Ecosystem Services: Developing Sustainable Management Paradigms Based on Wetland Functions and Processes

Abstract

In the late nineteenth century and twentieth century, there was considerable interest and activity to develop the United States for agricultural, mining, and many other purposes to improve the quality of human life standards and prosperity. Most of the work to support this development was focused along disciplinary lines with little attention focused on ecosystem service trade-offs or synergisms, especially those that transcended boundaries of scientific disciplines and specific interest groups. Concurrently, human population size has increased substantially and its use of ecosystem services has increased more than five-fold over just the past century. Consequently, the contemporary landscape has been highly modified for human use, leaving behind a fragmented landscape where basic ecosystem functions and processes have been broadly altered. Over this period, climate change also interacted with other anthropogenic effects, resulting in modern environmental problems having a complexity that is without historical precedent. The challenge before the scientific community is to develop new science paradigms that integrate relevant scientific disciplines to properly frame and evaluate modern environmental problems in a systems-type approach to better inform the decision-making process. Wetland science is a relatively new discipline that grew out of the conservation movement of the early twentieth century. In the United States, most of the conservation attention in the earlier days was on wildlife, but a growing human awareness of the importance of the environment led to the passage of the National Environmental Policy Act in 1969. Concurrently, there was a broadening interest in conservation science, and the scientific study of wetlands gradually gained acceptance as a scientific discipline. Pioneering wetland scientists became formally organized when they formed The Society of Wetland Scientists in 1980 and established a publication outlet to share wetland research findings. In comparison to older and more traditional scientific disciplines, the wetland sciences may be better equipped to tackle today’s complex problems. Since its emergence as a scientific discipline, the study of wetlands has frequently required interdisciplinary and integrated approaches. This interdisciplinary/integrated approach is largely the result of the fact that wetlands cannot be studied in isolation of upland areas that contribute surface and subsurface water, solutes, sediments, and nutrients into wetland basins. However, challenges still remain in thoroughly integrating the wetland sciences with scientific disciplines involved in upland studies, especially those involved with agriculture, development, and other land-conversion activities that influence wetland hydrology, chemistry, and sedimentation. One way to facilitate this integration is to develop an understanding of how human activities affect wetland ecosystem services, especially the trade-offs and synergisms that occur when land-use changes are made. Used in this context, an understanding of the real costs of managing for a particular ecosystem service or groups of services can be determined and quantified in terms of reduced delivery of other services and in overall sustainability of the wetland and the landscapes that support them. In this chapter, we discuss some of the more salient aspects of a few common wetland types to give the reader some background on the diversity of functions that wetlands perform and the specific ecosystem services they provide to society. Wetlands are among the most complex ecosystems on the planet, and it is often difficult to communicate to a diverse public all of the positive services wetlands provide to mankind. Our goal is to help the reader develop an understanding that management options can be approached as societal choices where decisions can be made within a spatial and temporal context to identify trade-offs, synergies, and effects on long-term sustainability of wetland ecosystems. This will be especially relevant as we move into alternate climate futures where our portfolio of management options for mitigating damage to ecosystem function or detrimental cascading effects must be diverse and effective.

Author was deceased at the time of publication

Appendices

Student Exercises

5.1.1 Classroom Exercises

5.1.1.1 Classroom Exercise #1: Tradeoffs of Ecosystem Services

A slope wetland that was impounded to benefit waterfowl in western North Dakota (Fig. 5.8) is an example of how converting one wetland type to another results in tradeoffs in ecosystem services. These types of wetland conversions present ideal examples to explore the topic of tradeoffs that have been discussed throughout this chapter. While observing Fig. 5.8, think about what tradeoffs may have occurred as a result of dam construction. Do you think these tradeoffs were considered in the planning process for this project? How might consideration of these tradeoffs have affected the decision to create a wildlife impoundment in this area? How do this chapter’s concepts of “ecological fit” and “sustainability” introduced in this chapter apply to this situation? Hint: When considering this last question, think about sedimentation and evapo-concentration effects as the natural flow of water through the slope wetland is intercepted by the wildlife impoundment.

Fig. 5.8

This photograph shows a slope wetland in western North Dakota. The open water area at the lower left is a wildlife impoundment that has flooded a large portion of this rare wetland type. Additional damage to vegetation is visible in the center of the remaining slope wetland plant community resulting from water inundation when levels in the impoundment are higher than in the conditions shown. Damage to the wetland plant community has resulted in formation of channels, further degrading the integrity of the slope wetland

As part of the functional assessment exercise provided at the end of Chap. 2 (Volume 3), you performed a functional assessment across a disturbance gradient of 2–3 wetlands within an HGM class/subclass. This exercise, and the accompanying exercise on synergistic effects, will expand upon that earlier exercise and provide you the opportunity to explore tradeoffs and synergies among ecosystem services occurring in one of these wetlands. The question to be answered for this exercise is: What are some of the potential tradeoffs of ecosystem services that occur when one modifies wetland functional processes with an aim to increase a specific regulating, provisioning, or cultural service? Generally, any time a management action is executed, one service may be promoted while another service decreases (note: the same can be said of natural events such as drought or flooding). For example, a wetland manager may lower the water level in a marsh to promote food production for ducks (Anatini) thereby increasing the provisioning of waterfowl. At the same time water is being drained, however, the manager is affecting other animals such as grebes (Podicipedidae) that may require deeper waters or, from a different service perspective, the manager may be releasing carbon dioxide, which affects climate change benefits.

