Tropical mountain ranges have more bird species than any other region on earth. One reason for this high diversity is that bird communities change dramatically from the lowlands to the tops of mountains as species drop out and are replaced by others. The proposed research seeks to understand why so many species are restricted to just a portion of the elevation range available on the slopes of tropical mountains. The Manu Road in the Andes of southern Peru was chosen as the study site because it has the highest bird species diversity in the world (>1000 species). The researchers will first seek to determine the range of elevations that each species can potentially occupy based on their ability to tolerate different temperature ranges. Then, for species that do not occupy the entire range of conditions that they can tolerate physiologically, the researchers will study how interactions with other species, such as predators and competitors, may instead determine where species can live.
Tropical mountains have been targeted as the region where climate change will have the greatest impact on plants and animals with small ranges. More than a quarter of the world's endangered bird species are restricted to narrow elevation ranges on tropical mountains. Over the next century, many species of tropical mountains will have to move upslope as temperatures increase. Anything that prevents species from successfully moving to new environments upslope will greatly increase their risk of extinction. Currently, however, almost nothing is known about tolerances of any tropical species to changing temperatures. Species interactions are also likely to affect the extent to which species can move upslope in response to warming temperatures. This research will be the first to provide these data for many different species in a hyper-diverse region. The research team will also interact extensively with local communities, train many students from the US and from Peru, and generate resources such as photo-illustrated bird guides that can be used by the general public.