Conclusions and Recommendations
Environmental variability, driven both by natural processes and by human forces, is pervasive at virtually all temporal and spatial scales. We can observe environmental change in local neighborhoods over individual lifespans, infer it from stories told by grandparents, and recognize it in both historical documents and in the data captured by geohistorical records. In a changing world, understanding the patterns, processes, and principles governing the participation of biological systems in environmental change—and understanding how those systems respond—is a scientific and societal priority of the highest rank. Our growing understanding of physical environmental change must be linked with a major effort to understand the response of biotic systems to environmental change. Both wild and managed biological resources are of extraordinary significance for human welfare, and consequently how they change in response to climatic and other environmental change is of great importance. If we are to achieve this goal, analysis of the geologic record needs to become a full partner to the empirical analysis and modeling of present day biological systems.
To promote significant and timely progress in understanding the geologic record of ecological dynamics, we recommend that a substantive new research effort be focused on the three research initiatives described below, in order to (1) further our understanding of the basic principles of ecological organization and dynamics; (2) enhance our ability to predict the response of biological systems to climate change in particular; and (3) provide a means to distinguish between anthropogenically- and non-anthropogenically-caused changes in biological systems. These topics are
ripe for scientific exploration, and have great societal relevance. Success will require new investment in the general field of biogeosciences, as well as support for infrastructure that encourages research integration, collaboration, and coordination among earth scientists and biologists.
Research efforts will require substantial material support because biological systems are complex entities with dynamics spanning a broad range of scales that are affected by chance and historical contingency. The inherent complexity of biological systems at all scales—individual species, guilds, communities, biomes, biosphere—and the increasing footprint of human activities over the last several millennia and centuries—requires that we bring the full panoply of scientific approaches to the problem of understanding ecological dynamics. In the past, geohistorical analysis has received little effort compared with that expended on ecological modeling, modern observations, and manipulative experiments. This is despite the extraordinary potential of the geologic record for yielding essential information on patterns and processes of biotic response to environmental change. As outlined in the preceding chapters, advances over the past two decades have revolutionized earth scientists’ ability to date and extract critical biological and environmental information from the geologic record. Moreover, biologists increasingly realize that long-term historical perspectives are vital for answering a host of biological questions, both fundamental (e.g., principles of community organization and individual species response) and particular (e.g., timing of biotic change relative to natural and human stressors in a given region).
Until now, limited use of the geologic record reflects long-standing uncertainties about the adequacy of geohistorical information for answering ecological questions. These uncertainties are now largely resolved—a broad and diverse array of geohistorical records are demonstrably suitable for addressing ecological questions. The limited use of the geologic record also reflects the cultural, disciplinary, and administrative barriers that separate the earth and biological sciences. Analysis of the geologic record of ecological dynamics cannot be tackled without a significant commitment in effort and funds, and without renewed emphasis on genuinely multidisciplinary research both by agencies and by individuals. Without such change, only a few earth scientists (researchers, reviewers, supervisors, fund managers) will identify biological problems as falling under their disciplinary mandate. Similarly only a few biological scientists will find it practicable to acquire the skills needed to analyze geohistorical records, no matter how important geohistorical data are to the questions being addressed. However, like several previous national committees (e.g., NRC, 2001c, 2004; NSB, 2000), this committee considers that a deeper understanding of ecological dynamics should have a high scientific priority. As a matter of policy, federal agencies should take the lead
in facilitating and establishing means of achieving success in the analysis of the geologic record of ecological dynamics.
We identify the following three initiatives as being ripe for intensified exploration and having the highest scientific and societal relevance.
INITIATIVE 1: THE GEOLOGIC RECORD AS AN ECOLOGICAL LABORATORY
Recommendation: A deeper understanding of the origin, maintenance, and distribution of biodiversity and its importance to ecological systems is urgently needed. It is essential to expand fundamental research using the longer time perspectives of the geologic record to frame and test ecological theories at appropriate scales while encompassing a full range of earth conditions.
