20 Jan 2017
Today, we were accompanied by Felipe Velasco again, although this time instead of driving south toward Lake Tota we headed northeast toward the town of Mongua. We are extremely grateful for the time that Felipe has devoted to our efforts, as we would have had a difficult time finding these sites without him and it was reassuring to have a local person along. Our goal today was to explore and hopefully collect a core from Laguna Negra, a lake located in a different sort of paramo ecosystem. The drive was quite different than previous days, because we were able to see a much more industrial area of Boyaca. Between the cement factories and the steel mill, the pollution levels were quite high; in fact, much of the drive to Mongua smelled of a fragrant mixture of burning coal and diesel, and when we ascended the mountain above Mongua we observed a thick layer of smog in the valley. However, it was fascinating to see a fully functional steel mill, as gave me an appreciation of what Bethlehem Steel in Pennsylvania must have been like when it was operational. We observed many small family-owned coal mines along the road near Mongua, as this is the primary economic activity in this region.
Laguna Negra and the surrounding landscape was spectacular, and pictures really can’t convey the natural beauty of this place. While Jason and Jaime took measurements of the depth profile of the lake, I had the opportunity to hike around the lake margin. Unlike other lakes that we have visited, the lake margin was not peatland. Hypericum (St. John’s Wort) was common along the lake edge, along with a number of Carex species, and bright red Azolla grew in the littoral zone along with submerged aquatic plants like Myriophyllum. Inflow into the lake comes in the form of a spectacular waterfall, with abundant mosses and ferns growing adjacent to the waterfall in the perpetually humid environment.
The lake was about 9 meters deep with at least 3 meters of sediment, so we inflated a second boat, set our anchors, and commenced sediment coring. Mark Brenner and Felipe Velasco observed from shore, taking pictures of the coring process. We obtained several meters of mud, and once again we carefully kept the upper drive containing the mud-water interface upright on the trip back to Finca SanPedro.
On our way home we stopped in Mongua for some delicious empanadas and then went further down the road to Tópaga to take a look at the church on the main square. The Tópaga church is over 400 years old, and the inside is ornately decorated in gold. Colombia has abundant gold; in fact the yellow in the Colombian flag symbolizes the tremendous gold resources. This church in Tópaga is also probably one of the few churches that not only has artwork incorporating Jesus, the disciples, and other typical biblical representations, but also the devil. Yes, Lucifer himself is on a beam in the ceiling near the front of the church, directly center.
Our fieldwork is now complete. Tomorrow we will ship samples and cores from Sogamoso and then drive down to Bogota to pick up samples from our work in Manizales and prepare to depart on Sunday. This trip has been an amazing experience, and I feel extremely lucky to have had the opportunity to explore this fascinating country and see its amazing natural beauty. I am excited about this new collaboration, and the potential to develop long-term perspectives on water availability and ecology of the critically important paramo regions.
I sincerely thank Jaime Escobar for making this all happen. And I especially thank him for the doing all the driving!
Students in ecology (EES-152) at Lehigh University share pictures of our field activities via Twitter. Below are some highlights from a river ecology laboratory, which included one lab period of sampling, and another lab period focused on macroinvertebrate identification, quantification, and data analysis.
After discussing the ecology of freshwater marshes, swamps, and riparian wetlands, the Pymatuning wetlanders spent much of the day analyzing the macroinvertebrate samples that we collected over the past few days. We found quite a few taxa in the samples, and had fun identifying and tallying them. The students were excited to develop a “must-know” invertebrate list to go along with our “must-know” plant list. 🙂
There were big differences in the species composition of the four wetlands that we sampled, and the students will be examining and developing hypotheses to explain these differences over the next few days. Most of the taxa we found are shown below (mouseover for names), with a nickel for scale.
How will ecosystems respond to ongoing and future climate change? Will changes in ecological communities track temperature and precipitation in a linear fashion? Or will abrupt changes occur when particular climatic thresholds are crossed? What sorts of information might help us better anticipate future ecological change?
After a sweltering week of fieldwork, these questions seem quite timely….
