Flooding in Piazza San Marco, Venice
Venice is sinking, and the nearby Adriatic sea—like the global sea level—is rising. The city could, some estimates suggest, be underwater by the end of the century. Much of the trouble is due to Venice’s precarious, low-lying position in the middle of a lagoon, but human activity in the area has played a role in the city’s subsidence, as well. As Scott K. Johnson explains at Ars Technica:
The pumping of shallow groundwater in the mid-1900s also contributed to the problem. Water in the pores between grains of sediment provides pressure that bears some of the load. When pore pressure decreases, or water is removed completely, grains can be packed together more tightly by collapsing the pore spaces. As sediment is compacted, the land surface drops. While the effect was small (less than 15cm), Venice doesn’t have much wiggle room.
Above, the real deal; below, the clay models used to test predators’ reactions to local and foreign frog markings.
Sometimes, you have to make a thousand frogs from modelling clay to make your point.
A single species of poison dart frog sports ten completely different coloration patterns, depending on where they live. Are these color divisions being encouraged by the birds that prey on them?, wondered evolutionary biologist Mathieu Chouteau from the University of Montreal. To find out, he set out 1800 clay frogs, made by himself and his (saintly!) girlfriend, in the Peruvian forest.
Enormous stone statues, called moai, on Easter Island
What’s the News: Easter Island is often held up as an example of what can happen when human profligacy and population outpace ecology: Wanton deforestation led to soil erosion and famine, the story goes, and the islanders’ society declined into chaos and cannibalism. But through their research on Easter Island, paleoecologists Terry Hunt and Carl Lipo have unearthed evidence that contradicts this version of events. The Polynesian settlers of Easter Island prospered through careful use of the scant available resources, they argue in their new book The Statues That Walked; the island’s forests were done in not by greedy humans, but by hungry rats.
What’s the News: The loss of large animals is wreaking havoc on Earth’s ecosystems, according to a scientific review published in Science on Friday, causing food chains to fall into disarray, clearing the way for invasive species, and even triggering the transmission of infectious diseases. The decline and disappearance of these large animals, due in large part to human factors such as hunting and habitat loss, has such strong and wide-ranging effects that the review’s authors say it may well be “humankind’s most pervasive influence on nature.”
In the realm of meteorology, bats, birds, and insects are usually considered “animalas non grata,” since they create unwanted noise in the Doppler radar readouts used to study storms. But now, thanks to better radar station networking and the sharing of unfiltered data, ecologists have realized that these radar systems can be used as powerful animal tracking tools.
At last week’s American Association for the Advancement of Science meeting, researchers Thomas Kunz, Winifred Frick, and Phillip Chilson explained how Dopplar data can be used by ecologists. They call their new discipline aeroecology.
This melding of meteorology and ecology started with an “Aha!” moment:
“Dr Kunz and I were meeting Dr Chilson about a year ago over breakfast and they kept talking about the ‘QPE’, and finally I asked what it is,” Dr Frick told the meeting. It stands for quantitative precipitation estimator — a numerical method to measure how much rain there is in a storm front. “I paused and said, ‘you can estimate the number of raindrops in a raincloud? Do you think we could estimate the number of bats in a bat cloud?'” To calibrate their experiment, the team took a bat into a chamber where the degree to which it reflects radio waves could be measured. “From those measurements and using radar, we’ve been able to adapt those QPE measurements to a ‘QBE’ – a quantitative bat estimator,” Dr Frick said. [BBC News]