Over-harvesting
Mangrove trees the world over are used for firewood charcoal production as well as for construction wood and wood chips. While harvesting is a practice that has been ongoing for hundreds of years, it has got out of hand in recent times.
In some instances, faced with limited alternatives, if any, people in certain poor communities, such as St Thomas here in Jamaica, increasingly rely on mangroves for charcoal production, for example. The result is over-harvesting, which threatens the survivability of mangrove forests.
River changes
Dams and irrigation cause a reduction in the quantity of water that gets to mangrove forests, thus changing the salinity (salt) level of the water in the forests. Where salinity levels become too high, the mangroves die. Freshwater diversions may also threaten the survival of mangroves.
Erosion, which is caused by deforestation of land, may also deplete mangrove forests. This is so since deforestation increases sediment in rivers, which can undermine the mangroves' filtering ability.
Clearing
This involves