Skip to main content

National Center for Ecological Analysis and Synthesis

I have been asked to respond to James Browns essay "An Ecological Perspective on the Challenge of Complexity." As a historian of biology, I will reply with a mixture of historical and ecological perspectives. My general comment is that recent history of any sort is particularly difficult to assess in part because it is the passage of time that produces perspective and occasionally consensus. The histories written about a topic will differ in many ways, including whether the storyteller is a participant or an observer from outside the field. What may interest one about the topic might not occur to the other. Historians must strive to understand both the science and place it in a larger context that may be different than that used by the scientist. For example, what a scientist might declare a "dead end" might have great interest to a historian's analysis. The history of ecology is just now beginning to be written, and it will take time to sort out patterns of ideas, controversies, institutions, and social networks of scientific practice. Shifts in the nature, methodology and philosophy of ecology, tracked through its brief but turbulent history, do not reflect stagnation nor a need for a single organizing paradigm. Brown's call for greater synthesis of both data and ideas is certainly persuasive, but the past suggests the excitement of multiple independent approaches will provide an intellectually stimulating discipline.

In brief, Brown contends that while he can identify many theoretical and empirical studies between 1955 and 1975 that have substantially changed the discipline of ecology, he has trouble finding even a handful for the period 1975-1997. He says that although much good work is being done, it is not producing conceptual advances. He suggests a possible solution to this dearth is for ecologists to search for general ecological laws using a research program that focuses on emergent and general phenomena. They should use mechanistic models that are empirically tested and connected to other "established scientific laws." Brown presents his collaborative research on allometric scaling as one example of this research program.

I find two major difficulties with Brown's essay. First, I disagree that ecologists have seen little conceptual advancement in ecology over the last two decades. Perhaps what is in question is what constitutes a "conceptual advance." Many will claim that the recent "good work" to which he refers is indeed altering conceptual frameworks. I will list some of these advances, and also claim that it is too early in history to dismiss the last two decades as not producing theoretical or empirical advances that will "substantially change the discipline" of ecology.

What ideas prove useful to ecologists depends in part on their individual interests. What some might hail as advances are seen by others as minor ideas. Some advances in the last two decades that have inspired many younger ecologists have been non-linear dynamics and the fractal nature of pattern in ecology, the birth of conservation biology, the newer application of quantitative genetics to both basic and applied issues, the identification of behavioral and physiological mechanisms behind patterns of distribution and abundance, landscape ecology, how global change affects and is affected by biological communities, satellite image analysis, and new statistical methods based on computationally intensive methods. These areas should not be dismissed as merely producing more detail without conceptual frameworks. Equally important as these developments has been the rigorous assessment of theories and concepts which were put forth in the 1950s and 1960s without the level of empirical evaluation that contemporary ecologists expect of new ideas.

The research program that Brown suggests is but one model of ecological research. It provides a good framework for inquiry, but it is also vitally important to allow for serendipity, unbiased exploration and discovery in ecological research. Some grand ideas that stimulated ecology, like MacArthur and Wilson's island biogeography, HSS, ESS and many others might not have been proposed within such a program. Accident and discovery, noticed and expanded upon, have always played a large part in ecology. Brown's stated approach appears to follow a Popperian methodology that does not often suit how biological research is carried out in practice.

But perhaps in fact Brown's approach is not Popperian in that his example of allometric scaling does not have an experiment, nor does it eliminate any competing models. Body size data are often clouds of data with low goodness of fit measures but highly repeatable, scale invariant slopes for general associations among body size and many other variables. Because the model makes a general prediction, it may be of limited use in applied problems where specific predictions are needed. For example, although the respiration of a beetle may be a function of body size, its current diet, genetic composition, and many other factors will mean that much of the variance will remain unexplained. Just as Brown's constants have error bars, so too do the predictions, and yet his approach is one fruitful direction among many that can be taken in ecological research. It is interesting, different, and may be capable of identifying a mechanism that explains general patterns, but may be most useful as one among many approaches to doing research. In my own exploration of the history of ecology, I have been intrigued by how frequently ecologists have called for greater rigor as well as prediction in ecology. Ecology is similar in some ways to economics or meteorology because there are so many variables and many stochastic and non-linear processes. These challenges seem to have been more readily accepted by practitioners in other disciplines than ecology. Predictive models can be obtained and may be very robust, but precision will always be low. In contrast, in engineering, molecular biology, or other disciplines where many stochastic factors are controlled or manageable, prediction can be very precise. In fact it is remarkable how much important work has been carried out in the past two decades despite environmentally conservative governments, and in the face of dwindling support for individual researchers in environmental science, the increasing demands for researchers to read, publish and teach ever more, and the competition for limited jobs and journal space. It certainly can be difficult to identify important ideas in the mass of ideas published every month in expanded journals. Which ones will remain important over the years, and which ones will fade into, or rise from obscurity? Finally, it should be noted that in the face of rapid environmental degradation many excellent ecologists have turned their attention from fundamental ecological research to address pressing conservation issues. Obviously the intellectual excitement and growth of the field is still enough to attract a large number of enthusiastic undergraduates, graduates and advanced researchers.

Read original EcoEssay Series Number 1 article here

Read all EcoEssays in the series here