Scope 47- Long-term Ecological Research, An International Perspective

2.1 ECOSYSTEM RESEARCH: THE CORE SCIENCE OF US/LTER

The fundamental scientific concept underpinning the United States' Long- Term Ecological Research (US/LTER) is that of the ecosystem as a describable entity. This concept is strengthened by the hierarchical view of levels of resolution above and below the particular ecosystem. The concept includes the notion that ecosystems and components of ecosystems interact in both temporal and spatial dimensions. Subordinate and superordinate hierarchical levels need not be viewed as cryptic; they may be simple scalars like decimeters and decameters bracketing the meter or weeks and years around the season. In that context, an ecosystem property like primary production might be assessed at the level of the tree, the stand, or the forest, or for minutes, days, or years. Arguments about possible cybernetic qualities of ecosystems have been set aside in favor of furthering our collective ability to analyze ecosystem component entities and processes, to understand their interactions, and to represent them to others.

This is a systems ecology paradigm which demands integral participants from related disciplines and subdisciplines. This paradigm seeks actively to promote the synthesis of knowledge both within and among levels of resolution. It gains strength from a diversity of scientific inputs, and it challenges scientists to re-evaluate earlier conclusions.

2.2 GENESIS OF US/LTER

The United States' effort in Long-term Ecological Research (LTER) began formally in October, 1980, with six research grants. These were followed by five grants in January, 1982. After an interim of nearly six years, five projects were started in 1987, and three began in 1988. Two of the original studies have been discontinued. Seventeen projects are currently active (Table 2.1), as the result of four competitions for new proposals and two reviews of renewal applications.

The analysis provided here of the US/LTER is a qualitative one and is presented from the point of view of a science administrator and planner. Certain characteristics will be noted as either contributing to or detracting from an interactive network of LTER projects. Prospects for future directions will be enumerated. An assumption of primary importance is that it is unnecessary to justify the necessity of long-term ecological research, the validity of arguments in support of it, or the utility of results from it. Discussion of these parameters can be found in another publication (Callahan, 1984).

Table 2.1 US Long-term Ecological Research Projects (LTER site name; state; ecosystem type)

H.J. Andrews Experimental Forest; Oregon; temperate coniferous forest
Arctic Tundra; Alaska; tundra, lakes, streams. 
Bonanza Creek Experimental Forest; Alaska; taiga. 
Cedar Creek Natural History Area; Minnesota; temperate deciduous forest and savannah.
Central Plains Experimental Range; Colorado; shortgrass prairie. 
Coweeta Hydrologic Laboratory; North Carolina; temperate deciduous forest. 
Harvard Forest; Massachusetts; temperate deciduous forest. 
Hubbard Brook Experimental Forest; New Hampshire; temperate deciduous forest. 
Jornada; New Mexico; sub-tropical desert. 
Kellogg Biological Station; Michigan; row-crop agriculture. 
Konza Prairie; Kansas; tallgrass prairie. 
Luquillo Experimental Forest; Commonwealth of Puerto Rico; tropical rainforest. 
Niwot Ridge/Green Lakes Valley; Colorado; alpine tundra, forest, lakes. 
North Inlet; South Carolina; coastal forests, marshes, estuary . 
North Temperate Lakes; Wisconsin; lakes, temperate deciduous forest. 
Sevilleta National Wildlife Refuge; New Mexico; conifer woodlands, shrub-steppe, shortgrass prairie, desert.
Virginia Coast Reserve; Virginia; coastal barrier islands, marshes, estuary .

2.2.1 SETTING THE TONE

Planning for US/LTER began in 1976 and involved the research community along with National Science Foundation staff. The planning process was augmented in 1977 with the first of a series of three annual workshops. Nearly 100 members of the ecological sciences community participated in the workshops, including academic research scientists and scientists and science administrators from private and governmental sectors. Each of the workshops produced a report to the National Science Foundation (NSF) (NSF, 1977, 1979, 1980). These reports became an important documentary base in the development of fiscal and administrative resources for the support of LTER.

It is fair to say that LTER is now well known by a large portion of the community, and that it stands as an identifiable entity. Nonetheless, LTER has been the recipient of critical attitudes from the past. For example, it has been necessary to remind some observers that LTER is not a monitoring effort such as the National Weather Service, nor is it an inventory such as might be undertaken in a biological survey. Perhaps most difficult has been convincing critics that LTER is not the re-invention of the International Biological Program (IBP).

