Wetland ecology is a complex subject that draws from several scientific disciplines. While classroom lectures are necessary to teach the vast body of scientific data, there is no substitute for field and laboratory experiences to enrich learning. This paper describes methods for teaching a wetland ecology class based mainly on direct, hands-on field experiences for students.

“Help! I have to teach wetland ecology! What are you doing?” I was no stranger to this plea, having made it myself to colleagues years earlier. When I accepted a position teaching wetland ecology at the University of Maryland, I contacted people I knew who were leading similar courses, incorporated field and laboratory techniques that I had used in graduate school, and researched new methods to fill in the gaps. Many more techniques are available, however, than can be used in a semester-long course. The difficulty comes in selecting activities that students will like, finding the time and facilities needed, and determining the types and proximity of wetlands.

Courses in environmental biology or ecology lend themselves naturally to exciting outdoor experiences (e.g., Grove 1984; Stephens et al. 1988). Many of the field trips described in the literature, however, are travel-study courses lasting from a week to a month (Grove 1984; Lopushinsky and Besaw 1986; Stephens et al. 1988; Ferrier 1989). Only a few papers discuss how to incorporate field and laboratory exercises into semester-length ecology classes (Gill and Burke 1999; Cahoon 1996; Switzer 1995), possibly because of the difficulties of developing and implementing effective field exercises for a three-to-four-hour lab period.

Despite the wealth of possibilities for interesting activities in wetland ecology specifically, I have only found articles that describe using wetlands to teach ecology at a community college (O’Neal 1995) and others on wetlands as outdoor classrooms for primary and secondary school education (e.g., Texley 1988; Kerr 1996; Stewart 1998). In one interesting and effective module of an undergraduate ecosystem ecology class, students evaluated quantitative data from journal articles related to wetland biogeochemistry to see how the data corresponded to criteria for wetland delineation (Camill 2000). While this class did incorporate a lab, the focus of the paper was on a wetland biogeochemistry case study, which did not involve student field or lab work.

Wetland ecology is an increasingly popular course offering in the United States and elsewhere (a list of colleges and universities offering courses or programs in wetland science or ecology can be found on the Society of Wetland Scientists’ website at http://www.sws.org) and a subject students want to learn more about. From press stories about conflicts between developers and conservationists to media reports on heated debates in Congress over ecological funding, wetlands are making the news. They are becoming widely recognized for their role in flood storage, water quality improvement, recreation, and fisheries support (e.g., Mitsch and Gosselink 2000), not to mention their function as habitat for rare plants and animals. The regulation of wetlands as “Waters of the United States” under Section 404 of the Clean Water Act has led to an industry of environmental consultants, regulators, and lawyers that identify and delineate wetlands, mitigate wetland impacts, and develop and enforce wetland regulations and policy.

In my wetland ecology course at the University of Maryland, I discuss the scientific and socioeconomic elements of this complex, multidisciplinary subject. The basic sciences, which are the primary emphasis in my course, include plant biology, hydrology, soil science, biogeochemistry, ecosystem processes, and statistics and data analysis. Because students may find work in private industry or government, I also introduce the major aspects of applied wetland science, including wetland creation, restoration, mitigation, and assessment. Finally, because wetland scientists inevitably have to deal with regulators and the general public, I touch on political and economic issues related to wetlands.

The broad range of topics in wetland ecology is difficult to deal with in a traditional classroom setting. While lectures are critical for passing on technical and policy information in a systematic manner, they are not well suited for teaching field or laboratory techniques. To deal with the range of issues related to wetland science, I use a combination of lecture and laboratory sessions and occasional Saturday field trips.

Course Structure

The objective of the lecture, which meets one hour per week, is to provide as much information as possible on the major aspects of wetland science. (Click here to see a list of lecture topics covered in the course.) Because of the short time available for lecture, I rely heavily on Wetlands (Mitsch and Gosselink 2000), which is widely considered to be one of the best overall texts on the subject, and a publication on local wetlands (Tiner and Burke 1995).

