Studies of the population ecology, reproductive biology and conservation status of Crescentia portoricensis (Britton) [Bignoniaceae]

Abstract

Crescentia portoricensis Britton [Bignoniaceae] or higüero de sierra as it is commonly known (Woodbury, 1975) is an endangered shrub, strictly endemic to serpentine derived soils and to the Maricao and Susúa Forest Reserves in the western part of Puerto Rico. Due to the lack of information available on the current status of Crescentia portoricensis, an extensive search was performed for new individuals (including seedlings) and populations in likely localities in the forests and in adjacent privately owned areas. Observations on asexual reproduction in wild populations in the field were recorded. A study of the reproductive phenology was conducted. Observations on flower visitors were recorded, and plant characteristics based on Gentry’s (1980) key were examined on all individuals found to assess the extent and impact of hybridization. Fruits found on the ground as well as on plants in the field were observed for dispersal, and examined for agents of fruit and seed predation. This study reports 163 and 369 plants in eight and three populations for the Maricao and Susúa Forest Reserves respectively; no seedlings were found in any of the wild populations of the species. Roots were observed to grow on stems and branches that either rested on the ground or were buried. Plants were observed to flower throughout most of the year; flowers lasted nine days on the plants. Flower visitors and evidence of hybridization were not observed. Agents of fruit and seed dispersal were not observed, but it is assumed that seeds disperse by hydrochory, and termites were also observed feeding on seeds from an old fruit that fell on the ground. This study suggests that Crescentia portoricensis is vulnerable to extinction, and its conservation status should continue to be monitored.