Dean B. Premo
White Water Associates
Douglas R. Knauer
Wisconsin Department of Natural Resources
The need for practical application of aquatic ecosystem science to water quality and ecosystem health challenges has never been more pressing. Human activities and support systems are inextricably woven together with freshwater and aquatic ecosystems, yet human activities continue to degrade the quality of both. This paper discusses human impacts on aquatic ecosystems of the United States by reviewing the status of rivers, lakes, and wetlands and summarizing the most important sources of degradation and loss. It outlines areas where improved knowledge can help avoid and mitigate water resource problems; urges a commitment to interdisciplinary, interagency research on the part of governments, agencies, and scientists; cites two successful models of such commitment; and champions the role of monitoring in improving conservation technology and guiding future research.
One measure of the relevance of a natural resource science is how much it contributes to management of an environment stressed by innumerable human uses and activities. The paradoxical predicament of humans, who simultaneously require fresh water and intact aquatic ecosystems yet diminish the quality and amount of these resources, can be remedied only by concerted application of aquatic ecosystem science integrated with the efforts of many other disciplines and interests. This paper addresses several issues that compel and frame applied research in aquatic ecosystem science.
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Freshwater Ecosystems: Revitalizing Educational Programs in Limnology Applied Aquatic Ecosystem Science Dean B. Premo White Water Associates Amasa, Michigan Douglas R. Knauer Wisconsin Department of Natural Resources Monona, Wisconsin SUMMARY The need for practical application of aquatic ecosystem science to water quality and ecosystem health challenges has never been more pressing. Human activities and support systems are inextricably woven together with freshwater and aquatic ecosystems, yet human activities continue to degrade the quality of both. This paper discusses human impacts on aquatic ecosystems of the United States by reviewing the status of rivers, lakes, and wetlands and summarizing the most important sources of degradation and loss. It outlines areas where improved knowledge can help avoid and mitigate water resource problems; urges a commitment to interdisciplinary, interagency research on the part of governments, agencies, and scientists; cites two successful models of such commitment; and champions the role of monitoring in improving conservation technology and guiding future research. INTRODUCTION One measure of the relevance of a natural resource science is how much it contributes to management of an environment stressed by innumerable human uses and activities. The paradoxical predicament of humans, who simultaneously require fresh water and intact aquatic ecosystems yet diminish the quality and amount of these resources, can be remedied only by concerted application of aquatic ecosystem science integrated with the efforts of many other disciplines and interests. This paper addresses several issues that compel and frame applied research in aquatic ecosystem science.
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Freshwater Ecosystems: Revitalizing Educational Programs in Limnology Four topics related to applied research are discussed. The section on human impacts on aquatic ecosystems outlines examples of the major societal concerns regarding degradation of aquatic ecosystems and characterizes the scope and severity of the problems. These issues are presented to illustrate the diversity of challenges that face today's aquatic ecosystem scientists. Often societal and scientific opinions differ as to the relative importance of these issues. The section on technology and research needs frames the diversity of practical knowledge required to address today's aquatic resource problems. The section on scientific infrastructure discusses the academic, governmental, private, and societal foundation necessary to advance aquatic resource conservation. The final section on monitoring management strategies, details the importance of careful review of management activities as the best way to improve conservation technology and to guide future research. It promotes monitoring as a legitimate research activity equally deserving of funds. HUMAN IMPACTS ON AQUATIC ECOSYSTEMS Human-caused impacts on aquatic ecosystems are inevitable. As aquatic ecosystems evolve, society's course of action should be to understand the rate of change that is occurring and to decide whether society can, or should, intercede to slow the processes that control change. These decisions require social, economic, and scientific considerations. There are numerous human-caused environmental impacts on rivers, lakes, ground water, and wetlands. Some of these impacts are highly visible, such as draining of wetlands and flooding of large tracts of land to create reservoirs. Other impacts are not so easily observed, such as the bioaccumulation of mercury in top predators and the loss of biological diversity in lakes sensitive to acid deposition. Finally, there are undoubtedly impacts unknown to the current generation of scientists. Under Section 305(b) of the federal Clean Water Act, states must report the status of water quality assessments to the Environmental Protection Agency (EPA). According to these state assessments, improvements in wastewater treatment have led to enhanced stream water quality in the 20 years since the Clean Water Act was first passed, but nonpoint sources of water pollution and toxic substances remain serious problems (EPA, 1994). The EPA recommends that states assess water quality based on the following individual beneficial uses: Aquatic life support: The water body provides suitable habitat for survival and reproduction of desirable fish, shellfish, and other aquatic organisms. Fish consumption: The water body supports a population of fish free from contamination that could pose a human health risk to consumers.
