SFS Annual Meeting

5/20/2019  |   14:00 - 14:15   |  254 B

PREDICTING HYDROLOGIC DISTURBANCE OF STREAMS USING SPECIES OCCURRENCE DATA Rapid landscape change coupled with a growing human demand for surface and groundwater have altered natural flow regimes of many rivers and streams on a global scale. Using a machine learning approach and long-term, georeferenced species occurrence data compiled by the USGS Aquatic Gap and state agencies, we modeled and mapped spatial patterns of hydrologic disturbance for streams in Arkansas, Missouri, and eastern Oklahoma. Fish presence/absence data had a similar overall model prediction accuracy of 77% (95% CI: 0.74, 0.80) as flow variables 76% (CI: 0.73, 0.80). Including topographic variables in the fish model increased the RF prediction accuracy to 90% (CI: 0.88, 0.92) compared to 86% (CI: 0.84, 0.89) for flow metrics. Correlation analysis of HDI by flow regime showed groundwater stable streams had the lowest disturbance frequency, with over 50% of stream reaches with low HDI located in forested land cover. HDI was highest for big rivers and intermittent runoff streams and streams associated with agricultural land use. Our results show that long-term georeferenced biological data can provide a valuable resource for predictive modeling of hydrologic disturbance for ungaged rivers and streams.

Daniel Magoulick (Primary Presenter/Author), Arkansas Cooperative Fish and Wildlife Research Unit, University of Arkansas, danmag@uark.edu;


J. Tyler Fox (Co-Presenter/Co-Author), Arkansas Cooperative Fish and Wildlife Research Unit, University of Arkansas, jtfox@uark.edu;


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5/20/2019  |   14:15 - 14:30   |  254 B

THE EFFECT OF EXTREME FLOOD EVENTS ON LARGE LAKES: ZOOPLANKTON COMMUNITY DYNAMICS IN LAKE CHAMPLAIN Lake Champlain experienced two major flood events in 2011: a record spring flood and a major Fall rain event. In this study, we assessed zooplankton community responses to major flooding a large lake. Responses were species specific including flood adapted, tolerant, or intolerant population impacts. We observed major shifts in community composition associated with flooding in 2011. Density patterns varied from reduced density (e.g, Daphnia retrocurva), to a neutral response (e.g., Diacyclops thomasi), to increased density (e.g., Ceriodaphnia spp.). The timing of responses varied by group. In rotifers, early (June) seasonality patterns were not impacted but population effects were observed in the summer (August-September). Taxa that increased or did not respond may be considered flood-adapted or flood tolerant. Lake Champlain zooplankton responses to 2011 flood events suggest that increased flooding under future climate change scenarios may have predictable impacts on large lake systems.

Timothy Mihuc (Primary Presenter/Author), SUNY Plattsburgh, mihuctb@plattsburgh.edu;


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5/20/2019  |   14:30 - 14:45   |  254 B

EFFECTS OF EXTENDED DROUGHT AND SUBSEQUENT FLOODING ON NUTRIENT DYNAMICS IN PRAIRE STREAMS Drought and flooding represent the dominant drivers of disturbance in intermittent streams. Effects of these drivers will be important to understand in the Great Plains, where drought risk and severity are expected to increase with climate change. Increases in drought severity may lead to longer dry periods in intermittent streams and intermittent conditions in streams that have historically been perennial. We used long-term water chemistry and discharge data measured on Konza Prairie Biological Station, Kansas, USA to examine effects of drought and rewetting on nutrient (C, N, and P) concentrations and export in prairie streams ranging from second- to fifth-order. There is a strong relationship between stream discharge and nutrient export, but the number of dry days preceding each flow event has small effect on nutrients compared to the magnitude of flow after drought. However, the effect of extended drought on nutrient export becomes greater in low-order drainages. These results suggest increased drought will affect nutrient export by headwater streams more than nutrient export by larger-order streams. This is likely due to more terrestrial influence in headwaters, and less processing time of terrestrial inputs in freshwater environments.

