Environmental Engineering Reference
In-Depth Information
CHAPTER 10
NOVEL ECOSYSTEMS
After dusk, the forests of the Caribbean island of Puerto Rico fill with the cry of the native frog called
the coqui. “Ko-kee,” the male frogs croak over and over, long into the night. Hence their name. Re-
searchers believe the first half of the call threatens other males, while the second half attracts females.
Whatever, after a few drinks, the local islanders reply: “
Soy de aquí como el coquí
” (I'm as Puerto Ric-
an as a coqui). The common coqui (
Eleutherodactylus coqui
) is the unofficial symbol of the island. It
turns up in folklore and pop songs and appears on T-shirts and coffee mugs. A few decades ago, as the
island's natural forests were replaced by sugar and coffee plantations, naturalists regarded the endemic
inch-long tree frog as being at serious risk. Now the frog is back. But it no longer croaks in the few
surviving scraps of native forest, where it has succumbed to a fungal disease. Most of its song comes
instead from new woodlands dominated by foreign trees, like the African tulip.
The coqui seems happy there, in what ecologists are starting to term “novel ecosystems”—composed
of new combinations of native species and species introduced by humans, but where the system itself
does not depend on humans to keep it going. Is this sacrilege, or is this the future? Is it an ecological ab-
omination doomed to self-destruct, or a model for protecting species and reviving nature in the modern
world?
Puerto Rico has a singular history. When Europeans arrived at the end of the fifteenth century, it
was thinly populated by a native seafaring people called the Taino, and still almost entirely forested.
Spanish colonists changed that, farming sugar in the lowlands and coffee and tobacco in the mountains.
The plantations spread further after the United States wrested control of the island during the Spanish-
American War of 1898. Sugar production peaked in the 1940s, by which time only 6 percent of the
native forests remained. The island's environment was a mess. With the trees gone, it suffered massive
soil erosion, and its rivers clogged with sediment. A series of big hurricanes added to the mayhem. The
coqui and many other species went onto endangered lists. The island's growing human population was
blamed and, fearing a Malthusian apocalypse on the island, US doctors began oral contraception trials
and started sterilizing the island's women.
But another future awaited. Export markets for sugar and other commodities declined. Smallholder
farming also faltered as rural people moved to towns to work in US-owned factories. The island exper-
ienced economic boom but agricultural collapse. The forests began to grow back into abandoned fields.
Between 1959 and 1974, land devoted to agriculture halved while forest cover rose tenfold to 60 percent.
It was “proportionately, the largest event of forest recovery anywhere in the world during the second
half of the twentieth century,” says Thomas Rudel, who studies land use at Rutgers University.
1
But it wasn't the native Caribbean trees that raced to plant their roots in the former sugar fields. Nat-
ive species balked at returning to the infertile, compacted, and sun-baked soils on crumbling hillsides
Search WWH ::
Custom Search