SCIENCE IN THE SERVICE OF BIOLOGICAL SURVEY
It follows from the considerations in Chapter 1 that a continuing assessment of the biological resources (species, communities, and ecosystems) of the United States will ultimately benefit the nation in many ways. The body of information that will be developed by the National Partnership for Biological Survey will help the country to meet many objectives and address such issues as the preservation of biota, the maintenance of ecosystems, and the sustainable use of biological resources.
One of the most important uses of the scientific information gathered by the National Partnership will be to assist decision-makers in addressing existing biological resource issues and anticipating future ones. The research activities discussed in this chapter are essential for gathering scientifically reliable information to support the decision-making process. Decisions based on inadequate, unreliable, or incorrect information can be unwise and costly. The chapter first reviews general criteria for setting priorities and then discusses strategies for conducting research on the species of plants, animals, fungi, and microorganisms of the
United States; the communities and ecosystems in which they occur; and the trends that affect the distribution and abundance of populations of individual species and of communities and ecosystems. As in all work of the National Partnership, success will require the extensive cooperation of scientists of many disciplines and from many institutions. Later chapters address the information needs of users and mechanisms to coordinate and manage the work of the Partnership.
Three themes will be emphasized here and in later chapters. First, priorities must be set for much research on biological resources in a new way that is more directly responsive to our nation's needs for better conservation, management, and sustainable use of those resources. Second, inventory, monitoring, and other research activities must expand beyond traditional, disciplinary lines to encompass well-designed, large-scale, interdisciplinary research initiatives on selected taxa, ecosystems, and geographic regions. Third, new interdisciplinary research initiatives must be explicitly designed to investigate functional relationships across different levels of biological organization, different spatial scales, and different temporal scales; the research needs to range from microsites to ecoregions, from individuals to higher taxonomic groups united by a common history, and from days and weeks to geological epochs. These initiatives will need to involve geological, hydrological, atmospheric, social, and other sciences as well as various areas of biology. The need for interdisciplinary environmental research has also been recognized by other NRC committees (NRC, 1990, 1993b).
There will always be more scientific questions to be addressed and more environmental concerns to be met than available human and financial resources can support. Therefore, priorities must be set.
No single criterion can be used to establish these priorities. Many scientific needs exist within the National Partnership and among its clients, and the information produced and managed by the NPBS will have many uses. But one of the strengths of the Partnership is that multiple criteria for setting priorities can be brought together. Potential priorities can be comprehensively evaluated, and individual agencies and organizations can take specific responsibility for addressing them.
Priorities for the National Partnership should be based on the degree to which proposed research advances one or more of the following goals:
Understanding the status and trends of biological resources that are changing rapidly, are rare, or are threatened by such factors as metropolitan growth, renewable land use, nonrenewable-resource extraction, and natural changes in the environment.
Learning about biological resources that are identified as important by legal mandates or for economic reasons, such as their status as possible sources of new products.
Performing research that will guide the remediation and restoration of damaged or degraded ecological systems.
Evaluating biological resources (species, groups of evolutionarily related species, communities, ecological systems, and landscapes) that are clearly important for science and society but for which relatively little information exists.
Doing studies that might lead to the maintenance or enhancement of biological diversity and to the long-term sustainability and functional integrity of ecological systems.
Understanding ecological processes that provide services, such as control of nutrient and soil loss, assimilation and degradation of pollutants, and maintenance of biological diversity.
Converting small investments of human and financial resources to relatively large returns in understanding of the status and trends of biological resources.
Several general considerations are important in developing priorities. An examination of existing records concerning the past geographic occurrence and condition of species and ecological systems provides a context in which to measure their current status and trends. The same is true for the examination of past management experiences or studies, especially if the information has been gathered in a standard way and is documented (NRC, 1986). For example, the projects for which environmental impact statements are written are potentially valuable experiments, but they are usually treated as one-time sets of observations, rather than as predictions of the consequences of planned manipulations. As a result, there is usually no monitoring to determine the effects of the projects. Such information would be of special importance in remediation and restoration, and those projects are often the only way to generate such information. Finally, priorities should be chosen to enable the National Partnership to carry out its work efficiently and cost-effectively.
The committee believes that the scientific activities and programs of the NBS should focus both on its responsibilities as the main biological research agency within the Department of the Interior and on its proposed role as the lead agency for the National Partnership. The large amounts of land managed by DOI (Fig. 1.1), along with the department's other responsibilities with regard to the nation's biota, make NBS especially important in providing key elements of a program to assess the status and trends of biological resources. The committee therefore recommends the following:
Recommendation 2-1: NBS should perform research needed for the management of lands within the jurisdiction of DOI and species for which it has responsibility. It should also ensure, both through its own scientific activities and its proposed role of national leadership, that needed research is performed to fulfill the central purpose envisioned for the National Partnership—to generate the information required to
understand the current status of the nation's biological resources, how that status is changing, and the causes of the changes.
Given the wide range of national needs identified in Chapter 1, the broad distribution of relevant research efforts in federal and nonfederal organizations, the wide range of management needs within the Department of the Interior, and the short time available to examine these programs and needs in preparation for this report, the committee believed that it would be most helpful by focusing its attention on research needs at the level of the National Partnership rather than concentrating on specific recommendations for NBS research activities. For this reason, most of the recommendations in this chapter apply to the Partnership as a whole and not specifically to the NBS or other participants. However, the committee recognizes that many factors will influence the formal creation of the proposed National Partnership and believes that DOI should work to ensure that needed research is done by NBS or other entities no matter what specific form the Partnership eventually takes. The recommendations below provide a general framework to help members of the National Partnership to develop their research programs, but more detailed examination, based on this framework, of research needs and priorities of key participants, including the NBS, could be usefully performed by an independent group of experts.
