Survival of Fishes in a Stormwater Retention Pond at the Watershed Nature Center, Edwardsville, Illinois

A study of the Upper Pond at the Edwardsville Watershed Nature Center (WNC) was conducted to discover the potential cause of fish kills in the small stormwater retention pond and to determine how the current populations of bluegill (Lepomis macrochirus), redear sunfish (Lepomis microlophus), common carp (Cyprinus carpio) and largemouth bass (Micropterus salmoides) can survive in the pond based on prevailing environmental conditions. Dissolved oxygen (DO) was measured from June 19 to December 5, 2019 at a site in the center of the open lake (4 m deep) and from a dock near the shore (1.1 m deep). Water temperature was measured intermittently at both sites from June 19 to November 4. In the open lake, oxygen levels reached a peak of 11.6 mg/L at the surface on July 2. Below 2.5 m DO remained less than 1.5 mg/L until Oct. 8 when it slowly began to rise reaching a high of 10.8 on Nov. 20. The dock station had similar oxygen levels. Temperature varied from a high of 31.2 °C on July 21 to a low of 6.5° C on November 3. The low DO in the pond results from a nearly continuous cover of duckweed (Lemna sps) which prevents interchange of oxygen with the atmosphere. It is likely that the low oxygen levels select for fish species that are physiologically and behaviorally capable of surviving hypoxia

Pre-settlement Vegetation of Greene, Jersey and Macoupin Counties along the Prairie/Forest Border in Illinois

The US Federal Government established the Public Land Survey (PLS) to survey federal land before sale to settlers in the early 1800’s. We used a Geographic Information System (GIS) and the PLS to explore the relationship among forests, fire frequency, topography, and soils in Greene, Jersey and Macoupin Counties in Illinois. The PLS data was digitized from microfiche copies of the survey in the Lovejoy Library at Southern Illinois University Edwardsville. The floodplains along the Illinois River supported a fire-intolerant forest of Salix sp., Populus deltoides, Acer spp., and Fraxinus spp. The floodplain is bordered by a line of bluffs which forms a region of broken topography supporting moderately fire tolerant species on alfisols. To the East is a region of mixed prairie and forest. The prairie was on flat mollisols where it was intermixed with the forest on and hillier slopes and alfisols. The forest areas supported highly fire tolerant forest trees with large diameters at large distances from survey points. Non-Metric Multidimensional scaling reveals a close relationship among topography, vegetation and soils. Forests were on hilly land. Prairies were located on level uplands where there were no firebreaks. Floodplains are just as level as prairies. They are also located on mollisols adjacent to the river. They are protected from fire by sloughs, swamps and lakes. The results of our study support the conclusion that topography and moisture is an important control on the geographical distribution of vegetation in the study area. These factors likely operated by controlling fire frequency

Pre-settlement Vegetation of Greene, Jersey and Macoupin Counties along the Prairie/Forest Border in Illinois

The US Federal Government established the Public Land Survey (PLS) to survey federal land before sale to settlers in the early 1800’s. We used a Geographic Information System (GIS) and the PLS to explore the relationship among forests, fire frequency, topography, and soils in Greene, Jersey and Macoupin Counties in Illinois. The PLS data was digitized from microfiche copies of the survey in the Lovejoy Library at Southern Illinois University Edwardsville. The floodplains along the Illinois River supported a fire-intolerant forest of Salix sp., Populus deltoides, Acer spp., and Fraxinus spp. The floodplain is bordered by a line of bluffs which forms a region of broken topography supporting moderately fire tolerant species on alfisols. To the East is a region of mixed prairie and forest. The prairie was on flat mollisols where it was intermixed with the forest on and hillier slopes and alfisols. The forest areas supported highly fire tolerant forest trees with large diameters at large distances from survey points. Non-Metric Multidimensional scaling reveals a close relationship among topography, vegetation and soils. Forests were on hilly land. Prairies were located on level uplands where there were no firebreaks. Floodplains are just as level as prairies. They are also located on mollisols adjacent to the river. They are protected from fire by sloughs, swamps and lakes. The results of our study support the conclusion that topography and moisture is an important control on the geographical distribution of vegetation in the study area. These factors likely operated by controlling fire frequency

The impact of nitrogen contamination and river modification on a Mississippi River floodplain lake

