TDA-IME Project Final Report June, 2013 the mud surface. Storks, pelicans, ospreys and cormorants feed on large fish and may roost or breed in mangroves. Passerines like warblers, woodpeckers and flycatchers depend on the invertebrate fauna associated with mangrove trees for food. Mangroves are also the nesting sites for a number of threatened bird species, for example spoonbills (Ajala ajala) and the milky stork (Mycteria cinerea). Few mammals are characteristic of mangrove habitats, but they include flagship species like the mangrove-adapted proboscis monkey in Borneo and the Bengal tiger, a top predator now restricted entirely to the Sundarbans mangrove forest. Most other mammal species occur in adjacent habitats, as well as mangroves; for example antelopes, deer, wild pigs and rodents. Monkeys are common in mangroves, where they feed as omnivores or herbivores. Macaques (Macaca spp.) forage on the mud for crabs and bivalve molluscs. They can also be a major pest in mangrove plantations because they have a tendency to uproot Rhizophora propagules (Gan, 1995), or feed on young Rhizophora prop roots. In contrast, langurs (Presbytis spp.) feed mainly on mangrove leaves and fruits. Bats are attracted to the abundance of insects, fruit and nectar in mangrove forests. Many species of insectivorous bats (Microchiroptera) consume considerable quantities of insects. In Peninsular Malaysia the long-tongued fruit bat (Macroglossus minimus) and the cave fruit bat (Eonycteris spelaea) feed on Sonneratia nectar and pollen and are major pollinators of Sonneratia flowers. Macroglossus has a strong association with Sonneratia trees and has never been recorded away from mangrove areas. Two species of otters are also common in the mangroves of Indochina; they are well adapted to the intertidal zone, being able to feed on fish, crabs and molluscs (Sivasothi and Nor, 1994). The above examples of mangrove-associated mammals demonstrate the interconnectivity between mangroves and other terrestrial habitats utilized by these same species. Domestic animals also graze in some mangrove areas, e.g. cattle, camels and goats in India, and cows in Viet Nam. Livestock can consume large quantities of mangrove foliage and thereby have a significant impact as degraders of mangrove forests. A number of animals that depend on mangrove ecosystems are at risk and have been recognized in the IUCN Red List of Threatened Species (Table 9). Habitat loss through conversion and human encroachment is a primary cause of their decline. These impacts on wildlife are likely to continue and increase as human populations expand. Protection of mangrove-dependent animals requires effective management of the entire mangrove habitat, especially critical areas like nesting or roosting sites for birds. Migratory species in particular, and those that require large territories, do not stay within borders, which is why transboundary protected areas may be essential for conserving some species. The most notable example is the Sundarbans mangroves shared by India and Bangladesh, which is vital for the future survival of the Bengal tiger. The particular challenges associated with aquatic migratory species, especially dolphins, are described in below. Migratory Species Mammals It is obvious that transboundary mangrove management is particularly relevant to migratory animal species, which include various taxa, from birds to mammals, fish and crustaceans. Dugongs and cetaceans are entirely aquatic mammals found in mangrove creeks and rivers. Dolphins, porpoises and whales visit mangroves periodically, including the Irrawaddy dolphin (Orcaella brevirostris). Although more remains unknown than known about this species (Maxwell and Lai, 2012), several reports indicate that it has an ecological tolerance for fresh water, as well as estuarine/mangrove and marine environments (e.g. Kreb et al. 2010). The presence of the Ganges River dolphin (Platanista gangetica) in the Sundarbans mangroves, 40
Transboundary Diagnostic Analysis of Indochina Mangrove Ecosystems
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