1. You are the manager of a Wildlife and Wetland Refuge on the Ashepoo River in South Carolina. The Corps of Engineers would like to build a dam on the Ashepoo River and you need to make a convincing argument as to how that would affect your refuge which consists of domed peat forests and tidal freshwater marshes. These wetlands would be flooded by the reservoir. Use the info I gave you in the powerpoint and your reading to list why this action would destroy your wetlands.
The wildlife who call the Ashepoo River home rely on specific conditions to continue surviving without needing to adapt. Some types of wildlife are not able to adapt as well as others. That said, destruction of habitat can lead to a series of detrimental impacts on wildlife. Specifically, since marshes are flooded year-round, it allows them to maintain strongly saturated soils which results in a certain type of vegetation (EPA n.d.). Building the dam would decrease the saturation levels and therefore take away conditions that the particular vegetation need to survive. The dam would also restrict essential nutrients from flowing through the system. As a result, the wildlife that feed on that vegetation would not be able to intake all the nutrients that they require.
Additionally, building a dam on the river would alter the existing conditions that form domed peat forests. For example, the pH of the soil is indirectly related to amount of organic content in peatlands. That said, the increase in water from flooding would raise the ecosystem’s pH (Mitsch and Gosselink 2015, 425). Also, characteristics of peatlands are responsible for slowing decomposition of plant material and enable the formation of peat (Flanagan n.d.). Moreover, peatlands actually require accumulation of peat instead of decomposition (Mitsch and Gosselink 2015, 416). However, influx of water and sediment would lead to increasingly more decomposition (Mitsch and Gosselink 2015, 416). The tidal freshwater marsh is a barrier keeping sediment from reaching the peat forest (Flanagan n.d.). They act as filters between the stream and the peat (Flanagan n.d.). However, the dam would kill the marsh which would make it so the peat forest would no longer be in isolation (Flanagan n.d.). Similar to the marsh itself, the altered conditions would lead to wildlife retreating away from the area to reside in a more suitable habitat.
2. Explain the connection between dry and wet cycles of alluvial cypress swamps using both websites and the Cypress powerpoint. How long can a swamp stay dry? What is the best cycle for cypress-tupelo forest health and regeneration? How does the hydrology feed the plant life of swamps?
Alluvial cypress swamps are flooded swamps associated with a river system (Flanagan n.d.). As the river floods, sediment laden water fills the channels and pools adjacent to the river (Flanagan n.d.). The cypress swamps are kept wet with slow flowing water most of the year by precipitation, the river, and its tributaries (Flanagan n.d.). When a flood occurs, flood waters fill the swamps and then are released slowly after the flood pulse is ceased. Depending on the swamp size, the water can be held in large swamps for weeks or small swamps for days (Flanagan n.d.). The flooded swamp is full with nutrient-rich water and lessens the flood pulse downstream (Flanagan n.d.). Flooding also corresponds with feeding the plant swamps in the adjacent river, and it is necessary in alluvial swamps for seed dispersal (Flanagan n.d.).
Still, in a cypress-tupelo forest, there are many different kinds of trees in the ecosystem. Less water-tolerant trees and shrubs live on islands above the water that are still within the swamp (Flanagan n.d.). At the same time, cypress and tupelos can continuously have a wet base (Flanagan n.d.). However, while cypress trees can tolerate their feet being wet for long periods of time, they need to germinate on moist land because they are not aquatic plants (Flanagan n.d.). The seedlings float during times of floods to the outer edges of the swamp and onto islands within the swamp (Flanagan n.d.). The cypress tree roots produce knees that aid in respiration, providing required oxygen to the root tissues (Florida Museum 2018). Cypress will usually lose their leaves during the drier fall and winter, then regrow them during the floods of spring and growing season of the summer (Florida Museum, 2021).
Further, the cypress swamp’s hydrology is composed of the crucial annual flooding and periodic drying (Flanagan n.d.). Swamps need to be completely dry roughly every ten years to allow for vegetation regeneration (Flanagan n.d.). Also, dry periods thin out the forest which reduces competition. Additionally, there is interplay between the flora and fauna. Fish spawn with the flood cycle. The fish move from the river into the pools and old channels to spawn (Flanagan n.d.). As the water level drops, the adult fish move back to the river and the small channels dry up. the small channels dry up (Flanagan n.d.). The small fish then hatch and grow in the isolated pools grow in the isolated pools away from large predatory fish (Flanagan n.d.). With the winter rains, the far pools and channels flood and are reconnected to the river (Flanagan n.d.). Then, the young fish move into the river and are better able to survive (Flanagan n.d.).
3. Compare bogs and fens.
The explanation begins with the first ice age. When the ice melted, lakes formed. Plants grew around the lakes. After many years, they died and sank to the bottom of the land. After hundreds of years, the lake became full of dead, wetland vegetation. It transformed into a fen. New plants, such as sphagnum moss grew on the surface of the fen. Over thousands of years, the sphagnum moss died and accumulated. Peat began to form. At this point, the fen became a bog. Trees began to grow in the bog. Bogs act as natural carbon sinks as they absorb greenhouse gases from the atmosphere. The plants in the bog absorb the carbon. When those plants die, the carbon is stored as peat.
a. How are they alike?
