The population of honeybees in the United States dropped by about 25 percent in the 1990s—a statistic that might not seem alarming until one considers that honeybees are the chief pollinators of commercial farms and frequent visitors to home gardens as well. Their demise highlights the threat to animal pollinators in general. The populations of hundreds of pollinators are now dwindling—owing to habitat loss, fragmentation of wilderness areas, the widespread use of pesticides and other chemical toxins, plus the emergence of parasites (such as two mites now ravaging U.S. honeybee colonies)—and these are just the species we know about. As these creatures become scarce, the plants that rely on them may also suffer. In her influential 1962 book, the biologist Rachel Carson warned of "silent springs and fruitless falls," and little has transpired in recent decades to allay those concerns.
In addition to hurting crop yields, the decline of pollinators can have a ripple effect throughout an ecosystem. As pollinators disappear, along with the plants they once sustained, animals that feed on the pollinators or plants may starve. Animals that feed on these animals, in turn, may also become endangered. The loss of a single pollinator, which may have previously attracted little notice, can have widespread consequences for an ecosystem.
The health of the rainforest canopy on Pacific islands such as Samoa and Guam rests largely in the hands, or wings, of giant bats called flying foxes. The bats pollinate about 60 percent of the trees that comprise the canopy and also eat flowers from rainforest vines that would otherwise attract pests, prompting one botanist to call them "the biological glue that holds the ecosystem together."
While most people are focused on "charismatic megafauna, the lions and tigers and bears," says University of Arizona entomologist Stephen Buchmann, "the little things that run the world, including bees, butterflies, bats, and hummingbirds, go unnoticed and unprotected until it is sometimes too late."
More than 80 percent of the world's 250,000 flowering plants depend on animal pollinators, and roughly 15 to 30 percent of the food eaten throughout the world comes from plants pollinated by these creatures.