Most ecological theories are derived from short-term observations and models. But the ecological and evolutionary processes operating at timescales beyond direct human observation have driven, and continue to drive, changes in biodiversity and biogeochemical cycling on local, regional, and global scales. A fundamentally important role of geohistorical data in ecological analysis is to provide empirical data from longer timescales. An understanding that extends beyond short-term observations is essential to (1) characterize longer-term ecological processes; (2) identify patterns and mechanisms that are masked by the variability inherent in direct, short-term observations; (3) identify which aspects of modern ecological systems are contingent on past events; and (4) permit ecological analysis under conditions different from those of today. Such tests of ecological theories, and their underlying assumptions, are necessary because ecological principles can be considered truly general only if they apply to ancient species and communities as well as to modern ones. The geologic record is thus an ecological laboratory providing access to a wide range of past “alternative worlds” from which truly general principles can be derived regarding the triggers, character, and rates of change of ecological properties and functions.
An understanding of these general principles is necessary not only to understand ecological response to past climate change and legacies of societal activities (Initiatives 2 and 3 below) but also to address basic questions concerning the dynamics of biodiversity at all spatial and temporal scales. Are the macroecological properties of communities across modern and ancient settings (including those lacking modern analogs) constant? Can taxa within guilds or trophic levels be substituted—in the
face of local extinction and immigration—without changing ecosystem properties? To what degree is spatial ecological variation comparable to temporal ecological variation? What is the impact on local diversity patterns of regional species pools that have been assembled over evolutionary timescales? Are areas of high diversity characterized by high speciation rates, or are they simply long-term accumulators (characterized by low extinction rates)? What is the role of local extinction on the influx of biotic invaders? What is the relative importance of physical environmental and biotic forcing on ecological and evolutionary change?
INITIATIVE 2: ECOLOGICAL RESPONSES TO PAST CLIMATE CHANGE
Recommendation: Climate change and its consequences are of enormous scientific and societal concern. A significant research initiative to pursue a richer understanding of how biotic systems have responded to and interacted with past climate change and variability is needed to provide a sounder basis for forecasting the ecological consequences of future climate change and variability.
Climate is a dominating influence on the distribution and abundance of organisms, the nature and rates of biogeochemical fluxes, the structure and composition of ecological communities, and the frequency and intensity of ecological disturbance. Geohistorical data show that Earth’s climate is capable of a wide variety of system states and modes of variability. To understand how biological systems are likely to react in the future, we need to understand how ecological systems have responded to climate change and variability in the past. Paleoclimate studies of ice cores, sedimentary records, tree ring series, and other records clearly indicate that the past two centuries have experienced only a fraction of the potential variability within the climate system. This is an inadequate sample of the range and nature of climate variation. As a result, ecological studies based on direct observation of current systems provide an inadequate sample of the array of biotic responses to climate change and of the potential consequences for biodiversity and biogeochemistry.
Understanding biotic responses to climate changes of the past is pivotal to forecasting how ecological systems are likely to respond to ongoing and future climate changes, whether natural or anthropogenic. Paleoclimate studies reveal that, just within the past 10,000 years, climates with no modern counterparts have prevailed over much of the globe, and abrupt changes in climate have occurred with unexpected magnitude and
rapidity. The near future is likely to include climate states with no modern analogs as well as abrupt climate changes. Just as paleoclimate records were critical to identifying important properties of Earth’s climate system and assessing risks and vulnerabilities to future change, paleoecological records of biotic responses to past climate change are critical to forecasting ecological responses to future change and assessing risks and vulnerabilities.
INITIATIVE 3: ECOLOGICAL LEGACIES OF SOCIETAL ACTIVITIES
Recommendation: Societal activities have impinged on the natural world in many ways, but the consequences and possible solutions to these impacts are unclear when some impacts are difficult to distinguish from non-anthropogenic variation. Intensified research on environmental and ecological conditions and variability before human impacts and on the geohistorical records of how societal activities have affected present day ecosystem dynamics is essential.
