Aquatic Fauna in Peril: The Southeastern Perspective
Edited By George W. Benz And David E. Collins
Rivers of the southeastern United States contain some of the world’s most diverse aquatic communities. The Southeast contains about 90 percent of the nearly 600 taxa of mussels and crayfishes (about 300 of each), approximately 73 percent of the aquatic snails, and about 50 percent of the freshwater fishes known from the continental United States (Burch, 1982; Hobbs, 1989; Williams et al., 1989; Warren and Burr, 1994; Neves, 1993; Lydeard and Mayden, 1995). Much of this diversity is found in the Tennessee and Cumberland rivers of the Mississippi Basin, and rivers entering Mobile Bay. Because of the Southeast’s high diversity and endemism and the widespread modification of its aquatic ecosystems, this region also contains a significant portion of our country’s endangered aquatic fauna.
Prior to settlement by Europeans, about 5.2 million km (about 3.23 million miles) of free-flowing rivers existed in the contiguous United States. However, only 42 free-flowing rivers longer than 200 km (124 miles) remain (Benke, 1990), and few of the Southeast’s major rivers have escaped impoundment. For example, over 3,680 river km (2,287 miles) or about 20 percent of the Tennessee River and its major tributaries have been impounded (Tennessee Valley Authority, 1971). The effects of these impoundments extend well beyond the actual reservoirs, including alteration of river habitats downstream of dams, loss of connectivity between upstream and downstream reaches, and isolation of tributaries by reservoir pools.
Impoundments coupled with decades of chronic environmental degradation have altered stream hydrology, destabilized benthic stream habitat, and resulted in other physical, chemical, and biological changes to aquatic communities (Karr and Dudley, 1981; Allendorf, 1988; Neves, 1993) in the southeast. Due to environmental abuse, some species have been lost, many other species that were once widely distributed now survive in a few isolated populations at a fraction of their former abundance. Some of these now isolated species are threatened with extinction. In addition to extinctions and extirpations, there has also been a collapse of the complex interactions between the diverse organisms that co-evolved in southeastern riverine ecosystems (Allendorf, 1988; Sheldon, 1988; Bruton, 1995).
Riverine ecosystems and their rare aquatic species are especially difficult to conserve, manage, and restore because of the linear, flowing characteristic of streams. Many competing and often conflicting demands are placed on watersheds and the rivers that flow through them. Threats often arise from relatively minor, but cumulative, factors that do not respond to a single corrective action. Many users of watershed resources are generally unaware or apathetic about conserving lower vertebrates and invertebrates that are essential to the ecological integrity of these systems (Allendorf, 1988; Master, 1991). Lack of public support has translated into a low priority for conservation and recovery of aquatic ecosystems. In spite of assaults on southeastern aquatic ecosystems, however, much of the region’s diverse aquatic fauna still survives in isolated stream reaches. Concerted and coordinated efforts among federal, state, and local government agencies, conservation organizations, and interested citizens are helping to insure that much of this rich natural heritage will be passed on to future generations.
In this paper, we will briefly describe the historic roles of natural resource agencies in managing our aquatic systems, outline steps to implement ecosystem management programs, provide examples of new initiatives that focus on ecosystem management as a means of protecting rare species and ecosystems, and discuss the role that science can play in management and protection.
Historically, aquatic conservation and management initiatives were primarily driven by the economic, recreational, and subsistence values offered by fisheries resources (Williams and Finnley, 1977). Thus, although about 90 percent of the fishes in the United States are nongame species (Warren and Burr, 1994), conservation and management activities have been historically directed primarily toward maintaining and enhancing a few recreationally or commercially valuable fish stocks. This type of management was generally accomplished through: stocking hatchery reared species; creating impoundments and providing cold water releases to create artificial downstream trout fisheries; regulating harvest through bag limits, size limits, and open and closed seasons; stocking nonindigenous species for game and forage; and by enforcing laws to prevent overharvest. Some habitat improvement work was carried out, but most efforts centered on enhancing stocks of particular game species. Only minimal effort was directed toward maintaining native, nongame components of aquatic communities. Attention was sometimes given to preserving habitat and water quality by setting and regulating toxic discharge limits and reviewing construction projects to provide guidance to minimize environmental impacts.
Although the historic role of natural resource agencies was and remains, in large part, targeted towards sport and commercial species, in the early 1970s, roles of these agencies began to expand when two significant environmental laws were passed by the federal government: the 1973 Endangered Species Act (ESA) and the 1977 Clean Water Act (CWA). Both acts focused attention on the plight and value (e.g., aesthetic, ecological, educational, historical, recreational, and scientific) of all species and their habitats. These acts mandated that biodiversity and the habitat that supports it be maintained. The ESA requires federal agencies to consider the effects of their projects on endangered and threatened species. The CWA, through its National Pollution Discharge Elimination System permit provision, regulates the discharge of pollutants into waters of the United States and aims to maintain the biological integrity of the receiving waters. Biological components of many streams have benefited through the implementation of these acts. Passage of other federal regulations (e.g., Fish and Wildlife Coordination Act, surface mining regulations, National Forest Management Act, National Environmental Policy Act) have also benefited aquatic organisms, their habitats, and water quality. However, agencies directed to implement remedial actions are often underfunded and understaffed (Hughes and Noss, 1992), and in some cases, the protection afforded has come too late to conserve the region’s sensitive aquatic resources.
