SURVIVAL OF RHIZOPHORA MANGLE PROPAGULES UNDER ENVIRONMENTAL STRESSORS IN THE CALANCALA BRANCH OF THE RANCHERÍA RIVER, COLOMBIAN CARIBBEAN.

Abstract

The survival of Rhizophora mangle propagules was assessed by direct seeding in the presence and absence of stressful factors (grazing of goats) and limitations factors of mangroves (hydric deficit and sunshine) in the Calancala branch of the Ranchería River, La Guajira, Colombia, assuming as hydric deficit the dry season, and sunshine the direct exposure to the sun. Four experimental plots of 100 m2 were established, located in different sunshine conditions, two under tree shade and two exposed to the sun. Some plots were enclosed in order to protect propagules from grazing, and others were exposed to grazing. Significant differences in propagules survival was found between conditions of hydric deficit (dry season) and availability of water (wet season) (χ² log-rank; p<0.05). In dry season the propagules did not survive because the low water availability and high sunshine. During rainy season, survival was greater in absence of goats grazing (0.46-0.96), in comparison with those exposed to goats grazing (0.0), because they ate propagules. In conclusion, survival of R. mangle propagules is affected by limitations factors and continuous grazing goats, this stressful factor required surveillance and control in order to mitigate damage to mangroves, and lead to environmentally responsible livestock practices.