SCIENTIFIC RESEARCH ON THE STATUS OF BIOLOGICAL RESOURCES
If the National Partnership for Biological Survey is to realize its purpose, it must greatly strengthen our understanding of the distributions and the factors that govern the distributions of species and higher taxa, communities, ecosystems, landscapes, and marine realms of the United States. To achieve that goal, the
work of the Partnership should meet the following objectives in assessing the status of the nation's biological resources:
To determine the identities and distributions of species that live in the United States. Discovering, describing, and classifying these species will make possible the accurate and efficient identifications needed for many purposes by decision-makers, scientists, and other users. Species need to be understood in the context of their groups, and that understanding necessitates broad, comparative studies of the species in these groups and access to large, representative collections. For species whose geographic ranges extend beyond the United States, information is needed about their distributions in other countries.
To use knowledge of relationships among species to produce predictive classifications. A classification that accurately reflects the relationships among species should improve our ability to predict which species are likely to have particular properties, even if they have not yet been studied in detail (Wheeler, 1990).
To determine the physical and biological factors that govern the distributions of species. Management and conservation decisions affecting particular species are problematic in the absence of information about such basic aspects of their biology.
To understand the population biology of species selected for intensive study, management, or conservation. Detailed understanding of the biology of populations will permit predictions about the consequences of decisions that lead to expansion or contraction of the geographic ranges of species.
To determine the types and locations of communities and ecosystems in the United States. Management strategies that deal explicitly with ecological units require accurate distributional information for these units.
To determine the factors that govern the distributions of communities and ecosystems. Unless the factors that shape and limit the distribution of individual communities are known, decisions intended to manage them sustainably might prove ineffectual.
To understand the effects of human settlement patterns (metropolitan growth, renewable land use, and nonrenewable-resource use) on species, communities, and ecosystems. Much of the current decrease in biological diversity in the United States is concentrated at the rapidly expanding urban-rural interface. Research is needed on the effects of suburbanization on biological resources, and on ways of reducing or mitigating these effects, and on the levels at which settlement can coexist with viable ecosystems.
What Species Occur in the United States? Where Do They Occur? How are They Related?
We need to know what species live in the United States, where they live, and how they are related to one another in an evolutionary sense. Modern classifications reflect patterns of common ancestry and can be helpful in predicting the occurrence of properties of poorly known organisms. Although no substitute for research on individual species, they are thus vital tools in the search for and management of biological resources and provide a frame of reference for biological research. For example, botanists can use classifications to decide where to search for chemicals of potential value to industry and medicine, and entomologists can use them to predict which parasites hold promise for the control of agricultural pests.
The United States has unparalleled taxonomic research capabilities in its public and private museums, botanical gardens, universities, and government agencies. In general, taxonomic research has not been focused specifically on the goals that the NPBS will fulfill, but the Flora of North America, Moths of North America, Birds of North America, similar current projects, and state biological surveys are important examples of the kind of taxonomic research that the National Partnership should perform. Australia (see Box 2.1) and Costa Rica have established national organi
Box 2.1: Environmental Resources Information Network: Australia's Response to the Need for Access to National Biological Survey Data
Australia has pioneered a two-pronged approach to surveying and monitoring its flora and fauna. Within the Australian National Parks and Wildlife Service, the Biodiversity Directorate administers the Australian Biological Resources Study (ABRS), the purpose of which is to collect and document information on the biota of Australia. The Environmental Resources Information Network (ERIN) Directorate is responsible for developing an information-management system and for assembling data on the flora and fauna and analyzing them for management purposes.
ABRS maintains editorial centers for its flora and fauna series and provides grants to taxonomic specialists to undertake the research necessary to classify and describe the plants, animals, and microorganisms of Australia. The grants address the highest-priority needs and are in the form of binding contractual agreements that specify products and a delivery schedule. This scheme ensures that careful scientific work will be done in a timely manner and that scientific attention is focused where it is most needed.
ERIN's mission is to provide geographically related environmental information of an extent, quality, and availability required for planning and decision-making. ERIN contracts with taxonomic specialists and uses data from the flora and fauna series to create its backbone of taxonomic information. It contracts with institutions that maintain biological collections to computerize data on the identities and places of collection of those specimens. This information is brought together with information on physical properties of the continent—climate, topography, soils, etc.—and with information on vegetation, ownership, and conservation status through geographic information systems (GISs). ERIN has developed computer programs that can predict how a species' distribution might change if average temperature increases or decreases; its programs can show correlations among species distributions; and its system can model expected impact on a species' distribution and population viability if part of its habitat is lost, for instance, through development. Individual institutions and specialist groups take responsibility, as custodians, for the quality and reliability of data made available to ERIN. Data standards have been established cooperatively between ERIN and the custodians to facilitate data transfer and sharing.
ERIN has several large-scale data-analysis projects. One is the Landcover Project, which aims to collate data on the distribution of species that make up the dominant groups of plants in the Australian landscape. Another project is the Murray-Darling Basin Project, which is reviewing the availability of environmental data for the area, defining the major ecosystems of the basin and assessing the relationship between the ecosystems and conservation reserves, and developing a strategic plan for the conservation of the ecosystems. A third project is the National Marine Information System, a comprehensive computerized marine-science information base that will include significant data on all aspects of Australian marine environments, including fisheries, mineral resources, ocean currents and climate, and the distribution of marine life around the Australian coastline.
By bringing together the expert knowledge of its biologists, the information held in its rich museum collections, and the innovative and focused use of data-management, analytical, and mapping computer programs, the Australian National Parks and Wildlife Service has assembled a powerful and far-reaching tool for understanding and managing its natural resources.
zations to study and document biodiversity. Their experiences suggest that even small investments in taxonomic research can yield results of importance to decision-makers.
