Potential Midterm Exam Questions

There are several formal and legal definitions of wetlands. These definitions are needed by scientists who conduct research on wetlands and by managers who are involved in enforcing regulations and laws concerning wetlands. Current United States legal definitions (US Army Corp of Engineers) define wetlands based on three primary indicators?
a.) In detail, what are these specific indicators?

b.) Which indicator would be the most important? Why?

c.) Given this type of defintion, discuss some of the potential difficulties in defining a wetland?

-U.S. Corp of Engineers definition: hydrophytic vegetation, hydric soils, and wetland hydrology.

Mitsch and Gosselink classify US wetland habitats into differing categories. Describe each of these wetland categories? What specific wetland habitat in the classification scheme occupies the largest area?

-Marine wetlands: associated with oceans and coastal environments
-Estuarine wetlands: where freshwater and marine waters interact, examples include tidal marshes and mangrove systems.
-Riverine wetlands: associated with rivers and streams, frequently influenced by flooding.
-Lacustrine wetlands: Associated with lakes
-Palustrine wetlands: Inland wetlands dominated by vegetation rather than large open-water systems. Includes many: marshes, swamps, bogs, forested wetlands, shrub wetlands, etc. because they occupy the largest area of the U.S. wetland categories in many classification schemes.

R.G. Wetzel (1990) Land-water interfaces: Metabolic and limnological regulators. In his article, Robert G. Wetzel opines that land-water interfaces (wetlands) often control the metabolic stability of adjacent water bodies. What does Wetzel mean by metabolic stability? What are some of the arguments made in his article that support his view?

You work for an environmental firm that delineates wetlands. A township has hired your firm to perform an environmental impact assessment on a local wetland. You are in charge of this assessment. One of the first tasks you must perform is a determination of the wetland water budget.

a.) What are the components of a wetland water budget? Provide a schematic diagram?

b.) You and a colleague determine that there are two main tributaries to this wetland. How could you determine a continuous “daily” input to this wetland without a lot of expended effort?

c.) How might the water budget for this wetland be different from other wetland types? Give two examples.

Briefly describe the ecological status of wetlands. Why are they unique? Are they “aquatic” or “terrestrial”? Why are they of interest to ecologists?

What are the major differences in aerobic and anaerobic organic matter decomposition? What factors will determine how quickly organic matter decomposes within a wetland? What kind of organisms will be involved?

Wetland soils have certain characteristics that are different from upland (terrestrial) soils.
a.) What components make up wetland soils?
b.) How do you determine you have a wetland soil?
c.) What component/processes are responsible for soil coloration?
d.) How is coloration determined?

Why does water saturation lead to anaerobic conditions in wetland soils? What factors might affect the rate at which a soil will become anaerobic after it is flooded? What is meant by increasing reducing conditions in wetland soils? How are increased reducing conditions formed in wetland soils?

Why are wetlands considered an important part of the global carbon cycle? What possible impacts might they have (both positive and negative) on global warming? What type of wetland system might be the most important in this regard? Why?

Discuss in detail some of the functional values of wetlands? Below is table from Mitsch et al. giving some estimated monetary values of various ecosystems? In this table estuaries are ranked very high. Why?

Mitsch and Gosselink indicate that wetlands are often considered as being sinks, sources or transformers of materials. What does this mean? Are wetlands one or the other, or can they be all three? Why? Give some examples.

You have been given the task of conducting a wetland delineation on a 10-acre parcel of land that is slated for urban development. The area is comprised of a three-acre lake surrounded by two acres of emergent vegetation. The remaining five acres is a mix of forested and scrub-shrub habitat (ex: woody species). The site is within the jurisdiction of the Army Corps of Engineers. Clearly explain what your approach would be for conducting a formal wetland delineation. Be sure to incorporate what available data you would use, the number of transects you might use onsite, and the number of sample locations within each transect. You may want to draw a hypothetical site plan justifying your answer.

R.W. Tiner (1991) The concept of a hydrophyte for wetland determination. In his article, Tiner examines the concept of hydrophytic plants and how they relate to wetland identification and delineation. Furthermore, he examines the adaptive feature of these plants to wetland habitats. Tiner states that wetlands must be properly identified. What is Tiner’s definition of hydrophytic vegetation? What is Tiner’s main argument for the application of the hydrophyte concept to wetland identification and delineation? What problems arise in the use of this concept? What additional factors does Tiner advocate in wetland identification and delineation? Are they justified? Why?