Galapagos Islands Mangroves

Galapagos Expert

Mangroves

Mangrove Swamps consist of a variety of salt-tolerant trees and shrubs that thrive in shallow and muddy saltwater or brackish waters. Mangroves can easily be identified by their root system. These roots have been specially adapted to their conditions by extending above the water. Vertical branches, pheumatophores, act as aerating organs filtering the salt out and allowing the leaves to receive fresh water.

Mangroves are thought to have originated in the Far East then over millions of years the plants and seeds floated west across the ocean to the Galapagos Islands. Mangroves live within specific zones in their ecosystem. Depending on the species they occur along the shoreline, in sheltered bays, and others are found further inland in estuaries. Mangroves also vary in height depending on species and environment. The Galapagos is home to 4 types of Mangroves:

Black Mangroves

Black Mangrove (Avicennia germinans) has the highest salt tolerant leaves of all the mangroves the leaves and is equipped with special salt-extracting glands. Trees grow to 65 ft (20 m) in height; the long spreading branches are covered by a dark brown bark. Leaves grow in pairs, leathery in texture with a narrow oval shape. The top leaf is dark green and the bottom is pale with hairs often coated with salt. The trees' yellow flowers grow in clusters developing into a green lima bean shaped fruit. Black mangroves have a carpet of short aerial roots or pneumatophores surrounding the base of the tree.

Red Mangroves

Red Mangrove (Rhizophora mangle) is the most common in the Galapagos named for its reddish wood. This species is used around the world as a source of charcoal and tannins for leather working. Trees grow to 72 ft (22 m) in height, yet red mangroves also can be seen as small bushes. The thick leathery leaves grow in pairs with a dark green leaf above and pale yellow leaf below. Red mangroves have yellow flowers that grow in groups of 2 or 3. Red mangroves can be seen growing near the low tide zone as well as at higher elevations mixed with other mangrove species.

Button Mangrove or Buttonwood

Button Mangrove or Buttonwood (Conocarpus erecta) is not a true mangrove, yet this tree usually found in the higher mangrove elevations. They have dark gray bark and leaves which are either oval, leathery and smooth green or sharply pointed with salt glands at the base. Buttons have green flowers that mature into a round purple fruit.

White Mangrove

White Mangrove (Laguncularia racemosa) grows into a shrub with aerial roots close to the water. They thrive in areas with infrequent tidal flooding. Leaves are smooth, oblong and light green in color with notched tips.

The Importance of Mangroves in the Eco-System

Mangroves are a unique part of the coastal ecosystem. The fallen leaves and branches from the mangroves provide nutrients that support a variety of sea life. The shallow waters within the Mangrove swamp provide a nursery for young fish, crabs, shrimps, mollusks and rays. Mangroves provide a nesting area for hundreds of bird species. In the Galapagos Mangrove Finch, Medium Ground Finch, Dark-Billed Cocos, Herons, Yellow Warblers, Mockingbirds and Small Ground Finch all can be found in the Mangroves.

Mangroves help protect the coastline from erosion, storm damage and wave action. They prevent shoreline erosion by acting as buffers, catching the soils and other materials that run off the land and stabilizing the soils and nutrients lost from erosion.

Threats to Mangroves

Resistant by nature, mangroves have withstood natural disasters for millions of years, now this valuable ecosystem is among the most threatened habitats in the world. Until recently these areas were considered useless wastelands making it easy for exploitation. The rapidly growing shrimp industry has been the biggest threat to the mangroves. Forests have been clear-cut in order to provide a cheap source of land and water for shrimp farmers. The dense forests are destroyed to make room for artificial shrimp ponds. Globally 50% of the mangrove forests have been destroyed due to clear cutting for shrimp farms. On the mainland of Ecuador between 20-50% of the mangrove forests have been demolished. Northwest region of Ecuador alone lost nearly 90% of its Mangroves.

Protecting Mangrove Forests

Protecting the mangrove forests requires educating the consumers in the wealthy nations that import these luxury shrimp products. Reducing the demand for pond-raised shrimp reduces the pressure on the mangroves. Stricter government laws and enforcement in protecting mangroves is also an important factor. Education at the local level as to the importance of preserving these swamps in order to maintain the coastal environment is essential.