The existing Long Term Resource Monitoring element (LTRM) framework on the Illinois River is a strong foundation to detect shifts in fish abundance and composition across multiple hydrogeomorphic strata and using multiple sampling gears, but it currently only collects data on the La Grange Reach of the Illinois River. Although this is informative to long-term trends on of the La Grange Reach, it is a compartmentalized indicator of a much larger system. In contrast, the Long Term Electrofishing program (LTEF) monitors a much larger latitudinal range of the Illinois River and portions of its upstream tributary, the Des Plaines River, but its sampling is largely restricted to main-channel areas and a single sampling gear, electrofishing.
In 2019, IRBS scientists began a complementary effort to better understand the Illinois River at the ecosystem-scale by building upon and expanding existing LTRM and LTEF effort in the Illinois River. Leveraging staff from regional partner agencies (USACE, IDNR, INHS, USWFS), this effort was deemed the “Multi-Agency Monitoring” program, or MAM for short. MAM expands water quality and fish community sampling to the full length and breadth of the “Illinois Waterway” (IWW), a term that defines the entire Illinois River as well as portions of the Des Plaines River and the Chicago Area Waterway System (CAWS). This new, regional partnership broadens the LTRM sampling framework to nearly 500 river kilometers of the Illinois Waterway, stretching from above the Lockport Lock & Dam near Lockport, IL, to the confluence of the Illinois and Mississippi Rivers near Alton, IL.
The impetus of this program was to study the ecological impact of large vessel navigation along the Illinois Waterway. An extended closure of navigation lock and dam structures led to a months-long and near-complete pause in large vessel traffic along the Waterway, providing a natural experiment for assessing the impact of this understudied anthropogenic stressor. An initial 3-year study led to several ecological insights and scientific research products highlighting the significant effects that large vessel traffic can have on the water quality and fish community of a large river (https://doi.org/10.1016/j.scitotenv.2024.172705; https://doi.org/10.5066/P9EQZV10).
Since the completion of the ‘Lock Closure’ project, the scientific objective of the MAM program has shifted. Invasive Bighead, Silver, and Grass Carp threaten to use the Illinois Waterway as a pathway between the Mississippi River Basin and the Laurentian Great Lakes Basin. Invasive carp are abundant in the lower Illinois River and, though currently at low abundance in the Des Plaines River and CAWS, have challenged the electric barriers in place to prevent their entry into Lake Michigan. With consistent, statistically powerful MAM sampling having occurred in both the high-density lower reaches and the low-density upper reaches of the IWW since 2019, the MAM program is now a unique resource in evaluating the success of monitoring and management programs such as harvesting carp to reduce their population size.
We consider MAM to be a nascent long-term monitoring program that can build upon the legacies of LTRM and LTEF. Like LTRM and LTEF, consistent monitoring of the water quality and fish community of the IWW will allow researchers to investigate a broad range of research questions of this growing ecological data set well into the future, but MAM may also be more flexibly directed to addressing the more immediate, management-relevant questions of today. As such, we intend the sampling framework of MAM to be adaptive to a shifting riverscape of pressing management challenges while maintaining fidelity to a long-term perspective that allows data collected far in the future to be backwards-compatible with data collected in its first year. This adaptive monitoring approach positions MAM as a valuable complement to the other monitoring programs entrusted to IRBS staff.
Staff from IRBS that work on this project are Brandon Harris, Mike Spear, Andrew Mathis, Madison Myers, and Jesse Williams.