In the rugged terrain of the Massif de la Hotte in Haiti, the story of the melastome plant family has been unfolding for more than a million years. However, Andre Naranjo, research assistant professor at FIU warns that biodiversity history could be erased in a matter of decades.
Economic conditions have driven many people to collect wood from Haiti's national forest, and as much as 70 percent of the forest habitat in Pic Macaya National Park on the Massif de la Hotte is gone. The research highlights extreme endemism — the phenomenon where species evolve to be rare, existing in one very specific location and nowhere else on Earth. The mountain range in Haiti is extremely species-rich, with various types of plants tucked in every nook and cranny. Naranjo, who is the curator for FIU's Wertheim Conservatory, calls the mountain range a "Goldilocks Zone" of plants. But with disappearing habitats, Naranjo warns these plants are at risk of completely disappearing within the next 50 years.
Miconieae, a plant group of the melastome family, are represented by about 400 species across the Caribbean; 200 of these are each found on a single island, Hispaniola, and about 150 are found only on Massif de la Hotte. Located at the end of the Tiburon Peninsula, the Massif de la Hotte offers the perfect habitat to survive: trade winds provide a cool, rainy climate that support cloud forest conditions that these plants need to thrive, Naranjo said. In evolutionary terms, the plants evolved into a bunch of different species over a relatively short amount of time — breaking off from their ancestors less than a million years ago.
By building an evolutionary tree using DNA extracted from preserved specimens collected in the 1980s and 90s, Naranjo and a team of scientists revealed a surprising timeline, which he calls a blink-of-an-eye in evolutionary and geological terms for the history of the world.
The diversification of the species occurred during the Pleistocene era — one of the most dramatic cooling events in the earth's history, he said.
At the beginning of the Pleistocene era, the earth shifted to an ice world state, with glaciers coming down continents, sea levels dropping, and the spread of drier climates with less water vapor. The microclimates along the Caribbean mountainsides became the only remaining refuges for the rainfall-dependent plants. The plants are a vital food supply to migratory birds and local pollinators. They also provide ingredients for local folk medicines. Naranjo hopes this latest research will put a spotlight on the dire situation facing Haiti's biodiversity and motivate people to action.
