The Island Ecosystem of Ambergris Caye

    As we all know, islands are beautiful and fascinating environments. They are home to a great number of species of plants and animals. It is difficult to know what sort of plants and animals existed on Ambergris Caye thousands of years ago, but it's safe to say that some of the species that we see today are not the same as the initial species. Islands are unique ecosystems because they are isolated; thus species have the opportunity to evolve much faster, almost an accelerated form of Natural Selection.

    Likewise, this isolation also makes island ecosystems incredibly susceptible to outside, or introduced species. Ambergris Caye, is an island that is particularly rich because of the presence of the world's second largest barrier reef. This reef, as it turns out, was responsible for the creation of the island, estimated

Reef Brief is a weekly column published in the San Pedro Sun
at 6,100 years ago (Dr. Sal Mazullo).  Many scientists believe that this caye, as well as the Florida Keys, were formed when sand and rock generated when the living reef built up and created land above the water. When the sand and rubble were pressed together under pressure, an island formed. Stability of the island has been maintained with the help of mangroves, which take root in the sediment surrounding the island.

    The ecosystem of Ambergris Caye subsequently evolved in relative isolation. Thus, when new species are introduced, the indigenous (native) plants and animals do not have the appropriate defenses to fend them off. These exotic species encounter an abundance of food and little or no predators, so they thrive and ultimately threaten indigenous species. Ambergris Caye has faced the introduction of many exotic species, including rodents, cats, dogs, green iguanas, and many insects. Most notably, the recent introduction of the Pink Hibiscus Mealy bug has threatened hibiscus plants, as well as other plants, such as the sea grape.

    There is no doubt, however, that the exotic specie that has most significantly impacted the island ecosystem is the human being. Humans are responsible for introducing many of the exotic species in the first place. Hotel establishments, for example, are responsible for introducing new plant species, which often carry diseases or insects to the island. These new species can often lead indigenous species into extinction. The World Conservation Monitoring Center reported that 75% of the 484 recorded animal extinctions since 1600 were island endemic species (species found nowhere else in the world). Of these, introduced species were responsible for 67% of the extinctions.

    Many islands across the world are facing problems resulting in the loss of indigenous species. A small island off of the Pacific Coast of Baja, California is an example of an island that is turning things around. The island experienced a significant loss in seabirds and lizards due to the presence of cats and rats. After eradicating the exotic species with the use of bait traps, as well as educating the community on island conservation, the island population of seabirds and lizards is finally making a comeback.

    The ecosystem of Ambergris Caye is relatively in balance, but we should take heed to the recent introduction of exotic species. Efforts need to be made to control additional exotic species from making this island their home. The Saga Society, for one, is making an effort to control the pet population on the island. We should keep in mind that the island ecosystem is extremely fragile and requires very little to upset its balance.

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