In addition to federal legislation, many states have recognized the plight of their natural heritage during the last 20 years and have passed legislation to protect nongame species. State Natural Heritage Programs, aided by The Nature Conservancy and their Central Biological Conservation Data System, now track the occurrences of rare species. These heritage programs are established in all 50 states and within several additional agencies and organizations (Warner, 1993). Also, several states have recently sponsored symposia or publications that, address management and conservation of rare aquatic species along with other groups of organisms (e.g., Terwilliger, 1991; Georgia Department of Natural Resources, 1992).
Over the past two decades, new environmental groups have formed, and existing groups have expanded their advocacy roles to insure conservation of aquatic ecosystems. Environmental education has become part of the curriculum in many schools, and numerous books and television shows have described the plight of our national and global biodiversity.
Although the ESA and CWA stress the need for ecosystem protection, some rare aquatic organisms are so geographically restricted that a single-species approach should continue to be a conservation option (Sheldon, 1988; Eisner et al., 1995). Some single-species efforts have been successful in the Southeast. For example, an extirpated population of the rare spring pygmy sunfish (Elassoma alabamae) was successfully restored by reintroducing adults from another location (Jandebeur, 1982; Mayden, 1993); the snail darter (Percina tanasi) was successfully translocated into several rivers in the Tennessee River system, (Williams and Finnley, 1977; Etnier and Starnes, 1993); watercress darters (Etheostoma nuchale) were successfully translocated in a spring in Alabama (U.S. Fish and Wildlife Service, 1993); and the rare spiny riversnail (Io fluvialis) has been successfully reintroduced into a Tennessee River tributary (Ahlstedt, 1991; and R. Neves, National Biological Service, pers. comm.).
However, in spite of these limited single species successes, aquatic ecosystems continue to degrade, and the list of aquatic endangered and threatened species steadily increases (Williams et al., 1989; Williams et al., 1993; U.S. Fish and Wildlife Service, 1994a, 1994b; Warren and Burr, 1994). Furthermore, although the status of some rare species has been stabilized or is increasing, few have been recovered to the point where they no longer need ESA protection.
It is now widely recognized that the future of rare aquatic species is best secured by protecting and restoring biological integrity of entire watersheds (Karr, 1990; Moyle and Sato, 1991; Williams, 1991; Williams and Williams, 1992). Land acquisition would appear to be the most obvious means of affecting watershed protection. Through ownership, management of aquatic ecosystems would become much less complicated, eliminating the need to coordinate restoration activities with numerous landowners of varied interests. Except under unusual circumstances, acquisition of entire watersheds is not feasible. Therefore, land acquisition cannot be used as a method of reasonably conserving more than a fraction of the Southeast’s aquatic fauna.
Ecosystem management is the most effective method of protecting the greatest number of species. Ecosystem management considers not just individual species or select groups of species, but takes a holistic approach to managing all communities that comprise the ecosystem by factoring in ecological relationships, land-use patterns, and threats to water and habitat quality. However, the complex nature of aquatic ecosystems and the watershed scale necessary for aquatic ecosystem protection is problematic. Ecosystem management is expensive, time consuming, and requires considerable coordination with and commitment from various agencies, organizations, and private individuals.
The following is a recommended series of steps for developing and implementing a watershed management program that follow an Ecosystem Management approach. These steps include prioritizing aquatic ecosystems in need of management; identifying all potential agencies and organizations with an interest in watershed management; prioritizing ecosystem threats; identifying strategies to minimize or eliminate threats; and most importantly, educating the ecosystem’s inhabitants and other stakeholders. Without a sound and comprehensive education program that reaches all potential stakeholders in the watershed, management efforts will be difficult and slow.
Carroll and Meffe (1994) recommended several criteria to help prioritize conservation and management efforts. These include identifying areas with the following: 1) relatively high numbers of endemic, rare, and declining species or keystone species or ecological processes; 2) small, fragmented habitats; and 3) systems exhibiting low resilience to perturbations. More specifically, Angermeier et al. (1993) described a protocol to help prioritize Virginia streams to enhance cost-effectiveness of preservation, enhancement, management, recovery, and restoration efforts. This protocol may be modified for use in other parts of the Southeast.
Because financial and time constraints are universal, it is important to prioritize watershed management efforts based primarily on faunal diversity and the likelihood of successful restoration. Some watersheds have much greater natural diversity than others, and under normal circumstances these should receive high priority for conservation efforts. However, some of the most diverse ecosystems may have been so altered that it is unlikely they can be conserved or restored with the level of resources currently available. It is also important to consider size of the target watershed. If the area of interest is too large, management and restoration problems may be overwhelming.
Still other criteria may be important to consider when selecting target watersheds. Ownership complexity should be a critical consideration. For instance, the Conasauga and Etowah rivers are large, diverse tributaries in the headwaters of the Mobile Basin, Georgia and Tennessee. The Conasauga River has its headwaters in two national forests (Cherokee and Chattahoochee) and is otherwise primarily agricultural in watershed land use. In comparison, although it is a larger system, the Etowah River has virtually no federal lands in its watershed, but has a much more diverse land-use pattern comprised of various mining, agricultural, and metropolitan Atlanta developmental activities that are rapidly changing current land-use patterns. Based solely on these criteria, a watershed project would seem simpler to initiate in the Conasauga watershed.
Another important factor that may help assess or rank communities in need of conservation efforts is biogeographic history of rare species in the system under consideration. A factor which may help in the prioritization process is whether the rare species evolved in the area or dispersed into it. For example, when faced with a decision between conserving a watershed containing a once widespread, ancestral species or one containing a species whose historical distribution was more local, the potentials of each to future generations may offer critical information to the selection process (Mayden, 1992). Preserving formerly widespread species may preserve genomes that produce more adaptable organisms, and organisms more suitable for dispersal into former ranges, should habitat conditions improve.
