Bats, outnumbered only by rodents in number of species and thus the second largest group of mammals, are a remarkable evolutionary success story. Now they have gotten even more interesting. Researchers of the Leibniz-Institute for Zoo and Wildlife Research in Berlin (Germany) and Boston University (U.S.A.) have discovered a place that harbors the highest number of bat species ever recorded.

In just a few hectares of rainforest in the Amazon basin of eastern Ecuador, they have found more than 100 species of bats.

Dr. Katja Rex and colleagues captured bats at several biodiversity hotspots in the New World tropics, in the lowland rainforest of Costa Rica, the slopes of the Andes and a site in the Amazon rainforest of Eastern Ecuador, at the Tiputini Biodiversity Station located adjacent to the Yasuní Biosphere Reserve.

Anoura geoffroyi pollinating Meriania sp. (Melastomataceae). See this page for a list of bat-pollinated flowers in Ecuadorian cloud forests, with photos and videos of each. Credit: Nathan Muchhala, University of Toronto

During many months of strenuous nightly field work, exposed to rain and mosquitoes, the researchers captured bats, identified species and recorded the total number of each species they captured. Based on these numbers, they calculated the species richness and diversity present in each of these forests.

“The forest at Tiputini Biodiversity Station is known as one of the global biodiversity hotspots with extremely high numbers of plant, insect and bird species” explains Dr. Christian Voigt (IZW, Berlin). “We expected a high number of bat species when we started our study, but we were amazed ourselves by our final estimates. This forest is just super diverse in life forms, including bats.”

Forests of the temperate zone are regionally inhabited by only 3 to 10 bat species which all feed exclusively on insects. In contrast, tropical forests harbour more than 10 times as many species as temperate forests. Now the researchers want to study how so many bat species manage to coexist together in such a small area.

“The forest is like a large city with people of various professions, some are specialised and some are generalists. The ecological role of bats in the forest is quite similar. Among bats we observed dietary specialists and generalists” states Voigt.

The Yasuní Biosphere Reserve and adjacent Tiputini Biodiversity Station are theoretically protected against logging and poaching by Ecuadorian law. However, recently, oil exploitation is threatening the forest since new oil fields were discovered in this region. During the past several years new roads have been constructed to access the newly discovered oil fields.

Conservationists fear that squatters will increasingly settle illegally in this pristine region as soon as the oil companies abandon these sites. This may turn out very badly for forest biodiversity.

Article: K. Rex et al. (2008). Species richness and structure of three phyllostomid bat assemblages. Biological Journal of the Linnean Society, DOI : 10.1111/j.1095-8312.2008.01014.x is published online at http://www3.interscience.wiley.com/journal/119878431/issue