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Freshwater Ecosystems: Revitalizing Educational Programs in Limnology Shellfish harvest: The water body supports a population of shellfish free from toxicants and pathogens that could pose a human health risk to consumers. Drinking water supply: The water body can supply safe drinking water with conventional treatment. Primary contact recreation or swimming: People can swim in the water body without risk of adverse human health effects. Secondary contact recreation: People can perform activities on the water (such as canoeing) without risking adverse human health effects from occasional contact with the water. Agriculture: The water quality is suitable for irrigating fields or watering livestock. Regarding these beneficial uses, there are five levels of use support recognized by the EPA: Fully supporting overall use: All designated beneficial uses are supported fully. Threatened overall use: One or more of the designated beneficial uses are threatened and the remaining uses are supported fully. Partially supporting overall use: One or more of the designated beneficial uses are partially supported and the remaining uses are supported fully. Not supporting overall use: One or more designated beneficial uses are not supported. Not attainable: The state has performed a use-attainability study and documented that support of one or more designated beneficial uses is not achievable. The EPA defines impaired waters as the sum of water bodies partially supporting uses and not supporting uses. The data on rivers, lakes, and wetlands below are from 1992 state assessments under section 305(b) of the Clean Water Act as summarized by EPA (1994) for use in the Congress. Rivers The United States has approximately 3.5 million miles of rivers and streams. Of the 642,881 miles of rivers assessed by the states in 1992, more than one-third did not fully support designated uses. The five leading sources of river water quality impairment listed by the states were (1) agriculture, (2) municipal point sources, (3) urban runoff or storm sewers, (4) resource extraction, and (5) organic enrichment or low dissolved oxygen. Forty-five states identified almost 160,000 river miles impaired by agricultural sources.
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Freshwater Ecosystems: Revitalizing Educational Programs in Limnology Lakes The United States has about 39.9 million acres of lakes (excluding the Great Lakes). Of the 18 million acres assessed by the states in 1992, 35 percent failed to meet designated use criteria at times, 9 percent frequently failed to meet designated use criteria, and less than 1 percent of the lakes could not be used at all due to irreversible natural conditions or human activity. Metals and nutrients are the most common causes of nonsupport. An example of metal problems is the accumulation of excessive amounts of mercury in top predator game fish in lakes throughout the Northern Hemisphere. More than 33 states have issued fish consumption advisories because of elevated concentrations of mercury in game fish. Nutrient problems were reported widely by states. Forty-five states reported that agricultural runoff is the leading source of pollutants, impairing more lake acres than any other source. Agricultural runoff includes nutrients, organics, and pesticides. Thirty states reported that siltation impaired lakes and reservoirs. Priority organic chemicals, such as PCBs (polychlorinated biphenyls), were reported as significant in the number of lake acres they impaired (ranking eighth). Another indicator of water quality problems in lakes is the growth of organizations such as the North American Lake Management Society (NALMS) that resonate a strong societal concern. By 1994, NALMS had 20 state chapters comprised of local citizens interested in solving or preventing lake water quality problems. NALMS has actively promoted the involvement of citizens in lake sampling under the umbrella of government environmental agencies. The number of volunteers trained in lake sampling is impressive: 600 in Wisconsin, 3,000 in Texas, and 1,500 in Florida. Wetlands When European settlers first arrived in America, about 89 million hectares of wetlands existed in what would eventually become the conterminous states. Today, more than half of the original wetlands have been destroyed by filling, draining, polluting, channelizing, clearing, and other modifications resulting from human activities. In their water quality assessments for the Clean Water Act, 27 states listed agriculture and commercial development as the leading cause of wetland loss. Of 14 states that identified sources of pollutants that degrade wetlands, 11 ranked agriculture as the number one source. Agricultural runoff includes excessive levels of nutrients, organic matter, and pesticides. A U.S. Fish and Wildlife Service study of wetland loss found that 1.1 million hectares of wetlands were lost over a nine-year period (mid-1970s to mid-1980s), or about 117,000 hectares per year. Although this is a seemingly unacceptable rate of loss, it is an improvement compared with the 1950s to 1970s,