The societal context of, and demand for, long-running ecological studies is diverse. The federal mandate for such an approach derives from law (for example, the National Environmental Policy Act) and from numerous executive-level reports. Within the United States' federal research structure there are a substantial number of antecedent programs of relevant character, such as National Environmental Research Parks (Department of Energy), Research Natural Areas (multi-agency), and Biosphere Reserves (US/Man and the Biosphere). Scientific interest in and demand for LTER was reaffirmed by the attendees of the NSF-sponsored workshops, who argued that a large portion of (perhaps most) ecological behavior is either not observed or is not accurately observed in the context of traditional two- or three-year grant-supported research projects. Another main  supporting argument stated that comparisons among the same kinds of variables  across a diverse array of ecosystem types should lead to more robust conclusions about ecological behavior. It is incumbent upon all LTER participants to recognize that the societal context is no more static than the scientific context for LTER: both change, although not necessarily in harmony. An adaptive approach is required, which can identify emerging scientific opportunities and successfully tie them to societal interests; for example, the logic of linking together Congressional interest  in climate change with the emerging International Geosphere/Biosphere Program  to derive the NSF's budget initiative focused on Global Geosciences. Within the Global Geosciences initiative, LTER has been successfully put forward as the locus of studies concerned with ecosystem dynamics.

2.2.2 CREATING A STRUCTURE

A decision made early in the genesis of US/LTER has proved to be unusually foresighted. That was the decision to provide external means for co-ordination and collaboration among the projects. It was recognized that the activities would be better accomplished if the costs of the activities were borne outside the individual project research budgets. Soon after the first projects began, a proposal was made by the associated project leaders, the LTER Co-ordinating Committee, that the NSF provide separate support for co-ordinating activities. Within a year of the first individual LTER project award, the first LTER co-ordination grant was made. Research groups who had only recently been competitors for LTER funding became co-operators and collaborators.

Two other decisions concerned the unity of the effort. First, LTER would be a fiscal undertaking of the NSF alone, and would not be dependent upon the behavior or budget-generating power of other agencies. Furthermore, within the NSF, one official would speak for LTER, both to the principals of the projects and to the community at large. However, unity was not intended to connote exclusivity. From the beginning, within the administrative structure of the NSF and in the projects, LTER has encouraged input from, and collaboration with, scientists who are not directly supported LTER participants and from other interested agencies.

2.2.3 SETTING STANDARDS

LTER specifications have consistently required that proposals address five core research areas drawn from the earlier series of workshop reports. The five core areas are:

1. Pattern and control of primary production;
2. Spatial and temporal distribution of populations selected to represent trophic structure;
3. Pattern and control of organic matter accumulation in surface layers and sediments;
4. Pattern of inorganic input and movement through soils, groundwater, and surface waters; and 
5. Pattern and frequency of disturbance to the research site.

How these core areas are treated in terms of conceptual approaches, specific questions, and analytical methods have been the primary foci of the peer scientific review of LTER proposals.

Project organizational structure for management of the science has also been an important determinant in the evaluation process. Although no fixed recipe has ever been dictated, certain more successful templates have been identified. Budget levels, in terms of maximum annual rates and future year amounts of funding, have always been specified by the NSF and enforced upon the projects except in unusual circumstances.

Data management was specified as a topic for attention in all announcements calling for proposals. As LTER has developed, data management has risen to a higher level of importance in the evaluation of both new and renewal proposals. Realistically, data management now has equal rank to the five core research areas, and requires an equivalent proportional allocation of fiscal, physical, and personnel resources.

2.2.4 FOSTERING COLLABORATION

As stated earlier, collaboration among LTER scientists has been a part of the plan from the beginning. In fact, it is a fundamental element of the LTER philosophy with its roots in the original workshop reports and preceding discussions. However, prospective project groups have encountered many unknowns as they have tried to find ways of satisfactorily and productively implementing the philosophy. In the first place, everyone can correctly insist that intense collaboration is already taking place within each LTER group as the project is conducted through the various subprojects, and certain types of interproject collaboration come easily as specialists in individual projects get to know each other and discover mutual interests. Through the LTER Co-ordinating Committee and its activities, scientists have been able to share their work and ideas in workshops, symposia, and other meetings on a fairly regular schedule. Nevertheless, persons at all levels of the US/LTER activity sense that collaboration among projects and scientists has not yet been fully developed. The missing level of development, which has come to be called 'networking', has become a major objective on all planes of LTER operations. The word 'network' is used to define an intensity of interaction that should far exceed the occasional exchange of written correspondence or telephone calls, the citation of papers, or even the conduct of parallel experiments. The definition includes all those things, but the 'network' is intended to be both more extensive and more intensive.

