Abundância, sobrevivência e crescimento de plântulas de Ipomoea pes-caprae (L.) R. Br. (Convolvulaceae) na Ilha de Santa Catarina, SC, Brasil

Abstract

Seedlings of Ipomoea pes-caprae occurred on nine of the beaches studied (n = 10) at Santa Catarina Island, (State of Santa Catarina) and in 21 monitored patches (n = 30); it did not occur at the smallest beach. Seedling densities varied from 0 to 5.2 m2, and these differences are in part explained by viable seed bank densities. Seedling survival was low (0.6%) considering the 2823 plants monitored over three years. The main causes of death were wave erosion and burial. No seedlings survived at the beach zone (n = 2684). Seedlings survived in the fore dune, in patches of Ipomoea pes-caprae (0.8%, n = 119), in recolonization areas where Ipomoea pes-caprae was partially removed (80.0%, n = 20) and in recent dune areas, which were reconstructed after intense wave erosion (four seedlings observed). Seedling growth was greatest at the latter. Experiments showed that one-month-old seedlings did not tolerate burial in 10 cm of sand. When buried by 5 cm of sand, 50.0% of the seedlings survived, but these had fewer leaves, lower biomass and lower allocation to root and shoot development. All established seedlings of Ipomoea pes-caprae were recruited in a period without wave erosion; habitat stability was a key factor in Ipomoea pes-caprae regeneration.