Ecosystem state shifts and long-term perspectives. The possibility of rapid transformation of ecosystems in response to climate change is of great concern to ecologists and land managers. Abrupt and dramatic changes in the composition and functioning of ecosystems, commonly referred to as “state-shifts,” have occurred in the past, and may be triggered by climate-induced disturbance events, such as fires or droughts. However, the past century of climate and ecological changes provide only a few examples of such events, and lack long-term perspectives on their effects. Paleoenvironmental records provide long-term perspectives on both climate and ecosystem dynamics, and are therefore well suited for studies of climate-ecosystem relationships.
The Northern Wisconsin Landscape. Northern Wisconsin is a land of lakes…and peat-accumulating wetlands (i.e., peatlands). When the glaciers retreated from this region, they left behind blocks of ice. These ice blocks melted and the depressions that were left on the landscape became the region’s many lakes and wetlands. These basins are commonly referred to as kettles or kettleholes, and are often occupied by lakes or peatlands – and in many cases contain some combination of both. Commonly, kettle lakes are bordered by a peatland that floats on a trapped water layer. When you walk on these peat mats, it feels like you are walking on a waterbed. “Quaking bogs,” “floating bogs,” and “schwingmoors,” are just some of the names used to refer to these unusual ecosystems.
Kettlehole ecosystems and paleoecology. Kettlehole ecosystems provide a range of benefits (i.e., ecosystem services), including habitat for biodiversity, groundwater recharge, sites of carbon storage, and areas for recreation. In addition, these systems have tremendous scientific value, particularly for the study of past ecosystem responses to climate variability, because they leave a detailed record of their own development in the form of peat and lake sediments. By collecting and examining sediment cores from these systems, much can be learned about how they have changed in response to past climate changes.
Recent research has demonstrated that extreme drought and water-level fluctuations probably trigger the initiation and expansion of peatland in kettlehole ecosystems (see related paper), effectively transforming the ecosystem from an open lake to a peatland (with or without a central lake). This transformation likely occurs quite rapidly (i.e., likely within a decade or so) and would be expected to cause abrupt changes in ecological communities and processes. For example, peatland establishment along the margin of lakes leads to changes in lake-water chemistry (e.g., higher acidity, higher dissolved organic carbon) and lakes with and without peat mats are characterized by very different aquatic communities and food-web structure. In fact, lakes with extensive peatland can become too acid to support fish populations. Furthermore, the transformation of kettle lake systems into peat-accumulating wetlands results in dramatic changes in biogeochemical processes, particularly rates of carbon storage.
We are investigating these ideas further by examining the history of peatland development in kettlehole ecosystems along a landscape gradient in northern Wisconsin. Our research aims to provide a long-term perspectives on the role of hydroclimate variability in triggering abrupt and permanent state shifts in ecosystems, as well as to better understand and characterize the immediate and long-term ecological consequences of these events. Such threshold responses are difficult to anticipate, and our results will hopefully provide a foundation for evaluating the relative sensitivity and vulnerability of ecological systems.
“Wading through the slimy ooze
You can drive away your blues
Romping through the swamp”
– Peter Stampel-
Two weeks of fieldwork in late June and early July. Nice work if you can get it? Not really. By the third day, we were almost drained of our life force by wood ticks and deer ticks (the ones that carry Lyme disease). What little blood remained in our bodies nearly boiled in the brutally hot temperatures that followed for the remainder of the work. However, we did manage to make a great deal of progress. The field crew included myself, Alex Ireland (postdoc, Lehigh University), and Michael Clifford (PhD student, Lehigh University).
Our work this summer was focused on two sites – Triangle Lake and Long Lake. The first several days were spent measuring basin depths with a probe rod so that maps of the underlying basin morphologies could be developed. We then collected a series of peat cores at the two sites, located along transects that captured the gradients of basin depth. The peat and sediments will be analyzed for plant remains and carbon content later this summer and fall, and used in conjunction with radiocarbon dating to determine when the peat-mat established in different portions of the basins. This information will allow us to reconstruct how and when the peat mat expanded at the two sites. The timing of peat mat expansion will be compared between the two sites, as well as to other sites in the region and to paleoclimate records, to assess the role of climate variability in triggering peat-mat expansion. Last winter we collected sediment cores from the central lakes that occupy the Triangle and Long Basins, and these will be examined to assess how the lake ecosystem responded to bog-mat advances of the past (see related blog post and video here). Ultimately the datasets from the lake and peatland components of the ecosystem will be integrated and used to develop a predictive model of bog mat expansion and impacts, which will be used to anticipate potential future changes in these valuable ecosystems. A short video highlighting some of our activities during the past few weeks is below.