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Freshwater Ecosystems: Revitalizing Educational Programs in Limnology when wetlands were lost at a rate of 185,000 hectares per year. This improvement, however, cannot be considered satisfactory, because the United States continues to lose wetlands at a rate of at least 1 percent per year in spite of mitigation and restoration attempts. The poor-quality wetlands that result from many mitigation and restoration efforts are no substitute for the lost habitats, processes, and functions of natural wetlands. Serious consequences have resulted nationwide from the loss and degradation of wetlands, including species decline and extinction, water quality deterioration, and increased incidence of flooding. TECHNOLOGY AND RESEARCH NEEDS The need for enhanced interaction among the subdisciplines of aquatic science is nowhere more evident than in the area of applying this science to management and conservation of freshwater resources. In fact, knowledge from other disciplines (including social science and education) is necessary to improve the ability to address challenges of management, mitigation, and perpetuation of aquatic resources. The fact that aquatic science favors an ecosystem approach demands this interdisciplinary perspective—one that includes humans as an ecosystem component to be considered in nearly every applied strategy. Specific aquatic science technology and research needs are too many to list but include such disparate subjects as on-site waste disposal systems, the relationship between macrophyte beds and fish production, the role of nitrogen in macrophyte growth, bioaccumulation, wetland functions, transport and deposition of toxics, waterborne pathogens, buffer zones, best-management practices, control of exotic species, water quality reference sites, and ecological risk assessments. Organizing these and many other needs, prioritizing them, and then tackling them with well-designed research is a daunting responsibility, but it is crucial to the perpetuation of aquatic resources. The field of conservation biology has promulgated the construct of coarse filter and fine filter in order to advance biodiversity conservation (Noss, 1987; Hunter, 1990). This approach is used by the Nature Conservancy to address management issues ranging from endangered species to ecosystem perpetuation (Hudson, 1991). Hunter (1990) provided a lucid description of this approach. The coarse-filter approach to perpetuating biodiversity involves maintaining a variety of ecosystems, and assuming that this will include the majority of species in a region. The fine-filter approach is used in the case of individual species known to be very rare and vulnerable to ''passing through" the coarse filter. A perpetual dilemma in applied aquatic ecosystem science is the need to proceed with management activities despite the lack of complete knowledge required to solve a particular resource problem. Given this reality, the fine- and
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Freshwater Ecosystems: Revitalizing Educational Programs in Limnology coarse-filter construct provides a feasible tactic for applying aquatic ecosystem science to conservation and management. A hypothetical example of the fine-filter approach would be the perpetuation of a natural breeding population of brook trout (Salvelinus fontinalis ) in a cold-water stream. Meeting this objective would involve identifying healthy populations and appropriate spawning habitat and using this and other specific information to design suitable management strategies to maintain conditions. In this case, the management focus is on a single species. Control of cyanobacteria in a lake is also an application of a fine-filter approach. An example of the coarse-filter approach would be to plan and implement a variety of watershed management practices that perpetuate habitat for a natural diversity of warm- and cold-water fish species in various parts of the watershed. In this approach, neither brook trout nor cyanobacteria is the primary focus, but both are affected by the prescribed watershed practices. A coarse-filter approach allows the management net to be cast wide, even in the absence of complete information, and increases the likelihood that desirable outcomes will result. The fine-filter approach is a desirable complementary tactic, allowing treatment of issues not satisfactorily addressed by a broader suite of management practices. In the context of management of aquatic resources, a coarse-filter tactic can equate to a landscape or watershed approach. Integrating the aquatic and terrestrial systems, including the riparian ecotones (transition zones), is a necessary strategy to management of most aquatic ecosystems. The watershed perspective represents one of the identified practical approaches to defining ecological management landscapes around which conservation participants can rally and cooperate (Rogers and Premo, 1994). This perspective provides the appropriate ecological context for applying aquatic ecosystem science to conservation and management. There are research needs in the social sciences that will advance application of aquatic ecosystem science to resource problems. Many difficult jurisdictional and socioeconomic questions are often unresolved. Who conducts the management? Who is responsible for monitoring? Who funds the research? Who regulates compliance? If a landscape or watershed approach is adopted, answers to these questions are even more complex. In the United States, the "command-and-control" approach to "end-of-pipe" pollution has been successful. What remains, however, are the onerous problems of nonpoint sources of water quality degradation and the challenges of inducing landscape owners and managers to cooperate in management and land use so that nonpoint-source pollution is ameliorated. These social science challenges are not unique to aquatic ecosystem management. They represent a research need for most fields of resource management (Gerlach and Bengston, 1994; Great Lakes Natural Resource Center, 1994; Rogers and Premo, 1994).
