Six years ago, the Smithsonian Tropical Research Institute in Panama funded Dr. Dagmar Werner, a German herpetologist, to study the high mortality rate of the green iguanas. Out of this research evolved the Green Iguana Management Project which Dr. Werner continues to direct today. Dr. Werner's research promises to provide an alternative enterprise for small farmers while helping save the threatened lizard and some of Central America's tropical forests.
Through the Green Iguana Management Project Dr. Werner is attempting to increase the population of green iguanas by breeding them in captivity and releasing them in farmer's forests from which some iguanas could be harvested. The task of raising iguanas in captivity was a challenging one which no one believed would be achieved as quickly as Dr. Werner did. She started by collecting pregnant female iguanas, and taking them to a natural iguana nesting site to lay their eggs. She discovered that the labyrinthine nests females dug made retrieving the eggs difficult. Since that experience she has used artificial egg-laying sites from which it is easy to retrieve the eggs. The artificial egg-laying sites consist of concrete or clay drainage tubes which lead to an egg-laying chamber of cinder blocks. After collecting the eggs they are incubated in small cylinders made of screening that rest on top of the ground. These incubators are covered with palm fronds to protect the young iguanas from too much sun, and from rain which could drown the hatchlings.
Hatchlings are contained and protected from snakes in enclosures of tall sheet metal walls. Wire netting strung over the enclosures protects them from opossums and hawks. Trees and thick branches placed in the enclosures provide shade and perches. On the ground, tiny bamboo compartments for lizards to hide in are raised on stilts and set in trays of water to keep out ants. Hatchling iguanas are about the length and thickness of a person's little finger, but in six months they more than double in length. There appear to be many advantages to raising iguanas in captivity. More than one half of Dr. Werner's iguanas reach sexual maturity by the age of two, a year earlier than in the wild. Nearly 100% survive in captivity, a vast improvement over nature, where 95% fall prey to predators in their first two years. The year-old iguanas weigh at least twice as much as their wild counterparts. They are raised on cheap high-protein supplements, fresh-cut leaves, flowers and fruits.
In Panama, feeding stations are placed near release sites to supplement the iguana's wild diet and encourage them to remain close for observation and later harvesting. To date, 8,000 lizards have been released in re-population programs in Central America. The survival rate in natural settings is high.
Farmers can raise iguanas in their fence-rows while reducing erosion by planting "shelterbelts" along field edges. Since iguanas are cold blooded they need both morning and afternoon sun to maintain their metabolism. Narrow strips of trees, instead of a dense forest would provide the iguanas with an optimal amount of sunlight.
Dr. Werner's model for iguana production in fence-rows employs strips of trees containing several rows of trees, stratified according to height. The tallest fastest growing species in the center are occupied by the largest iguanas, while fence post trees planted on the outside rows allow perches for smaller iguanas. Tree nurseries in Cabuya and Chupampa, Panama have been started and members of both communities are learning how to manage the trees for iguana farming. Twenty one farmers in Panama have begun planting shelterbelts for iguana raising. The researchers have identified 60 species of native plants that play some role in the iguana's feeding, resting, and defensive behavior. Iguanas have little use for the widely used introduced tree species. Trial plots of vegetation have been planted in strips 100 m long and 15-20 m wide. Dr. Werner calculates that a farmer could breed 90 six and-a-half pound iguanas a year from one hectare of forest stocked with yearlings. At about 50 cents a pound the small farmer could make a profit of $2.00 an iguana. This income would offset the cost of planting trees and losing that land from traditional crop production.
Werner is working with six Panamanian communities, and is involving others in Costa Rica, Honduras, and Guatemala. Countries that have expressed interest in her program include: El Salvador, Nicaragua, Colombia and Venezuela.
Essential to the success of the project has been community education. Dr. Werner established the Pro Iguana Verde Foundation, to continue the iguana project after Smithsonian funding terminated. The Foundation conducts research and promotes grassroots wildlife conservation.
Now in Costa Rica, Werner continues the captive breeding colony, research station, and conservation education program at La Avellana Wildlife Refuge in the Carara Biological Preserve. Currently, the project is in the preliminary stage of community education. Werner expects to begin releasing juvenile iguanas in January of 1990 in Costa Rica. The plan is to expand the iguana project to one new country in the region each year. The project, Werner concludes, "represents a happy marriage between economic development and wildlife conservation."
For more information contact:
Escuela de Ciencias Ambientales
Heredia, Costa Rica.