In 1990, the number of nests dropped to about 1,000. While some birds such as hawks, green herons, and anhingas are less sensitive to drought than other species, much ecologically specialized wildlife has died or been forced out of the region. In Everglades National Park, the alligator population has dropped from 50,000 to 10,000 in the last two years. Since the 1960s nesting wood storks have dropped 80 percent in the Everglades. Some scientists believe the bird is an indicator species that heralds the decline of other wading birds.
Brazilian pepper is a major problem.
Far worse is the melaleuca tree, particularly east of the levees enclosing the Water Conservation Areas. Introduced in an early attempt to dry out the region, the trees consume so much water that they can dry entire swamps. Unfortunately, by the time the importance of preserving the system's natural water flows and habitats was recognized, the melaleuca was firmly established. It deprives native plants of habitat because it grows so densely that no other vegetation can compete, and wildlife can find little food. Everglades National Park is still largely melaleuca-free because a buffer zone has been established around the park, and young melaleucas are removed as they appear.