Although watershed projects will generally concentrate on larger ecosystems that have relatively high levels of biodiversity and endemism, small, relatively depauperate aquatic ecosystems such as springs and caves should not be categorically dismissed from management considerations. In fact, these systems may represent high priorities for protection or management for several reasons: they contain uniquely adapted endemic faunas, exhibit extreme vulnerability and low resilience to relatively minor alterations, and show slow recovery from perturbations (Etnier and Starnes, 1991). These systems can often be protected with minimal effort and expense. Furthermore, projects focusing on said sites may be easier to coordinate than those encompassing larger watersheds because of the relatively fewer numbers of landowners and stakeholders involved and other factors associated with the small size of the area under consideration.
Some species inhabiting karst systems may be sensitive indicators of changes that occur in quality and quantity of groundwater for a region. For example, the Barrens topminnow (Fundulus julisia) has a small geographic range and is mainly restricted to a few spring-influenced areas in the Barrens Plateau region of central Tennessee. This species is highly susceptible to changes in habitat, water quantity, and possibly water quality. With increased demand on groundwater supplies in this region, many cool, heavily vegetated spring habitats, required by Barrens topminnows, have been impacted. Rakes (P. Rakes, Conservation Fisheries, Inc., pers. comm.) hypothesized that Barrens topminnows may be at a competitive disadvantage in other types of habitats. Regular monitoring of populations of this rare fish, and conservation, restoration, and management efforts aimed at helping the species are relatively inexpensive and require minimal effort (Rakes, 1994). However, Rakes (P. Rakes, Conservation Fisheries, Inc., pers. comm.) demonstrated how rapidly the topminnow population can change, thus indicating the need for management.
Other federal, state, and local agencies (e.g., U.S. Natural Resources Conservation Service, U.S. Environmental Protection Agency, U.S. Geological Survey, U.S. Bureau of Reclamation, state departments of natural resources, local planning commissions, and local and regional conservation organizations) may have active conservation-oriented programs in the watershed. The extent of agency and organization involvement in common watershed issues should be determined. Objectives of watershed projects should be made well-known, and wide support for these objectives should be nurtured. Many agencies actively seek partnerships to help reach conservation objectives. When one set of project objectives complements those of other groups, additional resource protection and recovery may be achieved without further expenditures.
Projects in river systems large enough to be used for water supply or transportation will require federal and possibly other permits. Any agencies and organizations responsible for planning and permitting in the project watershed should be notified of a project’s intentions. Once appropriate contacts have been made, natural resources of the watershed can be considered early in the planning and permitting process, and negative effects of any proposed actions may be avoided or mitigated. As Montgomery et al. (1995) suggested, resource use and conservation are not necessarily incompatible; the best available scientific information should be incorporated into the ecosystem management planning process so that informed decisions can be founded solidly on science.
Most current and proposed land uses or activities have similar effects on aquatic ecosystems, especially in the same geographic region. Conversely, there may be other threats specific to the project watershed. An analysis identifying stressors and stress points that affect aquatic species and their habitats, should not be restricted to the immediate stream corridor. The entire watershed should ultimately be examined for potential land uses or other activities that could negatively impact aquatic habitat quality. For example, small headwater streams, even though they are often less biologically diverse than other streams within a watershed, can greatly influence chemical and physical properties further downstream, and should not be considered unimportant or ignored (Rabeni, 1992). Comprehensive basin-wide environmental threat assessments that consider physical and biological characteristics should be carried out when feasible (Rabeni, 1992).
When threats are identified during the analysis, each should be evaluated for magnitude, imminence, and cost of reduction. The magnitude of a threat constitutes an estimate of the level of adverse effects it will cause to the system. It is important to determine whether the threat will have widespread and long-lasting effects, or if it will be localized, short-term, and of little overall consequence to the ecosystem. When short-term threats are identified and associated with a proposed project, it should be determined whether timing of the proposed project can be altered so that it interferes as little as possible with survival and reproduction of native animals. Imminence of a threat is an estimate of how soon it will affect the aquatic environment, and the limited time frame in which addressing the threat can be postponed until irrevocable damage to habitat is done. Imminent versus non-imminent threats should be identified and categorized as follows: immediacy of threat; scale of impacts; species, communities, or habitats affected; and time and financial expenditures necessary to negate the threat. Instream effects from some proposed projects or activities may not be readily apparent and thus can only be predicted or anticipated. Beyond this, impacts of some projects can be cumulative, slow-acting, not easy to observe or measure, and may show up on a temporal scale that is not often considered (Rabeni, 1992). Of course some threats, no matter how serious, may be too socially and economically costly to eliminate or mitigate.
Currently it is not possible to identify all factors threatening some ecosystems. The faunas in some watersheds are in decline for as yet unknown and possibly non-anthropogenic reasons. Further research may be needed to determine specific causes of faunal decline.
Once ecosystem threats have been identified and prioritized, strategies for their elimination or reduction should be developed. Usually there are a number of ways to address a problem, and alternatives should be evaluated in terms of time, cost, and probable effectiveness.
Agencies that have ultimate responsibility for regulating water releases from impoundments and zoning river basins for various uses must be reminded to consider ecological processes when considering holistic watershed management (Bruton, 1995). A cooperative approach with agencies, organizations, private landowners, and other individuals and stakeholders involved in the management project works best in the long-term. Various factors must be considered, including social, legal, and political issues, scientific and technical goals, and economic values (Gresswell and Liss, 1995).
