Klemow, Kenneth M. 1985. DEMOGRAPHY OF ASCLEPIAS TUBEROSA IN AN ABANDONED LIMESTONE QUARRY. Contributed paper: Ecological Society of America meeting. Abstract: Bulletin of the Ecological Society of America 66:209.
Asclepias tuberosa (butterflyweed) is a non-clonal, polycarpic herb that grows in localized populations on well drained sites. It is considered to be a rare plant in several states, including New York where it is listed as a protected species. Populations growing in a 50-year old abandoned limestone quarry near Syracuse, New York were examined from 1976 to 1981 to understand the factors that influence its abundance there. Population size increased during 1976, a year of abundant rainfall, because recruitment and survival of seedlings were both relatively high. During four drought-prone years that followed, rates of seedling recruitment and survival were both much lower, causing a marked decline in population size. The low rates of seedling recruitment were due primarily to rates of survival among seeds in the soil being low (<2%). Growth of A. tuberosa populations within the Syracuse quarry is inhibited primarily by low rates of seed and seedling survival, especially during years of drought. Conversely, populations persist because mature individuals live for many years, and because seedling recruitment and survival are high during occasional years of more abundant rainfall.