Below are a few descriptions of projects that I am currently involved with.
Quantifing benthic habitat in large rivers using side-scan sonar
I am using side-scan sonar imagery to map out large expanses of benthic habitat in the Yellowstone and Missouri Rivers. I am using this approach to guide macroinvertebrate sampling efforts over large scales. However, I also plan to use this spatial analysis to look into questions of scale and how it is related to riverine ecosystem function.
Hopefully the maps that I create will reach beyond my project and be used to answer a number of questions that watershed managers have (i.e. why are pallid sturgeon located in certain areas?, where are the best locations to most effectively sample target fish?, what is the influence of impoundment on the Missouri River and benthic habitat?, what role to tributaries in these large rivers play on habitat dynamices?, ect.)
Oxygen dynamics in upstream reaches of a large river impoundment: implications for larval pallid sturgeon
Recent work focusing on the population dynamics of pallid sturgeon in the upper Missouri River suggests that current hydrologic alterations (i.e. distance between major impoundments) may prevent natural recruitment and threaten long-term persistence (Braaten et al. 2008). However, the mechanism behind this hypothesis is uncertain. This study combines field measurements of dissolved oxygen, sediment microbial respiration estimates, and laboratory fish mortality experiments to present a hypothesis for how the impact of river impoundments may create a hypoxic zone that is inhabitable for drifting larval pallid sturgeon.
Collaborators: Chris Guy, Molly Webb, Kevin Kappenman, Hilary Treanor, and Jason Ilgen
Published in Fisheries: Guy, C. S., Treanor, H. B., Kappenman, K. M., Scholl, E. A., Ilgen, J. E., & Webb, M. A. (2015). Broadening the Regulated-River Management Paradigm: A Case Study of the Forgotten Dead Zone Hindering Pallid Sturgeon Recovery. Fisheries, 40(1), 6-14
I am currently gearing up to estimate rates of sediment microbial respiration and help with field dissolved oxygen measurements for the headwaters of Lake Sakakawea throughout 2015 and 2016. This project will be similar to the original study shown above that was done in the headwaters of Fort Peck Reservoir, however, we are planning to sample the dead zone multiple times throughout the year in an effort to understand temporal dynamics associated with different reservoir water levels.
Collaborators: Chris Guy, Bob Bramblett, and Allison Stringer
Trophic ecology of large river fishes
I am assissting with collecting and analyzing fish diets of abundant fish taxa in the Missouri and Yellowstone Rivers. This project aims to not only characterize feeding behaviors of native fish assemblages in these rivers, but also will look into questions of competition and resource use for the federally endangered palid sturgeon, as well as contributing to our energetic food webs.
Our undergraduate research intern, Nate Beckman, has helped out with collecting fish diets and is currently analyzing shovelnose sturgeon diets in the lab. Preliminary findings of his research indicate that diets of shovelnose sturgeon reflect the benthic habitat where they are found. Previously, it has been noted that diet overlap between the shovelnose and pallid sturgeon is low. However, most of these studies only collected diets from fish in a single type of habitat. Nate's research may shed light on overlooked areas where these two fish may compete for similar resources.
An energetic framework to guide the conservation of pallid sturgeon
Currently I am involved with a large project that uses population, community, and energetic approaches in concert to investigate the carrying capacity of hatchery-raised pallid sturgeon in the Yellowstone and Missouri rivers.
This project allows me to investigate a number of questions regarding energy flow in large rivers. I am in the proccess of combining large-scale habitat quantification with paired macroinvertebrate data to examine the impact of spatial scale on estimating macroinvertebrate production, locating areas in the landscape that are important for understanding pathways of energy flows to mobile consumers, and ultimately, estimating how much energy produced by macroinvertebrate communities is available to hatchery-raised pallid sturgeon across large spatial scales.
see below for the specifics....
Also, check out our project blog for more up to date info
Estimating macroinvertebrate production across large spatial scales
To date, most macroinvertebrate production studies are done on relatively small spatial scales. While these studies provide excellent ground work for estimating macroinvertebrate production in smaller streams, there is a paucity of information on production estimates for large rivers.
My objective is to develop an approach to estimate macroinvertebrate community production on a large scale in the Missouri and Yellowstone Rivers. I plan to incorporate recent developments in spatial analysis of benthic habitat using side-scan sonar, traditional sampling methods of macroinvertebrates, and a modeling approach relating macroinvertebrate production to a suite of physicochemical variables.
These estimates will then be used in food web analysis and hopefully will provide a realistic estimate of resource availability that mobile consumers such as fish require.