Wetland ecology at Pymatuning Laboratory of Ecology – Day 12
Human Impacts on Wetlands. Day 12 of wetland ecology began with an overview of human impacts on wetlands, with a focus on the history of wetland loss in the United States and the dramatic shift in societal understanding of wetland values that has occurred over the past century. For example, the government promoted and extensively funded wetland drainage projects from the mid 1800s until the 1950s, but those efforts have now largely replaced by policies aimed at protection or at least no-net loss. We then discussed the specific ways that both direct and indirect human activities modify, alter, and eliminate wetlands. Finally, we discussed the confusion surrounding the interpretation of laws that protect wetlands, particularly the Clean Water Act, and revisited the the recent Supreme Court decisions on the issue.
Peatland paleoecology. This afternoon we went to Titus Bog, and the students were able to observe a peatland firsthand – the only major wetland type that they had not yet had a chance to see in the field. Tim Lyons of the Audubon Society led us into the bog, and we were joined by Jerry McWilliams (Assistant curator of insects at the Tom Ridge Environmental Center Natural History Museum) and several other Audubon Society members. We pointed out various plant species along the way. A few species, such as leatherleaf (Chamaedaphne calyculata), cranberry (Vaccinium oxycoccus), and bog bean (Menyanthes trifoliata) were added to the students’ “must-know” wetland plant list, and the students were also able to get reacquainted with several old friends such as Sphagnum and the carnivorous sundew (Drosera sp.). We reviewed peatland developmental models in the field, and discussed the recent research (done at Titus Bog!) indicating that peatland development in kettlehole basins is not a gradual autogenic process, and instead appears to be an episodic process driven by climate variability (link to paper here). Connecting back to the topic of the morning, we briefly discussed the effect that extensive deforestation of the upland in the 1800s had on plant and microbial communities at Titus Bog, as well as how these changes likely altered rates of important processes like peat accumulation (more details on this can be found here). We noted that much of the bog is now surrounded by a forest buffer, but there is certainly fertilizer-laden runoff still entering the shrub swamp that surrounds the bog.
The students collected a peat core from near the center of the bog, and noted the strikingly different characteristics of the sediment with depth. The lowermost sediments were dark-gray lake muds (“gyjtta”) and uppermost sediments were composed of sedge peat and Sphagnum peat. Tomorrow we will examine the sediments more closely to determine how the plant communities at the site have changed over the past several thousand years.
Tim Lyons volunteered to take us on a hike into Hell’s Half Acre peatland, which was only located a few miles from Titus Bog and has a small population of pitcher plants (Sarracenia purpurea), another plant of nutrient-poor wetlands that supplements its nutrient intact with insects and other small organisms. Another fantastic day…and finally one that was really peaty.
PLE Day 12, a set on Flickr.