Recommendation 2-2: The National Partnership should determine what specimens and data representing the U.S. biota exist in the nation's institutional collections, both public and private.
Specimen collections are useful for many purposes (see Box 2.2). The large holdings in the United States should be studied and assessed, and the resulting information should be synthesized and made available. By taking stock of the information already available, scientists will be able to find the gaps in our knowledge and take steps to fill them. Some groups of organisms are poorly represented in collections and poorly understood. Examples
Box 2.2: Collections
Within public and private institutional collections in the United States are millions of specimens that document two centuries of exploration of our country and contain a rich trove of information about our flora and fauna. Such specimens are usually parts of organisms (a branch of a tree, a blood sample from a bird), entire animals or plants, or a number of individuals from a population. They are accompanied by information about where and when they were collected, what the place was like, and what other organisms were present. The specimens and their associated data give insight into the ideas of the researchers who have studied them. Collections of specimens are a critical component of the NPBS. In all but a few well-known taxa, identifications of species must be based on voucher specimens, without which frequent misidentifications are certain to be made. Faulty management decisions are likely to result from incorrect identifications. Collections are the repository for most of what we know about species diversity and are constantly pressed into use for new and often unexpected purposes. The tissues and organs of collected organisms may contain valuable information about the environment at the times they were collected. For example:
Natural history collections contain information that is invaluable to our understanding of biodiversity, its history, its current status, and its future. They are an essential resource for the study and management of the biodiversity of our nation.
include mites, nematodes, many groups of fungi, and marine invertebrates. For bacteria, DNA or RNA probes might reveal the extent of diversity, but these organisms are poorly known. Collections of bacteria in culture are indispensable for the further understanding of the group. Even for such well-known groups as plants and vertebrates, there are geographic gaps in our knowledge, and the available records might not have been gathered recently enough to indicate the present status of individual species.
Precise knowledge of what materials and data already exist will facilitate the timely provision of information to those who need it and will help scientists to identify gaps that warrant research. Tens of millions of specimens and facts have been accumulated through more than two centuries of exploration of the biological
diversity of the United States. However, because of the immensity of the country's collections and how they are dispersed, management of this information was impractical before the existence of modern computer technologies. The NPBS, with the NBS taking the lead, should assess, as rapidly and completely as possible, what we now know about the distribution of species in the country on the basis of records of collections. It should also determine the importance of this information for current and future research efforts.
Recommendation 2-3: The NPBS should discover, describe, classify, and map U.S. species of selected taxa.
The National Partnership should go beyond an inventory of information and collections and take decisive and forward-looking actions to fill important gaps already known to exist in our knowledge of U.S. biological resources. Taxa should be chosen on the basis of their economic, societal, or scientific importance and the length of time required to complete the task. Among those appropriate for immediate study are terrestrial, fresh-water, and marine vertebrates (all classes); plants (bryophytes and vascular plants); macrofungi; and selected fresh-water, marine, and terrestrial invertebrates (mollusks, crustaceans, mosquitoes, beetles, butterflies, moths, spiders, and ticks). Special attention should be given to taxa that occur in the areas where regional collaborative pilot projects are established (see Recommendation 2-13).
More complete species inventories and classifications for selected taxa will support environmental research of both immediate and long-term priority. For example, vertebrate, plant, fungus, and arthropod surveys in old-growth forests of the Pacific Northwest would improve the scientific basis for policies related to resource use and conservation. In such inventory work, special attention should be given to preserving specimens for DNA, protein, and other analyses that are particularly useful for evaluating relationships but are not usually possible with older specimens.
The Department of the Interior should initiate studies that pertain to its missions, including vertebrates, plants, fungi, and arthropods. The U.S. Department of Agriculture (USDA) should sponsor research through the Forest Service on taxa that occur in forest lands, committing an appropriate portion of its resources to address private-forest issues, and it should substantially increase support for its systematics-research laboratories (especially those studying fungi and insects). The National Oceanic and Atmospheric Administration (NOAA) should extend its research efforts to include noncommercial marine fishes and increase its survey, inventory, and taxonomic research efforts on marine invertebrate groups. The National Institutes of Health, the Department of Defense, USDA, and the Department of Energy should conduct or sponsor research on mosquitoes, ticks, and other vectors of disease and on potential sources of medicines, feedstocks, biomaterials, and foods.
Recommendation 2-4: Taxonomic specialists, collections, and databases should be established for large and important taxa for which research resources are inadequate, including taxa that live in terrestrial environments (e.g., fungi, nematodes, and arthropods), marine environments (e.g., polychaetes, crustaceans, and mollusks), and freshwater environments (e.g., protists, mollusks, and other invertebrates).
The United States needs to have specialists in all major and important taxa and on taxa for which no experts exist throughout the world. Species of many large and ecologically or economically important groups are unknown or currently unidentifiable because of a lack of relevant expertise. Clearly, an adequate scientific research program must include the training of specialists, support of surveys and taxonomic research, and the building of comprehensive collections of diverse taxa.
Our lack of knowledge of microorganisms and invertebrates, which are estimated to make up as much as 88% of all species, seriously hampers our ability to understand and manage ecosys-
tems. Fungi and arthropods associated with nutrient cycling in forests, for example, are only poorly known. For many parks and other protected areas, such groups as fungi and lichens, for which there are few available specialists, are little known or understood. Organisms that prey on or infect insects hold promise for cost-effective and environmentally benign control of insect pests, but the relevant parasitic wasps, nematodes, fungi, and protozoans have been little studied. Important proposals have been made to address this deficiency on a global scale (e.g., Hawksworth and Ritchie, 1993), and our national programs ought to be integrated with such efforts and constructed so to support them.