I begin the course with general information on wetlands, such as how they can be defined, the general types of wetlands that exist around the globe, the areal extent of wetlands, and wetland impacts. In the remainder of the course, I deal mostly with the “science” aspects of wetlands: their soil, hydrology, and plant and animal communities. But even if the lecture were three hours per week, it would not be possible to describe in sufficient detail the characteristics of all the wetland types. I therefore have chosen to focus on salt and brackish marshes for three reasons: (1) a tremendous amount of scientific research has been done in these systems; (2) many of the processes and factors operating in salt and brackish marshes are also the same as those found in other wetland types (e.g., hydrologic effects on decomposition and redox status, salinity effects on plants and animals); and (3) they are an important wetland type in the mid-Atlantic region and one that we see on field trips.

Finally, I introduce the applied wetland science topics of wetland assessment, restoration, mitigation, and construction. These topics are too broad to cover in any great detail (we have an entire course in our program devoted solely to constructed wetlands); however, we do visit restored and managed wetlands during the laboratory period, and students often look at restored or constructed wetlands during their group projects.

The bulk of class time is spent in the laboratory, which meets four hours per week. The goals of the laboratory are three-fold. First, I want students to see natural, restored, and managed wetlands common in the mid-Atlantic coastal region. Second, I want them to gain hands-on experience with common field techniques used in sampling or describing wetland soil, vegetation, and hydrology (these being three areas relevant to applied and basic wetland science). Last, I want them to analyze, summarize, and present environmental data effectively.

The laboratory is divided into two parts. During the first part, which comprises about two-thirds of the semester, we travel to various wetland sites, learn to identify wetland plants, and collect plant, soil, and hydrologic data (table 1). We have visited restored and natural, tidal and nontidal, and fresh and saline wetlands (both swamps and marshes) within a few hours’ drive of our campus. The methods we use are based on a number of sources (see table 1), which I compile into simplified written procedures to streamline the labs. Data collected during this part of the course are pooled; students e-mail me their data in spreadsheet files, which I combine and send to the whole class. Because we work in groups, replicate data are usually available for each sample location. Each student prepares a lab report on some aspect of the pooled data, and I give them individualized feedback on their writing style, data analyses, tables, and graphs. Also during this part of the semester, students work individually on a plant collection. [For project descriptions, see “Lab Components” below.]

For the last third of the semester, the students work in groups on a wetlands-related project of their choosing. At the end of the semester, each group delivers a presentation on their project accompanied by a detailed handout outlining their work complete with maps, tables, and graphs.

Lab Components

Plant Taxonomy
The ability to distinguish and recognize plants typical of wetlands is a critical tool for describing and delineating wetlands. While plant communities of a particular area are a result of hydrology, soil, climate, and other factors, plants are the most readily recognizable feature of wetlands. For this reason, we begin learning common wetland plants during the first laboratory session. Students collect plant specimens, identify them using taxonomic keys or field guides, and create pressed dried specimens. I require the Field Guide to Coastal Wetland Plants of the Southeastern United States (Tiner 1993), which contains excellent illustrations and descriptions, as well as easy-to-use taxonomic keys.

Students are required to submit a collection of at least 25 species of plants mounted and placed in plastic sheet protectors in a three-ring binder. Specimens must include flowering or fruiting material and leaves, and be labeled with scientific and common names and location and date collected. After grading the plant collections I return them so that the students will each have a “mini-herbarium” they can use in the future. Invariably some students find this project to be the most satisfying aspect of the course, possibly because a successful collection requires an artistic sensibility that they rarely have the opportunity to apply elsewhere in their studies.

