Author(s)

M. Anand, B.C. Tucker & R. Desrochers

Abstract

Ecological monitoring of terrestrial ecosystem recovery from man-made perturbation: assessing community complexity M. Anand, B.C. Tucker & R. Desrochers Biology Department, Laurentian University, Sudbury, Ontario, Canada Abstract The dynamics of ecological complexity are presented from an area severely damaged by air pollution to understand the effect of perturbation intensity on long-term recovery dynamics of forest communities. Perturbation is assumed to be most intense near the smelter and to decrease with distance. Complexity is assessed using Shannon entropy as well as a contemporary measure of structural complexity. We find that while total complexity and diversity increase with decreasing perturbation intensity, structural complexity does not. It is also uncovered that community-level dynamics are more predictable than species- level dynamics. The data were analyzed using multivariate methods to determine how spatial pattern and groupings produce trends in community-level dynamics. The perturbation gradient is characterized by a continuum of understory communities with colonizing and metal-tolerant species proximal to the pollution source and sensitive species at distal sites. The overstory community mimicked this pattern, but vertical structure was found to be important in characterizing the gradient. Ecological monitoring of the multi-level effects of pollution on ecosystems is important for understanding the full implications of multiple stressors in the environment. 1 Introduction With ever-increasing threats to biodiversity by man-made perturbation, and in particular by industrial pollution, the importance of extensive and long-term monitoring of the effects of these on ecosystem diversity and complexity is critical. Quantification of these attributes, however, is not always intuitive [1]. Understanding spatiotemporal patterns of diversity has been a central question in ecology for over a century, prompting widespread investigation into the best methods of quantification [2, 3]. Diversity indices, though varied, generally include both number of species and their relative proportions. These simple

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