Our lack of information on marine habitats is also critical. Of the 70 phyla of living organisms, 43 are either exclusively marine (20) or partially marine (23), but gaps in our taxonomic knowledge of many groups of marine organisms are numerous and broad (Ray, 1988).
For fungi, algae, and bacteria, which are critical in the functioning of ecosystems, organizations that maintain living collections, such as the American Type Culture Collection, should be supported. The functioning of the multi-billion-dollar biotechnology effort in the United States alone demands the maintenance of such facilities and underscores the need to add to their collections rationally and aggressively. From a scientific point of view, this approach constitutes the only way to gain an adequate, comparative, verifiable understanding of the groups involved. In a more general sense, the living collections of botanical gardens, zoos, and insectaria are comparable, and such groups as the Center for Plant Conservation, which assembles genetically adequate samples of the threatened and endangered plants of the United States, ought also to be encouraged and supported.
Why Do Species Occur Where They Do?
Surveys of species distribution, abundance, and population
structures provide only part of the information necessary for managing the nation's biotic resources. An understanding of ecological requirements of species is also needed for their management, protection, and restoration, as well as for developing models that can be used to predict their likely distributions and responses to environmental changes. We need basic knowledge of the natural history of species, their patterns of genetic variation, habitat requirements, interactions among widely separated populations, life-history characteristics, feeding habits, reproductive biology, interactions with pollinators, predators and competitors, and vulnerability to anthropogenic disturbance and habitat fragmentation.
Because detailed biological information would be desirable for hundreds of thousands of species, adopting criteria for determining the order in which species are chosen for study is crucial. Species can be selected on the basis of whether they might be ecological indicators; are important to the functioning of ecosystems; represent distinct phylogenetic (evolutionary) lineages; represent taxa that are believed to be declining; have potential or demonstrated economic, scientific, or societal worth; or are at the margins of their geographic distributions. For example, although details of projected climate change due to carbon dioxide emissions cannot be predicted, monitoring populations at the extremes of their distributions might permit early detection of the effects of potential climate change. A high priority should therefore be placed on establishing baseline data on the current status of indicator taxa at range extremes.
The National Biological Survey should perform research on ecological requirements for taxa from ecosystems of current national concern (e.g., Pacific Northwest old-growth forests or coastal estuaries) and from diverse, biologically significant ecosystems (e.g., native forests of Hawaii or unique areas within our national parks, such as the Great Smoky Mountains National Park). USDA should lead research on taxa that fall within its mission, such as agriculturally important insect and plant pests, such beneficial species as pathogenic nematodes and predatory
insects, and introduced species; the national forests should be of primary concern. NOAA should target both marine fishes and little-known marine invertebrates for detailed study; for example, the recent decline of Caribbean reef corals, including those in U.S. waters, might be largely the result of the catastrophic decline in a single species of sea urchin (Lessios, 1988). The U.S. Geological Survey should provide leadership in researching the histories of species and ecosystems as interpreted from the fossil and geological record. Taxonomists and ecologists should participate in the selection of species, and priority should be given to team research.
Recommendation 2-5: Identify and thoroughly study the biology of selected species that have significant economic, scientific, or aesthetic value or play a key role in a threatened biogeographic area or ecological habitat.
Because informed management decisions depend on detailed understanding of the biological habits and requirements of species, it is important to identify species relevant to environmental issues of high priority and initiate the process of accumulating fundamental knowledge about them. For example, the population biology of threatened and endangered species is obviously a subject of high interest (Falk and Holsinger, 1991). Targeted research on selected species should inform the NPBS about future needs, as well as urgent existing problems. Special attention should be given to key species in the pilot project areas described under Recommendation 2-13.
What Communities and Ecosystems Occur in the United States? Where Do They Occur?
Recommendation 2-6: The NPBS should develop classifica-
tion systems for ecological units—such as communities, ecosystems, and landscapes—that will provide consistent terminology for recognizing, mapping and monitoring trends in the distribution and status of those units. The NPBS should also move rapidly to define a set of core ecosystem attributes and protocols for sampling, measuring, and recording those attributes. NBS should play a major direct role in these efforts.
Classification systems for communities, ecosystems, and landscapes are needed for recognizing and mapping them and for communicating information about their status, distributions, and trends. There are currently no broadly accepted classification schemes for such ecological units above the level of species, and no single classification system is likely to serve all management purposes. Community classifications for terrestrial, fresh-water, and marine habitats have been established by The Nature Conservancy and have proved useful for setting conservation priorities. However, classification schemes for aquatic systems are generally poorly developed and rarely applied.
Ecological classifications are extremely important for the management of biological resources on an ecosystem and regional basis, and they need to be developed as fully as possible according to broadly based criteria. The same criteria can be used to design specific classification systems for particular purposes.
With the advent of better technologies for handling spatial data, classification and mapping are no longer limited by such a priori constraints as the need to limit a map to four colors. Instead, geographic phenomena can be described with a set of attributes that can be selectively weighted and combined for a posteriori classification and mapping. For example, specific terrestrial units within a region can be described in a database according to their geology, geomorphology, vegetation height, canopy leaf type, vertical stratification, and canopy floristic composition. Regional vegetation or ecosystem patterns can then be remapped in many ways on the basis of different classification rules.
That approach obviates a single, general-purpose classification system and can serve a wide range of users. Because the basis for classification is more value-neutral than with traditional systems, resulting information will have a stronger scientific basis. Thus, although we need standard ecosystem classification schemes for monitoring and reporting purposes, the databases from which the classifications are generated should record preclassified ecosystem data. To that end, the National Partnership should give high priority to defining a set of core attributes for characterizing vegetation, habitats, and ecosystems and then establishing standard methods for measuring and recording those attributes (see, for example, Bolton, 1991; DiCastri et al., 1992). Eventually, this approach will lead to national and international databases that can be analyzed to uncover patterns in ecosystem structure and composition and to evolve more functional classification systems.
