Researchers warn of extinctions in the tropics

Many of the world’s tropical protected areas are struggling to sustain their biodiversity, according to a study published by an international team of scientists.

Maureen Donnelly, FIU Department of Biology professor and associate dean of the College of Arts & Sciences, is one of more than 200 scientists who contributed to Averting Biodiversity Collapse in Tropical Forest Protected Areas, a study published in Nature earlier this month. The study examines more than 30 different categories of species — from trees and butterflies to primates and large predators — within protected areas across the tropical Americas, Africa and Asia-Pacific. Researchers estimated how these groups had changed in numbers over the past two to three decades, while identifying environmental changes that might threaten the reserves.

William Laurance, lead author and professor at James Cook University in Australia, said their conclusion was that while most reserves were helping to protect their forests, about half were struggling to sustain their original biodiversity. Widespread declines were identified among a wide variety of species. The researchers found that reserves that were suffering most were those that were poorly protected and suffered encroachment from illegal colonists, hunters and loggers.

Donnelly, who has spent more than 30 years studying neotropical amphibians and reptiles in Central and South America, provided data on the decline in the abundance of common amphibians and reptiles in La Selva, Costa Rica.

“Enigmatic declines are mysterious declines that occur for an unknown reason,” Donnelly said. “Most enigmatic declines of amphibians in the tropics have been sudden and drastic because of infection by the chytrid fungus, whereas the La Selva declines were slow and somewhat subtle.  Our results suggest that ‘protection status’ may not be enough to protect biodiversity.”

Deforestation is advancing rapidly in tropical nations and most reserves are losing some or all of their surrounding forest.

The bottom line, the researchers said, is that a better job needs to be done in protecting the protected areas — and that means mitigating both their internal and external threats, and building support for protected areas among local communities. Such efforts will help ensure protected areas are more resilient to future threats including climate change.

“We have no choice,” Laurance said. “Tropical forests are the biologically richest real estate on the planet, and a lot of that biodiversity will vanish without good protected areas.”