We have completed two weeks of wetland ecology at Pymatuning Lab of Ecology… only one more week to go. The Pymatuning wetlands spent the morning discussing freshwater marshes, swamps, and riparian wetlands. We examined vegetation dynamics, food web structure, and biogeochemistry of each of these wetland types, paying particular attention to similarities and differences. Our discussion of the vegetation dynamics of freshwater marshes highlighted the importance of seed banks, climate variability, and herbivores like muskrats (Ondatra zibethicus) in controlling interannual-to-multidecadal scale ecological changes in these systems. The topic turned out to be quite appropriate for today, given the results from our camera traps in the afternoon. We then went over the midterm exam, spending a considerable amount of time working through the details of how nitrogen cycling occurs in the context of the aerobic and anaerobic layers of wetlands. The students all promised that they would study the details of the nitrogen cycle, and other biogeochemical cycles in wetlands, if these will reappear on the final exam. I won’t disappoint.
We then went to Pymatuning Creek Marsh to collect the shallow wells that we installed last week to record water-level fluctuations within different vegetation zones. We also collected the camera traps. Clearly white-tailed deer occasionally use the marsh, but the students were particularly pleased that they captured video of a muskrat. There was clear evidence of them in the marsh, as there often is marsh environments; however, they tend to be active at night or around dusk so they are not often seen.
The video is embedded below.
And a raccoon….
Today was the midterm exam. The students looked a bit tired this morning. The first half of the exam was in the classroom and the second half was in the field. Word on the wetland street is that the first part was challenging, but the plant identifications were straightforward. As it should be.
We went to Geneva marsh this afternoon and began sampling macroinvertebrates as part of a comparative ecology project. We will sample marsh and shallow pond sites under open and closed canopies, and sites with and without fish. Two wetlands were sampled this afternoon, including Geneva marsh itself and a nearby pond. The students then spent the rest of the afternoon isolating the macroinvertebrates from their samples. One student in the class has been proclaiming that he really wants to see a walking-stick insect (because as he says, they don’t really want to be seen). I think he was pleasantly surprised that we did collect the “wetland-version” of this morphology today, a water-stick insect (family Nepitae).
Tomorrow we will sample another two sites and begin to identify and tally our collections.
After a breakfast of energy-rich waffles, the Pymatuning wetlanders slowly descended the rungs of the redox ladder into the world of wetland biogeochemistry. The microbes rule this world, and we examined the ways they make living by examining nitrogen, iron, manganese, sulfur, and carbon cycling in wetlands. Electron acceptors, photosynthesis, oxidation, reduction, aerobic respiration, diffusion, mineralization, nitrification, denitrification, sulfur bacteria, photosynthetic sulfur bacteria, redox potential, ferric iron, ferrous iron, nitrogen fixation, sulfer-reducing bacteria, extended glycolysis, heterotrophs, chemoautotrophs, facultative anaerobes, obligate anaerobes, methanogenic bacteria, cation exchange capacity, and other trophic-genic-ifications until our brains were full and it was time to cool off in the marsh.
We spent much of the afternoon at Pymatuning Creek Marsh, where the students established transects along the moisture gradient from the edge of the wetland to the interior, and quantified the distribution of vegetation, water-table depth, and pH. While the students collected data I had a little time to quietly explore the marsh a bit, and I took a few pictures…
It was hotter than yesterday and the deer flies (Chrysops sp.) were relentless. Much blood was lost. But we obtained the necessary data and managed to collect a few more plant specimens. This group of students has a fantastic attitude and they are all quite a lot of fun. We returned to the lab to press plants and sort out the unknown plant species that they encountered along the transects.
Tomorrow we will explore the lacustrine wetlands of Pymatuning reservoir, and visit a swamp and some shallow water environments to round out our “must-know” plant list for the first week of class.
And a few more students are now contributing to the twitter feed: #PLEwetlands
A few students have started using twitter to share photos from our fieldwork using the hashtag #PLEwetlands. These will also be retweeted through @LehighEcology and some will be embedded into these daily summaries.