Anthropogenic nitrogen contamination has increased in ecosystems around the world (frequently termed the “nitrogen cascade”). Coke production for steel manufacturing is often overlooked as a source of nitrogen to natural ecosystems. We examined sediment cores from a Horseshoe Lake, a floodplain lake located just East of St. Louis Missouri (USA) to test whether a coking plant effluent could be traced using stable isotopes of nitrogen and diatom microfossils. The distribution of δ15N values in surface sediment samples from the lake shows the highest values near the coking plant effluent. Analysis stable isotopes of nitrogen from sediment cores using a binary mixing model showed three sources of nitrogen since 1688 CE. The first source (active between 1688 and 1920 CE) had a calculated δ15N value of -.8±.4‰. After 1920 a second source with a δ15N of 20.2±2.0 ‰ became active. The diatom microfossil assemblages present from 1688 CE to the late 1800’s are dominated by the planktonic species Aulacoseira granulata and periphytic and benthic genera Gomphonema, Cocconeis, and Lyrella. After the late 1800’s the diatom assemblages are dominated by Staurosira species indicating a shift of species from high flow riverine environments to epipelic species from a lake environment. Our results show how stable isotopes of nitrogen can be used to track nitrogen inputs from industrial sources. They suggest that the high nitrogen input has not been a major source of eutrophication in the lake

A 1600-year record of human impacts on a floodplain lake in the Mississippi River Valley

In North America, land use practices of the last two centuries have strongly influenced aquatic communities and freshwater quality, but the impacts of prehistoric land use on freshwater resources remain poorly documented. Here we investigate the influence of prehistoric and historical land use on Horseshoe Lake, Illinois, USA, an oxbow lake in a floodplain of the Mississippi River that is adjacent to Cahokia, the largest prehistoric indigenous population center north of Mexico. Diatom assemblages from Horseshoe Lake’s sedimentary record track shifts in aquatic environmental conditions over the last ca. 1600 years. During the period of prehistoric population growth and agricultural intensification associated with Cahokia’s emergence (ca. 600–1200 CE), the relative abundance of Aulacoseira granulata—a planktonic diatom associated with shallow eutrophic lakes—increased. Following the abandonment of Cahokia in the 14th century CE, the diatom flora of the lake shifted from planktonic Aulacoseira taxa to the epiphytic taxa Cocconeis and Gomphonema. This shift in diatom assemblages is consistent with a reduction of nutrient inputs to the lake and/or reduced fishing pressure as prehistoric populations abandoned the area. Following the intensification of historic settlement after 1800 CE, diatom assemblages shift to epipelic species of small Staurosira and Fragilaria, indicating a reduction in aquatic macrophytes and increased turbidity. Our results document prehistoric indigenous impacts on a freshwater system beginning nearly 1000 years before European colonization of the Americas and demonstrate the antiquity of human impacts on freshwater resources in North America

A 1600-year record of human impacts on a floodplain lake in the Mississippi River Valley

In North America, land use practices of the last two centuries have strongly influenced aquatic communities and freshwater quality, but the impacts of prehistoric land use on freshwater resources remain poorly documented. Here we investigate the influence of prehistoric and historical land use on Horseshoe Lake, Illinois, USA, an oxbow lake in a floodplain of the Mississippi River that is adjacent to Cahokia, the largest prehistoric indigenous population center north of Mexico. Diatom assemblages from Horseshoe Lake’s sedimentary record track shifts in aquatic environmental conditions over the last ca. 1600 years. During the period of prehistoric population growth and agricultural intensification associated with Cahokia’s emergence (ca. 600–1200 CE), the relative abundance of Aulacoseira granulata—a planktonic diatom associated with shallow eutrophic lakes—increased. Following the abandonment of Cahokia in the 14th century CE, the diatom flora of the lake shifted from planktonic Aulacoseira taxa to the epiphytic taxa Cocconeis and Gomphonema. This shift in diatom assemblages is consistent with a reduction of nutrient inputs to the lake and/or reduced fishing pressure as prehistoric populations abandoned the area. Following the intensification of historic settlement after 1800 CE, diatom assemblages shift to epipelic species of small Staurosira and Fragilaria, indicating a reduction in aquatic macrophytes and increased turbidity. Our results document prehistoric indigenous impacts on a freshwater system beginning nearly 1000 years before European colonization of the Americas and demonstrate the antiquity of human impacts on freshwater resources in North America

Tracking Change in the Illinois River using Stable Isotopes in Modern and Ancient Fishes

The Illinois River has been heavily modified by human activities. We examined the nitrogen and carbon stable isotope composition of collagen from fish bones in two Native American middens comparing them to modern fishes in the River today. We also compared ancient and modern fishes to three reference samples – 1) Illinois River phytoplankton 2) backwater lake sediment and 3) tissue from riverside trees. We found a large increase in δ15N values in modern fish bone collagen relative to ancient collagen. However, there is little change in δ13C between ancient and modern samples. Bone collagen from invasive carp species (Hypopthalmichthys and Cyprinus) are similar to modern phytoplankton. All fishes are different from riverside trees and backwater lake sediment. The large shift in δ15N values between ancient and modern fishes is probably caused by contamination of the river by Chicago treated wastewater and by denitrified fertilizer run-off. Our results indicate a major change in nitrogen biogeochemistry in the modern river. Comparisons between ancient and modern δ13C values suggests little change in feeding behavior of fishes between ancient and modern times. However, our data for invasive carps suggest strong competition with native planktivore