight the dramatic effects of hurricanes on tropical streams, which serves to underline the need for long-term data to understand how stream ecosystems respond to unpredictable extreme events.

Pablo E. Gutiérrez-Fonseca (Primary Presenter/Author), University of Costa Rica, pabloe.gutierrezfonseca@gmail.com;


Alonso Ramírez (Co-Presenter/Co-Author), North Carolina State University, alonso.ramirez@ncsu.edu;


Catherine Pringle (Co-Presenter/Co-Author), Odum School of Ecology, University of Georgia, cpringle@uga.edu;


Pedro J Torres (Co-Presenter/Co-Author), Odum School of Ecology, University of Georgia, torresp@denison.edu;


Alan Covich (Co-Presenter/Co-Author), Odum School of Ecology, University of Georgia, a.covich@gmail.com;


William H McDowell (Co-Presenter/Co-Author), University of New Hampshire, bill.mcdowell@unh.edu;


Todd Crowl (Co-Presenter/Co-Author), Florida International University, facrowl@gmail.com;


Omar Perez-Reyes (Co-Presenter/Co-Author), Department of Environmental Sciences, University of Puerto Rico, omar.perez@upr.edu;


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