Plant Community Development in an Abandoned Limestone Quarry; A Demographic Assessment

Abstract

Colonization of plants in an abandoned limestone quarry near Syracuse, New York has proceeded slowly since the site was mined 50 years ago. To understand plant community development in the quarry, populations of four dominant monocarpic species ( Erucastrum gallicum, Melilotus alba, Picris hieracioides and Echium vulgare ) were intensively monitored from 1976 to 1981 on two sites that differed in density and substrate character: the sparse and dense sites. Measurements of substrate properties on each site and rainfall were also made and related to population performance. Densities of all species fluctuated during each year due to episodes of seedling recruitment followed by heavy mortality that appeared to primarily result from desiccation. Densities also varied between years, apparently due to variability in rainfall. Densities of P. hieracioides declined during the study whereas those of E. vulgare increased. No overall trend was observed in the other species. Annual fluctuations in density were consistently less pronounced on the dense site, apparently due to ameliorating influences of both vegetation and substrate. Community development in the quarry appears to be temporally erratic, depending upon variability in rainfall and its influence on the individual species.