Galapagos Islands mangrove forests
Extending along the shores of many islands, one finds forests of mangroves of four species: red, black, white and button. A rich concentration of nutrients and plankton flows in and out with the tides, making mangrove forests important breeding and nursery grounds for fishes and invertebrates. They are also used as nesting sites by many birds.
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 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 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 (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.