Reasons for reforestation success and failure with three mangrove species in Colombia
Background
This study examines the mortality and growth rates of the propagules, seedlings and saplings of three native mangrove species (A. germinans, L. racemosa, and R. mangle) in order to determine the ecological factors that influence tree growth and survival in deforested mangroves with restored hydrologic conditions on the Caribbean coast of Colombia.
Goals & Methods
To understand mortality and growth rates , two highly disturbed sites were chosen with low salinities and low temperatures. Since the optimal water levels were unknown, flooded soils, wet soils, and dry soils were compared at both sites. The impact of planting time on mortality was also tested in saplings.
Conclusions & Takeaways
For the propagules, both A. germinans and L. racemosa only became permanently established in flooded and shaded plots, with moist soil and low salinities; R. mangle had the lowest mortality and permanent establishment was not drastically affected except where there were drastic increases of desiccation and salinity. For the seedlings, both L. racemosa and A. germinans, showed high mortality rates, especially in dry plots and both were affected greatly by dust from dry season trade winds in areas where they were not protected by larger bushes. The extremely high mortality of both propagules and seedlings of A. germinans was directly related to predation by J. evarete caterpillars.In general, mortality was much lower in all species when planted as saplings. With regard to planting time, both A. germinans and R. mangle showed lower mortality rates when planted in December, at the end of the rainy season; for L. racemosa saplings there was no difference in mortality between the groups planted at the beginning and the end of the rainy season. The author found that all species developed best at sites with low salinities and a water level near the soil surface.
The results of the experiment suggest that the highest mortalities are found in the propagules and saplings of both L. racemosa and A. germinans, while the best survival rates are observed in R. mangle propagules and L. racemosa saplings.
Reference:
Reasons for reforestation success and failure with three mangrove species in Colombia. Forest Ecology and Management. 2000;131:201–214. doi:10.1016/s0378-1127(99)00214-5.
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