To begin this exercise, develop a set of three scenarios with each scenario’s focus being to increase a different service of interest within one of the wetlands you studied in the functional assessment exercise. Write a paragraph or two describing each scenario. Include a brief description of the wetland, your goal (i.e., which service you are attempting to modify), and management actions needed to reach your goal. Table 5.1 provides examples of services that you can draw upon, or better yet, create examples of your own. Using what you have learned in this and previous chapters (especially from the functional assessment exercise you completed), estimate the change, either positive or negative, resulting from the management actions described in each scenario for the service of interest and five other ecosystem services provided by the study wetland. Think about the changes in functional processes services needed to bring about the desired change in the service you are focused on maximizing and the effects that these changes may bring about to the other services provided by the wetland ecosystem. Revisiting the wetland(s) that you visited in the functional assessment exercise will be of great use in helping you to identify these services and underlying processes.

Table 5.1 Examples of wetland types or locations managed toward various utility class endpoints

Once you have identified the effects of the management actions described in your scenarios, create graphs for each scenario showing the positive and negative changes resulting from the effort to increase the service you selected. Tradeoffs are best identified when the effects of an action on multiple ecosystem services can be simultaneously quantified and/or visualized. Spoke and wheel type graphs (Fig. 5.9) can be used to visualize multiple services simultaneously, thereby identifying potential tradeoffs. When creating your graph, be sure to think carefully about all of the processes involved within the wetland ecosystem and how each might affect a particular service. Pay particular attention to supporting functions/services. We provide a blank spoke and wheel graph template for your use in this exercise. However, feel free to use a computer graphing program or another graph type if you think that it better suits your needs.

Fig. 5.9

Spoke-and-wheel graphs depicting potential outcomes of the four Millennium Assessment scenarios (Bennett et al. 2005) on ecosystem services provided by wetlands. The bold line in each graph represents the response of the wetland ecosystem in terms of services provided to society under a particular scenario. Values between 0 and 1 indicate a positive response; those between 0 and −1 indicate a negative response. The Global Orchestration scenario represents a society controlled by global markets with a slow, reactive approach to global environmental problems. The Order from Strength scenario represents a society that is focused on economic security and protection giving little attention to common services provided by ecosystems. The Adapting Mosaic scenario represents a society focused on local ecosystem management and improving knowledge about ecosystem functioning. The TechnoGarden scenario represents a society relying on technology and engineered ecosystems to provide needed goods and services. The bold line in each graph represents the response of wetland ecosystem in terms of services provided to society under a particular scenario

Looking at the completed graphs, discuss within your class how a decision to purposefully increase the provisioning of a particular service might be affected by consideration of the tradeoffs that occur. Do you think that better decisions can be made when multiple services are considered simultaneously rather than when single services are considered in isolation? If a particular service is negatively affected to an unacceptable extent, is there another way to increase the targeted service while simultaneously reducing the unintended impact to this other service? Perform a literature search and find an example of a study that quantifies the results of a management action on a single wetland service. In the discussion by the author(s), are potential effects on other ecosystem services identified? Also, see if you can find an example in which the author(s) examines multiple ecosystem services and discuss potential tradeoffs.

5.1.1.2 Classroom Exercise #2: Synergistic Effects on Ecosystem Services

In the previous exercise, you focused on identifying and evaluating trade-offs associated with managing wetland ecosystems toward various utility-class endpoints. Knowledge of these trade-offs is necessary for making sound decisions about how a society chooses to manage wetland ecosystems and their services. However, while considering trade-offs is required for sound decision-making, treating them as isolated effects can also lead to faulty decisions. In this exercise, we will explore a second type of interaction among services that should be considered in the decision-making process: synergisms. Synergies occur when multiple forces affect an ecosystem service in a manner such that their combined effect is greater than the effect that would be anticipated by considering each force separately. That is, these forces operate in a multiplicative or exponential rather than an additive fashion. As an example, Euliss and Mushet (2004) explored the impacts of water development on aquatic invertebrate, amphibian, and plant communities of wetland ecosystems in western North Dakota. They found that increases in water depths, hydroperiods, and dissolved salts had profound effects on the biotic communities of wetlands that had been excavated to increase the provisioning of waterfowl habitat and cattle watering services. The synergistic interactions of water depth, hydroperiod, and dissolved salts produced invertebrate, amphibian, and plant communities that could not have been predicted by considering any of these three factors separately.

