Status of Coral Reefs of the World 2000

Status of Coral Reefs of the World: 2000
ANTHROPOGENIC THREATS TO CORAL REEF BIODIVERSITY
A broad spectrum of anthropogenic stresses is causing degradation of the coral reefs
throughout the regions of southern tropical America. It is anticipated that these threats will
probably continue; however, there are insufficient data and direct evidence to
demonstrate clear cause and effect relationships in this region.
Sedimentation
Increased sedimentation appears to be the most damaging stress recorded for all coastal areas
in the region. Negative impacts including losses in coral cover, reproduction and growth were
reported at: Cahuita reef, Caribbean coast of Costa Rica; Golfo Dulce, Pacific side of Costa Rica;
Santa Marta area in the Colombian Caribbean; and Morrocoy Natural Park, Venezuela. However,
the only historical record of sedimentation rates are at the Cahuita site, where sediment
concentrations continue to increase and live coral cover continues to drop. In most areas,
deforestation is the major cause of sedimentation and nutrient pollution increases as logging
and land clearing for agriculture continue in inland forest and mountain areas. Until more
diversified and equitable economic alternatives are found for most all of the countries in this
region, it is anticipated that agriculture and logging threats to reefs will remain unabated.
Sewage Pollution
This is another important source of nutrients which has increased considerably in recent
years due to high population growth rates in the coastal and inland cities, all of which
discharge untreated domestic waste. Sewage pollution poses a major threat to most
coastal ecosystems in the region. While there is anecdotal evidence of negative impacts on
coral reefs, no conclusive studies have been performed.
Resource Extraction and Tourism
Coral and fish exploitation is also a threat to coral reefs in coastal areas from subsistence
and commercial fisheries, as well as tourism-related activities. Continued fishing pressure,
often with the use of damaging extractive methods e.g. dynamite, has resulted in the overexploitation
of the main commercial species throughout the region. Reef tourism has
increased enormously and is becoming a major economic alternative for all countries. For
example, tourists visiting the Abrolhos National Marine Park in Brazil increased over 400%
between 1980s and 1990s, and tourism numbers in Cahuita Natural Park, Costa Rica grew
from 31,000 to 100,000 over the same period. However, tourism has also generated a wide
array of threats, including coral extraction, over-exploitation of fish resources, damage to
coral colonies by swimmers and divers, anchors and boat propeller damage, increased
sewage and garbage, increased sediment loads from construction etc.
Oil Pollution, Mining and Coastal Development
The major impact from oil pollution and mining was observed at Bahía Las Minas along the
Caribbean coast of Panamá, where reefs have been affected since the 1960s and coral
cover has declined to less than 4%. Entire reefs have also been destroyed in the San Blas
region (Caribbean Panamá) during mining for construction and landfill. Coral mining is an
important activity in many Brazilian coastal cities where corals were used to construct
fortresses centuries ago and continue to be mined for modern beach resorts now. Coastal
and riverine developments that have changed river flows and discharges have resulted in
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