Montgomery et al. (1995) described ecosystem management as a proactive planning process that may involve mitigation of adverse environmental impacts of human activities. Moyle and Moyle (1995) recommended that potential resource users determine cost-benefits of proposed use of this resource and "pay" for its degradation or alteration if appropriate. Although economic values of natural resources may be difficult to quantify, a comparison of the values associated with a healthy, functioning aquatic ecosystem and a degraded or altered ecosystem resulting from previous, poorly planned projects may be insightful — especially when considering the long-term viability of co-evolved aquatic resources versus the short-term economic gains of a proposed project.
Dunn (1993) described an example where this approach was used to help conserve freshwater mussels. As mitigation for a project impacting a significant mussel bed in the Ohio River, 5,000 mussels were removed from the project area and relocated within the system (Dunn, 1993). A trust fund also was established to fund monitoring of relocated mussels and future research on Ohio River Basin mollusks. Appalachian Power Company, once responsible for spills that affected aquatic fauna in the Clinch River, has funded studies on life history and reproduction of native mussels in this portion of the Tennessee River system.
Education is critical to the success of any restoration or conservation program. Informing various participants in the ecosystem project, other stakeholders, and the general public about project objectives and methods should begin early and be a continuing process as the project proceeds. Therefore, the education effort should strive to reach all levels within the community including young school children, community leaders, civic groups, and federal and state agency personnel.
Examples of grass roots programs with strong education components that address river conservation needs include Adopt-a-Watershed, a natural resource education program in which young students adopt a local watershed and follow it as a focal point in their science curriculum through grade 12. Incentives for public school projects like Adopt-a-Watershed, the Better Education Starts Today projects in Alabama, and the Harpeth River Project in Tennessee (see below) will greatly further educational efforts. Numerous nationwide grass roots watershed protection and management groups have also been organized to address various aspects of the ecosystem approach to watershed management outlined herein.
Many private organizations have hosted workshops or developed and distributed literature and other educational materials to agencies, organizations, businesses, and the general public on better management of riverine resources. For example, The Georgia Conservancy recently devoted an entire annual conference to protection of Georgia’s waterways which included presentations by House Speaker Newt Gingrich, U.S. Department of the Interior Secretary Bruce Babbitt, and various conservation leaders. The Georgia Conservancy also recently produced an award-winning video called "Stream of Conscience," and the U.S. Fish and Wildlife Service funded companion literature on conservation and protection of riverine ecosystems in that state.
There is a growing body of literature that addresses various aspects of restoring, recovering, and managing aquatic ecosystems. Articles appear regularly in many scientific journals (e.g., Aquatic Ecosystem Health, Bioscience, Conservation Biology, Environmental Management, Restoration Ecology). Entire journal issues have been devoted to freshwater ecosystem conservation, restoration, and management (e.g., Freshwater Biology Volume 29, Number 2, 1993; Journal of the North American Benthological Society Volume 12, Number 2, 1993; Restoration Ecology Volume 3, Number 3, 1995). Numerous books on riverine ecosystem management are also available (e.g., Doppelt et al., 1993). While some of this information may be too technical for the general public, it is invaluable to scientists and other resource managers actively involved in riverine ecosystem management and restoration.
Several publications of various governmental and other organizations also focus on riparian and watershed management. These include "Riparian Forest Buffers: Function and Design for Protection and Enhancement of Water Resources," jointly produced by the U.S. Forest Service with various state and private forestry organizations. NPS News-Note is a monthly U.S. Environmental Protection Agency periodical with information on the control of nonpoint-source water pollution and the management and ecological restoration of watersheds. Much of this educational information can be obtained free of charge from these agencies or organizations.
Tear et al. (1995) suggested that general indifference to garnering public support and establishing a sound educational program has been a key reason for poor performance of recovery efforts for listed species. It is important for professionals responsible for the recovery of these species to participate in this public education effort (Bruton, 1995). It is also important for these professionals to persuasively communicate to policy makers, resource managers, the business community, other professionals, and the news media why aquatic species and ecosystems are important. Through such mechanisms, public policy may be influenced to achieve financial support for conservation education and management of aquatic systems.
Following are examples of ways that many federal and state natural resource management agencies and conservation organizations have positively responded to this new, more holistic approach, and how they are now emphasizing ecosystem management in addition to individual species management.
Ms. Mollie Beattie, the late director of the U.S. Fish and Wildlife Service (USFWS) realized that the old, piecemeal approach to conservation problems was not working well. Because of this, she emphasized that her organization would advocate and demonstrate for the management of ecosystems in their entirety. This philosophy has led the USFWS’s reorganization according to ecosystem boundaries and development of plans for these ecosystem units. The ecosystem approach has led to better coordination among USFWS programs by focusing activities on common goals. It has helped to concentrate outreach and education efforts on ecosystem problems, and it has encouraged USFWS employees to become more active in establishing and funding partnerships with other agencies and groups. Many of the projects described below have received financial support from the USFWS.
The U.S. Forest Service (USFS) and the Bureau of Land Management, in conjunction with the National Fish and Wildlife Foundation, have embarked on a new program, Bring Back the Natives, that stresses the concept of ecosystem management (Williams and Williams, 1992). The Bring Back the Natives program encourages the formation of partnerships between federal and state agencies, private landowners, and other stakeholders to protect and restore watersheds so that populations of native species can be recovered. To date, this program has involved modification of livestock and timber management practices, restoration of riparian habitat, and reintroduction of extirpated populations of native fish species.
Although most of the projects thus far have involved streams in the western United States, the USFS is cooperating with the Tennessee and North Carolina wildlife resources agencies, the USFWS, and the National Park Service in a project to restore extirpated populations of four federally listed species (smoky madtom, Noturus baileyi; yellowfin madtom, N. flavipinnis; duskytail darter, Etheostoma percnurum; and spotfin chub, Cyprinella monacha) on a Little Tennessee River tributary (Shute et al., manuscript in preparation).