James Guinnip (Primary Presenter/Author), Kansas State University, jguinnip@ksu.edu;


Walter Dodds (Co-Presenter/Co-Author), Kansas State University, wkdodds@ksu.edu;


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5/20/2019  |   14:45 - 15:00   |  254 B

IMPLEMENTATION OF A MUTI-PARTNER, COLLABORATIVE EFFORT TO MANAGE AND MONITOR POST-FIRE WATER QUALITY IN A LARGE NORTHERN CALIFORNIA LAKE. During summer 2018 the Mendocino Complex wildfire burned over 450,000 acres, geographically the largest fire in California’s post-settlement history. The burn scar was mostly located within the upper watershed of Clear Lake, a 303(d) listed nutrient impaired waterbody in Lake County and the state’s largest freshwater lake. Not only is Clear Lake home to sensitive floral and faunal species and supports traditional Native American uses, but Clear Lake provides drinking water to 40,000 residents and activities such as fishing and recreational boating generate substantial tourism dollars. A multi-partner, interagency collaborative post-fire action plan was immediately implemented to identify 1) locations most likely to contribute post-fire pollutant and sediment loads 2) locations most likely to benefit from on-the-ground best management practices to limit post-fire impacts and, 3) best stream and lake sample sites to monitor post-fire water quality. This paper will discuss development of this effort, specific actions implemented, outcomes, and status of Clear Lake. Conclusions from this effort might be useful to organizations and agencies when partnering and collaborating on management and monitoring in freshwater systems with large or impaired waterbodies, of which current post-fire water quality research is limited.

Angela De Palma-Dow (Primary Presenter/Author), Lake County Water Resources Department, Adepalmadow@gmail.com;


Sarah Ryan (Co-Presenter/Co-Author), Big Valley Band of Pomo Indians EPA , sryan@big-valley.net;


Richard Muhl (Co-Presenter/Co-Author), California Regional Water Quality Control Board, Richard.Muhl@waterboards.ca.gov;


Greg Dills (Co-Presenter/Co-Author), Lake County Resource Conservation District , lakecountntyrcds@gmail.com;


Amy Little (Co-Presenter/Co-Author), State Water Resources Control Board Division of Drinking Water , Amy.Little@waterboards.ca.gov;


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5/20/2019  |   15:00 - 15:15   |  254 B

HURRICANE DISTURBANCE DRIVES TROPHIC CHANGES IN NEOTROPICAL MOUNTAIN STREAMS IN PUERTO RICO Hurricanes dominate the disturbance regime of many tropical ecosystems. While the impact of these disturbances on terrestrial environments has been well studied, their effects on stream ecosystems are less understood. Here, we quantified the response of the stream food web to two major hurricanes (Irma and Maria, both category 4) that hit Puerto Rico in September 2017. We assessed changes in basal resources (i.e., algal periphyton and leaflitter) and Layman’s community-wide metrics using the isotopic composition of 13C and 15N. Basal resources, macroinvertebrates (from different trophic levels) and terrestrial predators were sampled in two second order streams before (Feb-2017), immediately after (Nov-2017) and 9mo after (June-2019) the hurricanes. Both streams were heavily shaded pre-hurricanes. Post-hurricanes, periphyton contribution increased for most consumers that had previously fed on leaflitter. Indices of community-wide metrics were low, indicating decreased trophic diversity 2mo post-hurricanes. Our study showed that hurricanes change the trophic base from allochthonous to autochthonous resources via changes in the physical environment (canopy damage). Findings are fundamental to our understanding of the impact of these extreme events, which will be more severe and frequent according to climate change predictions.

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;


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5/20/2019  |   15:15 - 15:30   |  254 B

THERMAL LIMITS AND RESILIENCE OF HYDROPSYCHIDAE IN FIRE-AFFECTED ARID SOUTHWESTERN STREAMS Landscape disturbances of wildfire can have dramatic effects on the thermal regime of aquatic systems. Aquatic ectotherms must cope with thermal variability as habitat temperatures are repeatedly modified by indirect fire effects that include overland flow, flood pulses, and heavy sediment loads that alter stream morphology and water quality. In 2011, the Las Conchas wildfire burned one-third of the Valles Caldera National Preserve in northern New Mexico. Streams within the Preserve were differentially affected with some exhibiting continued channel alteration, turbidity, and highly variable temperature regimes seven years post-fire. The objective of this research was to characterize the effects of disturbance-altered thermal regime on larval Hydropsyche oslari growth. Preliminary results suggest that chronically-altered streams yield reduced H. oslari biomass and affect timing of emergence that is asynchronous with recovered streams. High maximum daily temperatures and diel temperature variability appear to be negatively correlated with instantaneous growth rates. Defining temperature metrics that affect the growth and development of ectothermic invertebrates are important to understanding the responses of aquatic biota to wildfires.

Lauren Kremer (Primary Presenter/Author), New Mexico State University, lkremer@nmsu.edu;


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