Fwd: [graffis-l]CORAL FEEF'S AND PROFOUND HUMAN CHANGES

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>Humans Have Caused Profound Changes In Caribbean Coral Reefs

>Posted by: " Mark Graffis " mgraffis mgraffis

>Wed Jan 9, 2008 6:26 pm (PST)

>http://www.terradaily.com/reports/Humans_Have_Caused_Profound_Changes_In_Caribb\

ean_Coral_Reefs_999.html

>

>Humans Have Caused Profound Changes In Caribbean Coral Reefs

>

>Coral reefs in the Caribbean are slowly being degraded due to the

>simultaneous effect of coastal development, which increases fishing and

>pollution, and agricultural land use, which increases agrichemical

>discharges and sedimentation, and lastly ocean warming. Without immediate

>attention of countries in the region, coral reefs may be soon beyond

>repair. Credit: Photos by Humberto Bahena and Henry Wolcott, Mark Defeo,

>Tyler Smith, Steve Spring, Stephen McGowan from Marine Photobank.

>by Staff Writers

>Halifax, Canada (SPX) Jan 09, 2008

>Coral reefs in the Caribbean have suffered significant changes due to the

>proximal effects of a growing human population, reports a study published

>in the Proceedings of the Royal Society of London, B. " It is well

>acknowledged that coral reefs are declining worldwide but the driving

>forces remain hotly debated, " said author Camilo Mora at Dalhousie

>University, Halifax, Canada.

> " In the Caribbean alone, these losses are endangering a large number of

>species, from corals to sharks, and jeopardizing over 4 billion dollars in

>services worth from fisheries, tourism and coastal protection, " he added.

>

> " The continuing degradation of coral reefs may be soon beyond repair, if

>threats are not identified and rapidly controlled, " Mora said. " This new

>study moves from the traditional localized study of threats to a

>region-wide scale, while simultaneously analyzing contrasting

>socioeconomic and environmental variables, " he added.

>

>The study monitored coral reefs, including corals, fishes and macroalgae,

>in 322 sites across 13 countries throughout the Caribbean. The study was

>complemented with a comprehensive set of socioeconomic databases on human

>population density, coastal development, agricultural land use and

>environmental and ecological databases, which included temperature,

>hurricanes, productivity, coral diseases and richness of corals. The data

>were analyzed with robust statistical approaches to reveal the causes of

>coral reef degradation in that region.

>

>The study showed clearly that the number of people living in close

>proximity to coral reefs is the main driver of the mortality of corals,

>loss of fish biomass and increases in macroalgae abundance. A comparative

>analysis of different human impacts revealed that coastal development,

>which increases the amount of sewage and fishing pressure (by facilitating

>the storage and export of fishing products) was mainly responsible for the

>mortality of corals and loss of fish biomass.

>

>Additionally, the area of cultivated land (a likely surrogate for

>agrochemical discharges to coral reefs) was the main driver of increases

>in macroalgae. Coral mortality was further accelerated by warmer temperatures.

>

> " The human expansion in coastal areas inevitably poses severe risks to the

>maintenance of complex ecosystems such as coral reefs, " Mora said. " On one

>hand, coral reefs are maintained due to intricate ecological interactions

>among groups of organisms. For instance, predators prey upon herbivorous,

>herbivores graze on macroalgae, and macroalgae and corals interact for

>their use of hard substrata.

>

> " Given the intensity of these interactions the effects of a threat in

>anyone group may escalate to the entire ecosystem. On the other hand, the

>array of human stressors arising from changes in land use, exploitation of

>natural resources and increases in ocean temperature (and perhaps

>acidification) due to an increasing demand for energy, are significantly

>affecting all major groups of coral reef organisms.

>

> " The simultaneous effect of human threats on coral reef organisms and the

>potential escalation of their effects to the entire ecosystem highlight

>the critical situation of coral reefs and the need to adopt an

>ecosystem-based approach for conservation and an integrated control of

>multiple human stressors, " he added.

>

>The study also showed that the effective compliance of fishing regulations

>inside Marine Protected Areas (MPAs) has been successful in protecting

>fish populations. But coral mortality and macroalgae abundance showed no

>response to the presence of MPAs.

>

>That was explained by the general failure of MPAs in the Caribbean to

>account for threats such as land runoffs and ocean warming.

> " Unfortunately, the degradation of the coral reef matrix inside MPAs may,

>in the long term, defeat their positive effect on fish populations, " Mora

>said. " This further highlights the need for a holistic control of human

>stressors, " he added.

>

> " The future of coral reefs in the Caribbean and the services they provide

>to a growing human population depend on how soon countries in the region

>become seriously committed to regulating human threats " , Mora said.

>

> " Although coral reefs will experience benefits of controlling fishing,

>agricultural expansion, sewage or ocean warming, it is clear that

>underlying all these threats is the human population. The expected

>increase of the world's human population from 6 billion today to 9 billion

>for the year 2050 suggests that coral reefs are likely to witness a

>significant ecological crisis in the coming half century if effective

>conservation strategies, including policies on population planning, are

>not implemented soon, " he added.

 

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