The National Park Service (NPS) is currently working in conjunction with the Office of Surface Mining to reclaim abandoned mine lands in the Big South Fork National River and Recreation Area (BSFNRRA) (S. Bakaletz, BSFNRRA, pers. comm.). This program will benefit several federally listed mussel species and one listed fish species. The water quality improvement associated with this initiative will also benefit sport fisheries and other recreational uses in the BSFNRRA.
As part of the fish restoration project on the Little Tennessee River tributary (see above), Great Smoky Mountains National Park has restricted stream access to livestock, and park officials have initiated restoration of degraded riparian zones in the project watershed. The NPS also has implemented fish and benthic invertebrate sampling in the Park to monitor success of this restoration.
The U.S. Geological Survey (USGS) National Water Quality Assessment has identified 60 major hydrologic systems in the United States for assessing and monitoring our nation’s water quality (U.S. Geological Survey, 1995). Long-term monitoring of aquatic macroinvertebrates and fishes is an integral part of these projects. A comparison of the historical and current biota of the watershed of concern and an analysis of possible reasons for extirpation of aquatic species is one of the initial steps in assessment of target watersheds. These assessments are intended for use by policy makers and managers to prioritize water quality issues and to coordinate projects within watersheds (U.S. Geological Survey, 1995).
The USGS is also assisting the National Biological Service (NBS) in a USFWS-funded study on the North Fork of the Holston River, an upper Tennessee River tributary.1 The project’s goal is to reintroduce components of the historic mussel fauna into this river. Much native fauna was eliminated by mercury contamination from a chemical plant in Saltville, Virginia. Through efforts of the states of Virginia and Tennessee, U.S. Environmental Protection Agency, Tennessee Valley Authority, and other organizations, the lower North Fork Holston River now appears suitable for reintroduction of a mussel community (S. Ahlstedt, USGS and R. Neves, USGS, both pers. comm.).
1 Editors’ footnote: since this chapter was finalized the National Biological Service has become the Biological Resources Division of the USGS.
The Clean Water Initiative of the Tennessee Valley Authority (TVA) has established a watershed protection and restoration program within the Tennessee River system. TVA has formed multidisciplinary River Action Teams composed of biologists and water resource specialists that work within specific sub-watersheds in the Tennessee River drainage (Tennessee Valley Authority, 1995). Teams document valuable resources within their respective watersheds and identify pollution sources and other stressors that impact those resources. Once specific problems are pinpointed and solutions are identified, teams work to bring together appropriate people and organizations needed to improve the health of the watershed (Tennessee Valley Authority, 1995).
Recently, TVA has also structurally modified several of its dams. These modifications are designed to improve water quality, dissolved oxygen concentrations, and flow regimes to benefit aquatic organisms in tailwaters (Anonymous, 1995). In 1994, 386 river km (240 miles) in the Tennessee River Valley showed water quality improvements (Tennessee Valley Authority, 1995).
The U.S. Environmental Protection Agency (EPA) is known for its assessments of factors that affect public health. However, in 1988 as a result of citizen concern for ecological issues (e.g., global climate change, habitat loss, declines in biodiversity, effects of pesticides and toxic chemicals), EPA began to focus more on ecosystem integrity. The result was an initiative to develop guidelines for conducting risk assessment for ecosystems (U.S. Environmental Protection Agency, 1992). EPA is currently developing Ecological Risk Assessment Guidelines (ERAG), using a series of test watersheds that include the Clinch and Powell rivers, headwater tributaries of the Tennessee River. ERAG will provide methodology to evaluate ecological effects of environmental stressors (e.g., chemical, physical, biological) that adversely impact ecosystems, communities, populations, or individual species. Once developed, this protocol should prove valuable for identifying environmental stressors and ascertaining the degree of threat for each. This in turn will facilitate prioritization of actions needed to address these stressors.
The Southern Rivers Council (SRC) is a newly formed group of professional aquatic biologists in the Southeast, interested in conserving biodiversity of southeastern streams. The SRC’s mission is to facilitate funding for and to coordinate projects that restore the region’s important aquatic habitats. The SRC also seeks ways to take an active role in aquatic resource education. Although SRC is just two years old, several ecosystem-oriented projects have already received funding from private sources with matching funding from the National Fish and Wildlife Foundation. Two of SRC’s first projects focused on streams in the Tennessee River drainage. These include streambank restoration and erosion control on Shuler Creek, and water quality improvements in North Chickamauga Creek (Southern Rivers Council, 1995). Sediment in Shuler Creek from an adjacent road and eroding stream banks has altered a biologically significant portion of the Hiwassee River. The water quality of North Chickamauga Creek has been seriously impacted by acid mine drainage and urban pollution.
Various state natural resource agencies are also focusing on watershed conservation. For example, the Virginia Department of Game and Inland Fisheries (VDGIF) has undertaken a watershed protection and enhancement project on Copper Creek, a major tributary of the Clinch River in southwest Virginia (S. Bruenderman, VDGIF, pers. comm.). A number of rare mussels, fishes, amphibians, reptiles, and bats depend on Copper Creek and its riparian corridor for their existence. Recent surveys have documented a decline in the creek’s mussel and fish communities, and nonpoint-source pollution appears to be the primary problem (S. Bruenderman, VDGIF, pers. comm.).
