| | | Defortestation

From WikiVerde

Deforestation and inappropriate land use in watersheds draining to the Caribbean have resulted in significant erosion and sediment loads affecting reefs. Non-point source pollution from pesticides and agricultural runoff, as well as wastewater from growing municipal and industrial development along the coast, are degrading coastal water quality and contributing to eutrophication. Coastal tourism and port expansion have resulted in habitat loss and degradation through conversion of mangroves, dredging of seagrass beds, and siltation of reefs. These interactive and cumulative effects are likely to play an increasing role in the dynamics of reef community structure and their resilience to natural disturbance. Reefs on the Pacific coast are subject to frequent bouts of cold upwelling water, which favour the growth of macroalgae and limit the growth of corals. By contrast, during El Niño years, seawater temperatures can rise to over 30oC and stay high for weeks, resulting in coral bleaching. Coral diversity is very low because these reefs are isolated from the Pacific centres of high diversity by enormous distances, and from the Caribbean side by land that closed the connection between the two seas 3.5 million years ago. The reefs are usually close to land and are heavily impacted by large amounts of sediment runoff because of heavy rainfall. There is also intense bioerosion by burrowing sea-urchins, boring molluscs, and other animals. This erosion is so intense that most of the reefs are decreasing in coral rock content, not increasing like most other reefs in the world. The crown-of-thorns starfish are persistent predators on these reefs and have caused serious damage in the past.