Environments and ecosystems have been profoundly affected by societal activities. Because the effects are far-reaching and began long before the advent of direct observations, the geohistorical record is the only source of information on (1) how ecosystems functioned in the absence of human influence; (2) the natural range of environmental variability and ecosystem function; (3) how ecosystems have responded to progressive human impacts; and (4) which aspects of present day environmental variability and ecosystems are a legacy of past societal activity. Geohistorical records constitute an archive of the natural state of ecosystems before significant societal impact, and of how ecosystems have been transformed by past and ongoing human activity.
The effect of societal activity on natural environments and ecosystems is an unintentional global experiment already in progress. However, the initial conditions of this experiment are largely unknown because the onset of human interactions with these systems—both intentional and unintentional—predate scientific monitoring efforts. There is thus no control for time in this experiment; completely natural habitats are no longer available either locally or globally to use as benchmarks for comparison with habitats or regions of known impact. Similarly, so-called natural variability (i.e., unaffected by societal activity) in environments and ecosystems can be rigorously estimated only by reference to the geological record.
Acquiring such knowledge of pre-human baseline states and natural
variability is essential for discriminating between anthropogenic and non-anthropogenic change in species, biotas, and ecosystems. Insights into the sensitivity and response of ecosystems to human activities are critical in developing strategies for conservation and restoration; thus this initiative has significant potential for practical benefits to society. In seeking to predict and manage ecosystems in the face of future environmental perturbations, whether natural or societally driven, we must take advantage of the opportunity to understand how societal activities have affected ecosystems in the past. Understanding the ecological impact of past societal activities is also crucial for the recognition of persistent effects—legacies—that may continue to influence ecosystems long after the causative societal activities have ceased.
FACILITIES AND INFRASTRUCTURE
Funding and Personnel
Recommendation: Funding levels for research on the geologic record of ecological dynamics must reflect the research’s technological needs and the societal importance of understanding the biological response to environmental change. Funding should be structured to ensure that both research and graduate training take full advantage of collaborative opportunities across disciplines.
Federal research funding on the geologic record of ecological dynamics has not kept pace with the increased costs of geochemical analyses, high-precision dating, large numbers of samples, the establishment of databases vital to synthetic studies, and the need for collaboration among investigators and students from multiple disciplines. In addition, funding has not kept pace with the increased interest in this topic within the scientific community that has resulted from society’s increasing need to predict and manage future biotic change.
Although it may be predictable that a review committee will call for increased funding or other commitment of new resources to a field, it is a fact that new kinds of research cannot be pursued without changing the resource allocation. Within the National Science Foundation (NSF), support for core programs in the Division of Earth Sciences (EAR) and the Directorate for Biosciences (BIO) should be increased. Such programs have supported the development of many of the innovative concepts and techniques essential for research in ecological dynamics and have supported the training of students now poised to conduct research in this area. Con-
tinued low proposal success rates will stifle further innovation and discourage research just as the disciplines have reached a critical point. The need for integrative studies, almost certainly requiring the collaboration of researchers from both directorates, also requires the investment of funds into cross-directorate initiatives such as those proposed above. Some existing cross-program and cross-directorate efforts could incorporate and foster geohistorical analysis of ecological dynamics with relatively little modification of their mandate by adoption of one or more of the initiatives identified above (e.g., as an initiative under the Biogeosciences Program, or the Biocomplexity in the Environment Program). The review panels for these programs and the Advisory Committee for Environmental Research and Education (ERE), which has oversight over the Foundation’s environmental science portfolio, should include one or more individuals with expertise in geohistorical records relevant to biosphere analysis. Accordingly, we see two modes of support within NSF for geohistorical analysis of ecological dynamics, one through core programs for smaller projects, and the other through cross-divisional and cross-directorate initiatives intended to stimulate collaborative research on this topic. Assessing the ecological consequences of past climate change and variability is a critical missing element of NSF’s component of the U.S. Climate Change Science Program (CCSP). The closest existing program, Earth Systems History (ESH), cannot accommodate an expanded mandate to include biotic responses without erosion of its current activities and commitments. A significant increase in funding to ESH, together with participation on panels and administration of individuals with expertise in geohistorical analysis of biotic responses to climate change, would be one potential solution. Such an expansion could take advantage of the paleoclimate expertise of the ESH community and fuse it with the ecological perspectives of the paleobiology community. Alternatively, a companion program to ESH, concentrating on biotic responses to past environmental change, could be developed within NSF.
