We left Palo Verde early in the morning and headed off for the mangrove forest. I had seen mangroves before, but only the smaller shrub-like plants, not a forest full of tall trees with very large roots sticking out of the ground. Needless to say I was very excited. Once we arrived there, we walked past the entrance of the forest that was composed of the smaller shrubs, and Mau and Pablo were explaining to us how the zonation of a mangrove ecosystem woks due to different plants being able to tolerate different salinity levels in the soil. We walked farther in, and all of a sudden the smaller shrubs turned into massive, eighty-foot-tall trees! We sat on a dead tree trunk lying on the forest floor and started observing the ecosystem, comparing it to other ones we have seen at Las Cruces and Cuerici. There was a very open understory, with not much diversity in plant and animal species. The roots of the trees could be seen almost twenty feet off the ground in some cases. The reason for the low biodiversity and trees having roots out of the ground is because many living organisms have trouble surviving in conditions with high salinity, so the organisms found in these mangroves have adapted ways to survive there. Mau explained to us how some mangrove plants have pores in the leaves that secrete the salt the roots are taking in, and others send all of the salt to the older leaves because they will be falling off the branch soon. In addition, since the clay is very good at holding water for long periods of time, and the presence of water makes it is hard for gas exchange to occur underground, mangroves have lenticels on the roots above ground that are used for gas exchange, which is one of the reasons why the roots come so high above ground. After discussing more about different adaptations plants and animals have in a mangrove ecosystem, we talked about the importance of mangroves. They are very good storm barriers that help protect the mainland, they help reduce erosion that can occur along bodies of water, and they help filter pollution that is heading from rivers out into the ocean. We then sat around on the very tall roots and had lunch, enjoying the beauty of the forest. It was very interesting to learn about mangroves, because there are less and less mangrove ecosystems due to the rising of sea levels and humans destroying them, so it is important that more people get educated on the importance of mangroves.
Andres Ripley, Wheaton College