The Great Green Macaw en route to extinction

The great green macaw (Ara ambigua) has a limited distribution in the Atlantic wet lowlands of Central America, from Honduras to northern Colombia, with a small isolated population in Guayaquil, Ecuador. In Costa Rica, this species is currently limited to the Northern Zone, more specifically to the area between the San Carlos, San Juan, and Sarapiquí rivers extending to the northern foothills of the Central Volcanoes Range. It highly depends on the almendro tree (Dipteryx panamensis) both for feeding and nesting substrate. This species is listed in Appendix I of CITES, which means that it is endangered.

The Great Green Macaw Research and Conservation Project, begun in 1994 as a study of the ecology and habitat needs of this species in the Northern Zone, has developed an important biological data base on this species, which in fact represents the only significant information of this type in Central America. The project was started by conservation biologist George V. N. Powell, PhD., who was concerned about the diminishing range of the great green macaw following the increasingly intensive clearing of its forest habitat for cattle grazing and agriculture. The project is currently backed by the Tropical Science Center, which also manages the Monteverde Cloud Forest Biological Preserve. The concerns of the project's founders were supported by the project's first-year findings that the nesting range of these macaws in Costa Rica had already been reduced by 90% since the early Twentieth Century.

Preliminary studies found that the great green macaw's limited distribution and relatively large home range, combined with its dependence on a complex array of food resources, make it a potential "umbrella species," one whose habitat needs incorporate those of many other species. In other words, protecting the habitat and resources used by a resource-demanding species like the macaw will benefit a multitude of other species that reside in these lowland wet forests. Understanding the amount and types of habitats required by these macaws, therefore, is of critical importance to establish conservation priorities in the Northern Zone. The Northern Zone currently lacks a strict protected area and has had the highest deforestation rate in the country over the last two decades, facing both legal and illegal cutting that have left less than 30% of the original forest standing. Nevertheless, several studies underline that the forests in this region still maintain a high species diversity which is among the most diverse in Central America .

In both the reproductive (San Carlos) and non-reproductive (Sarapiquí) zones of the great green macaw, we have observed an alarming decrease in the number of green macaws, the size of their groups, the occupancy of known nest sites, and in the size of the active breeding area. The potential breeding area has decreased as forest in the region has been cleared, and breeding activity has become concentrated in a core zone with a higher density of forest and less human activity.

In the first years of the study, the project estimated the great green macaw population in Costa Rica to be approximately 35 reproductive pairs, a number which now seems optimistic. Scientific literature estimates that to remain viable, the macaw population must consist of at least 50 breeding pairs, even over the short term. A population smaller than this is considered to lack the genetic diversity to maintain itself in the face of environmental or genetic catastrophe. It is assumed, therefore, that the small great green macaw population of Costa Rica depends on the more extensive habitat and presumably larger macaw population in the Indio-Maíz Biological Reserve in Nicaragua. Nevertheless, Costa Rican logging incursions across the San Juan River into the Indio-Maíz are increasingly common, and they emphasize that even this reserve, one of the most important in Central America, is not out of range from the chainsaws. Costa Rica's great green macaw population is already in a precarious and fragile condition, and the loss of remaining forest habitat in northern Costa Rica or southern Nicaragua may push it to regional, if not global, extinction.

The principal cause of the decline of the great green macaw population is uncontrolled deforestation throughout the Northern Zone, which threatens the habitat and resources used by the macaws. It was hoped that the new Forestry Law of 1996 and "pioneer" forest management techniques would aid forest conservation efforts. Unfortunately, this has not happened, and the data collected by the project clearly demonstrate that despite some positive changes in the forestry sector in Costa Rica, the great green macaw continues to disappear from its last remaining breeding area. The management plans that were applied throughout in the area since 1991 seriously altered the floristic and structural composition of natural and already intervened forest.

The survival of the great green macaw depends on the availability of adequate, intact forest habitat. The population of great green macaws in the Northern Zone cannot recuperate or even be sustained if deforestation is not stopped. In view of the highly threatened status of the forests that are the critical habitat of the great green macaw, a conservation plan must be undertaken immediately that will protect sufficient habitat to maintain a minimum viable reproductive population of macaws in Costa Rica.

We therefore propose the following actions for conserving the remaining lowland Atlantic forests:

•  The establishment of Maquenque National Park in the great green macaw's priority breeding area (60,000 ha) proposed by the Executive Committee of the San Juan-La Selva Biological Corridor.

•  The application of a reasonable Environmental Services Payment for the absolute protection of forests outside this park.

To implement these actions, we recommend that cutting of forest in the critical nesting zone of the macaw be restricted or prohibited as well as the harvest of almendro . At the very least, the Environmental Services Payment system must be reformed immediately to assist and encourage private initiatives to conserve remaining forest patches and decrease the wood harvesting rate in the region. To promote sustainable development in the Northern Zone and the conservation of the great green macaw, this system should redirect environmental service payments to those that favor protection of remaining intact forest, allow farm owners to extract non-wood products, including medicinal plants, fruits, and seeds, and support reforestation initiatives with native trees that are both commercially important and benefit the great green macaw.