Other federal agencies should also be able to support research in this area, particularly in those topics especially appropriate to their missions. The Environmental Protection Agency’s STAR (Science to Achieve Results) graduate fellowship and grant programs are especially relevant and effective. The National Oceanographic and Atmospheric Administration (NOAA) can build on its strengths in paleoclimate reconstructions to incorporate biotic responses to climate change as an explicit part of its research mandate. NOAA already has a long tradition of involvement in research on paleoclimate and in research and management of marine fisheries. While this has led to some productive interactions between Quaternary scientists, biologists, and physical oceanographers, little of
this research has used geohistorical data or methods to analyze past ecosystems in the context of NOAA’s mandate to provide climate forecasting.
The existence within the U.S. Geological Survey (USGS) of both geologic and biologic expertise is highly favorable for integrative, collaborative efforts using geologic records of biological systems, and, in particular, Initiative III (Ecological Legacies of Societal Activities) is in close accord with the agency’s environmental missions. The USGS has both the facilities and the expertise for coring and for the sedimentary and paleontologic analysis of those cores, and it would be logical for geohistorical analysis to be a standard portion of many, if not most, place-based research studies having an environmental component. At present many of these studies sample only surficial sedimentary deposits or conduct only real-time monitoring to acquire environmental and biological information. For example, the South Florida ecosystem and Chesapeake Bay projects of the USGS could easily extract ecosystem information as well as proxy indicators of prior conditions. Systematic paleoenvironmental and paleobiologic analysis will enable the USGS to meet its goal of providing science for a changing world. For settings, methods, and taxonomic groups for which it lacks expertise, the USGS could partner effectively with other agencies having common research and management interests as well as with research universities and institutes. For example, very few NSF-funded Long Term Ecological Research (LTER) sites have used geohistorical data on environmental change and biotic response, although these represent superb opportunities for the nation to leverage long-term investments of biological effort and funds. Some structures for partnering with academia already exist within the USGS in the form of cooperative units.
The nature of research on the geologic record of ecological dynamics should be structured to encourage and support the collaboration of professional biologists and geologists, as well as the training of a highly flexible next generation of scientists who take such interactions for granted. To foster this, we recommend establishing a postdoctoral program by the NSF whereby new Ph.D.s would collaborate and have as their mentors PIs from other directorates—such matches have the advantage of engaging scientists very early in their careers, with potential for a longer period of positive downstream effects. The USGS already has a postdoctoral program to bring new ideas and expertise to the agency, and this could be modified, enlarged, or partially committed to specifically match biologists and geologists on integrative geohistorical projects. We also recommend the introduction of Doctoral Dissertation Improvement Grants (DDIGs) to NSF’s Directorate for Geosciences (GEO). These grants in the Directorate for Biosciences are a proven means of encouraging graduate students to go beyond traditional approaches to a research topic.
Laboratories for Geologic Analysis of Ecological Dynamics
Substantial support for research in natural laboratories and for actual or virtual collaborations and facilities is needed to focus intellectual efforts and research tools on the three initiatives described above.
Natural laboratories: Long Term Ecological Research (LTER) and Geologic Time Ecological Research (GTER) Projects. Among existing programs, Long Term Ecological Research sites (LTERs, funded by the Biosciences Directorate) have been one of the most successful for lengthening the time perspective of ecological studies—over the 24 years of the program, 26 sites have been established and are generating observations of natural (and in some instances experimentally manipulated or extensively societally modified) habitats. Existing LTER projects represent a superb opportunity to couple systematic long-term biological monitoring with ecological and environmental observations from times before the instrumental record. Support should be provided for collection and analysis of geohistorical information at or near these sites, using sediment cores from lakes, peatlands, and estuaries, tree ring analyses, cave deposits, skeletal accumulations, and packrat middens to acquire information on both the character and rates of environmental change and the biotic response to that change. Integration of such geohistorical data with the LTER site’s observational record and with the results of on-site experiments will build the temporal perspective necessary to detect decadal and longer ecological trends and to discriminate between natural and human-driven changes. In many cases, the best potential areas for obtaining geohistorical records may be outside the boundaries of specific LTER sites, but such geohistorical records can provide representative case studies or regional perspectives relevant to the individual LTER missions. Notwithstanding the potential advantages of connecting LTER observations to adjacent geohistorical records, excellent geohistorical records should be sought in places where they can address critical ecological problems—in estuaries, reefs, tropical lakes, and habitats now strongly affected by societal activities.
