Belize has the lowest population density of any Central American country and one of the lowest in the world. Belize's low population density and very high retention and protection of natural areas means that most of Belize's terrestrial plant and animal species are relatively secure.

However, some iconic bird species are now very rare including the scarlet macaw and harpy eagle, and a few amphibians have declined due to emerging pathogens and perhaps other causes. Large mammals including the jaguar and Baird's tapir are suffering from increasing habitat fragmentation and rural development. The black howler monkey has declined in many areas and efforts are being made for its protection and rehabitation in the Sartenejan Region.

Sustainability America is focussing on some animals found in the Sartenejan region; tarantulas, Baird's tapir, amphibians, reptiles, and land snails

Although well protected by fishing exclusion areas and protected areas the marine environment of Belize is largely threatened by the decline of the Belizean coral reef as part of the general decline of the Caribbean ecosystem.