Biologists with VDGIF have undertaken a four-pronged approach to address problems in Copper Creek: 1) interagency participation — other natural resource agencies working in the basin were contacted to increase their awareness of the problems and to help determine the best way to coordinate efforts to address these threats; 2) identification of critical areas — the basin was intensively surveyed to identify areas critical to survival of rare species; 3) identification of threats — areas where physical habitat and water quality have been degraded were identified; and 4) public outreach — public education efforts were begun to encourage cooperation between landowners and natural resource organizations. As part of this education effort, a citizen’s guide to the ecology of Copper Creek was produced (Flynn et al., 1994).
For over 40 years, The Nature Conservancy (TNC) has been successful in conserving biological diversity (Master, 1993). Historically, TNC’s conservation efforts have been accomplished by acquiring and managing individual tracts of land. However, TNC recently began to emphasize protection of rare species through a larger, ecosystem approach referred to as "Bioreserve" protection (L. Master, TNC, pers. comm.). Because it is impractical and undesirable to create bioreserves entirely through land purchases, TNC seeks to protect and enhance biodiversity in these areas by minimizing or eliminating threats to the ecosystem and by developing partnerships with local residents, landowners, business and industry, government, and other private organizations to develop means that promote ecologically compatible human uses.
The Horse Lick Creek Bioreserve lies within a relatively unpopulated watershed in Kentucky which is partially owned by the USFS. This bioreserve project, a cooperative effort primarily between TNC, USFS, and the Kentucky State Nature Preserves Commission, has concentrated its efforts on public education, purchase of key properties, and control of nonpoint-source pollution.
The Clinch River Bioreserve is located within a much larger watershed which includes the Clinch River and its major tributary, the Powell River. The valley is primarily rural with some small communities. Coal mining is extensive in the Powell River sub-basin. This bioreserve contains over 400 rare plants and animals, 13 federally endangered freshwater mussels, and a labyrinth of caves and underground streams that support two endangered bats and more than 50 globally rare cave organisms. The Nature Conservancy has established two field offices in the valley and has become involved in numerous conservation programs, including the following: 1) a cooperative program utilizing funds and assistance from the USFWS, TVA, other federal agencies, Tennessee Department of Agriculture, and Tennessee Wildlife Resources Agency, and local landowners to restore riparian habitat to help control nonpoint-source pollution; 2) a cooperative project with the Cave Conservancy of Virginia, the Virginia Cave Board, and the Virginia Department of Conservation and Recreation to develop cave management agreements with private landowners; 3) scientific research involving several universities to determine habitat needs of the valley’s rare species; and 4) coordination efforts with local planners, government agencies, and private industry to explore environmentally sound methods for treating sewage, harvesting timber, and mining coal.
In a community near Nashville, Tennessee, four local high schools have "adopted" the Harpeth River of the Cumberland River drainage as their environmental laboratory. In addition to performing field and laboratory analyses, they also use the river as the focus for a multicultural education curriculum. For example, students in public relations classes and visual and performing arts have become involved in relating the importance of the area’s resources, as well as problems and possible solutions, to the "real world." This project began with one teacher and has received funding from several local businesses and from the Tennessee Arts Commission. To date, over 1,000 students have participated in this project. The goal is to educate the entire community to the values of the Harpeth River and its aquatic community (Raines, 1994).
The state of Alabama has also encouraged environmental projects in public school systems with their Better Education Starts Today (BEST) Environmental Projects. The subjects of these projects are often local aquatic species that have state or federal protected status. Depending on the age group of the class undertaking a project, field and/or laboratory work on a species or its habitat may be included. Some examples are Everett’s (Everett, 1994) elementary school project on the federally endangered shiny pigtoe pearly mussel (Fusconaia cor) in the Paint Rock River and Slade’s high school projects to determine habitat and water chemistry requirements of the rare spring pygmy sunfish (Elassoma alabamae) (Pine, 1993; Elam and Burge, 1995).
In addition to the programs and projects described above, there are numerous, active local conservation and restoration groups throughout the Southeast. Some of these groups have been in existence for over a decade and are well supported, financially and otherwise. A few examples of these types of organizations with watershed emphasis are the Cahaba River Society (Alabama); Friends of the Clinch and Powell Rivers (Tennessee); the Little Tennessee River Watershed Association (North Carolina); and the Broad River Watershed Association (Georgia). These grass roots groups should be applauded and supported for their efforts, as they are critical to the success of aquatic biodiversity conservation.
Meffe and Carroll (1994) suggested that the role of the conservation scientist is to collect information suitable for preservation of biodiversity and long-term viability of ecosystems. Conserving important aquatic habitats as we confront the continued development that is inevitable, will require good ecological research that supports the development of management recommendations. Montgomery et al. (1995) also emphasized that the new perspective in ecosystem management necessitates scientific investigations that precede land-use planning for a particular watershed. These scientific investigations will ensure that emphasis is placed on resource conservation and that all proposed activities in the watershed are compatible with this primary goal. This important information should be communicated quickly by informal methods (e.g., talks at conferences, internet interest groups) so that it may be used to help manage crises that may arise. However, political and legal constraints are frequently encountered when attempting to protect rare species or ecosystems, and detailed documentation is often necessary to prioritize conservation or recovery efforts. Therefore, in addition to the information methods mentioned above, ecological information should be objectively collected and published in peer-reviewed journals.
Scientific investigations will be needed to focus at several scales and in a wide variety of areas so that resource managers will have the information required to assess the status and specific needs of riverine communities and sensitive species. Landscape-level processes and pathways that influence water quality, flow regime, physical habitat, energy flow, and biotic interactions are of utmost importance in managing riverine systems for biotic integrity. However, detailed information on the scale necessary to recover or conserve populations of imperiled species is also important.
