Date of Graduation
Master of Science in Biology
La Toya Kissoon-Charles
Leaf decomposition in streams is an important ecological function facilitated by bacteria, fungi, and macroinvertebrates. Metal contamination can decrease leaf decomposition rates and reduce macroinvertebrate abundance and diversity. In the current study, I focused on mining-contamination in well-buffered streams in two different Missouri mining districts with varying extents of mining contamination, Big River and Pierson Creek. I measured decomposition rates of sycamore leaves, and abundance and diversity of macroinvertebrate shredders in leaf pack experiments with a full-factorial design to determine the effects of metal contamination of leaves and stream substrates. Comparisons were made between leaf packs upstream and downstream of mining contamination sources, as well as between the origin location of leaves. In Big River, leaf decomposition rates were higher downstream of mining contamination than leaves upstream. Overall, mining contaminated leaves had higher decomposition rates than non-contaminated leaves, regardless of reach placement over the 123-day winter experiment. In Big River, macroinvertebrate shredder abundance was higher and diversity of macroinvertebrate shredders was lower upstream of mining contamination. Opposite decomposition and macroinvertebrate trends were observed in Pierson Creek over the 50-day spring experiment. Decomposition rates were higher in leaves upstream of mining contamination than leaves downstream. In Pierson Creek, macroinvertebrate shredder abundance was higher downstream of mining contamination and macroinvertebrate shredder diversity was lower downstream of mining contamination. Contaminated leaves had higher decomposition rates than non-contaminated leaves in Big River, regardless of reach placement, while decomposition rates were similar in Pierson Creek. This could be due to differences in the magnitude of mining contamination. Leaf type did not influence macroinvertebrate shredder abundance or diversity for either stream, but reach location did. This could be due to physical and chemical stream characteristics. Future studies on mining contamination effects on leaf quality and substrate characteristics and subsequent impacts on decomposition rates could lead to a better understanding of specific ecosystem interactions and inform future management decisions.
decomposition, macroinvertebrates, mining contamination, sycamore, shredders, leaves, streams, leaf pack, Big River, Pierson Creek
Biology | Entomology | Natural Resources and Conservation
© Leslie Marie Hatch
Hatch, Leslie Marie, "Decomposition and Macroinvertebrate Shredder Colonization of Autumnal Shed Sycamore Leaves in Mining-Contaminated Streams" (2022). MSU Graduate Theses. 3776.