2.3 EVOLUTION OF US/LTER

LTER in the United States has not been a static entity. It has undergone an evolutionary process on at least three levels: organizational, conceptual, and technical. The conceptual level has already been discussed at some length, and it needs only to be restated that the central LTER concept is the ecosystem.

The development of LTER has combined a carefully measured pace with continuity at the executive level. We have tried to be assertive in developing fiscal resources that would remain part of the agency's base funding and would not stand out as a special (and possibly ephemeral) program. However, in developing the LTER portion of the budget, great emphasis has been placed on predictability as well as on opportunity. Predictability refers to the annual core operating budgets for LTER projects, which are set in advance on an extended time scale of several years. These budgets have provided the ability to request and defend the essential LTER fiscal resource in the most reliable way. Opportunity refers to the sum of efforts to generate more money for the support of LTER by the identification of initiatives that fit well with the overall concept and capabilities of LTER.

Essentially, all funding for LTER has come to the NSF as new money and not by reprogramming existing base funds. To take this approach, it is necessary to identify new initiatives or to participate in new opportunities. As an example, the LTER concept fits with the emerging planning, within NSF and the US federal science establishment, for US participation in the International Geosphere/Biosphere Program (IGBP). NSF also tries to respond to the signals being sent by project leadership and participants with regard to their technological and personnel needs for emerging scientific challenges. These signals can often be translated into fiscal initiatives within the agency. An appropriate example is NSF's recently begun initiative to provide technologies which are pertinent to Remote Sensing and Geographic Information Systems (GIS), tailored to meet the needs of individual projects and with an obvious tie to the predictable needs of IGBP.

In an organizational or management concept, the US/LTER operates in a mode of mutual induction. The NSF tries to induce the projects to generate salable output (salable in the sense of having the power to influence the budget process in a positive manner) while the projects attempt to induce the NSF to provide them with more money for research. As long as both parties subscribe to the mutuality of the relationship and the national economic/political environment remains favorable, this concept remains valid. However, changing times may require a change of tactics within the overall strategy, which is aimed at increasing the ecological sciences community's identification with, and subscription to, LTER as a productive means of supporting ecological research.

With interproject collaboration as a main goal in LTER, the NSF has wisely looked for ways to promote harmony, and avoid disharmony among projects. The NSF has provided for a separate co-ordination budget to take most of the financial burden for their activities off the individual project budgets. With regard to the project budgets themselves, NSF has gone even farther: project budget totals are specified in advance at identical levels for all projects. Within those constraints, the leadership of each project is free to allocate the resources as they deem most appropriate. When opportunities are developed for extra money, the approach has been to make the funds available to all projects as supplements to their base budgets. Perhaps the most useful way to promote harmony and to augment the total research support at an LTER site is through the development of LTER-related satellite projects. Whether funded by NSF or by some other agency, such projects add structural strength, diversity, and resources to the available pool.

National Science Foundation staff support for LTER has been minimal. Recent additions in staff have included one person whose full-time efforts are directed toward interproject co-ordination, including the identification and promotion of opportunities for collaborative research. Approximately half of the effort of another new staff position is directed at developing electronic networks among projects.

For the last year, an internal LTER management group, consisting of the five most pertinent scientific staff, has met regularly to address planning issues such as technology acquisition, networking opportunities, and budget development.

The decision was made early on that LTER proposals would be subject to the same type of review that is imposed upon all other competitively submitted research proposals by the Division of Biotic Systems and Resources (BSR). For the first group of new LTER proposals, we followed our standard pattern of requesting ad hoc reviews by mail and convening an advisory panel to review the proposals. All subsequent rounds of proposal review have utilized only an advisory panel. The experience with ad hoc reviews was disappointing in that opinions were uncharacteristically divergent, often missed the point, and were generally not useful. An assessment of the problem was that the proposals were of a new type and unfamiliar to the reviewers, and were therefore difficult to judge in any comparative sense. Proposal success rate in the LTER review process has been similar to that for general research proposals, about 20%.