As you observed in Exercise #1, trade-offs in ecosystem services most often are evaluated through changes in provisioning or regulating services. In the Euliss and Mushet example, an increase in the provisioning of waterfowl habitat and cattle-watering services led to an easily observed trade-off of decreased habitat for native plant, invertebrate, and amphibian communities adapted to the shallower waters, shorter hydroperiods, and dissolved salt concentrations reflective of the semi-arid nature of the region. However, determining the strength or even the direction of synergistic interactions remains a major challenge to the management of ecosystem services (Rodríguez et al. 2005).

For this exercise, revisit the graphs you constructed in Exercise #1. Your graphs depict provisioning, regulating, and/or cultural services. However, synergisms primarily occur at the level of wetland functional processes. Thus, the identification of these processes is key to estimating the sustainability of any particular provisioning, regulating, or cultural service. Additionally, as we highlighted throughout this chapter, some changes to functional processes develop so slowly that it might take years before clear evidence of their effects on services becomes evident. These critical but slow-acting processes may cause positive or negative synergistic influences on the services we seek to enhance. Decomposition rates in wetlands and how they are altered when wetland hydroperiods are manipulated to be longer or shorter than normal; geochemical processes leading to changes in solute concentrations when historic flushing or evapotranspiration rates are modified; and hydrologic processes leading to the chronic accumulation of sediments in a wetland are all examples of functional processes that can change slowly over long periods. Some supporting services may react so slowly that their effect on other wetland services is ignored or not even considered. Such a strategy can be a careless one if our goal is to manage for long-term sustainability of wetland ecosystem services.

For this exercise select one provisioning, regulating, or cultural service that you maximized in the graphs developed in Exercise #1. You have already identified several trade-offs associated with focusing management towards increasing this service. Now take a more in-depth look at the consequences of this management strategy. Create a list of functional processes that you believe can have an effect on the service you selected. Try to include at least one process that may change very slowly over time and that might often be overlooked. Now create a diagram (as in Fig. 5.10) that illustrates the connection between the functional processes and the service you selected. While creating your diagram, think about synergistic connections among functional processes and identify these connections in your diagram. One way to create your diagram would be to connect two or more processes that you believe would have synergistic effects with lines that intersect. After the lines intersect, use a line width wider than the combined width of the lines that intersected to finish the connection to the service you selected (see Fig. 5.10). Continue connecting processes to the service until all connections and synergisms are identified. If the diagrams created by each student (or group of students) are created in a manner that allows them to be viewed by the entire class, use these to discuss the idea of synergisms. Now that the synergistic relations have been identified, revisit the graphs you created in Exercise 1 of this chapter. Do you see any services where you would change the extent of the positive or negative change based on consideration of potential synergisms?

Fig. 5.10

Example figure showing connection between ecological processes and a service of interest. Changes in line widths indicate synergistic effects

Suggested Reading

Allen JA, Keeland BD, Stanturf JA, Clewell AF, Kennedy HE Jr (2001) A guide to bottomland hardwood restoration. U.S. Geological Survey, Biological Resources Division Information and Technology Report USGS/BRD/ITR-2000-0011. U.S. Department of Agriculture, Forest Service, Southern Research Station, General technical report SRS-40, 132 pp

Bolen EG, Smith LM, Schramm HL Jr (1989) Playa lakes: prairie wetlands of the Southern High Plains. Bio Sci 39:615–623

Brinson MM (1990) Riverine forests. In: Lugo AE, Brinson MM, Brown SL (eds) Forested wetlands, vol 15. Ecosystems of the world. Elsevier Science Publishers B.V., Amsterdam

Clark JR, Benforado J (1981) Wetlands of bottomland hardwood forests. Elsevier Scientific Publishing Co., Amsterdam

Euliss NH Jr, LaBaugh JW, Fredrickson LH, Mushet DM, Swanson GA, Winter TC, Rosenberry DO, Nelson RD (2004) The wetland continuum: a conceptual framework for interpreting biological studies. Wetlands 24:448–458

Euliss NH Jr, Smith LM, Wilcox DA, Browne BA (2008) Linking ecosystem processes with wetland management goals: charting a course for a sustainable future. Wetlands 28:553–562

Euliss NH Jr, Smith LM, Liu S, Feng M, Mushet DM, Auch RF, Loveland TR (2010) The need for simultaneous evaluation of ecosystem services and land use change. Environ Sci Technol 44:7761–7763

Gosselink JG, Lee LC, Muir TA (1990) Ecological processes and cumulative impacts: illustrated by bottomland hardwood wetland ecosystems. Lewis Publishers, Chelsea

Hodges JD (1997) Development and ecology of bottomland hardwood sites. For Ecol Manage 90:117–125

Sharitz RR, Mitsch WJ (1993) Southern floodplain forests. In: Martin WH, Boyce SG, Esternacht AC (eds) Biodiversity of the southeastern United States: lowland terrestrial communities. Wiley, New York, pp 311–372

Smith LM (2003) Playas of the great plains. University of Texas Press, Austin

Smith LM, Haukos DA, McMurry ST, LaGrange T, Willis D (2011) Ecosystem services provided by playa wetlands in the High Plains: potential influences of USDA conservation programs and practices. Ecol Appl 21:S82–S92