Some ecophysiological aspects of primary production by mangroves in North Queensland

Introduction: Mangroves are trees or shrubs which grow in the intertidal zone along protected coasts in warmer parts of the world. They are widespread throughout the Indo-Pacific region, where they are thought to have evolved, and also occur extensively in Africa, the Caribbean, the Gulf of Mexico, and in the South American tropics. In Australia, mangroves form a discontinuous coastal fringe extending from the tropical northern coastline rich in species diversity, to as far south as Corner Inlet (38o 45’ S, 46 o9’E) on the temperate southern coastline of Victoria, where only Avicennia marina occurs. At the present time 36 species of mangrove representing 22 genera and 20 families, have been recorded from Australia (N.C. Duke, personal communication). The total area of mangroves in Australia is estimated to be 11,500km², of which about 97% is found north of the Tropic of Capricorn (Galloway, 1981). Mangroves traditionally have been used in many countries for timber, firewood and other products. Only in the last decade or so have mangroves also become appreciated for the role they play as a nursery and habitat for a wide variety of organisms, including many species of prawn and fish of commercial value. For these organisms, mangroves provide a source of reduced carbon in the form of leaves, wood and other debris which falls from the trees and contributes to detritus-based food chains in bays and estuaries.