-rkb and awi-
A fun video highlighting some of the fieldwork:
The Lehigh Canal was built in 1827 to transport coal from the upper Lehigh Valley. The canal was in operation until the 1940s, and it is now primarily used as a recreational trail for hiking, walking, and biking. Within the Bethlehem-Allentown-Easton area, it has all the problems of an isolated natural area surrounded by development (habitat degradation, invasive species, eutrophication of the canal), not to mention the legacies of once being a transportation corridor (e.g., even more invasive species). However, regardless of these problems, the area still provides considerable ecosystem services, including recreational opportunities, a great path for carbon-neutral commuting to work (for me!), and an easily accessible place to observe nature within the greater Bethlehem area.
Below are a few observations, made by students along the towpath this semester…highlighting the educational value of this interesting legacy of Lehigh Valley history.
Restoration at Sand Island
Last weekend, Dennis Scholl of the Delaware and Lehigh National Heritage Corridor led a group of volunteers in an effort to replant native species along the canal just east of Sand Island in Bethlehem, PA. I spent many hours of my youth exploring this area, visiting the playground, walking the bridge, and returning via the towpath adjacent to the canal. The area, and particularly the banks of the canal and river, were thick with vegetation. Although located in the center of the city of Bethlehem, as a child I really believed that we were walking deep in a magical forest. However, a few years ago most understory vegetation was cleared, giving it the appearance of a park. You could see through the trees all the way to the streets of Bethlehem. Of course, the intentions of this work were good – much of the understory vegetation was composed of invasive species, and native species were extensively planted in their place – but a lot bare ground remained. However, the removal of the vegetation didn’t just change the appearance of the area; without the thick vegetation the area became vulnerable to increased erosion, which was made worse by the unusual rain and flooding of last year. I hope the new restoration effort succeeds in reintroducing local plants to all of the areas of Sand Island, turning it back into a magical forest in the middle of the city of Bethlehem.
As I was on a bike ride near the Lehigh River, I came across something that we had just discussed in class – a fish ladder! To me, the ladder looked like a very difficult maze for the fish to navigate. The dam was originally constructed to help boats cross the river and was called the chain dam because there was a link chain across the river to prevent boats from falling over the edge of the dam. The entrance to the ladder was surprising small – only 2 meters or so wide. It is hard to believe that a fish could find it, let alone actually decide to enter it.
Apparently the ladder was added to the dam in 1992. One year fish tallies were made to assess how many fish actually use the ladder. 645 fish made it up the ladder from March 31-June 7. The tallies were achieved by using cameras that recorded the ladder 24 hours a day. The tapes were then looked through by interns, and the fish were each counted. Must have been about as exciting as counting sheep.
I observed a fish or possibly an eel that seemed to be stuck to one of the concrete walls. I wonder how many fish die in the ladder each year, or from injuries sustained while trying to navigate the maze? Perhaps another job for the interns….
Turtles, Turtles, and More Turtles
Today after class, I went for a run on the canal path. Usually I don’t pay much attention, but today I happened to look into the canal and saw a painted turtle basking in the sun! I continued to look for them while I ran. I saw another immediately…and then another right after! So I decided to count and by the end of my run I had seen 36 turtles! I have always assumed that the murky, algae-covered waters of the canal couldn’t possibly contain any life besides some bottom feeders. However, after a little research I discovered that painted turtles are extremely common in Pennsylvania, and they prefer slow-moving water and ditches where algae and insects are abundant. So in contrast to what I had thought, the canal is probably really good habitat for them.
I think that one of the most salient aspects of conservation is its applicability to human life – a fact nicely highlighted by the above episode of NPR’s All Things Considered. While I personally value the natural environment in and of itself, I understand the necessity to recontextualize environmental protection in terms of human welfare in order to gain wider support. It is only through understanding that the environment provides human life with its sustenance and survival – even if we are active shapers – that large-scale policy shifts will occur to facilitate environmental protection.