2.3.1 BUILDING A CONSTITUENCY

The dominant role of non-LTER scientists (i.e. not directly participating in an LTER project) in the peer review process, coupled with their participation in the early formative period, constitutes a substantial base of broad community input to LTER. However, these kinds and amounts of participation are not viewed as sufficient to give major substance to the element of US/LTER philosophy which regards LTER projects (their sites, scientists, data bases, and general working environment) as resources available to the entire ecological research community. Several more direct mechanisms have been identified to induce higher rates of collaboration:

1.  The leaders of each project must clearly state that the project welcomes such collaboration, and they must show that they are prepared to assist collaborators;
2. Project groups must have, or strive to create, physical facilities to accommodate collaborators from outside the parent institution;
3. The LTER co-ordination effort includes a specific operational mandate to support the participation of other scientists in LTER-sponsored topical workshops;
4. LTER-sponsored and LTER-related symposia are regularly organized in the context of major national professional meetings;
5. Under the auspices of the LTER/Co-ordinating Committee, two publications are distributed to the broader community: the LTER Network News and a brochure containing descriptions of all the research sites.

These mechanisms are all more or less informational approaches. Special funding opportunity programs of the NSF are regularly used to encourage the conduct of research at LTER sites by scientists not directly supported by LTER grants. Women's programs, small college faculty programs, post-doctoral fellowships, and mid-career fellowships are all being utilized in part to expand the LTER-associated community. A new opportunity has recently been announced as available to all current grantees of the BSR Division. This opportunity is for funding supplements, as extra money available to projects already in place, and for research at LTER sites to expand the scope of the research already funded to include samples from or comparisons with LTER sites. The community response to this new opportunity was enthusiastic. Of 31 applications received, 12 supplementary awards of funds were made. The intent is to continue this special opportunity for at least two more years.

Numerous related and proactive mechanisms are being employed by the National Science Foundation together with LTER project leaders to expand the community of scientists who rely on LTER as a resource for the productive pursuit of their research interests. In the sense of scientific infrastructure, it is an explicit goal to make LTER a widely accepted resource for research, a resource that might be characterized as a new kind of ecological research environment. It is to be hoped that this new research environment will promote collaboration among scientists, challenge many of them with new concepts and approaches, allow them to ask questions that in other contexts could not be asked (or answered), and lead them to synthesize information in new ways. In pursuing the goal of developing LTER projects as a resource for research in many aspects of environmental biology, and in ecosystem research itself, a unique LTER identity is being created as a broad community of scientists is called upon to collaborate in ways that would not otherwise be likely.

2.3.2 ORGANIZATION OF THE PROJECTS

Among the US/LTER projects there are as many variants of internal project organization as there are projects. The NSF has not attempted to create formal specifications for organization; however, the most successful of the projects share certain characteristics in their organization and in their mode of operation. The foremost of these characteristics is that of leadership. Those projects that have multiple (i.e. three to five) intellectually strong leaders are the most effective ones.

The second important feature of the most successful projects concerns the creation of a project team which is both philosophically and operationally compatible. One group has even gone so far as to include an organizational psychologist in the project cadre who actively engages in team building and conflict-resolution exercises. Whatever the mechanism, it has become apparent that research team identity is of great importance.

Careful attention must be paid to intraproject communication. In spite of individual protestations to the contrary, it seems unlikely that too much effort can be spent in this way. The LTER groups that are most effective have regularly scheduled, all-participant meetings. A major addition to intraproject communication can come from encouraging (even requiring) participants to assist others in scientific areas that are far removed from their own specialties or central interests.

The pattern of intraproject allocation of fiscal resources is vital to the maintenance of team spirit. Effective project leaders will apportion their budgets in accordance with the diverse requirements of the entire integrated research effort. The allocation of salary, support personnel, and equipment for the singular benefit of the most senior team members can be counted on to generate dissatisfaction and dysfunction.

2.3.3 LTER NETWORK ORGANIZATION

The first manifestation of organizational structure at the LTER network level was the Co-ordinating Committee mentioned earlier. The first major act of the committee was to develop a proposal for separate co-ordination support. The committee also assumed the function of sponsorship of an array of technical committees, of which data management and meteorology were among the first, with modeling a more recent addition. These committees and more ad hoc topical groups have organized many technical workshops for the benefit of LTER and the community at large.

A more recent creation of the Co-ordinating Committee is the Executive Committee. This four-member subgroup recognizes the need for the Co-ordinating Committee to act more expeditiously now that the network has grown to include 17 projects. The Executive Committee provides a mechanism for timely interaction between the NSF and the LTER network. For several years, a modest 'office' structure has assisted the Chairman of the Co-ordinating Committee to carry out the operational functions of the Committee. That office is now completing a major expansion of its duties and staffing.

