Structure and Function of Successional Vascular Plant Communities in Central New York

Abstract

Succession of vascular plant communities was studied on fields in central New York abandoned for the previous 4 to 36 yr. Changes within fields as they aged were consistent with the overall pattern of change between fields. Over the period covered, Phleum pratense was replaced successively as the major species by Solidago altissima, Picris hieracioides, and Cornus racemosa. Succession was accompanied by increased biological diversity, reduced dominance, decreased energy flow per unit biomass, and increased stability to a pulse perturbation of inorganic nutrients. Although soil phosphorus is an important factor influencing community function on the fields studied, the fertilization experiment indicated a fundamental reorganization of community relationships during succession which reduces community responsiveness to fluctuations in soil nutrients. Increased diversity resulted from the partitioning of constant density and net productivity among increasing numbers of species. Accompanying the increase in diversity was decreasing seasonal synchrony of resource demands among the constituent species pool. Although successional stages could be arbitrarily recognized by the taxonomic identification and growth forms of dominant species, there was a gradual and continuous change in structural and functional properties of the plant community, and no objectively definable stages could be delimited. These studies indicate that a failure to determine productivities of individual species may seriously distort the evaluation of community properties.