Similar to bogs, fens are mostly a northern hemisphere phenomenon (EPA n.d.). They occur in the northeastern United States, the Great Lakes region, the Rocky Mountains and much of Canada — and are generally associated with low temperatures and short growing seasons, where ample precipitation and high humidity cause excessive moisture to accumulate (EPA n.d.). They both provide important benefits in a watershed, including preventing or reducing the risk of floods, improving water quality and providing habitat for unique plant and animal communities (EPA n.d.). Like bogs, fens formed when glaciers retreated (NatureWorks n.d.). Fens are often found near bogs and over time most fens become bogs (NatureWorks n.d.).
b. How are they different?
The main difference between a fen and a bog is that fens have greater water exchange (NatureWorks n.d.). Fens differ from bogs because they are less acidic and have higher nutrient levels (EPA n.d.). Therefore, they are able to support a much more diverse plant and animal community. These systems are often covered by grasses, sedges, rushes and wildflowers (EPA n.d.). Over time, peat may build up and separate the fen from its groundwater supply (EPA n.d.). When this happens, the fen receives fewer nutrients and may become a bog (EPA n.d.). On the the other hand, bogs receive all or most of their water from precipitation rather than from runoff, groundwater or streams (EPA n.d.). As a result, bogs are low in the nutrients needed for plant growth, a condition that is enhanced by acid forming peat mosses (EPA n.d.). The sphagnum peats of northern bogs cause especially acidic waters (EPA n.d.). The result is a wetland ecosystem with a very specialized and unique flora and fauna that can grow in these conditions called acidophiles (EPA n.d.).
c. Chose either a bog or fen and discuss how you would restore this ecosystem that was degraded by human activities (can be mining, development, agricultural etc.)
Since 1995, Premier Tech has completed restoration works by reintroducing Sphagnum on more than 1,900 acres of bog across Canada and the United States (Bloodnick 2021). I appreciate incorporating a model that the United States has learned from elsewhere into this discussion. The Groupe de recherche en écologie des tourbières, under the direction of Dr. Line Rochefort of Université Laval in Quebec, carried out a project aimed at developing techniques to restore harvested peatlands. Reissued since its original release in 1997, this tool remains today the reference for Canadian peat moss producers, who are committed to the sustainable management of peatlands and the protection of unique ecosystems, such as peat moss harvesting sites (Bloodnick 2021). The approach used in Canada promotes the reintroduction of peatland species to accelerate the formation of a new plant carpet, as well as water management to raise and stabilize the water table (Bloodnick 2021).
This first step aims to prepare the peat bog so that the fragments of plants that will be reintroduced can settle and grow in the best possible conditions. A few objectives are targeted, such as allowing for greater water retention on the site, promoting uniform water distribution, removing surface peat that would prevent contact between the plant fragments and the peaty substrate, and removing or use the vegetation present on the site (Bloodnick 2021). To accelerate the formation of a new plant carpet, the practice in Canada is to introduce plants, especially Sphagnum mosses, which are partly responsible for the unique characteristics of ombrotrophic bogs (Bloodnick 2021). Plant harvesting involves shredding the surface vegetation and then collecting it (Bloodnick 2021). Once the plants have been harvested from the donor sites, they must be spread over the site to restore in the correct quantity, to form a uniform layer on the peaty substrate (Bloodnick 2021). To help them to become established, straw is used as a protective cover (Bloodnick 2021). In addition to creating a roof for the plants in the form of a layer of air that remains cool and moist on the soil surface and isolated from the ambient air, it helps to maintain the water table at a higher level and prevents damage to the plants by frost heave (Bloodnick 2021). Fertilization is an optional step, which can be carried out in the first few years after restoration (Bloodnick 2021). Restoration monitoring is conducted for at least 10 years after restoration is started, often for scientific research purposes, to further the knowledge we collectively have in this area.
Bloodnick, Ed. 2021. “6 Steps to Restore a Peat Bog”. Pro Mix. Accessed July 20 2021. https://www.pthorticulture.com/en/training-center/the-6-steps-to-restore-a-peat-bog/
EPA. n.d. “Classification and Types of Wetlands” Accessed July 18, 2021. https://www.epa.gov/wetlands/classification-and-types-wetlands#fens
Flanagan, Kathryn. n.d. “Peatlands – South Carolina” PowerPoint. Accessed July 18, 2021.
Flanagan, Kathryn. n.d. “Freshwater Swamps – Cypress/Tupelo Alluvial Swamps” PowerPoint. Accessed July 18, 2021.
Florida Museum. 2018. “Cypress trees are well-adapted to water-logged soils in the Everglades.” https://www.floridamuseum.ufl.edu/southflorida/habitats/cypress-swamps/.
Mitsch, William J., and James G. Gosselink. 2015. Wetlands. John Wiley & Sons, Inc.
NatureWorks. n.d. “Bogs, Fens and Pocosins” Accessed July 18, 2021. http://www.nhptv.org/natureworks/nwep7f.htm
Comment by Will Magnum:
In regard to question 1, the initial sentence provides me with an initial thought that Ashepoo river is vital to the ecosystem. Wildlife that lives in the ecosystem cannot adapt to changing environments which convinces me that a dam would disrupt the whole ecosystem. The levels of pH are also to be noted when considering a dam because an increase or decrease can kill vegetation that supports the ecosystem as primary and secondary producers. The lack of wildlife and vegetation needing to adapt to changing environments has caused the ecosystem to form a sort of homeostasis. The lack of certain resources would cause wildlife to retreat and now there are species dying out because there is an imbalance in population. You do a great job of providing great opinions backed by evidence. I am convinced to not build a dam but I may be biased, thanks for the great post!
Good point that the levels of pH are important to note when considering vegetation health. Plants being producers, it does pH itself does have astronomical implications in the entire food chain’s context.