On March 10-12, 1997 a small workshop on "Universal Phenomena in Ecology?" was held at the Santa Fe Institute (SFI), Santa Fe, New Mexico. It was supported jointly by SFI, through a grant from the Thaw Charitable Trust, and the National Center for Ecological Analysis and Synthesis (NCEAS), which is supported by the National Science Foundation. A small number of invited participants, representing diverse areas of ecology and some other disciplines, and several visiting scientists, postdocs, and graduate students from SFI attended. At a minimum, all participants seemed to find the workshop to be very stimulating - forcing them to think how their own work and area of specialization related to the "big picture" of ecology. After some time discussing the possible existence of universal ecological patterns and processes, the participants broke into subgroups and discussed four topics. The subgroups developed a conceptual framework and preliminary action plan to address their topic.
COMMUNITY ASSEMBLY AND INVASIBILITY
The self-organized assembly of ecological communities is a universal phenomenon of ecology. It occurs as a successional process following disturbance, but is also an ongoing process in response to extrinsic environmental change and species invasion and extinction. Despite substantial recent work on assembly, there is no general theory of the process. Plans were laid to begin a three-part research effort:
Subgroup members: F. Davis, J. Lawton, M. Leibold, P. Morin, W. Murdoch, C. Pahl-Wostl, and D. Tilman.
The discrete as opposed to continuous organization of the natural world, and especially of species in ecological assemblages, is a longstanding and inadequately resolved debate in ecology. New ideas on patterns and underlying ecological and evolutionary mechanisms of assembly and interaction, recent development of new statistical and analytical tools for detecting discontinuous distributions, and implications of the spatial and temporal discreteness of assemblages for environmental policy and management all make this an important issue to reexamine. Two activities are planned:
development of simulation models and theoretical analyses, which would begin by exploring the utility of object-oriented (METAMAP) or agent-based (ECHO and SWARM) platforms to model the process of species assembly at three levels: individual organisms, habitat patches, and ecological landscapes or gradients.
Subgroup members: S. Harrison, C.S. Holling, S. Levin, H.R. Pulliam, and O.J. Reichman.
LINKAGES BETWEEN INDIVIDUAL ORGANISMS AND ECOSYSTEMS IN THE EXCHANGE OF ENERGY AND NUTRIENTS
The processing of energy and nutrients have been studied at the levels of both individual organisms and ecosystems, but there has been little effort to study the constraints and mechanisms by which each level influences the other. It was decided to focus initially on nutrients, because theoretical models and empirical studies could be grounded on well understood principles of physics and chemistry (conservation of matter, chemical stoichiometry) and biology (allometry, different elemental composition and requirements of different functional groups). The plan is to incorporate existing data and mechanisms from both organismal biology and ecosystem ecology into models of the flows and feedbacks that govern system-level trophic structure and dynamics.
Subgroup members: J. Brown, C. Curtin, L. Hedin, T. Keitt, W.Murdoch, and M. Pace.
ALLOMETRIC SCALING IN BIOLOGY
This is an area of ongoing research at SFI. G.B. West, J. Brown, and B. Enquist haverecently developed a model that appears to account for the quarter-power exponents of scaling ofmetabolic rate, lifespan, and many other biological variables with body mass. Having published the general model (Science 276:122-126, 1997), which is based on the fractal-like design ofresource distribution networks, they plan to:
explore implications of the model for scaling of life history and ecological variables;
host a workshop/symposium on "Scaling in Biology, from Organisms to Ecosystems" at SFI in October 1997
Subgroup members: J. Brown, B. Enquist, and G.B. West.
While plans are still being developed, at least some members of the subgroups intend to work and collaborate on the above topics. Proposals may be submitted to SFI, NCEAS, andother sources to support literature review, data compilation and analysis, mathematical andsimulation modeling, and other follow-up activities. Participation in these efforts is not intendedto be limited to those who attended the workshop. Individuals interested in getting involved are encouraged to contact members of the appropriate subgroup, SFI,or NCEAS.
Written by J. Brown for the Steering Committee: C.S. Holling, S.Levin, and D. Tilman.