Scientific Accomplishments of the Long Term Ecological Research Program: An Introduction

Articles Scientific Accomplishments of the Long Term Ecological Research Program: An Introduction On the premise that today’s complex environmental challenges require innovative long-term study over many types of habitat and over large areas of the landscape, the National Science Foundation established the Long Term Ecological Research (LTER) Network. The LTER Network consists of 24 sites located throughout the climates and habitats of North America and Antarctica. Although the scale of research and specific research foci differ across sites, the LTER sites share a commitment to the long-term perspective and to measurements that extend over decades. Researchers at these sites study many species and environmental variables, from bacteria to bison and from air temperatures to soil moisture. Synthetic results include an analysis of the relationship between diversity and productivity in multiple ecosystems; a model of the workings of an entire ecosystem at one site; and a compilation of regional effects of changes in temperature, precipitation, and nitrogen deposition. Sites are funded for 6 years at a time, with the expectation that continued high-quality research will lead to a decades-long project. Keywords: LTER Network, long-term ecological research, LTER accomplishments, LTER history, LTER description H ow and why is the Long Term Ecological Research (LTER) Network’s approach to ecological studies different from that of other networks? One difference is that each LTER project has the opportunity to choose its own research focus. The result is a wide variety of topics and projects that take advantage of the diverse habitats around the research sites and the diverse scientific skills of the research teams and participating institutions. Strong scientists remain on the projects, attracted by opportunities for multidisciplinary research, synthesis, and experimental manipulations that may last 20 years or more.Yet these opportunities for diversity are balanced by commonalities across sites that result from their belonging to the LTER Network. One requirement for inclusion in the network is that all data must be available on the Internet. Another is that every site should include research on some of the five LTER core research areas, which include primary production, decomposition, and disturbance (see table 1 in Hobbie et al. 2003). This ensures that all sites carry out a broad range of research and that comparisons among sites are possible. Moreover, comparisons and syntheses across sites are actively encouraged through the availability of small grants to measure a process at a number of locations that might include both LTER and non-LTER sites. In addition, cooperative and comparative research is a requirement for renewal of each LTER project; proposal reviews take into account the amount of cooperative and comparative research to be produced. Another major difference between the LTER Network and other networks is the structure of the LTER program. Once NSF holds a competition and a panel selects a site for funding, continuation for an LTER project is judged every 6 years by a panel whose criteria include scientific progress; quality of publications, management, and education; and degree of cooperative work with other sites. After the initial competition, sites no longer compete against one another for continuation. Equality of resources and a fundamentally cooperative attitude among sites are now basic characteristics of the LTER program. The LTER statistics are impressive. More than 1200 scientists take part in the network. There are educational programs for grades kindergarten through 12, for undergraduates, for graduate students, and for postdoctoral fellows. Twelve thousand LTER-related journal articles were published from the start of the program in 1980 through 1995. Seven books, each of which synthesizes research at separate sites, have been published, and 13 more are in preparation. There is a cooperative program with international LTER programs in more than 20 countries; most of these programs were modeled after the US LTER Network. Thousands of data sets are available on the Internet. On average, each LTER site leverages its NSF funding threefold. John E. Hobbie (e-mail: ) is codirector of the Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543. His research interests extend from microbes in salt marshes to Arctic aquatic ecosystems. © 2003 American Institute of Biological Sciences. January 2003 / Vol. 53 No. 1 • BioScience 17 JOHN E. HOBBIE Articles Past, present, and future long-term research The central, organizing intellectual aim of the LTER program is to understand long-term patterns and processes of ecological systems at multiple spatial scales. The programmatic challenge faced by the LTER Network is fostering this central aim while maintaining the site diversity and independence that keep the quality of the projects high. However, despite the habitat diversity of 24 sites in freshwater, marine, estuarine, forest, grassland, desert, urban, and agricultural locations, many of the site questions and foci overlap (table 1 in Hobbie et al. 2003). For example, 11 sites list the topic “climate forcing and climate change” as an important focus. In addition, notwithstanding the great habitat diversity and hence the variety of site topics, the number of ecological processes to be studied are limited. The controls of these processes have many basic similarities worldwide, as is evident from the success of the Long-Term Intersite Decomposition Experiment Team (LIDET), which determines the effects of substrate quality and macroclimate on decomposition at 17 LTER sites (Kratz et al. 2003).The LIDET project has resulted in an understanding of how this fundamental process operates under different environmental conditions. Ecological processes and present species assemblages cannot be understood in isolation. It is now clear that every system is undergoing long-term change and that long-term changes can only be studied with long-term measurements. As explained by Turner and colleagues (2003), LTER projects can monitor and lead to understanding of slow events, and also of the infrequent events that are often important shapers of ecosystems. The LTER data sets are now extensive enough to provide valuable predisturbance baseline data for the biota of a lake before an invasion of two new species, for example, or for the productivity of a tropical forest before a hurricane. LTER sites are a valuable focus for long-term research activity. Hobbie and colleagues (2003) liken the network to a fleet of research vessels in oceanography, where the concentration of expertise, technical capability, and quality of data attract diverse research projects. They conclude, “Colocation of research projects makes efficient use of costly data and long-term experimental manipulations; it also increases the possibilities for creative breakthroughs from interdisc (...truncated)