Mangroves help sustain Cayman

They may not be as colourful and spectacular to look at as Cayman’s coral reefs.

Nor do they have the same tourist pulling power, but the role of mangroves within Cayman’s delicate eco-system is no less important.

Geddes Hislop

Biologist Geddes Hislop gave an informative talk on Caymans mangroves. Photo: Joanna Lewis

The National Trust’s monthly mangrove boat tour aims to educate and inform participants about Cayman’s mangrove, taking an informative look at the mangrove forests that make up the central mangrove wetlands, the ecological heart of Grand Cayman.

The tour highlights the pivotal role they play within Cayman’s environment.

Last held aptly on Earth Day, more than 30 participants joined the tour with biologist Geddes Hislop and National Trust development and educational specialist Marnie Laing.

Teeming with life and providing important nurseries for Cayman’s coral-reef fish, these partially submerged trees have a variety of functions, vital to the health of Cayman’s environment.

During the tour Mr. Hislop explained how they help keep Cayman’s seas crystal clear, protect Cayman from shoreline erosion and prevent damage to surrounding coral reefs while also providing nutrients that feed into surrounding ecosystems.

He added that the mangroves act as an effective barrier against storm surges, dampening wave energy and subduing large waves, while providing an ideal habitat for birds and a wealth of marine life, offering sanctuary and food and maintaining fish stocks.

The boat visited mangroves in the North Sound region. Mr. Hislop gave an informative lecture explaining the different mangrove trees in Cayman; the black mangrove, red mangrove and white.

He also pulled up a mangrove root to demonstrate the diverse life the wetlands harbour.

‘The mangrove boat tours are very popular as more and more people become interested and concerned about our environment,’ Ms Laing said.

‘As it was Earth Day we had arranged a larger tour boat to take us out. Normally we take a much smaller boat out which can accommodate just 14 so as we can get much closer to the mangroves.’

According to the National Trust, about 1,500 acres of the Central Mangrove Wetland are protected by marine parks law. The mangrove wetland currently covers an area of about 8,500 acres and efforts are underway to increase the area of the wetlands under protection.

‘Awareness is a very important part of conservations. We need to change people’s behaviour and perceptions. Currently a lot of people see mangroves as wasteland and therefore not useful. They don’t understand how important they are,’ Mr. Hislop said.

‘A huge amount of the mangroves have been lost in Cayman, especially on the west of the island. It is very worrying and has reached a critical point. At the moment we don’t know what the breaking point is, but if we go beyond it we will see a change in regional climates with many areas becoming as dry as East End. There will be less moisture in the air and there will be more dirt and silt in our sea water. It could be devastating.

‘We have to put some effective planning laws in place and we need more research.’

Mr. Kenneth Ebanks, director of planning, explained that there is legislation in place designed to protect the mangrove buffer, an area of predominately red mangroves stretching 300 to 1,000 feet from the sea inland, and that development in such areas is prohibited, except in exceptional circumstances.

Cayman’s mangroves are to receive an additional boost in the form of a Habitat Action Plan which is to be developed under the Darwin Initiative, a UK government grant scheme promoting biodiversity protection and the sustainable use of natural resources. The plan will mean accelerated, targeted conservation research and management of the mangroves.

Mangrove boat tours for May and June are already sold out. Call the National Trust on 949-9012 or email www.nationaltrust.org.ky to be added to the waiting list. Tours cost $10 for trust members, $15 for non-members. Refreshments provided.

MANGROVES

Mangrove trees live inmost of the sub-tropical and tropical countries of the world, growing along sheltered coastlines providing an important link between the land and the sea.

These woody, seed-bearing plants range in size from tall trees to small shrubs and are highly adapted to their salty environment and lack of oxygen that would kill other plants.

The black and white mangroves make use of special roots that grow vertically above the ground like snorkels. These roots allow the tree to absorb oxygen from the air when the ground is completely awash with salt water and the soil is low in oxygen. Black mangroves excrete salt through their leaves and on a dry day it is possible to see the salt crystals on the leaves.

Red mangroves are the best adapted for living in salt water and can usually be found nearest the sea, often actually growing in the water.