The Land Builders
A special destination for us, as we’ve been slowly making our way through the Exuma island chain here in the central Bahamas, has been the Exuma Land and Sea Park. Similar to our Canadian National Parks, Bahamians had the foresight (the Park was established in 1959) to set aside an area in this region that would preserve special flora and fauna. Today, the park, which is 44 km (22 miles) stretching north to south with 15 major Cays and many smaller ones, is considered to be the most pristine and possibly the most beautiful area in all the Exumas. And what we’ve seen so far certainly fits that description. Our first mission in the park is to find the “land builders” on Shroud Cay.
The Land Builders We anchored in the lee (shelter) of Shroud Cay as the trade winds blew its 20 knots from the east. In the morning, with the rising tide, we picked our way through the outer ring of islands via a small inlet entering into a large mangrove swamp area. We had entered the world of the “land builders”.
To our surprise, the so-called “swamp”, which covered the entire centre of the Cay (an area 2km by 1.5km), didn’t feel very swamp-like at all. We both expected to see tall, dark, dense trees standing in mirky brown water. Instead, we slowly motored along an open little shallow creek, about 2 – 3 m wide with its crystal clear water that had a slight blue-green tinge. Red Mangroves lined both sides of the creek and were no more than 1.5 m tall. These small “trees” had unusual curved roots that looked more like incredibly long fingers reaching out into the sand. It’s said that the roots of Mangroves are incredibly strong, like anchors, and it’s considered to be a safe place to tie off your boat in the event of a hurricane. I hope we don’t have to find THAT out.
Mangroves are marine plants that grow on tropical seashores around the world. Yet they are essentially terrestrial plants. They grow on land. What’s most significant about these plants is that they are considered “land builders”, like Lichens that grow in the Boreal forest in Canada. However, unlike Lichens, they are unique in their adaptation to a marine environment. They use salt water by removing the salt and secreting it in glands found on the leaves. As they do this, they slowly “recover” the ocean floor and convert it into dry land. Four different Mangrove species work alongside each other in sequence to accomplish this amazing change. As each mangrove species colonizes or occupies an area, it transforms or changes it into a slightly more terrestrial or land environment and makes it less suitable for itself. This incredible process is called Ecological Succession.
Ecological Succession In the Shroud Cay swamp, we saw the Red Mangroves with their incredible finger-like roots. These tangled roots are home to countless sea creatures and they stifle water currents. This stifling of the water currents causes sediments to accumulate around the roots. After years of accumulation of the sediments, the next in line in the mangrove procession – the mud-dwelling Black Mangrove – grows. Black Mangroves have breathing roots which stick straight up out of the mud and provide air for the underground roots. The Black Mangroves transform or change the mud into hard ground where the White Mangrove takes over. Transformation continues until the land is fertile enough for the Gray Mangrove or Buttonwood. The Gray Mangrove takes over from the White Mangrove and is a tree that grows to a height of 6 – 8 m with twisting branches. Now the succession is complete with the ocean floor converted to dry land. Incredible.
Ah…a magnificent process that is safely protected in the Exuma Land and Sea Park for all to see in years to come. Thank goodness.