The NSF has begun to provide funds for physical networking among projects in order to promote and support scientific collaboration. When completely realized, this plan should provide an everyday, openly accessible means of communication, not only text communication, but also fully user-transparent support for joint activities, from experimental design through interactive graphics in data analysis and manuscript preparation. The system will. be computer supported at all levels, perhaps utilizing the NSFnet supercomputer network, and should provide ready access to distributed data bases, support the analysis of remotely sensed data, and employ the best generally available geographic information system (GIS) technology.

2.3.4 US/LTER TECHNICAL METHODS

No directed attempt has been made to require all LTER projects to practice the same data acquisition or analytical methods. However, there has always been an element of the LTER philosophy which states that individual projects should strive to make their data usefully comparable with similar data from all other LTER projects. Comparability will be stronger if it derives from the excellent quality of documentation of the conditions under which, and the methods by which, data were collected, and if the data sets meet closely matched statistical indices of reliability. That is, comparability will be better if the methods are designed to fit the ecosystems being addressed and the people employing the methods.

It is the attitude of the NSF toward the means by which data are generated, and the protocols by which the data are maintained and accessed for synthesis and reporting purposes, that the projects should use the best generally available technology for gathering and handling data, and should be aggressive in the identification and testing of new technologies which may be adaptable to LTER needs. In our accumulated experience, the two main impediments to progress along those lines are the limited ability of the NSF to provide new money above project base budget levels, and the lack of enthusiasm by investigators to spend new money on switching methods when they would rather spend it in other ways. So far the push-pull interaction has worked fairly positively, and several new technologies are being pursued. However, while the NSF wishes the projects to utilize new methods effectively, it does not necessarily require that they invent them.

 2.4 EVALUATION

 2.4.1 DIFFICULTIES

It is unfortunate that the US/LTER operation did not recognize earlier the formal organizational structure that would be required for interproject collaborations in the network of projects, a network which grows increasingly complex. It is the lack of structure which has caused the slow rate at which interproject collaborations have been identified and actuated. Similarly, the network is now beginning to realize the need for the adoption of standards of performance with regard to some types of data, and especially with regard to how and in what formats the data are maintained.

Some difficulties have been attributable to NSF and its ability to do its part of the job. Chief among these has been our inability to bring to bear sufficiently regular and critical on-site reviews of projects. The long gap (nearly six years) between the second and subsequent rounds of competition for new LTER funding was not good. Too much catching up has had to be done by newer project groups, whose input would have been easier to assimilate earlier. Both of these difficulties relate to internal constraints on resources.

Establishing LTER as a recognizable entity with a character of its own in the scientific community has not been easy. Establishing an identifiable profile on the outside while avoiding a 'special' designation on the inside are not easily compatible tasks. However, continuity is essential in that it is the key to maintaining a functional identity and to creating a constituency that is willing to speak positively for the effort.

It has been difficult to guide the effort without appearing to direct it with a heavy hand. The freedom to do whatever research is appealing by whatever means seem appropriate is zealously defended by the academic research community. That is as it should be. It is also important that the agency managers be able to choose the best tactics for maintaining and increasing the fiscal resources available to support the effort. The effective meshing of these two considerations has required a willingness to accommodate and compromise on both sides. The relationship is now a productive one.

2.4.2 POSITIVE, TIMELY DECISIONS

Some of the best decisions that were made in the creation of the LTER project, which have already been presented in some detail, although in a diffuse pattern, in this chapter, are summarized here:

1. Single agency core funding for LTER;
2. All new money for LTER;
3. Single program officer responsibility for LTER;
4. Pre-defined core areas for organizing proposals;
5. Separate support for most co-ordination efforts;
6. Close interaction between the Foundation and projects; and
7. Efforts to broaden the LTER-affiliated community.

Perhaps the soundest decisions were those that pertained to maintaining US/LTER as a genuinely competitive grants emphasis. That is, LTER has not been given an inside track, and all projects in the course of their conduct and all proposals in the quality of their content must meet the highest competitive standards of evaluation. Nothing has been formally institutionalized, and individual projects that fail to meet competitive standards can be, indeed have been, discontinued.