Morning lecture was focused on formal wetland classification systems, with a focus on those used in North America. Admittedly, formal wetland classification schemes are not that exciting, but everyone must have had enough coffee, or ate enough of made-to-order eggs at breakfast, to make it through. After an overview of Cowardin et al. classification system (used by the Fish and Wildlife Service), we took a much-needed walk to some wetlands right outside the classroom. There the students applied their knowledge by fully classifying two wetland areas. We were lucky enough to observe some red-winged blackbird chicks (Agelaius phoeniceus), although mom and dad were not at all pleased that we were nearby.
After a overview of wetland hydrology, we got our waders from the PLE stockroom and headed to Morgan Swamp in Ohio. There, Karen Adair gave us an overview of the preserve and the mission of the Nature Conservancy, and also provided some advice for students interested in conservation and environmental science careers. We then took a hike through a really spectacular mosaic of swamp and mesic forest, dominated by American Beech (Fagus grandifolia), Eastern Hemlock (Tsuga canadensis), and yellow birch (Betula alleghaniensis). I had never done this hike before and it was very much worth it; a few of the beech trees were as large as some of the old growth trees I have seen. We also observed a large eastern ratsnake (Pantherophis alleghaniensis) along the trail.
We then put on waders and entered the preserve from another location, where we examined a 14-year old mitigation wetland, a series of vernal pools, and a large marsh and shrub-swamp. Crossing the mitigation wetland proved to be challenging, and 7 out of 8 of us went deeper than our waders were designed for. Nothing says wetland ecology like a student hollering, “I’m taking on water!” while other students snap pictures. We observed a number of wetland plants, and added a few to the “must-know” list including Sphagnum, reed-canary grass (Phalaris arundinacea), moneywort or creeping jenny (Lysimachia nummularia), common spike-rush (Eleocharis palustris) and three-way sedge (Dulichium arundinaceum).
I’m looking forward to installing a few wells and camera traps tomorrow at Pymatuning Creek Marsh, and beginning our plant collections.
The Pymatuning wetlanders discussed wetland restoration this morning, including an examination of the Florida Everglades Project, which is the largest wetland restoration ever attempted. We discussed the history of environmental degradation in South Florida and how it altered the hydrology and biogeochemistry of this unique wetland complex. The students were happy to apply their knowledge of Phosphorus cycling toward understanding some of the problems and challenges that the restoration effort is attempting to fix.
We had a short break, during which the students finished mounting a few labels on their plant collections and collectively cleaned the wet lab of peat, mud, dead macroinvertebrates, and various other byproducts of our recent explorations. We then briefly discussed treatment wetlands, highlighting the use of these created wetlands to treat things like municipal wastewater, non-point source pollution, and acid mine drainage. I then provided a brief overview of the course and its structure, highlighting what this hard-working group students has accomplished in only three weeks. Then we had one last bit of fun exploring some of the wetlands in the littoral zone of Pymatuning Reservoir via canoe. The students used the rest of the afternoon to study for tomorrow’s final exam.
The Pymatuning wetlanders wrapped up two weeks of the wetland ecology course today by first examining swamps and riparian wetlands and then heading out to Pymatuning Creek Marsh to collect the wells and data loggers that we installed last week. The collection of the wells proved difficult, but the students were creative and managed to recover them all.
We then visited Dr. Rick Relyea’s research laboratory where his research team told us about the interesting experimental work they are doing in ecotoxicology, community ecology, and behavioral ecology. The students had many questions, and it was nice to be able to give them direct exposure to this sort of cutting-edge research.
We returned to lab and spent the afternoon identifying and tallying our macroinvertebrate samples. We found many new macroinvertebrate types this year, and I am looking forward to seeing the results.
After discussing freshwater marsh ecology and seed banks this morning, the Pymatuning wetlanders headed into the field to sample macroinvertebrates. We will be comparing the composition of macroinvertebrate communities in several shallow ponds and marshes, at both closed-canopy and open-canopy sites, as well as shallow ponds with and without fish. We spent the afternoon picking the macroinvertebrates out of the samples, and identifying and counting them. So many bugs! Going to be more work to do tomorrow. More pictures at end…