For decades, scientists have worked to understand the intricacies of biological diversity—from genetic and species diversity to ecological diversity.
As they began to comprehend the depths of diversity across the planet, they noticed an interesting pattern. The number of species increases drastically from the poles to the equator. This phenomenon, known as the latitudinal gradient of species diversity, has helped define the tropics as home to most of the world’s biodiversity. Scientists estimate that tropical forests contain more than half the species on earth, from plants and insects to birds, amphibians, and mammals.
These biologically rich areas are known as biodiversity hotspots. To qualify as a hotspot, a region must have at least 1,500 vascular plants species occurring nowhere else and have 30 percent or less of its original natural vegetation. In other words, it must be both irreplaceable and threatened.
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