Wednesday, May 28, 2008 - 10:15 AM
393

Inundation schedule of leaf litter affects microbial colonization and shredder preference in temporary woodland wetlands

Scott A. Wissinger, Martyn D. Inkley, and Miranda L. Mumford. Biology Department, Allegheny College, Meadville, PA 16335

Terrestrially derived leaf litter dominates energy budgets of wetlands in temperate deciduous forests. Relatively little is known about the role of invertebrates in processing detritus in forested wetlands compared to headwater streams. We first studied the distribution, life history, and diets of cased caddisflies (Phryganeidae and Limnephilidae) that inhabit temporary woodland pools in Pennsylvania, and then conducted a field experiment to compare decay rates and microbial colonization of maple leaves under different inundation schedules. Leaves incubated in the field under permanent and semi-permanent conditions had higher fungal and bacterial biomass, and lower C:N ratios than those incubated under temporarily wetted conditions. To determine the effects of these differences in litter nutritional quality on shredder preference, we conducted a laboratory experiment with larvae of one of the species of caddisflies (Nemotaulius hostilis) at our study site. Larvae spent twice as much time foraging on permanent and semi-permanent litter than on litter incubated under temporary conditions. Our data suggest that 1) invertebrate shredders potentially play a major role in detritus processing in wooded wetlands, and 2) inter-annual shifts in drying regime should alter processing rates, and hence the mobilization of energy and nutrients in leaf litter to the wetland food web.


Web Page: detritus, wetlands, caddisflies

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