One of the most frequently cited reasons for enacting environmental policy is just this: that the environment holds an enormous untapped wealth of resources that could, potentially, be used by humans. The NPR story highlights this; while often times the ocean might be overlooked by the everyday citizen, it does cover over seventy percent of the earth’s surface. With that large of a footprint, it seems obvious that it potentially contains numerous untapped human resources. For example, the drug Briostatin was originally derived from a type of marine moss animal (a species of Bryozoan, Bugula neritina) and has been tested as an inhibitor of cancer-cell growth, particularly in combination with other drugs. It is also currently being explored as a treatment for Alzheimer’s disease. How many other potential pharmaceuticals lie under the sea?
“It’s another example of how human activities alter the environment in unexpected ways that can often come back and bite us” reads the sign off to the above podcast from Scientific American entitled West Nile Virus and Bird Diversity. Ecological complexity underlies much of the study of biodiversity and conservation. Whether the end goal is land-use policy or pure wilderness preservation, this complexity must be considered when valuing natural ecosystems and the services they provide humans. The above podcast briefly highlights how the citification of previously rural land has reduced bird diversity, and in turn lower bird diversity has been linked to higher numbers of human incidences of West Nile virus. Mechanisms are unclear, but studies suggest that increased diversity within an ecosystem often reduces the proportion of suitable hosts for a disease. For example, a similar mechanism characterizes Lyme disease occurrence and transmission. Small (less than about 5 acres) forest fragments contain lower species diversity than larger forest tracts, and also harbor more Lyme-disease carrying white-footed mice. Smaller forest fragments have been shown to have a greater number of infected ticks – another unexpected consequence of human activities that is (literally) coming back to bite us.
Conservation efforts that seek to repackage issues in terms of human welfare will ultimately, in my opinion, be successful. Though I don’t personally see this as the only reason for protecting the environment, the pragmatic side of me understands its necessity. Whether it is the economic assessment of ecological services, or a more general understanding of the interconnectivity of humans and ecosystems, long-term conservation goals will only be met through appealing to the humanistic human. If not, the environment risks damage, and our own ignorance may again….come back to bite us.
This week at a meeting of Green Action, a student club at Lehigh University, a representative from Bethlehem Backyards for Wildlife came to our meeting to suggest that Lehigh certify a few more areas on campus as NWF (National Wildlife Federation) wildlife habitats. The location surrounding STEPS was certified a few years ago, but she was asking for our help in creating and identifying more sites.
Bethlehem Backyards for Wildlife is a much smaller branch of the Garden for Wildlife program run by the National Wildlife Federation. The goal of the program is to have people register their yards, local schools, or college campuses as Certified Wildlife Habitats.
What exactly does it take to certify an area as a good wildlife habitat? A range of resources need to be present, including food, water, shelter, and places for small animals and birds to raise young. To provide a source of food, you can establish plants that provide nectar, nuts, seeds, and berries and/or install feeders. Water sources might include a pond, fountain, creek, or simply a bird bath. Low lying shrubs or bushes are ideal for providing shelter, and a place to raised young. Bird houses or other types of artificial shelters can also be used.
The program also encourages communities to “plant for biodiversity” by planting native species instead of non-native or invasive species. It also encourages participants to plant just a few individuals of various plant species instead of many of single kind. Even more importantly, they support the use of natural, safer alternatives to chemical pesticides and fertilizers.
How did Bethlehem Backyards for Wildlife form? The Garden for Wildlife program of NWF offers a certification for Community Habitats, providing an incentive for backyards, schools, and even businesses and other public places to make protecting wildlife habitats a priority. Interestingly, the entire city of Bethlehem is currently seeking certification. As well as creating wildlife habitats, the group holds gardening workshops and community clean ups.
So what can we do at Lehigh? We at the Green Club are going to determine what areas can already be certified on the campus, and assess ways that resources like water, food, and shelter can be added to other areas. What can you do at home? Investigate how you can make your backyard more wildlife friendly and then certify it! Currently there are 154,375 locations that have been certified. Hopefully you can help increase this number!!!!