As Raven (1992) and Noss (1994) recommended, field biologists and taxonomists will be needed, but the current trend at universities is to de-emphasize field research in favor of more empirical laboratory research. If field research is needed to support conservation programs, new avenues of funding need to be developed to attract professionals and students, or perhaps the current method of funding allocations should be carefully considered. Lydeard and Mayden (1995) suggested that conservation funding be proportionally divided among federal agencies in various regions according to relative biodiversity and potential threats.
Following is a list of specific research areas which scientists interested in furthering the cause of ecosystem management in the Southeast may become involved. These activities include research at both scales (landscape-level and species- or population- level) described above. Recommendations are also included that will help government agencies to incorporate this information in management plans for southeastern aquatic ecosystems.
Management regimes that support community function will affect long-term ecosystem management. Therefore, processes and pathways critical to the functioning of riverine communities need to be described. For example, identifying corridors necessary for movement to spawning habitats, movement between juvenile and adult habitats, and access to refugia during stressful periods is critical. Further, we must quantify the suitability of habitats in terms of the system’s capacity to support these critical processes. This may also involve an analysis of spatial heterogeneity and connectivity among habitats and the amount of temporal variability or stability present.
To understand how alternative management regimes affect the important pathways and processes discussed above, detailed information will be needed to describe the instream impacts resulting from changes in land use, riparian development, and water resource development. Siltation resulting from activities on land is often assumed to cause the degradation of aquatic habitats and resultant extinctions and extirpations (see Rabeni, 1992; Neves, 1993; Williams et al., 1993). Currently, however, there is little evidence specific to the Southeast that conclusively documents and correlates land-use activities outside and within the riparian corridor with the status of aquatic organisms or their habitats. Additional research is needed to determine whether recommendations for widths and vegetation types for riparian buffers are appropriate for various stream sizes, taxonomic groups, and physiographic provinces present in the Southeast.
In addition to land-use activities, water-use activities also affect stream habitats. As mentioned above, and illustrated by Dynesius and Nilsson (1994), few southeastern streams are spared from impoundment. Reservoirs act as settling basins for sediments, and water releases from them can drastically alter sediment transport. More research is needed to make recommendations for minimizing the impacts of these regulated systems on native riverine fauna. For example, Milhous (1994) briefly described research that resulted in recommendations for flows appropriate to flush sediment from streams where important tailwater trout fisheries existed. Milhous (1994) suggested additional research was needed to determine flow recommendations that would prevent silt from settling on stream bottoms in the first place.
Discharge of chemicals into streams is permitted by federal and state regulations. However, the test organisms used to set the limits on water quality parameters may not tell us how more sensitive species will be affected. Little information is currently available on the toxicity of many compounds to sensitive fish and freshwater mussels.
If environmental limits are set for the most sensitive species in an ecosystem, other species will also be protected. Research is needed to determine the environmental tolerance limits of sensitive species regarding various water quality parameters (e.g., dissolved oxygen, pH, turbidity, temperature).
Neves (1993) recommended customizing testing to set water quality parameters for various pollutants, according to watershed. This could be done by using surrogate mussel or fish species most closely related to the rare species within those watersheds as the test organisms; phylogenetic data, as discussed below will support the proper choice of surrogates. Neves (1993) further recommended using the larval (glochidia) stages of these mussels as test organisms to make the tests better reflect effects on the most sensitive life stages of these benthic organisms. Neves (1993) suggested that because sediments can be involved in the long-term storage of toxics, current surface water quality standards may not be sufficient to protect benthic species. More research is needed to describe the relationship between water quality, sediment toxicity, and abundance and diversity of benthic organisms.
Research that allows analysis of dispersal and recolonization abilities of species is important in the context of landscape-level processes. This information may provide insight on the importance of connectivity between watersheds in maintaining communities, and may also provide guidance on managing fragmented populations. At another scale, data on population dynamics also provide information critical to conserving or recovering imperiled species.
Little is known concerning the levels of population structure and geographic fluctuations that normally exist in local populations of aquatic species, how local populations interact with each other, or in the larger scale, metapopulations. If baseline data for long-term population and metapopulation fluctuations are available, positive changes related to restoration efforts or negative changes related to degrading influences may be more accurately assessed.
Some local populations may be more important for the long-term viability of a species; they may serve as sources of individuals for dispersal and recolonization when other more ephemeral local populations become extirpated. For example, Freeman and Freeman (1994) and Strange and Burr (1995) implied important dispersal and recolonization mechanisms in the long-term maintenance of the federally endangered amber darter, Percina antesella and the threatened blackside dace, Phoxinus cumberlandensis, respectively. As Tear et al. (1995) noted, this important information is usually lacking in recovery plans for listed species.
On the scale of conserving individual imperiled species, Strange and Burr (1995) provided information necessary for managing blackside dace. They performed genetic surveys to determine the metapopulation structure of the species and described significant genetic divergence among populations. In providing specific recommendations for recovery actions for this species, they emphasized that reintroductions must be carefully planned to conserve the genetic structure of the various populations. This species inhabits small streams in the upper Cumberland River Drainage. Many of these streams have been degraded by coal mining activities, and captive propagation and reintroduction has been suggested as the means to restore extirpated populations. Therefore, the genetic information reported by Strange and Burr (1995) is critical to conservation efforts for blackside dace, in that they allow for the proper choice of parental breeding stock for reintroduction efforts.
Even in restored watersheds, the abundance of some species may be so low that successful reproduction is unlikely or species no longer have access to portions of their former range because of habitat barriers. Propagation and reintroduction technologies may be needed to restore extirpated populations in recovered watersheds, to augment small existing populations, or to restore extirpated populations.
