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agroforestry – Land-use systems that combine agriculture and forestry practices to create a more holistic, integrated, profitable and sustainable system of food and fiber production.

alpaca – (Lama pacos) A small-sized relative of the llama. Alpacas stand about 1.5 meters tall and weigh about 50 kilograms. The alpaca is found in the Andes Mountains of Chile, Peru and Bolivia. It has been domesticated for 5,000 years, mainly for its long, fine, silky wool.

Amazonia – The watershed of the Amazon River and its tributaries. Amazonia covers about 40 percent of South America (7,050,000 km²) – half rainforest and the rest savannah ("campo") or scrubby woodland ("cerrado"). Amazonia covers substantial parts of Bolivia, Peru, Guyana, Suriname, Colombia, Ecuador and Venezuela, though most of the Amazon basin lies within Brazil. It is the largest tract of undeveloped forest and greatest single concentration of biodiversity in the world.

amphibians – A group of cold-blooded vertebrates that includes frogs, salamanders and caecilians (wormlike amphibians). They do not possess any scales, feathers, or hair and will often have moist permeable skin making them susceptible to environmental changes; because of this they are considered indicators of ecosystem health. Many species of amphibians can survive both on land and in the water, which is where most lay their eggs. Their larvae go through a developmental process known as metamorphosis, which may be quite complex. As they mature to adulthood they will often move to land. Scientists believe that proto-amphibians were the first vertebrate animals to leave water and become terrestrial.

anoas – Two species of small (150-300 kilograms), endangered relatives of the buffalo found only on the Indonesian island of Sulawesi: the lowland anoa (Bubalus depressicornis) and the mountain anoa (Bubalus quarlesi). They are unusual among buffalo because they rely on undisturbed forest. Anoas live alone or in pairs rather than in herds, except when the cows are about to give birth.

apalis – (Family: Sylviidae) Small (about 10 centimeters) warbler songbirds found in Southern Africa. Apalis eat fruit and insects. Many species are restricted to open grassland and scrub habitat.

aquaculture – The farming of freshwater and marine organisms including fish (such as salmon or tilapia), shrimp, oysters, mussels (and other mollusks), crustaceans, crocodiles, alligators, amphibians and plants. Land-based systems include fish raised in flooded rice fields; aquatic-based systems generally use floating pens to rear juveniles under captive conditions. Concerns with aquaculture include the escape of invasive species, which may spread disease, and pollution from high concentrations of organisms in "fish farms."

aquatic – Growing or living in or upon water.

araucaria – Tall (up to 40 meters) evergreen trees, such as the monkey-puzzle tree of Chile or the Norfolk Island pine, native to Oceania and South America.

arboreal – Living in trees or adapted for living in trees.

armadillo – Cat-sized, armored mammals, found in warm, dry areas of South America. They are related to sloths and anteaters. They dig burrows and dig for insects, although they occasionally eat plants, berries or bird eggs, or scavenge dead animals. Females give birth to identical quadruplets. Unlike other mammals, young develop from the same egg and a single placenta.

atoll – A nearly circular island initially formed by a volcano, which eroded leaving a coral island consisting of a reef surrounding a lagoon.