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Bats Use Water Ripples to Hunt Frogs

AUSTIN, Texas — As the male túngara frog serenades female frogs from a pond, he creates watery ripples that make him easier to target by rivals and predators such as bats, according to researchers from The University of Texas at Austin, the Smithsonian Tropical Research Institute (STRI), Leiden University and Salisbury University.

A túngara frog will stop calling if it sees a bat overhead, but ripples continue moving for several seconds after the call ceases. In the study, published this week in the journal Science, researchers found evidence that bats use echolocation — a natural form of sonar — to detect these ripples and home in on a frog. The discovery sheds light on an ongoing evolutionary arms race between frogs and bats. (more…)

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Tropical forest carbon absorption may hinge on an odd couple

A unique housing arrangement between a specific group of tree species and a carbo-loading bacteria may determine how well tropical forests can absorb carbon dioxide from the atmosphere, according to a Princeton University-based study. The findings suggest that the role of tropical forests in offsetting the atmospheric buildup of carbon from fossil fuels depends on tree diversity, particularly in forests recovering from exploitation.

Tropical forests thrive on natural nitrogen fertilizer pumped into the soil by trees in the legume family, a diverse group that includes beans and peas, the researchers report in the journal Nature. The researchers studied second-growth forests in Panama that had been used for agriculture five to 300 years ago. The presence of legume trees ensured rapid forest growth in the first 12 years of recovery and thus a substantial carbon “sink,” or carbon-storage capacity. Tracts of land that were pasture only 12 years before had already accumulated as much as 40 percent of the carbon found in fully mature forests. Legumes contributed more than half of the nitrogen needed to make that happen, the researchers reported. (more…)

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Earth’s Highest Coastal Mountain on the Move

The rocks of Colombia’s Sierra Nevada de Santa Marta—the highest coastal mountain on Earth—tell a fascinating tale: The mountain collides and then separates from former super-continents. Volcanoes are born and die. The mountain travels from Peru to northern Colombia and finally rotates in a clockwise direction to open up an entirely new geological basin. Smithsonian scientists were part of a four-year project to study Santa Marta’s geological evolution. Their findings are published in the October 2010 special issue of the Journal of South American Earth Sciences.

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1200 Howler Monkeys on Panama’s Barro Colorado Island

The fifth Howler Monkey census at the Smithsonian’s Barro Colorado Island research station in Panama, organized by Katie Milton, professor in the department of Environmental Science, Policy & Management at the University of California, Berkeley, revealed that monkey numbers have not changed significantly since the first census 33 years ago.

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