DISTRIBUTION OF A RESTRICTED LOCALLY ABUNDANT SPECIES - EFFECTS OF COMPETITION AND NUTRIENTS ON COREOPSIS-LANCEOLATA

To determine if there is a trade-off between competitive ability and growth in unproductive conditions in Coreopsis lanceolata L. (Asteraceae), two studies were carried out. In one, a survey of natural populations quantified environmental para-meters and plant traits. The results indicated that these habitats are characterized by low soil moisture and low nutrient availability; densities of C. lanceolata were negatively correlated with densities of other species. The second study was a transplant garden experiment in which three levels of nutrients and two levels of competition were manipulated. One garden was adjacent to a natural population and the second was in a more productive area where C. lanceolata did not occur. Plants grew, survived and reproduced better in the area where C. lanceolata did not occur if competitors were removed. Nutrient effects were transient and only affected growth soon after application. The trade-off between competitive ability and growth in unproductive habitats may be responsible for the distribution of C. lanceolata and other restricted locally abundant species which often are habitat specialists.