Vegetation Sampling
Describing plant communities is necessary for delineating and assessing wetlands for biological diversity, wildlife habitat value, and other purposes. Working in groups of three to five people, students perform qualitative, semiquantitative, and quantitative sampling in a number of different wetland types (table 1). Measures of abundance used include cover, density, frequency, and biomass of plant species determined using plot and line-intercept techniques. Students also use the Corps of Engineers Wetlands Delineation Manual (Environmental Laboratory 1987; can be downloaded from http://www.wes.army.mil/el/wetlands/) and the National List of Plant Species that Occur in Wetlands (Reed 1988; this version as well as the 1996 draft version can be downloaded from http://www.nwi.fws.gov/bha/) to determine if the areas they have sampled contain hydrophytic (i.e., wetland) vegetation.

In their lab reports, students gain experience analyzing and presenting vegetation data. Working with vegetation data is rarely a straightforward task because there are a number of ways to analyze and present the data and there are multiple species to deal with.

Soil and Hydrologic Methods
Again working in groups, students examine soils in soil pits or cores for indicators of hydric (i.e., wetland) soils. The wetlands delineation manual (Environmental Laboratory 1987) and Field Indicators of Hydric Soils In the United States (USDA 1996; the 1998 version can be downloaded from http://www.statlab.iastate.edu/soils/hydric/) are used to identify and describe hydric soils. Soil samples are collected and analyzed in the lab for organic matter content, bulk density, and percent moisture (table 1). Soil salinity, an important parameter in salt and brackish marshes, is measured in the field by squeezing water from soil through filter paper in a large syringe and determining salinity using a refractometer. Salinity of surface water or water in cored holes is measured using a refractometer or a portable salinity meter.

Quantifying the hydrology of a particular wetland requires long-term measurement of hydrologic parameters, such as surface water inflow and outflow, water level, and ground water flow. However, there are several measurements that can be used to identify the presence of wetland hydrology. One is the oxidation-reduction, or redox, status of soils, which is a critical measure of the biogeochemical environment of wetlands that is dependent on hydrology. Wetland soils are predominantly anaerobic because of soil waterlogging, but contain areas of aerobic conditions as well, which together create an environment conducive to microbial transformation of substances. A simple but visually effective way to demonstrate the chemically reducing environment in wetlands is to stick large nongalvanized nails into wetland and nearby upland soils, return in a few weeks, and observe the amount of orange coloration on the nails. The upland nails will typically be more orange (rusty, oxidized iron) than the wetland nails, which will be pristine or contain dark patches (gray, reduced iron). Another simple visual test is to use an a,a’-dipyiridil solution, which turns pink when placed on soils containing reduced iron (Environmental Laboratory 1987). A more quantitative approach is to use platinum redox electrodes to measure redox potential, which can be purchased or made (Faulkner et al. 1989; Patrick et al. 1996). The meaning of the redox potential measurements seems to be clearer to students after they have done the visual tests.

Other indicators of wetland hydrology are described in the wetlands delineation manual (Environmental Laboratory 1987) that can be used to determine if a particular area exhibits wetland hydrology. These include observation of watermarks on trees, sediment deposited on vegetation, drainage channels or scouring, standing water, and saturated soils. Along with vegetation data, students analyze and present soil and hydrologic data from these exercises in their lab reports.

Group Project

Working in groups of three to five (not necessarily the same groups as in the first portion of the course), students design and implement a study of some aspect of wetland ecology. To help students identify a project, I begin with a brainstorming activity where I write potential project ideas on the board and discuss the problems with or value of their various ideas. We have about a month in which to collect data for a project, so time is a crucial consideration in developing meaningful projects. We then break into groups for discussion of these ideas, returning after about 30 minutes to the board to identify broad group topics and assign class members to the various groups. This phase of project development usually takes two to three hours.

