Iguana killings highlight island conservation challenge

Posted: 25 November 2008

The killing of seven rare blue iguanas in Grand Cayman Island earlier this year has drawn attention to the vulnerability of island species as development activity and growing human numbers put more pressure on these fragile ecosystems.

Reporting on the incident, Ben Block, a staff writer for the Worldwatch Institute, said investigators are still unsure why someone would attack the rare blue iguanas. A captured breeding programme has revived the reptile's population, but the rapid growth of the island population has made conservation efforts more difficult.

The killings were a major blow to the recovery of the rare blue iguana, found only on Grand Cayman, a 262-square-kilometre limestone outcropping in the western Caribbean. As few as 10 of the animals existed in 2002, but the breeding programme has since increased the population to about 340.

Blue iguanas
Blue iguanas
Investigators are unsure why someone would attack the rare blue iguanas. A captured breeding programme has revived the reptile's population, but human overpopulation remains a leading threat.
Block says the rising number of human residents is a problem that is challenging the recovery of island species not just in the Caribbean, but around the world.

An influx of immigrants to Grand Cayman, which has among the world's highest living standards, has led population size to jump 32.5 per cent since 2000, according to Caribbean Community Secretariat statistics. In recent decades, the iguanas were nearly driven to extinction with the construction of highways and the expansion of residential areas. As the number of residents continues to grow, these habitat pressures will likely continue.

Writing in World Watch magazine, Block says other island nations are facing similar challenges. Human populations in the Caribbean and Pacific are averaging a 1 per cent annual growth, due in part to persistent high fertility rates and poor access to reproductive health services. On the Marshall Islands, Samoa, and the Solomon Islands in the Pacific, more than 40 per cent of the population is younger than 15 years, according to Secretariat of the Pacific Community statistics.

The land and natural resources required by rising human populations, coupled with the pressures of global climate change and the spread of invasive species, have made island species among the most threatened in the world. Of the 724 recorded animal extinctions over the past 400 years, about half were island species, according to the Convention on Biological Diversity.

Recent conservation drives are beginning to preserve more island territory. Through the Global Island Partnership, a government-led initiative launched in 2006, Micronesia, Grenada, and Jamaica have promised that at least 20 per cent of their terrestrial and marine areas will be protected by 2020.

In Grand Cayman, a new conservation law - debated in the legislative assembly in August - could lay the groundwork for a system of protected areas on the island. Meanwhile, the government has been negotiating an agreement that may set aside shrubland for the blue iguana. "What we need is an area of shrubland large enough to accommodate an estimated 1,000 animals to have a self-sustaining wild population," said Gina Petrie, director of the island's Department of Environment.

As the memory of the iguana attacks continues to resonate in the minds of Grand Cayman residents, support for iguana conservation remains high, Burton said. But he acknowledges that steady population growth leaves him with only a short window of opportunity. "We don't have a lot of time to secure the protected areas," said Fred Burton, director of the recovery programme. "If we lose a couple of years, we'll find the options we're looking at now won't be options anymore."

Source: Worldwatch Institute, Eye on Earth, www.worldwatch.org.