Activities within the new National Ecological Observatory Network (NEON) program should go beyond the monitoring, experimentation, and modeling of biotic systems in present day real time. Incorporation of retrospective data describing both past biotas and environmental variability is essential to efforts in ecological forecasting, and thus geohistorical analysis should be made a formal and integral part of the network’s mandate.
The committee also recommends Geologic Time Ecological Research (GTER) projects as a promising platform for research on ecological dynamics. A GTER project would designate a particular habitat type, criti-
cal region (e.g., land bridge, oceanographic gateway), (paleo)latitudinal belt, environmental gradient, or time interval as a natural laboratory for focused, collaborative study for a five- to ten-year period. Comparable to LTER sites, the Plate Boundary Observatory of EarthScope, or an Ocean Drilling Program cruise, a GTER program would invite proposals for research on one or more of the initiatives proposed here. For example, a long-lived modern lake basin would provide the opportunity to extend observations of current processes back in time—using the fossils and proxy environmental data derived from cores—to address all three of the initiatives identified here. A region known to have undergone past habitat fragmentation (e.g., as a result of tectonic creation of a broad region of complex topography) would constitute a useful laboratory to examine the effects of tectonics on non-analogous faunas. The Panama Paleontology Project1 (focused on the marine biotic response to the Neogene uplift of the isthmus; funded by NSF and the Smithsonian Institution) is a useful example of a collaborative project that targeted a critical area and time interval in order to explore fundamental principles of biosphere behavior. The project involved a major investment in new geologic and paleobiologic fieldwork and analysis, and provides a valuable temporal framework for understanding the historical events that shape present day biological systems in both oceans. Acquisition of geohistorical data on the South Florida ecosystem by the USGS and partner agency scientists as part of the effort to restore this ecosystem is an excellent example of an applied project of this type.
Research collaborations. Research collaborations are envisioned as actual or virtual forums for the analysis, synthesis, and modeling of existing data and for the general exchange of intellectual capital. These collaborations might take a form similar to the NCEAS (National Center for Ecological Analysis and Synthesis) funded by NSF’s Biosciences Directorate. In such a setting, collaborative working groups could focus for short periods (multiple meetings over one to two years) on integrative ecological and paleoecological problems that require meta-analysis or synthesis of some combination of empirical and model-generated information. The former Pliocene Research, Interpretation, and Synoptic Mapping (PRISM) project of the USGS, which targeted global paleoclimates of the Pliocene, demonstrates how federal agencies with intramural researchers can lead collaborative projects, although the focus of this particular project was more on physical environmental reconstruction and improved age determination than biotic response. This collaboration demonstrates the con-
cept of using a past interval of geologic time—rather than a geographic site or region—as a laboratory to better understand natural systems with relevance to future change.
Synthesis centers and virtual collaborations represent innovative ways to foster integrative work among biologists, paleobiologists, and physical scientists. Resident postdoctoral students associated with such efforts can provide both interdisciplinary training and continuity for ongoing projects.
The committee also recommends support for annual or biannual, multi-day research workshops focused on these interdisciplinary research initiatives. Such workshops could be in conjunction with existing professional meetings or take the form of gatherings like Penrose or Chapman conferences. Such meetings are extremely valuable for intellectual exchange, networking, and the formation of new research collaborations, and will be essential for breaking down some of the administrative and cultural barriers that exist between the biological and earth sciences. For example, the cross-directorate Biocomplexity in the Environment Program at NSF, the Exobiology Program at the National Aeronautics and Space Administration (NASA), and the STAR Program at the Environmental Protection Agency (EPA) all require their current Principal Investigators and graduate fellows to attend annual meetings in order to exchange research results and to network. We recommend forums that are similar in style, but that are not limited to individuals funded by a particular program or agency. Private, non-profit, federal, and state organizations are all potential sponsors of such efforts.