A week later, each group submits a brief proposal that includes background literature on their topic, research questions or hypotheses, and proposed methods. The methods can include those we have experienced in lab or other techniques that they are familiar with or want to learn. I review their proposals and work with the groups individually over the course of a lab period to refine their study design and methods. Some groups develop excellent research questions, but I need to guide them toward something manageable and emphasize that their projects will probably raise more questions than it will answer, given the short time frame available (many ecological studies span years). Other groups need input on asking relevant questions and tailoring the methods to address those questions. Additional issues that we deal with during this project development phase include selecting study sites, deciding how many replicates they will have and how many times they will sample, and adapting methods to best answer their specific research questions.

After the groups finalize the experimental approach to their project, they spend the bulk of the remaining three to four lab periods and time outside of class collecting and analyzing data. This allows them to make repeated measurements at their study sites. During the last lab period, each group delivers a 30-minute presentation on their project using slides, overheads, or a computer projector. Each group also submits a handout to the entire class that includes a detailed written outline of their project as well as figures and tables. The format of the handout follows typical scientific format (Introduction, Methods, Results, and Discussion), although I generally urge them to combine results and discussion for the presentation. The presentations usually occupy an entire four-hour lab period because of questions, discussion, technical glitches, and a break halfway through.

When given the freedom to come up with research ideas, many of my students rose to the occasion and went beyond what was necessary to create exceptional projects (fig. 1). The topics they have chosen encompass basic ecological questions as well as aspects of applied wetland science, such as functional assessment, wetlands delineation, and wetland construction and restoration.

What Works and What Doesn’t

A common thread appeared after two years of responses to course evaluation questions: students find the hands-on aspect of the course very useful. Written student comments on end-of-semester evaluations included “Field experience was great!” and “Fieldwork aspect is very useful!” Some students also told me that analyzing and presenting data from a project they had designed and implemented was a great experience and that the presentations were the best they had seen in any class. Responses on student evaluations supported this, indicating that the lab activities were valuable in increasing their experimental design, data analysis, and communication skills (table 2).

On the negative side, this course can be difficult to schedule because it is hard to predict how much time will be required for field and lab activities and administering the group project. Thus, some level of disorganization usually occurs, although this has improved with repeated teaching of the course. For example, I have had to shift due dates for some of the assignments and field trips because they conflicted with my original dates for starting the group project. One student commented, “The class lab project could have been better structured.” Some students also were unclear about how to approach the lab report, which is based on data collected on various parameters at a range of sites during the first portion of the course. One student “found requirements for lab report vague” and another said politely, “Making the lab report description clearer would be helpful.” Students find it difficult to write the lab report in standard scientific format because the data do not fit neatly into a single hypothesis or question, but I view this as a valuable exercise because the students have to think about the data they want to analyze rather than follow a “cookbook” lab report model.

Another issue is the time required to find field sites, work out the details of the methods, and obtain the necessary equipment. After teaching the course several times, however, I found that my time input has decreased, with only minor modifications necessary to keep the course up-to-date and interesting (for me as well as the students!).

I concluded from both the course evaluations and my years of teaching that wetland ecology is a course that greatly benefits from field and laboratory activities. Most regions of the world contain wetlands, and field and laboratory exercises relating to soil, vegetation, and hydrology are easy to do and do not require expensive or complicated equipment. I have found that coupling lectures with an excellent textbook is an efficient means of passing on scientific and technical information to students, and field and laboratory activities help them to see the connection to that information. The fieldwork also gives students knowledge of an ecosystem that cannot be conveyed in a classroom lecture. The colors, sounds, smells, and textures experienced in a real wetland leave a lasting impression that make the facts and figures all the more relevant.

Andrew Baldwin is an assistant professor of natural resources management, department of biological resources engineering, University of Maryland, College Park, MD 20742; e-mail: ab174@umail.umd.edu.

Acknowledgments

The author would like to thank Irv Mendelssohn of Louisiana State University for teaching excellent wetland courses that influenced his own teaching style, Steve Faulkner, also of LSU, for helping with techniques related to wetland biogeochemistry, soil, and hydrology, and Paula Tanner Baldwin and anonymous reviewers for helpful comments on the manuscript.

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