"Emergency" measures may also need to be developed to ensure preservation of as many aquatic organisms as possible under disaster conditions. For example, cryopreservation techniques are being developed to store sperm and eggs or larvae of freshwater mussels (R. Neves, USGS, pers. comm.). Because of the advent of the zebra mussel invasion in the Southeast, techniques for temporarily holding freshwater mussels are also being investigated (R. Neves and J. Layzer, both USGS, both pers. comm.).
Monitoring should be an important component of ecosystem management. Montgomery et al. (1995) and Kondolf (1995) suggested various factors important in stream ecosystem management and restoration projects. Monitoring was an important component of both sets of recommendations. Because watershed projects may be overwhelming in scope, relatively unimpacted reference sites in a watershed that focus on the entire community at that site, or sampling that regularly monitors the status of sensitive species throughout the watershed can efficiently supply important data needed in a large project. Although totally undisturbed aquatic communities are rare, systems that are relatively undisturbed should be monitored to serve as references for recovering ecosystems. Data obtained through monitoring are also needed to evaluate and document the success or failure of projects that aim to preserve or restore ecosystem biodiversity. Management activities can then be revised accordingly (Kondolf, 1995; Montgomery et al., 1995). Baseline (i.e., pre-project) and long-term monitoring data are needed to assess how various land uses influence water quantity, quality, sediment action, and temperature throughout watersheds as well as how they impact specific sites within watersheds (Rabeni, 1992). On the scale of individual species, and as described above, Inouge (1988) recommended regular monitoring to develop long-term data sets on population variability.
Adams and Alderman (1993) recommended that state resource agencies, in cooperation with biologists from other organizations, develop a checklist including historical distribution and an evaluation of the current status of all aquatic species occurring in various states. Regular monitoring that would allow for periodic re-evaluation of the status of sensitive species was also recommended by these authors. If these aforementioned recommendations were followed, sensitive or geographically restricted species would be monitored and possibly considered for protection or management before populations dwindle below a threshold of sustainability.
In the future, many ecosystem projects may focus on remnants of larger systems. At the larger scale, genetic data will help identify sources of diversity among populations. This information may be useful in prioritizing activities or in revising management schemes. On a smaller scale, genetic data collection will allow an assessment of the rate of genetic change in remnant populations, especially for short-lived animals.
Genetic data provides information essential for developing phylogenies that describe relationships among and between species. These phylogenies may then be used to predict life history strategies and resource requirements of sensitive or rare species in a watershed. Studying a species directly is often difficult or may not be advisable or authorized because of its rarity. By using phylogenetic methods, species can be selected as surrogates for rare or sensitive species. For example, as suggested by Neves (1993), these surrogates can then be used for testing and setting water quality limits that would protect the rare species in a particular watershed.
Within a watershed, phylogenetic methods can also help to identify attributes of species that may be most vulnerable to degradation (Mayden, 1992). For example, laboratory experiments with the relatively common bloodfin darter, Etheostoma sanguifluum, were performed before initiating a captive propagation attempt for the very rare, federally endangered boulder darter, E. wapiti (Shute and Rakes, 1994).
These investigations indicated that boulder darter larvae, unlike many other darter larvae, may drift with the current for several days before settling to the benthic existence typical of adults. Therefore, while managing or restoring habitat in the immediate vicinity of existing boulder darter populations may conserve these populations, actions far downstream may be even more important in the long-term maintenance of the species. By ensuring that there are areas with appropriate boulder darter habitat downstream, the dispersing larvae may enable the population to expand.
Ecosystem management does not mean that the needs of individual species are forgotten. At an ecosystem level, declines in the abundance of sensitive species can be a warning signal of stressful conditions and degradation of habitat or water quality that otherwise might not be easily quantifiable or noticed until conditions are severe or irreversible. Therefore, monitoring the status of individual species may be one relatively simple way to evaluate the success of ecosystem management activities.
Tear et al. (1995) summarized recovery plans for listed species and noted little or no biological information in many of the plans. Life history requirements of many rare or sensitive species are virtually unknown. For example, as described above for boulder darters, snail darters, and amber darters (Freeman and Freeman, 1994) may be rare because larvae drift in the current for several days before settling to the benthic existence typical of adult darters. Therefore, habitat appropriate for juveniles may be the factor restricting these rare fishes to limited stream reaches. Life history information specific only to the adult portion of the life cycle of these fishes may not provide all of the information needed for long-term protection.
Specific information on spawning habitat and breeding season are still to be determined for many rare fishes, and fish hosts necessary for mussel reproduction are poorly known. Neves (1993) reported that the fish hosts have been identified for less than 20 percent of freshwater mussels.
Many disciplines have a role to play in managing and conserving rare aquatic resources. Herein we have made recommendations for expanding historical management methods and focusing scientific research to support conservation of our highly diverse southeastern ecosystems. To be successful in this venture, however, communication between various types of researchers, policy makers, and those responsible for management is imperative, and may result in strong partnerships linking many different stakeholder groups. In addition to scientific input, public opinion must also be considered. An educated public is critical to this process.
Gresswell and Liss (1995) described management responsibilities as extending beyond the immediate constituencies to future consumptive and nonconsumptive users and to the aquatic resource itself. Aldo Leopold (Leopold, 1949; pages 224-225) over 40 years ago anticipated ecosystem management when he stated, "A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it tends otherwise." Proper ecosystem management will preserve entire native biotic communities. Protecting threatened and restoring extirpated components of aquatic ecosystems are critical activities that support this reasonable management.
We thank George Benz, Mary Freeman, Carol Johnston, Richard Neves, Charles Nicholson, and Phil Pister for their suggestions which greatly improved this manuscript.
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