Databases and Collections
Recommendation: Publicly available databases and natural history collections can promote collaboration, reduce duplicated effort, facilitate large-scale synthetic studies, and provide critical and at times irreplaceable data and research opportunities. Federal agencies should play an important role in sustaining and enhancing community efforts to build and improve such entities.
Data are the currency of research in the geological and biological sciences. For this reason, the maintenance and accessibility of data in either digital form (e.g., electronic databases) or physical form (e.g., museum collections, cores, paper records) are essential for the effective and efficient conduct of ecological dynamics research. The number and size of online databases have grown enormously in the past decade, and are sure
to increase even more in the next decade as the pressure increases for greater access to the results of publicly funded research. Previously collected data and natural history collections must be maintained and accessible, and repositories for newly collected data should be provided. We are being overwhelmed with data even as we labor to find more. Enhanced federal support is therefore critical for the expansion of community-wide database efforts and for the maintenance of existing collections and archives, including the discovery and integration of metadata. In addition to their archival function, databases provide a vital platform for the synthesis and analysis of data at scales that would have been impossible in the past—they are a powerful new research tool.
Natural history and geoscience collections often provide vital information on environmental and biotic conditions before human impact, access to materials that can be used to test critical hypotheses in the earth and life sciences, and fossil and live-collected specimens no longer available in the field. An important attribute of natural history and geoscience collections is that they have lasting value. Collections are frequently studied by new investigators to answer questions that had not been previously anticipated. These unanticipated uses often arise when new analytical techniques make it possible to acquire different or improved information from previously studied material. In addition, collections are especially important when re-sampling is either impossible or impractical. The original sites of many collections are no longer accessible and live-collected specimens from periods before extensive human impact provide irreplaceable and invaluable baselines. Preserving and curating existing collections will require significant allocations of space as well as some ongoing input of curatorial resources, but without such collections, attempts to characterize past biotic and environmental change and understand their interconnections will be severely compromised. Previous recommendations that have focused on geoscience data and collections (NRC, 2002b), including museum collections, have equal applicability to the broadly interdisciplinary data that will be needed by the geoscience and bioscience communities to address the complex biosphere issues outlined above.
Enhancement of Capabilities for Age Determination and Correlation
Recommendation: The research efforts proposed here require additional support for dating facilities, for the cost of dates in research projects, and for the development of techniques critical for high-resolution age determination and correlation.
Improvement in the application of geohistorical records to understanding ecological dynamics requires improvement in three aspects of geochronology: (1) enhanced resolution of radiometric dates; (2) greater understanding of the temporal resolution of fossil assemblages themselves; and (3) improved tools for correlation—the assignment of isolated geohistorical records to a high-precision timescale.
High-precision radiometric dating is expensive, time consuming, and frequently constitutes the money-limiting or rate-limiting factor in paleobiological research. There is a clear need for support of low-cost, fast-turnaround laboratories for radiometric dating and related chronostratigraphic analyses (e.g., radiocarbon, volcanic ash, geochemical markers). The existing geological timescale also lacks sufficient resolution in many places to adequately determine rates of biological and geological processes. Targeted research aimed at providing a high-resolution (better than 0.1 percent accuracy) timescale is needed. As the resolution of the geologic timescale is progressively refined, there is a continuing need to improve the accuracy of geochronologic techniques. Pertinent issues here include resolving differences between labs in data standardization and handling, decay constants, and other aspects that limit inter-laboratory comparison of results. Additionally, the number of groups pursuing extremely high-resolution analyses is very small, which suggests a need to either establish national facilities for this work or spread best practices to a greater number of facilities. Attention is also needed to provide improved statistical techniques—e.g., where a series of dated horizons are available in a single section, the overlapping uncertainties should allow refinement of error estimates; however, the statistical basis for such refinement has yet to be developed.