Useful classification systems will permit clear delineation of all included ecological units. They should serve as a predictive base for anticipating interactions among ecosystems and their physical environments. The ecological units recognized should correspond to the distribution of constituent species whose protection is likely to afford protection to the entire community. A hierarchical structure of such classification systems is likely to prove useful, even though effective conservation and management strategies would normally deal with subordinate levels within the system (Bourgeon, 1988; Orians, 1993).
Why are Ecosystems Found Where They are?
Recommendation 2-7: The National Partnership, with the direct involvement of NBS, should stimulate research to understand and develop a predictive theory of keystone linkages and keystone species and should work toward developing predictive models that facilitate sustainable management of communities and ecosystems in the United States.
Valuable though ecological classification systems might be, they contain little information about why ecosystems are found where they are. The members and kinds of species living together in ecological assemblages are determined by both local and regional processes, including current and historical interactions between organisms and the physical environment. Individual species have specific ranges of tolerance of physical environmental conditions, but the actual range of environments occupied is reduced by interactions with other species. Competition, predation, and parasitism happen only among organisms living in the same area, but the kinds and numbers of individuals available to interact depend on regional-scale processes. For example, a small isolated community is likely to receive many immigrants that belong to species living in adjacent but different communities, whereas most immigrants to portions of large, extensive communities come from other parts of the same ones. Interactions with humans occur at all spatial scales. The result of all these interactions is a recognizable, but not identical, assemblage of species that occupies a particular zone of environmental conditions.
The interactions that structure ecological assemblages range from strong to weak. Ecologists refer to very strong interactions as keystone linkages and to species that exert the strongest influences on the composition and functioning of the assemblages of which they are a part as keystone species. Keystone linkages and species are often identified empirically after the fact. Ecological theory cannot yet predict where keystone features will be found, although experience shows that some higher taxa, such as large echinoderms in the ocean, typically play a keystone role. Developing a predictive capability is important because it would enable direction of attention to elements and interactions whose maintenance is critical to the continued and undiminished production of important ecosystem services.
Recommendation 2-8: The NPBS should encourage research on restoration of degraded environments.
Terrestrial and aquatic ecosystems of the United States have been degraded by human activity. Although restoration has been attempted often, it has rarely been successful (NRC, 1992). Understanding why communities and ecosystems are found where they are and how they interact with adjacent assemblages is also necessary as a foundation for methods of restoring degraded and damaged ecosystems. To restore a community, we must know what the community was like before it was degraded, how many and what kinds of organisms are likely to arrive in the area without human assistance, and what conditions are necessary if arriving individuals are likely to colonize successfully.
Research is needed on restoration methods that will work in the highly varied terrestrial and aquatic environments of the United States. Successful restoration also depends on historical analyses that permit an assessment of the types of ecosystems that can persist in an area.
Efforts in restoration biology can take advantage of the large-scale ''experiments'' represented by major development projects that are required to file environmental impact statements (EISs). The EIS amounts to a prediction of the extent and kind of impact a project will ultimately have on the local environment. Scientists can learn much from this process if EISs are done in such a way as to establish a baseline and if appropriate follow-up monitoring is done to learn the eventual ecological impact. Properly done, such "experimentation" can reveal what kinds of projects have more or fewer environmental impacts than expected. It might not be practical to treat all EISs this way, at least initially; but specific case studies can be chosen to represent common classes of environmental problems for which knowledge of the success or failure of specific management decisions could inform future approaches.
Recommendation 2-9: The NPBS should identify target areas for restoration. As a pilot project, NBS should lead the Partnership in an assessment of the rivers of the United States
to identify those most appropriate for restoration according to biological indicators. The effort should be coordinated with current work of the Corps of Engineers, the U.S. Fish and Wildlife Service, the Environmental Protection Agency (EPA), and the U.S. Forest Service.
An important role for the NPBS would be to identify target areas for restoration. As an example, consider the flowing waters of the United States, which have been highly affected by human activity. We lack an inventory of the rivers of the United States that would permit setting priorities for restoration of rivers or river segments (NRC, 1992). There is a need for a national river inventory that would place the nation's rivers in three categories: healthy, degraded, or highly degraded. Rivers characterized as "degraded" should be selected for aggressive restoration efforts. Mildly degraded rivers could be improved with a modest investment. Within that class, restoration priorities can be based on potentially valuable species, recreational value of the ecosystem, or other criteria. A similar inventory could prove useful for targeting restoration efforts in other types of ecosystems.
Recommendation 2-10: Current chemical assessments of pollution sites (terrestrial, fresh-water, and marine) should be augmented by NPBS research to develop biological assessment protocols.
The detection and characterization of polluted sites (fresh-water, marine, and terrestrial) by EPA and other agencies now rely almost exclusively on chemical assessments of habitats. Among the many species that have such habitats are many that might serve as biological indicators of pollution. Research should be done to identify such indicator species and learn enough about their biology to make it possible to recognize warning signs of particular kinds of pollution. Pollution assessment through such biological approaches is potentially more cost-effective, quicker,
and more useful than chemical methods. The indicators should also prove useful for tracking the remediation of basic pollution problems.
