Wetland ecology at Pymatuning Laboratory of Ecology – Day 9
Vegetation Dynamics and Macroinvertebrates. We finished up our coverage of peatland paleoenvironmental archives this morning and then looked in more detail at the ecology of freshwater marshes. We discussed the importance of seed banks in many marshes, and used the specific example of how droughts, seed banks, and muskrat population sizes can drive vegetation dynamics in prairie pothole wetlands. The students then spent the rest of the morning working on identifying and quantifying their macroinvertebrate collections from Geneva marsh and ponds.
Swamps and Mosquitoes. This afternoon we visited Kingsville Swamp and a nearby riparian area along Conneaut Creek in Ashtabula County, Ohio. At Kingsville Swamp, we compared and contrasted the vegetation and water chemistry with Hartsville Swamp (adjacent to Pymatuning Reservoir), which we visited last week. Given its high topographic position in the landscape, Kingsville Swamp likely receives a greater proportion of its water budget from precipitation, and its dark-brown water was much more acidic than Hartstown Swamp (5.2 versus 8.1 pH) and contained more dissolved organic carbon. Along the swamp edge the canopy was dominated by silver maple, black ash, and hemlock. As we progressed further into the swamp, there was more standing water and it became shrub dominated, with black chokecherry, highbush blueberry, and buttonbush creating a nearly impenetrable shrub-forest. In fact, only the bravest and most dedicated students ventured very far into the shrubs, despite my encouragement and the hordes of mosquitoes that were waiting to accept energy donations on behalf of the ecosystem.
Riparian Wetlands. Most of students enjoyed the creek and riparian area in the Blakeslee-Barrows Preserve more than the swamp, perhaps because it was quite scenic and lacked the hordes of mosquitoes. Here we observed riparian vegetation and thought about the ecological and hydrological linkages between the creek and surrounding floodplain in preparation for tomorrow’s lecture on riparian wetlands. We observed several locations where groundwater was entering the margins of the stream, and noted that oxidized iron was being deposited at the interface of the creek and the groundwater entry point. The students applied their knowledge of biogeochemistry to explain this observation. It was a hot afternoon, and many students decided to take a swim in the creek.
PLE Day 9, a set on Flickr.