Late Quaternary researchers will benefit particularly from access to low-cost, quick-turnaround radiocarbon dating, and from development and dissemination of statistical tools for age-model development. Accelerator Mass Spectrometry (AMS) dating is opening up many new questions and applications, making high-precision dating (decadal to centennial scale) possible in a number of contexts. Such precision requires large numbers of dates for each site, as well as rapid turnaround. Investment in AMS dating facilities that will provide rapid dates at low cost would enable a wide array of questions to be addressed by the community. Although calibration of radiocarbon age estimates to calendar years Before Present (BP) is now routine, the available tools and software are primitive and inadequate for community needs. Statistical tools for age calibration and calculation of age-depth models for sediment sequences are urgently needed. A modest investment aimed at developing these tools and incorporating them into freely available and user-friendly software would yield
a major return in quality and quantity of high-precision paleoecological studies.
How much time is represented in a bedding plane full of fossils? Even when strata can be dated to a high precision, the fossils contained within those strata may represent an accumulation over hundreds to thousands of years. It is necessary to determine whether there are any general rules for the degree of time-averaging in different depositional systems and environments. If such rules can be discovered, they would help determine the best age-dating systems for particular types of studies. Extensive application of radiocarbon or calibrated amino acid dating is vital for such work. The new NSF-funded amino acid racemization dating laboratory at Northern Arizona University may serve as a model for a facility that provides dates at a cost-effective price to a broad community of users.
Increased attention is also needed for improved high-resolution correlation between stratigraphic sections, allowing the assignment of isolated geohistorical records to a high-precision geologic timescale. As geochronology improves, the temporal diachroneity and other difficulties associated with traditional biostratigraphy for relative age correlation will become limiting constraints. Advances in geochronologic resolution must be matched by improved methods of correlation based on rigorous and quantitative biostratigraphy (e.g., ordination and optimization) and better statistical analyses of the quality of the fossil record (e.g., confidence intervals). Support is needed for chronostratigraphic databases that will facilitate comparison and correlation among records. A critical issue for understanding many biotic and environmental events in the geologic record, and testing hypotheses for their causes, is the temporal relationship between marine and terrestrial events. Determining whether particular marine and terrestrial events were simultaneous will require more accurate and more comprehensive high-resolution correlations between marine and terrestrial sections. Cross-correlation is an especially important issue during critical biotic events such as mass extinctions. For such important intervals in Earth history, attaining high-resolution correlation between marine and terrestrial sections will require targeted, collaborative efforts.
Enhancement of dating techniques, and new developments in methods for the correlation of geohistorical records—both with one another and with a high-precision timescale—suggest that very high levels of temporal resolution are readily achievable. We envision a correlated geologic timescale with a resolution of better than 1 million years through the Paleozoic, 0.25 Ma for all stage-level boundaries through the post-Paleozoic, with higher resolution through the Cenozoic. Centennial-scale resolution should be routinely possible for the past 25,000-35,000 years,
with annual to decadal resolution and correlation possible for many sites within the past 15,000 years.
Enhancement of Methods for Environmental and Biotic Reconstruction
Recommendation: The research efforts proposed here require additional support to develop and refine techniques that can extract high-precision environmental and biotic information from geohistorical records.
Proxy indicators of past environmental change provide the essential evidence needed to assess the nature, rate, and magnitude of the biotic response to that change. Additional research is needed to develop proxy indicators that can be applied in older geohistorical records, to evaluate the preservation of geochemical proxies, and to develop measures of short-term environmental variability. Reconstructing the range of natural variation in past environments is needed to detect environmental changes that exceed the natural background.
Proxy indicators are also needed to recognize microscopic and macroscopic components of past biotas that are not preserved as conventional fossils (e.g., biomarkers, stable isotopes). Proxy indicators for ecological attributes such as abundance, trophic relationships, and growth rates are important for recognizing how ecosystem function changes in response to environmental change. Although impressive technological advances now permit the recognition of biotic elements based on distinctive organic molecules preserved in geohistorical records, this research area is still in an early stage of development. There is enormous potential to use biomolecular methods to recognize the presence, abundance, and biochemical significance of biotas that are not preserved as conventional fossils. Improved understanding of biomarker diagenesis is essential for biomarkers to be used in deeper time.