Interactions among Ecosystems
The survival of species and the maintenance of essential ecological services commonly depend on patterns of species migration and transport of materials among ecosystems over an enormous range of spatial scales. Thus, local changes in one ecosystem might have major consequences far beyond their immediate range of obvious impact. Examples include the suspected reduction of North American songbirds due to tropical and temperate habitat destruction and fragmentation effects, including lower productivity and survival (Terborgh, 1989); decreases in salmon due to migration restrictions, nonpoint pollution, and sedimentation; and decreases in aquatic species due to point and nonpoint pollution, sedimentation, introduction of exotic species, changes in hydrology, and loss of wetlands (Thorne-Miller and Catena, 1991). Most such examples involve either outright habitat destruction that interrupts the movements, breeding, or seasonal survival of widely ranging species; increases in the natural flux of materials from terrestrial "source" to aquatic "sink" habitats; or unexpected impacts on one habitat as a direct result of modifications made in another. In any case, effects can be highly specific, as in the interruption of the life cycle of symbionts that depend on particular hosts, or much more general, as exemplified by the dramatic alteration of the entire Lake Erie ecosystem by the accumulation of nutrients. Impacts can move from one terrestrial habitat to another, from terrestrial to aquatic habitats, or from fresh-water to marine habitats. The pesticide DDT, for example, applied to agroecosystems, became concentrated as it moved up terrestrial and aquatic food chains (Carson, 1962).
Many harmful ecosystem interactions can be restricted to a
single watershed or forest, but most are broader in scope and transcend local or even regional political boundaries. The National Partnership can play a critical coordinating role in the identification of important shifts in ecosystem interactions and the gathering of existing and new information on the magnitude of habitat alteration or the material flux responsible. These activities should lead to the identification of a small number of critical model systems for intensive study. The systems should be included in the group of projects referred to in Recommendation 2-13. Important candidate systems that are already the focus of considerable local and federal attention include the effects of agriculture and land development on fresh-water and marine ecosystems in South Florida (see Box 2.3), and the loss of flyway habitat of migrating birds (see Box 4.1)
DETECTING TRENDS IN BIOLOGICAL RESOURCES
The purpose of studying trends is to identify biological resources that are changing in quality and quantity and to determine why they are changing. The resources whose changes are of interest include species and their constituent populations, evolutionarily related groups of species, ecological communities, and ecosystems.
The importance of identifying trends in the condition of resources and determining the causes of changes is highlighted by the increasing evidence of rapid declines in important groups of organisms. For example, a rapid decline in populations of at least half the species of mushrooms has been documented in Europe (Arnolds, 1988, 1991; Gulden et al., 1992). Those fungi are fundamental to healthy ecosystems because they form intimate associations with plant roots, and the associations increase the rate at which the roots absorb nutrients from the soil and make it possible for plants to survive in the particular ecosystems where
Box 2.3: South Florida and the Everglades
The South Florida landscape is dominated by a series of closely linked wetlands and aquatic ecosystems that extend from the Kissimmee River and Lake Okeechobee in the North through the Everglades and Florida Bay to the Florida Keys in the South. The Everglades is the largest wetland ecosystem in the contiguous 48 states and has been the subject of intense controversy about the ecological effects of drastically reduced and altered patterns of water drainage and increased nutrient inputs from North to South due to flood control, agriculture, and human settlement.
Attempts to assess status and trends of terrestrial and marine biota in South Florida have been hampered by ignorance of the biology of many species, especially invertebrates and lower plants, which have been ignored except by a few systematists. For example, the endangered Florida Snail Kite is almost exclusively dependent for its food on one species of fresh-water mollusk, the apple snail. A real-estate developer would never plan a human community without serious consideration of the location of supermarkets. Yet, agencies have been forced to make major decisions about habitat protection for the Snail Kite with very little knowledge about its sole source of food (National Audubon Society, 1992).
Failure to monitor components of adjacent ecosystems (e.g., wading birds in the Everglades, phytoplankton in Florida Bay, and reef corals in the Keys) has delayed understanding of their close interdependence. This failure has greatly increased the probable costs for environmental restoration over what would have been required if the necessary scientific assessments had been made sooner.
There is also no well-established regional infrastructure to bring together status and trends data on organisms and conditions in disparate environments. Moreover, much existing information is effectively unavailable for lack of local resources and personnel to access and interpret crucial remote sensing data, as for algal abundance and productivity in Florida Bay.
The management authority for different biota, habitats, and water resources is fragmented—scattered among federal, state, and county agencies that work under different and sometimes conflicting missions and mandates. For example, the U.S. Army Corps of Engineers and the South Florida Water Management District share responsibilities for
water-resource management. The U.S. Fish and Wildlife Service, the National Park Service, the National Oceanic and Atmospheric Administration, the Florida Bay and Biscayne Bay State Parks, the Florida Game and Freshwater Fish Commission, and the Florida Department of Environmental Protection all have jurisdiction over various marine and terrestrial protected areas and wildlife in the region. Counties and state agencies share jurisdiction over land-use planning, zoning, development, and resource use. Much ecologically important land is owned privately. While some is managed for conservation, most is used for agriculture or human settlement.
South Florida is by no means unique in this fragmentation of authority, which interferes with the abilities of agencies and the private sector to address a common set of environmental problems and needs. Closer coordination is clearly needed.
Important local initiatives have begun. Secretary Babbitt recently announced an agreement among major parties to reduce harmful nutrients and improve water flow to the Everglades. This initiative and subsequent actions would be greatly assisted by the proposed National Partnership for Biological Survey. For example, cooperative studies involving the National Biological Survey, the Corps of Engineers, the South Florida Water Management District, and universities could use existing water-control structures to determine how Everglades ecological communities respond to different water-supply regimes. Such knowledge is essential for effective restoration and sustainable use of this great wetland.
they occur. The causes of the decline are not fully known, but both air pollution and acid rain are suspected contributors. Determining the causes is made more difficult by the decrease in the number of taxonomists and ecologists studying fungi and by lack of sufficient attention paid in the past to the distributions of fungi.
The trends portion of a status and trends program should have the following objectives:
To identify trends in a timely manner so that corrective actions can be taken while multiple options are available. Typically, the later a corrective action is taken, the fewer and more expensive are the ones that remain. Generally, an ounce of prevention is worth a pound of environmental restoration.
