The geographic feature known for its unique ecosystem in Madagascar is its biodiversity. Madagascar is renowned for having an extraordinary range of endemic species, including various lemurs, chameleons, and unique flora that are not found anywhere else in the world. This island's long geographic isolation has led to the evolution of unique ecosystems, making it a high-priority area for conservation efforts. The diverse habitats, ranging from rainforests to deserts, support these species and are crucial for maintaining ecological balance within the region.