Factors affecting the size of Drosera rotundifolia in fens and bogs.

Abstract

Due to a high tolerance for variations in resource availability, generalist species have the ablility to survive in a variety of habitats. However, survival does not equal success. One habitat may have optimum conditions which allow individuals of the population to have a faster growth rate and larger size than those individuals in another habitat. This study examined the effects of two different habitats on size in the insectivorous plant Drosera rotundifolia. Sundews were measured in 1 m2 transects throughout Waldron Fen and Mud Lake Bog. Nutrient concentrations (nitrogen and phosphorous), pH, and insect abundance and biomass were tested at each site. Although there was no difference in nutrients, pH, and insect availability between the two sites, D. rotundifolia at the fen were significantly larger and appeared to grow faster than those at the bog. Size class distribution was also significantly different at the fen and the bog, with a higher percentage of large plants at the fen and than at the bog. Intraspecific competition and waterlogging may be responsible for the differences in size and growth rates seen within these two habitats.