To learn how local actions, both individually and collectively, influence processes and products elsewhere. Spatial interconnectedness is important. As projects study selected ecosystems in detail, potential impacts of ecosystems and their components on one another should also be monitored.
To reduce uncertainty about risks so that expensive remedial actions are not undertaken unnecessarily. Faced with great uncertainty about risks, decision-makers are likely to take action to avoid any risk because they cannot afford to remain passive when the possibility of great risk cannot be ruled out. The more accurate the available information, the more appropriate and cost-effective the steps taken will be.
To evaluate the effectiveness of management decisions. One of the requisites of adaptive management is that options that are chosen should be evaluated by monitoring the changes in the managed resource, and the management plan then revised accordingly.
To direct attention to areas where problems are most likely to develop in the near future. Among such areas are urban expansion zones, estuaries, rivers, and zones of intensive resource management and extraction.
Data Useful for Determining Trends and Their Causes
Trends in the status of biological resources cannot be identified or understood unless a solid database on the identification and distribution of the resources is available. Collections and related literature are a primary source of information on the past status of
species and ecosystems. The information they contain needs to be computerized and made efficiently and rapidly available. Sampling procedures need to be set up to ensure that records of selected taxa and ecosystems are kept up to date. Historical information on several time scales is needed:
Within recorded history. Data on the distributions and status of natural resources within historical time are provided by specimens in museums and herbaria, photographs, written records, archival aircraft and satellite imagery, and oral histories. Such information is especially valuable because it is potentially more complete than information from the more distant past, because the causes of changes are likely to be human actions similar to those operating today, and because it can help predict what resource status is potentially achievable if the adverse effects of human actions are sufficiently reduced in the future.
Within postglacial times. Paleoclimatologists and paleoecologists are able to reconstruct climates during the last glacial period and the period during which the glaciers retreated to approximately their current positions. They can also reconstruct shifts in the distributions of organisms and ecological communities that accompanied climatic changes. Those long-term records reveal that the ranges of species shifted at varying rates and that species assemblages differed strikingly from any found today. If climate change occurs, whether naturally or as a result of human activity, information about ecological responses to past change will be useful for managing ecological communities in the face of future shifts.
Over geological times spans. Although data on long-term, evolutionary changes in the earth's biota are inevitably less complete than data from the more recent past, they provide valuable insights into the evolution of the groups of species found today, how they achieved their current distributions, and what happened when organisms from different geographic regions interacted with one another for the first time. For example, when
North America and South America were joined by the formation of the Panamanian land bridge about 3 million years ago, many species of mammals crossed that bridge in both directions. At first, there was in increase in the number of mammalian species in South America, but over time many groups of South American mammals became extinct, probably as a result of competition with and predation by North American mammals (Marshall, 1985).
Given that human activities are resulting in massive exchanges of species between continents, extinctions and ecological adjustments of biotas will continue to increase in intensity in the future. For example, invasion of alien species is the major cause of extinctions in the Hawaiian Islands today (see Box 2.4) and has had substantial effects on many mainland ecosystems (Mooney and Drake, 1986). Detecting invasions of exotic species and minimizing the impacts of their colonization of the United States is an important use that decision-makers will make of information from the National Partnership.
Data on Current Trends
Because the dominant organisms in many ecological systems, such as trees and corals, are long-lived, many important changes in ecological communities and ecosystems are too slow for us to sense directly (Jackson, 1992). Our abilities to interpret slowly operating cause-effect relationships are even poorer. Therefore, processes acting over decades are hidden and reside in what has been called the invisible present (Magnuson, 1989). In the invisible present, change can be occurring but undetected because of confounding factors. Only long-term sustained monitoring and research can reveal these slow but important changes.
Recommendation 2-11: The National Partnership should identify and monitor the status and trends of organisms sensitive to climatic and pollution factors, such as amphibians,
mollusks, songbirds, reef corals and other marine invertebrates, and fungi.
Changes in distributions and abundance of species are important indicators of impending problems. They can direct attention to areas where improved understanding of the causes of changes will be especially useful to decision-makers. Species whose ranges and abundance are increasing provide signals as valuable as those from species whose distributions and abundance are decreasing. Studies at the margins of ranges of species are particularly important for understanding the patterns of adaptation of those species to extreme conditions and their likely response to change.
Recommendation 2-12: The NPBS should perform research to identify the most useful biological indicators of ecological trends.
Because the goods and services that the nation receives from ecological communities depend, in part, on their functional integrity, indicators of functional-integrity are important to develop and monitor. Whereas ecologists can identify general indicators, much work needs to be done to determine which attributes are most usefully measured in particular ecological communities and for particular management purposes (Karr, 1987). Some indicators will have direct relevance to policy or management objectives (e.g., responsible use of an economically valuable species whose viability depends on specific functional properties of an ecosystem). Others will serve primarily as signals to direct general attention to a region or type of ecological community. All indicators should be judged against standards of repeatability and precision so that changes and trends can be unambiguously detected.
Before a monitoring and assessment program is established, considerable investment is needed to identify the most useful indicators. Procedures for doing so include workshops, seminars,
Box 2.4: Hawaii and the Pacific Islands: An Urgent Conservation Priority
Strikingly different from the continental United States are the island systems of the Pacific Ocean for which the United States has current or historical responsibility. These comprise some 2,300 islands in eight political jurisdictions extending over an area much larger than that of the 48 states. In these islands, there are more endemic organisms per unit of land area than anywhere else in the United States and possibly more than anywhere else on earth. Over three-quarters of the bird and plant extinctions in the United States have occurred in Hawaii, where 34% of the country's endangered plant species and 40% of the nation's endangered bird species are found; another 30 bird species in Micronesia are proposed for federal listing. Thus, the Pacific is a priority for preserving biodiversity, with its rapidly changing political and economic situations—and time is running out. These island habitats and their associated marine communities can be dealt with effectively only through well-coordinated field research focusing on species inventories, adequate ecological information, and especially the role of alien-species invasion in island communities. In dealing with Hawaii, the unincorporated U.S. territories, American Samoa and Western Samoa, the Commonwealth of the Northern Mariana Islands, the Republic of Palau, the Federated States of Micronesia, and the Republic of the Marshall Islands, the organization of a separate office within the NBS and of special attention within the NPBS seems indispensable.
