1.6 million years ago, a bird's flight over Haiti's Massif de la Hotte mountains sparked an evolutionary wonderland. This mountain range, nestled in southwestern Haiti, is a hidden gem of plant diversity. A study in the Botanical Journal of the Linnean Society has revealed that this region is a hotbed of unique plant species, and it also uncovered the flight paths of birds that initiated this evolutionary boom. The Caribbean islands are recognized as one of the world's 36 biodiversity hotspots, and within this, Hispaniola (the island encompassing Haiti and the Dominican Republic) boasts a third of its plant species as endemic, meaning they are found nowhere else on Earth. The Massif de la Hotte mountains, in particular, are home to an unusually high concentration of these endemic species, making it a biodiversity hotspot within a hotspot. So, what's the secret behind this small mountain chain's remarkable plant diversity? The answer lies in the study of melastomes, tropical plants with seeds primarily dispersed by birds. Hispaniola is home to 130 endemic species of melastome, and by analyzing their DNA alongside historical data, researchers created a family tree illustrating the evolution of these species over time. Many of the ancestors of today's melastomes originated from Cuba, and millions of years ago, they were carried to the Massif de la Hotte by birds that ate their fruits. These birds then flew to Haiti, and the seeds, excreted in their droppings, sprouted and diversified into new species over time. This process occurred at least 19 times, with one instance resulting in the evolution of 18 new species from a single original species. The study not only sheds light on plant biodiversity but also reveals the ancestral flight paths of these birds, which traveled over 100 kilometers. However, climate change and deforestation now threaten the plants of the Massif de la Hotte. Most of the melastomes there thrive at elevations above a kilometer, and as the world warms, they find themselves between a rock and an empty sky. The team behind the study hopes their findings will contribute to the conservation of these unique plants. So, the next time you think of Haiti, remember the hidden gem of plant diversity nestled in its Massif de la Hotte mountains, and the birds that helped create it.