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Freshwater Ecosystems: Revitalizing Educational Programs in Limnology A challenge of the landscape approach is developing cooperation among resource agencies charged with various aspects of maintaining the integrity of aquatic ecosystems or the quality of drinking water. Too often policies and activities directly conflict or are poorly coordinated. Research that provides guidance for cross-agency cooperation would be beneficial to applied aquatic ecosystem science. There is also a need for improved education. Policymakers and managers have an ongoing need for information. Education must also extend to interest groups, including environmentalists, industry representatives, school children, and other members of the public. Good technology and well-intentioned goals will contribute little to conservation of intact and functioning aquatic ecosystems if they cannot be translated into practical action in specific watersheds. Effective restoration, conservation, and perpetuation of water resources must integrate sound science with practical approaches that can be understood and accepted by the public. SCIENTIFIC INFRASTRUCTURE The most difficult part of implementing the interdisciplinary research model is that most government agencies, universities, and other public and private institutions have not demonstrated a willingness to relinquish their territorial claims on individual parts within the ecosystem. Within government environmental agencies, a department of fisheries often has a much different mandate and environmental perspective than a department of water resources management. For example, during a Clean Lakes project in Kentucky, watershed nutrient reduction plans were being discussed with the Division of Water for a eutrophic 21-hectare lake even as state fisheries biologists added nutrients directly to the lake as part of a standard practice to maintain a productive ecosystem. From a fisheries perspective, a very nutrient-rich lake resulted in a better fishery. From a water quality perspective, the overabundant plant biomass and lack of dissolved oxygen in summer throughout much of the water column was a concern. Separate administrative units within state government needed to integrate their efforts to sustain a lake ecosystem that could support a sport fishery, assimilate the watershed nutrient loads, and improve water quality for other recreational endeavors. Similar circumstances exist for universities. The college of agriculture may focus its attention on promoting a very high soil phosphorus buildup without considering the water quality concerns expressed by the college of natural resources. The solution requires a policy and financial commitment by governments to make applied interdisciplinary research a priority. Equally important is progress by the scientific community to overcome territorial problems associated with individual recognition versus team effort.
