Common Properties and Mangrove Deforestation



Common properties and mangrove deforestation

Introduction

The mangrove is a unique and irreplaceable ecosystem, home to incredible biodiversity and to account between one of the most productive in the world. It is home to a variety of life, migratory birds, sea creatures and reptiles plus associated plant species. Mangroves also protect the coast from erosion caused by hurricanes periodically afflict these tropics for centuries have provided many resources to local populations. Common uses of mangrove ecosystems are fuel wood extraction, housing materials and, most importantly, fishing and seafood harvesting, among them have many crustaceans. The extent to which human impacts are mediated through abiotic and biotic factors is related to disturbance type and has important implications for ecosystem management. Removal of dominant mangroves changes biotic and abiotic processes inshore and may lead to an increased supply of algal spores from cleared mangrove areas. This may promote overgrowth on inshore tropical coastal habitats such as coral reefs and sea grass beds by fast-growing algae and cyan bacteria compounding increased reef sedimentation and reduced habitat for juvenile reef species. The relative importance of biotic versus abiotic mechanisms in ecosystem processes can be strongly controlled by such disturbances (Curran, 2002).

However, this conceptual information has not been sufficiently applied in mangrove systems to assess mechanisms by which human disturbance affects community structure and the implications for management, conservation and restoration of impacted systems. Management and restoration strategies are dependent on whether the species removed is a keystone or dominant species and the resulting direct and indirect effects on both biotic and abiotic factors. For example, successful restoration of forest understory following clear cutting, recovery of coral cover on reefs overgrown by macro algae, or re-establishment of predatory fish upstream of human-made barriers requires an understanding of how the type of human disturbance contributes to shifts in ecosystem functioning. Removal of a keystone species has a direct biological effect on other species, which, in turn, indirectly affects physical characteristics such as space. For example, removal of the sea star Pisaster ochraceus from the rocky intertidal zone caused an increase in abundance of the mussel Mytilus californianus (a biotic effect) leading to an indirect effect of space reduction (a physical/abiotic effect). On the other hand, removal of a dominant such as an ecosystem engineer (organism that modifies its own habitat) or a structure-creating species has a direct physical effect on its habitat, leading to an indirect biological effect on other species in the community (Adams, 2009).

For example, clear cutting a forest precipitates physical changes (light, temperature, nutrient shifts) that affect which early succession species colonize that area (a biological consequence). Identifying the type of human disturbance and the category or guild of species affected is important to understanding the cascading effects that will result. Tropical coastal marine ecosystems including mangrove forests are severely threatened by anthropogenic alteration. These disturbances include cutting and clearing swaths of mangroves for lumber, clearing and filling mangrove areas. Mangroves also serve as nursery grounds for juvenile reef ...