Given the importance of an improved understanding of ecological dynamics, the complexities of the scientific problem, and the time that is needed to train individuals and refine methods for merging biological and geological information, the committee recommends a decadal-scale commitment to applying geohistorical methods to address issues of ecological dynamics. Such a coordinated effort would be highly effective both as a means of tackling important problems and as a vehicle for promoting the integration of earth and biological sciences. Judging from other disci-
plines, a decade is the minimum time frame for sustained support that is realistically needed to cause genuine change in the scientific community. A decade provides time for multiple initiatives to be rotated through calls for proposals, with a round of renewals for each, so that significant numbers of ambitious projects can be undertaken and new careers can be shaped.
Ideally, the combined earth science and biological communities should have opportunities to intensify and diversify research effort in all three of these complementary directions, and we would expect that different federal agencies might take the lead with different initiatives. All of these initiatives should be used as opportunities to increase interactions across the interface of the earth and biological sciences, and whenever possible should be funded across—rather than within—divisions or directorates of agencies (whether research is intramural or extramural). Most would be good vehicles for partnerships among federal agencies or among federal agencies, universities, and museums.
Initiative 1 (The Geologic Record as an Ecological Laboratory) will be of direct interest to the academic community, which is funded primarily by NSF, but is unlike any previous program in proposing that paleo- and neo-biologists focus on ecological rather than exclusively evolutionary issues. The existing Biocomplexity in the Environment (BE) Program, or its successors, would be a natural home for this topic, as would the Biogeosciences Initiative (currently administered out of EAR in the Directorate for Geosciences). This initiative might also be attractive to the USGS as a research topic, requiring the teaming of scientists across disciplinary boundaries or with university and museum scientists (e.g., through LTERs, existing “place-based” projects of the USGS, or newly proposed GTER projects). Research synthesis using databases, meta-analysis, and re-analyses of collections will be important methods for much of this research; and these are common modes of collaboration between scientists from diverse institutions and between empiricists and modelers.
Initiative 2 (Ecological Responses to Past Climate Change) will require close collaboration and coordination between the paleoclimate, paleoecology, and ecology communities. Ongoing federal funding initiatives centered on past climate change and variability do not currently encourage such coordination. ERPCC is an initiative aimed at documenting ecological responses to past climate change and assessing their implications for sustaining biodiversity and ecosystem services in the face of global change. Funding of such work would need to span NSF directorates, USGS disciplines, NASA, and NOAA; it would be an appropriate addition to the U.S. Climate Change Science Program.
Initiative 3 (Ecological Legacies of Societal Activities) is a natural topic for support by a wide range of federal agencies, including both intramural and extramural research programs at EPA, because of its applied as well as basic research aspects. This initiative differs from existing efforts, however, in its explicit focus on bringing geohistorical methods and materials to bear on the issues. Within NSF, this initiative—like the other two initiatives—would be a part of the Environmental Research and Education portfolio, and would find a logical home in the Coupled Human-Natural Systems Program within BE, or its successor program. This is another natural topic for partnerships among agencies or universities through LTERs as well as USGS and EPA programs focused on particular regions or habitats, but would also be appropriate for synthetic analysis or modeling at regional and global scales.
We do not list these agencies and specific programs to be prescriptive, but rather to give examples of how these initiatives that stress geohistorical methods complement—or are natural extensions of—existing programs.
Only geohistorical data—the organic remains, biogeochemical signals, and associated sediments of the geological record—can provide a time perspective sufficiently long to establish the full range of natural variability of complex biological systems, and to discriminate natural perturbations in such systems from those induced or magnified by humans. Such data are crucial for acquiring the necessary long-term perspective on modern systems. Information from past environmental states, both like and unlike those of the present day, provide the empirical framework needed to discover the general principles of biosphere behavior necessary to predict future change and inform policy managers about the global environment.