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Freshwater Ecosystems: Revitalizing Educational Programs in Limnology There are several models that have been successful at integrating across institutional and environmental disciplines. Two examples are the Experimental Lakes Area (ELA) and the Long-Term Ecological Research (LTER) program. Both examples are based on a commitment of federal dollars for support. The mandate for ELA was to conduct applied research to solve priority environmental problems (e.g., eutrophication and acid rain). To accomplish that mandate, the federal government of Canada financed the site operation, assigned federal scientists to the location, and encouraged interdisciplinary research. The commitment of federal funding encouraged the development of on-site laboratories and logistical facilities and the continuous collection of basic water quality information. The success of the ELA approach is not measured in the number of publications, although there are many (e.g., Schindler, 1974, 1988; Fee, 1976; Schindler and Turner, 1982; Schindler et al., 1985, 1986; St. Louis et al., 1994), but in the value of attracting interdisciplinary teams of scientists with individuals representing universities as well as federal and provincial governments to conduct holistic research on real and pressing environmental problems. The LTER model involves federal funding to establish environmental monitoring and research sites throughout the United States. In the case of LTER's aquatic program for temperate lakes, the funding is directed to the University of Wisconsin to establish a suite of lakes and their respective watersheds in northern Wisconsin to act as sentinels for long-term regional changes in the environment. Federal funds help support on-site laboratories and logistics at the Trout Lake university facilities and a continuous monitoring of a variety of lake and watershed parameters. As in the ELA model, the advantage of supporting an established site to conduct holistic environmental research is that it attracts interdisciplinary studies to the area. For example, an interdisciplinary, multi-institutional study on the biogeochemical fate of mercury in lakes was attracted to the Trout Lake university facilities because of the existing laboratory and scientific support. The $5 million project involves scientists from three universities, two federal agencies, three private contractors, and state government, with combined expertise in analytical chemistry, atmospheric chemistry and transport, aquatic microbiology, ground water hydrology and geochemistry, fisheries, biology, physicochemical and biological limnology, and environmental modeling. Many valuable contributions resulted from this effort (e.g., Bloom, 1989; Fitzgerald and Watras, 1989; Wiener et al., 1990; Bloom et al., 1991; Krabbenhoft and Babiarz, 1992; Watras and Bloom, 1992; Porcella, 1994; Watras et al., 1994). Both of these programs attracted scientists from a variety of disciplines and institutions who worked together to solve aquatic resource problems needing attention by decisionmakers. Essentially, if resources are allocated
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Freshwater Ecosystems: Revitalizing Educational Programs in Limnology to building an infrastructure that is conducive to multi-institutional, interdisciplinary cooperative research, top-quality scientists will become involved. MONITORING MANAGEMENT STRATEGIES It is clear that society cannot wait until all scientific questions are answered before acting to perpetuate healthy aquatic ecosystems. Research, education, and management must proceed simultaneously, but always with a feedback mechanism through which each can be assessed and altered if insufficient or undesirable outcomes are detected. Management activities themselves, sometimes large-system manipulations, can be viewed as primary tools for experimentation, fueling a process that is often called "adaptive management" (Walters, 1986). The adaptive management approach is an ongoing effort. New scientific knowledge is integrated continually into practical and appropriate management strategies. Techniques may require frequent refinement and alteration. Society's goals for the desired state of its resources in the future require consideration and update. For this process to continue successfully, effective long- and short-term monitoring of the integrity of existing aquatic ecosystems or changes resulting from management regimes is crucial. Nevertheless, the preponderance of public and private research dollars is funneled toward projects that test theories or design mathematical models. The assessment of effects of management strategies is often not perceived as being scientifically rigorous enough to deserve a share of limited funding (Noss, 1990). Yet monitoring the efficacy of science applied to the solution of problems of aquatic ecosystems is a critical step toward improvement. In addition, such research often results in fundamental scientific findings. REFERENCES Bloom, N. S. 1989. Determination of picogram levels of methyl mercury by aqueous phase ethylation, followed by cryogenic gas chromatography with cold vapor atomic fluorescence detection. Can. J. Fish. Aquat. Sci. 46:1131–1140. Bloom, N. S., C. J. Watras, and J. P. Hurley. 1991. Impact of acidification on the methyl mercury cycle of remote seepage lakes . Water Air Soil Pollut. 56:477–492. Environmental Protection Agency (EPA). 1994. National Water Quality Inventory: 1992 Report to Congress. EPA 841-R-94-001. Washington, D.C.: EPA. Fee, E. J. 1976. The vertical and seasonal distribution of chlorophyll in lakes of the Experimental Lakes Area, NW Ontario: Implication for primary production estimates. Limnol. Oceanogr. 21:767–783. Fitzgerald, W. F., and C. J. Watras. 1989. Mercury in the surficial waters of rural Wisconsin lakes. Sci. Tot. Environ. 87/88:223–232. Gerlach, L. P., and D. N. Bengston. 1994. If ecosystem management is the solution, what's the problem? Eleven challenges for ecosystem management. J. For. 92(8):18–21.
