The Kingdom of Rarities Read Free Page A

or overrun with pigs, rats, or other invasive species—the threatened species that lived in that dot is gone: vanished forever. Rarity then becomes the precursor to extinction or, at least, its preexisting condition. Alternatively, if you save the place, you save the rare species—conservation in black-and-white.
    Our results provided some new insights and a number of surprises. First, despite there being 20,000 species on the IUCN Red List, only 800 species found at 600 sites (some species shared the same site) met our criteria. Second, half of the species limited to a single site turned out to be amphibians. Third, many single-population species were restricted to isolated mountaintops. A botanist on our team, George Schatz, cautioned the vertebrate specialists against any euphoric notion that saving the world’s rarities might be as easy as saving some isolated mountaintops where few people live. “Remember,” he warned, “the 250,000 or so vascular plant species have yet to be evaluated for levels of threat. At least 10 percent of these are known only from the single site where they were first collected.” There is a joke among field biologists that rarity is partly a natural phenomenon and partly the result of some less energetic biologists failing to wander far enough from the road or the fieldstation in surveying their specialty. There may be an ounce of truth to that, but the idea that the populations of many plant species, and the insect species they host, could be so few only reaffirms the important role of rarity, especially in the tropics.
    The next question for our group of biologists was which rare species or place we should try to save first. This exercise drew us to a global map and triggered much debate. “Here.” Mike Parr leaned over northern South America to point out the location of a mother lode of rarities. His pen tip lingered on a massif that stood by itself in northern Colombia, the Sierra Nevada de Santa Marta. The solitary giant sat about 42 kilometers from the Caribbean coast and about 115 kilometers from where the sawtooth eruptions of the northern Andean chain began. Santa Marta in Colombia, like Mounts Kilimanjaro and Udzungwa in Tanzania, Mount Cameroon on the border of Nigeria and Cameroon, and Mount Kinabalu in Sabah, Malaysia, are but a few of the dozens of solitary mountains in the tropical belt that are hotbeds of natural rarities. Why this might be so was one of the questions I wanted to investigate.
    â€œHere is where I want to go next,” I said, pointing to the Zapata Swamp on the island of Cuba. Considered the Cuban version of the Everglades, this freshwater swamp is home to the Cuban crocodile, the Zapata wren, the Zapata rail, and two species of hutia (a guinea pig–like rodent) found nowhere else in Cuba, the Caribbean, or anywhere else. In the same swamp are the only robust populations of several Cuban birds—the Cuban sparrow, Fernandina’s flicker, Gundlach’s hawk, and the blue-headed quail-dove—proving that rarity is not confined to tropical mountains or even rain forests.
    As we populated the map in front of us and delved into the causes of rarity for the 800 species that met our conditions, we saw another insight into rarity confirmed. Some of these species had likely always been rare, such as the 13 frog species sharing the same genus and the same mountaintop in Haiti, the Massif de la Hotte; others on the list had been made rare by human activities. Some species had been much more common during an era whenthe climate was different from what it was during our mapping project—colder, hotter, drier, wetter. They were now climate refugees. Some species had been doing fine at a single site until rats arrived on their island. We realized that we had to consider all the different causes of rarity to better understand which species would be likely to persist without much conservation effort. We needed to know which