2.5 PROSPECTS FOR THE FUTURE

Constraints upon the prospects for growth in the number of LTER projects include the ability of the scientific community to perform, the availability of appropriate research sites, and the capacity of the sponsoring agency to administer the needs of large, complex research projects. The Foundation has accepted the fact that there must be some functional maximum for concurrently active LTER sites. This does not necessarily mean that there can be no new LTER projects once that ceiling is reached, if it is reached. We have already witnessed the occurrence of some attrition among projects. It should be possible to accommodate limited numbers of new applications in the future as long as the total number of operant projects remains below the effective ceiling.

Assuming that LTER continues to prove its worth in the highly competitive arena for budgetary attention, there are several augmentations that have appeal. The acquisition and operation of technologies to promote 'on-line' collaboration among scientists has been mentioned previously. Much can be accomplished in that manner. Continuing the effort to identify and adapt new analytical technologies to LTER objectives deserves increased attention; the distribution and implementation of productive technologies will command major support.

Expansion of the web of LTER affiliations requires significant investments of both human and fiscal resources. Domestically, LTER could grow to become significant in the area of graduate education as well as in research. Fulfilment of the vision of LTER as a resource for diverse kinds of ecological and related research will probably command investments in physical plans that have not  yet been made. At the international level, US/LTER must be somewhat more aggressive in identifying and supporting joint endeavors and exchanges among research groups. Application of LTER data and syntheses to the resolution of major global environmental questions will require special efforts and expansion in new directions.

It is useful to ask, 'What if we had it to do all over again, would we do it differently?' There is no single-dimension answer to these questions, but a few of the obvious partial answers are worth discussing. It would not be wise to constrain the applications to a suite of biogeographically predetermined ecosystem types. Such a constraint would probably act negatively on the pool of potential LTER research groups and on their ability to create competitive proposals. The 'core areas' have served as a useful organizing tool for LTER proposals and projects, and they should not be viewed as having limited the investigations. These areas have been the foci around which subprojects are organized, and from which independently competitive proposals have been derived for more detailed studies of, for example, organic decomposition or the role of animals in imposing more complex structures on ecosystems. Neither of these characteristics would be productively changed.

It is difficult to address the question of whether LTER has caused the discovery of anything of a scientifically fundamental nature at this time. To do so is to appraise the long term after only a short period. However, a positive partial appraisal is possible. LTER has brought considerable attention to bear on the myth of  'average' or 'normal' conditions of ecosystem behavior. I am tempted to say that almost any variable that falls within close proximity of a long-term average value should be regarded with suspicion. Of course that is not true, but it does now appear that many apparent annual averages for both biotic and abiotic variables are of severely limited utility in characterizing ecosystems. Inherent variability is simply too great. Similarly, the occurrence of significant disturbance in ecosystems appears to be frequent. Many scientists would assert that disturbance is the major determinant of ecosystem character in that it keeps the system 'stirred up' by imposing spatial variety which promotes biotic diversity. It can also be noted that many ecological conclusions have previously been founded upon transitory behavior that is often directly counter to longer-term ecosystem changes. These are not 'discoveries' per se; however, more attention to these questions has been brought to bear more quickly than would probably have occurred under pre-LTER conditions.

As judgments are made of the US/LTER undertaking, we should hope that they are made with the understanding that LTER is an experiment. It represents a departure from past ways of doing things. Evaluators should strive to understand that LTER is not a static entity but a dynamic one. The visage of LTER that exists today is not the same as that of eight years ago, nor is it the same as will exist in a few more years. With regard to paradigmatic, technological, and organizational changes, more scientists are likely to move forward more rapidly than they would without LTER.

Beyond the level of basic ecological science, LTER will play an increasing role in providing inputs to the management of natural resources. At the very least, LTER projects, by their very existence, create identifiable centers of expertise for particular types of ecosystems. In addition, LTER projects have from the beginning encouraged and benefited from the participation of scientists employed by resource management agencies.

2.6 ACKNOWLEDGMENTS

Expressing appreciation to individuals who have played significant roles in the creation of US/LTER would be an almost endless task. In lieu of that, my thanks go to the ecological sciences research community of the United States and to the staff of the National Science Foundation.

2.7 REFERENCES

Callahan, J.T. (1984). Long-term ecological research. BioScience, 34, 363-367.

National Science Foundation (1977). Long-Term Ecological Measurements. Report of a Conference. Woods Hole, Massachusetts.

National Science Foundation (1979). A New Emphasis in Long-Term Research. Woods Hole, Massachusetts.

National Science Foundation (1980). Long-Term Ecological Research (LTER). Indianapolis, Indiana.