After 8 weeks of field and lab work, data analysis, and research writing, our REU students finished the season with a well-attended symposium held at the National Great Rivers Research and Education Center. Researchers, educators, and students from throughout the area stopped by to hear about the research our REU students conducted throughout their 8 week experience.
Ari and Tom presented results of their temporal analysis of the relative abundance of catfishes (Ictalurus spp.) and buffalo fish (Ictiobus spp.) size classes. They found that through a 2,000 year time span, there is a change in fish sizes within the two genera they tested. This relative size decline may be attributed to anthropogenic influences, as well as biases associated with data collections.
Stevie and Paige’s work focused more on temporal changes in the relative abundance of a selected number of fish taxa over time. Surprisingly, their results indicated that although archeologists have recorded changes in plant-based subsistence practices, sociopolitical organization, and material culture related to time, this same relationship is not documented in the relative abundance of fishes or the ways in which people use fishes in the Lower Illinois River Valley.
Curtis and Erin examined changes in diversity represented in archeofaunal and present-day datasets. Looking at the relative abundance of various species represented in these two types of datasets, as well as the presence and absence of these species, they found that diversity between modern and archeological times significantly are dissimilar. They did not find significant differences among archeological collections representing different time periods, however.
Maddie and Abby also examined the relative abundance of fish size classes through time, but with two genera of catfish, forktails (Ictalurus spp) and bullheads (Ameiurus spp.). They focused on these genera because forktails prefer habitats with swift currents, whereas bullheads prefer slow-moving currents. By examining temporal changes in size structures, they inferred that modern-day water management practices may be impacting riverine habitats and thus, the relative size classes of individuals from these two genera.
Nigel and Lily were interested in deep-time changes to backwaters of the Illinois River. To investigate this, they examined frequency changes of fishes that prefer backwater habitats to those that do not using both archeofaunal and modern datasets. Bowfin, a species that prefers backwaters, has a documented temporal decline in abundance, whereas members of the sunfish and bass family, Centrarchidae, show an increase. They suggested that the increase in the abundance of centrarchids likely is related to the current practice of stocking bass as a sport fish. Bowfins are not a sport fish and this decline may indicate a loss of backwater habitats.
All the advisors and students involved with the REU would like to thank everyone who made the symposium possible and all those who attended. We would also like to thank the staff of NGRREC who offered suggestions for the student posters, as well as presentation style. Stayed tuned as we update the application deadline for 2016 and post more activities of the 2015 REU.