Digital Commons Network^™

Environmental Drivers Of Leaf Breakdown Rate In An Urban Watershed, Ashley Rachelle Cook

Master's Theses

Leaf litter breakdown is a critical ecosystem process in urban streams, but environmental conditions in urban streams may generate confounding effects on breakdown rates. Reduced abundance of macroinvertebrate shredders may slow breakdown, but rates may increase if high nutrient concentrations stimulate microbial decomposers and if flooding enhances leaf fragmentation. We used the litter bag technique to measure the relative importance of multiple environmental drivers on breakdown of eastern cottonwood (Populus deltoides) leaves at 5 sites throughout the North Branch of the Chicago River watershed. Sites spanned a gradient of urbanization, but no specialized macroinvertebrate shredders were present at any sites. …