In Hawaii, making up only 0.2% of the land area of the United States, there are more than 10,000 unique species of plants, animals, fungi, and microorganisms—more than 90% of all the native species there. Starting with the arrival of the Polynesians 1,500 years ago and accelerating after the arrival of Europeans nearly 300 years ago, humans have already destroyed 90% of the dry forests, 61% of the mesic forests, 42% of the wet forests, and 3% of the subalpine forests of these ecologically diverse islands. Yet biodiversity is of critical importance to the future of Hawaii, in relation to land development, tourism, the preservation of unique species and for many other reasons. The integrated approach of the NPBS can powerfully influence the course of development and the future of biodiversity there.
Nonnative species are a special threat in Hawaii and throughout the Pacific. Their populations should be monitored closely through a coop-
erative effort of the federal, state, local, and nongovernment agencies involved. Controlling these alien species is of critical importance for the preservation of native communities, to protect agriculture, and to retain options for the future. For example, banana poka (Passiflora mollissima) has already smothered over 70,000 acres of native forest on two islands and threatens to spread rapidly over additional forested areas. The brown tree snake (Boiga irregularis ) introduced on Guam has brought about the extinction of nine of the 11 species of native land birds since 1975. Hawaii is invaded successfully by at least 20 new nonnative invertebrates each year, with as many as 39 recorded for a single year (Nature Conservancy of Hawaii, 1992). Some of these species are destructive to native species, others are injurious to agriculture, and still others cause problems for human health.
Cooperation among a number of different entities—including several departments of the state government; conservation groups led by The Nature Conservancy; the University of Hawaii's Center for Conservation, Research, and Training and other units; botanical gardens linked by the Center for Plant Conservation; and the Bishop Museum—appears to offer a promising direction for developing appropriate strategies for the management of biodiversity in Hawaii in the context of regional development. The recent adoption of a State Natural Area Partnership program, which will provide 2:1 matching funds to private landowners for long-term stewardship on their lands, is of special importance nationally and would doubtless work well in other areas. The development of a State Secretariat for Conservation, housed at and partly funded by the University of Hawaii, is another promising effort to contribute to the integration of conservation efforts in Hawaii. The kind of partnership among federal agencies that is envisioned in the NPBS could complete the picture and make the single area that represents one of our most critical conservation priorities a model for the rest of the country.
and, where necessary, pilot projects. Retrospective analyses might help to identify indicators that would have been especially useful in the recent past if they had been used systematically. The NBS should be directly involved in this research.
REGIONAL COLLABORATIVE PROJECTS
Recommendation 2-13: The NPBS should establish pilot projects in key selected regions of the United States, in which terrestrial, fresh-water, and marine communities and their interactions will be identified, characterized, mapped, and monitored.
Our nation's biological resources are so great that management strategies aimed at single species are often impractical or ineffective in preserving or restoring them. Therefore, effective management requires that assessments of status extend from individual species to the ecosystems in which they live and that these assessments include an understanding of key mechanisms and the processes that regulate them. A more detailed knowledge of what makes ecosystems work as they do and how they are being affected by human activities that fragment and degrade them will help us to deal with the increasingly complex legal questions pertaining to land use and water management.
To develop this cross-scale and multidisciplinary information, the NBS should work with other members of the National Partnership to choose a series of pilot projects targeted at areas that are changing rapidly because of different types of human activity (for example, metropolitan development, agricultural expansion, and resource extraction); areas of high biodiversity; areas in which diverse fresh-water, terrestrial, and marine ecosystems interact closely; and areas that are ecologically unique. A series of workshops should be conducted to determine which areas to select and how to design the projects.
The projects should be designed to produce detailed ecological understanding of a range of ecosystems for comparison with other studies as starting points for long-term monitoring and as the first pieces in a national network that should ultimately include all major kinds of ecosystems. Equally important, these projects can serve to develop and refine methods for conducting future re-
search more efficiently and effectively. Some of these sites would be ideal places to conduct all-taxa biological inventories (Yoon, 1993).
These projects should not be limited to taxonomic and ecological research. Evolutionary changes often accompany environmental ones and merit careful analysis. For example, the evolution of resistance to chemical pesticide has often occurred within a few generations or years (Georghiou, 1972). The genetic structure of salmon populations can change rapidly and markedly in a few generations in response to the rearing and releasing of hatchery fish (Gross, 1991). On a longer time scale, understanding the changes that have occurred in North American environments through geological time provides a baseline for comparison of the current status and trends. The projects should also involve other disciplines as appropriate, such as geology, hydrology, atmospheric science, and the social sciences.
If the sites of the studies are well chosen, the projects can be especially useful in producing the kinds of scientific information that is needed to manage ecosystems effectively. They can also provide important opportunities for cost-effective collaboration among participants and for implementing an adaptive approach to priority-setting and management. Such an approach could be especially useful in areas like southern Florida, where many agencies and other organizations have separate or overlapping jurisdictions in one watershed and can operate under different or conflicting mandates (Box 2.3). In many cases, the studies might be able to take advantage of existing research and management programs (e.g., in reserves or long-term research areas) run under the auspices of various participants.