Kiamichi River and water scarcity

The Kiamichi watershed is now a case study for an international group examining water scarcity and social-ecological systems.

Congratulations to Traci Popejoy for her new publication in Hydrobiologia.

Popejoy, T., C. R. Randklev, S. Wolverton & L. Nagaoka. 2017. Conservation implications of late Holocene freshwater mussel remains of the Leon River in central Texas. Hydrobiologia  DOI 10.1007/s10750-016-3041-y


We are looking for a postdoc to join our lab


Shifting hotspots: How do consumer aggregations interact to influence resource heterogeneity and fluxes in streams?

We are seeking a Postdoctoral Associate to work on an NSF funded project examining how interacting groups of consumers influence resource heterogeneity in streams. This is a collaborative project between Caryn Vaughn at the University of Oklahoma and Keith Gido at Kansas State University. The postdoc would be based at the University of Oklahoma in Norman. Start date is flexible, but we would like someone to start as soon as possible. Caryn is here at the meeting and can be reached at The project is described below.

Aggregations of consumers create hotspots of nutrient regeneration and material flux that promote resource heterogeneity, increasing biodiversity. Understanding how different types of aggregations interact to influence resource distribution and fluxes is a key knowledge gap, particularly in how these dynamics change across spatial and temporal scales and environmental gradients. Stream fish and mussel assemblages are known to generate biogeochemical hotspots, but have very different characteristics based on species life history and behavior. Long-lived mussels are localized, stable, immobile, long-term hotspots that provide relatively constant nutrient subsidies. Shorter-lived fishes are mobile, widespread, short-term hotspots that provide nutrient subsidies more dependent on hydrologic conditions.

Our project asks: (1) Where and when do fish and mussel hotspots overlap? and (2) How does overlap between these groups influence nutrient recycling and the distribution of resources throughout a stream network? We are using an integrative approach that incorporates species distribution mapping, correlative field studies and a mechanistic mesocosm experiment. To determine the spatial and temporal overlap of mussel and fish hotspots, a biomass distribution model will be generated for mussels and fishes under different hydrologic conditions in two rivers. To determine where and when each group’s function is strongest, path analysis will be used to characterize associations between nutrient dynamics and resource distribution when mussels and fish overlap (summer low flows) and when fish are more dispersed (fall higher flows). To explore mechanistic contributions of mussel and fish assemblages to nutrient and food web dynamics, experiments will be performed in large, replicated, flow-through experimental streams where the movement of nutrients from consumer aggregates (mussel and fish excreta) through the rest of the food web will be tracked with stable isotopes. Lastly, ecosystem dynamics will be scaled to whole rivers using fish and mussel distribution and hydrologic data generated in the field study.

Social assessment of ecosystem services


We have a new paper out that shows how social assessment of ecosystem services can be used to weigh tradeoffs among water resource uses for future watershed management and planning.  


Welcome Traci Popejoy, new PhD student

I am interested in conservation biology, biogeography and community ecology in freshwater systems. I believe multiple forms of evidence are essential to support conservation discussions. For my master’s thesis, I compared freshwater mussel shells from two archaeological sites to a contemporary survey and discussed the conservation implications of this comparison, such as potential habitat change. I look forward to adding to my ‘conservation tool box’ by researching nutrient cycling in Oklahoma streams.traciweb2

Carla Atkinson wins 2015 Hyne’s Award

Two Hyne's Award Winners

Two Hyne’s Award Winners

We are VERY proud of Dr. Carla Atkinson for winning the Hynes Award at the Society for Freshwater Science meeting in May. We are also proud of Dr. Daniel Allen for bringing home this award last year. #vaughnlab


SFS 2015 Hynes Award: Dr. Carla L. Atkinson

Dr. Carla Atkinson is a community and ecosystem ecologist who is interested in how species traits maintain essential ecosystem functions and how land use and climate change may interact to impact a species’ role and its survival within the ecosystem. Her research has focused on the importance of species traits on ecosystem processes, effects of species loss on ecosystem function (i.e. nutrient cycling and storage), and the consequences of land use change on aquatic ecosystems. Dr. Atkinson worked with Dr. Alan Covich at the University of Georgia for her masters studying trophic niche overlap of native and invasive bivalves. In 2013 she obtained her PhD from the University of Oklahoma under the advisement of Dr. Caryn Vaughn where her dissertation research focused on the impact of freshwater mussels, one of the world’s most imperiled faunal groups, on nutrient cycling in streams. As a postdoc under Dr. Alexander Flecker at Cornell University from 2013-2014, she examined the functional traits of tropical and temperate stream insects including body stoichiometry, trophic ecology, and excretion rates under physiological stress due to simulated climate change. She is now an Assistant Professor in the Department of Biological Sciences at the University of Alabama.


We are excited about receiving three years of funding from the National Science Foundation for our project “Shifting hotspots -How do consumer aggregations interact to influence resource heterogeneity and fluxes in streams?”. This is a collaborative project with Kansas State University.