Abstract: Located along the coast of Arecibo and Barceloneta, Caño Tiburones is a natural reserve and the largest wetland on the island of Puerto Rico. In the year 1940, Caño Tiburones 7,000 acres of fresh water and land became salinized due to poor management of hydraulic pumps and lack of knowledge of the wetland’s hydrology. Changes in salinity levels of a predominant freshwater wetland could have noticeable consequences on its ecosystem function. In order to restore the ecological integrity of the wetland, it is essential to understand how salinity alters its ecology. One of the driving forces of a wetland ecosystem functioning is leaf litter decomposition. Leaf litter decomposition rates directly affect a wetland ecosystem’s nutrient cycle as the degradation of the former releases various elements vital for the growth of primary producers, back into the environment. There are contrasting results of the effects of salinity levels in leaf litter decomposition. Thus, it is imperative to better understand how leaf litter decomposition rates respond to high and low salinity levels in Caño Tiburones. In this work, we will present a proposed conceptual model aimed at determining whether variation in salinity in Caño Tiburones promotes the fastest decomposition rate as well as changes in stoichiometry and fatty acid profiles. Our goal is to present our conceptual model to experts in order to gain feedback.
This concept study aims to perform a reciprocal transplantation experiment to evaluate whether high salinity levels affect the rate at which leaf litter decomposes, and leaf litter stoichiometry, and food quality in terms of fatty acid profile are affected. The methodology to be used to measure leaf litter decomposition is the bag method. Bags 15cm x 15cm each with 5g of dry leaf litter will be divided and placed on each site. Six bags will be collected a month after being placed within the wetland monthly for a year. The decomposition rate will be measured utilizing the Olsen decay model. The leaves used for this investigation belong to the species Laguncularia racemosa as it is the most abundant plant in the wetland.
Preliminary results indicate that the leaf litter decomposition rate was higher in the site with lower salinity ( T-test; p-value is .00001). The reciprocal transplant experiment showed that the salinity rather than site of origin is the strongest factor driving leaf litter decomposition (Oneway ANOVA; p-value is .000159).
