摘要：Gordon Baskerville's thoughtful piece makes a number of points, explicit and implicit, that must underlie any efforts at management. Ecological science, indeed, most often is focused only on one scale at a time, and the problem of relating phenomena on different scales is too rarely addressed. Efforts to predict responses of forests and grasslands to global change, for example, ultimately depend on understanding how individual plants respond to changing environments, but we do not understand well enough how to scale up from such information to the responses of ecosystems. The dynamics of marine ecosystems, as another example, emerge from the interactions among individuals and with their local environments, on scales of the order of the sizes of those individuals. I do not agree with Baskerville that the pressures of good science forbid work from being carried out at the relevant levels for management. The powerful decades of research by Bormann and Likens and their associates at Hubbard Brook, the elegant whole-lake manipulations of Schindler, and the classic studies of Paine in the intertidal all provide evidence of long-term studies carried out at the level of whole systems, and using the experimental method that is a necessary corollary of the importance of exploring far-from-equilibrium dynamics. Yet all of these investigators would agree that whole-system studies must be related to processes mediated at lower levels of integration, and that one of the greatest challenges for management is in relating dynamics across scales. The fishery manager need look no further than his or her own system, in which conflicts between actions and interactions at the level of individuals and consequences at the level of the whole fishery create paradoxes and challenges that have been acknowledged since the dawn of fisheries management. The "Tragedy of the Commons" is the eloquent caricature of this very situation.
