A Study of Lichen Ecology in Central Long Island, New York

The epiphytic lichens of eleven forest stands in central Long Island were sampled by the random pair method and the stands are arranged in a continuum based on their epiphytic flora. This continuum exhibits certain discontinuities resulting in ecologically different segments. The distributions of the common lichens along this continuum gradient are analyzed. Most lichens are shown to have their greatest frequency in the mature oak woods. It is suggested that if moisture and light are recognized as important factors in lichen distribution on a local level, the mature oak woods can be regarded as a point of compromise between the dry but well lighted pine-oak barrens and the moist but poorly lighted sub-climax woods. The host-specificities of the eight common lichens for Black Oak, White Oak, and Pitch Pine are analyzed using Cole's Index of Interspecific Association and significance tests. Parmeliopsis placorodia was extremely specific for Pinus rigida; Graphis scripta, Lecanora leptyrodes, and Parmelia saxatilis were highly specific for Black Oak. It is noted, however, that the host-specificities in one vegetation type sometimes differ from those in other veaetation types. This study was undertaken to expand our knowledge of the lichens of Long Island. The area is especially interesting floristically because of its unusual geographic position; the northern limit of the southeastern coastal plain element overlaps the southern limits of several northern elements. Although the central and eastern portions of the island still exhibit a rich and varied lichen flora, little collecting has occurred since the 1920's and 30's when Roy Latham was especially active. The lichens of the western portion of the island have mostly disappeared due to urbanization, and only scattered herbarium specimens and literature reports attest to their former prominence. The specific aims of the study were (1) to determine the ecological niches of the common lichens of the area; (2) to determine the hostspecificities of the common lichens for the area; (3) to set up permanent quadrats for a long term growth rate project, and (4) to secure floristic data on the lichens of central and eastern Long Island. Since much work is still to be done on the growth rate and floristic studies, they will be discussed at some future time. This paper is confined to the ecological investigations. 1 This study was supported by a New York State Museum and Science Service Graduate Study Honorarium for Summer Research. 2 Contribution No. 60-18 from the Department of Botany and Plant Pathology, Michigan State University, East Lansing, Michigan.