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Freshwater Ecosystems: Revitalizing Educational Programs in Limnology Great Lakes Natural Resource Center. 1994. Seeing the Forest Through the Trees: A Model Biodiversity Collaboration Strategy for the Lake Superior Basin. Ann Arbor, Mich.: National Wildlife Federation. Hudson, W. E. 1991. Landscape Linkages and Biodiversity/Defenders of Wildlife. Washington, D.C.: Island Press. 196 pp. Hunter, M. L., Jr. 1990. Wildlife, Forests, and Forestry: Principles of Managing Forests for Biological Diversity . Englewood Cliffs, N. J.: Prentice Hall. 370 pp. Krabbenhoft, D. P., and C. L. Babiarz. 1992. The role of groundwater transport in aquatic mercury cycling. Water Resour. Res. 28:3119–3128. Noss, R. F. 1987. From plant communities to landscapes in conservative inventories: A look at the Nature Conservancy (USA). Biol. Conserv. 41:11–37. Noss, R. F. 1990. Indicators for monitoring biodiversity: A hierarchical approach. Conserv. Biol. 4:355–364. Porcella, D. B. 1994. Mercury in the environment: Biogeochemistry. Pp. 3–19 in Mercury Pollution: Integration and Synthesis, C. Watras and J. Huckabee, eds. Boca Raton, Fla.: Lewis Publishers. Rogers, E. I., and D. B. Premo. 1994. Model biodiversity management plan—Scientific section In Seeing the Forest Through the Trees: A Model Biodiversity Collaboration Strategy for the Lake Superior Basin. Great Lakes Natural Resource Center. Ann Arbor, Mich.: National Wildlife Federation. Schindler, D. W. 1974. Eutrophication and recovery in experimental lakes: Implication for lake management. Science 184:897–899. Schindler, D. W. 1988. Effects of acid rain on freshwater ecosystems. Science 239:149–157. Schindler, D. W., and M. A. Turner. 1982. Biological, chemical and physical responses of lakes to experimental acidification. Water Air Soil Pollut. 18:259–271. Schindler, D. W., K. H. Mills, D. F. Malley, D. L. Findlay, J. A. Shearer, I. J. Davies, M. A. Turner, G. A. Linsey, and D. R. Cruikshank. 1985. Long-term ecosystem stress: The effects of years of experimental acidification on a small lake. Science 228:1395–1401. Schindler, D. W., M. A. Turner, M. P. Stainton, and G. A. Linsey. 1986. Natural sources of acid neutralizing capacity in low alkalinity lakes of the Precambrian Shield. Science 232:844–847. St. Louis, V. L., J. W. M. Rudd, C. A. Kelly, K. G. Beaty, N. S. Bloom, and R. J. Flett. 1994. Importance of wetlands as sources of methyl mercury to boreal forest ecosystems. Can. J. Fish. Aquat. Sci. 51:1065–1076. Walters, C. 1986. Objectives, constraints, and problem bounding. Chapter 2 in Adaptive Management of Renewable Resources, W. M. Getz, ed. New York: Macmillan. Watras, C. J., and N. S. Bloom. 1992. Mercury and methylmercury in individual zooplankton: Implications for bioaccumulation. Limnol. Oceanogr. 37:1313–1318. Watras, C. J., N. S. Bloom, R. J. M. Hudson, S. Gherini, R. Munson, S. A. Class, K. A. Morrison, J. Hurley, J. H. Wiener, W. F. Fitzgerald, R. Mason, G. Vandal, D. Powell, R. Rada, L. Rislov, M. Winfrey, J. D. Krabbenhoft, A. W. Andren, C. Babiarz, D. B. Porcella, and J. W. Huckabee. 1994. Sources and fates of mercury and methylmercury in Wisconsin lakes. Pp. 153–177 in Mercury Pollution: Integration and Synthesis, C. Watras and J. Huckabee, eds. Boca Raton, Fla.: Lewis Publishers. Wiener, J. G., W. F. Fitzgerald, C. J. Watras, and R. G. Rada. 1990. Partitioning and bioavailability of mercury in an experimentally acidified Wisconsin lake. Environ. Toxicol. Chem. 9:909–918.