Sunday, August 11, 2013

Hot: Biodiversity and climate from historical documents

I found another example of sustainbility in unexpected places among the stories I included in last night's Overnight News Digest: Science Saturday (Atlantic Hurricane Season forecast) on Daily Kos.  Both involved scientists examining unorthodox documentary sources to determine the history of biodiversity in two parts of the world.  First, Virginia Gewin of Nature explained how Ancient art fills in Egypt's ecological history.
Mammal populations shrank during three abrupt climate shifts over the past 6,000 years.

Ancient Egyptian rock inscriptions and cavings on pharaonic tombs chronicle hartebeest and oryx — horned beasts that thrived in the region more than 6,000 years ago. Researchers have now shown that those mammal populations became unstable in concert with significant shifts in Egypt’s climate.

The finding is based on a fresh interpretation of an archaeological and palaeontological record of ancient Egyptian mammals pieced together more than a decade ago by the zoologist Dale Osborn. Thirty-eight large-bodied mammals existed in Egypt roughly six millennia ago, compared to just eight species today.

“There are interesting stories buried in the data — at the congruence of the artistic and written record,” says Justin Yeakel, an ecologist at Simon Fraser University in Vancouver, British Columbia, who presented the research this week at the annual meeting of the Ecological Society of America in Minneapolis, Minnesota. For example, the philosopher Aristotle said 2,300 years ago that lions were present, though rare, in Greece; shortly thereafter, the beasts appeared in the local art record for the last time, Yeakel says.

Overlaying records of climate and species occurrences over time, his team found that three dramatic declines in Egypt’s ratio of predators to prey coincided with abrupt climate shifts to more arid conditions. The timing of these aridification events also corresponds to major shifts in human populations at the end of the African Humid Period, about 5,500 years ago; during the Akkadian collapse, about 4,140 years ago in what is now Iraq; and about 3,100 years ago, when the Ugaritic civilization collapsed in what is now Syria.
One of the points I make to my students every semester is that humans plus climate change equal extinctions.  This article supports that point.

The other article examined more recent events on the other side of the planet, as Christopher Joyce of NPR described how Old Hawaiian Menus Tell Story Of Local Fish And Their Demise
In the early to mid-1900s, the islands of Hawaii were a far-away, exotic destination. People who managed to get there often kept mementos of that journey including kitschy menus from Hawaiian fine dining restaurants and hotels like like Trader Vic's and Prince Kuhio's.

Now these old menus are serving a purpose beyond colorful relics from the past.  Kyle Van Houtan, an ecologist with the National Oceanic and Atmospheric Administration, says he's found a scientific purpose for the menus.

Years ago, he traveled to Hawaii to study sea turtles. He wanted to know where they ended up. In a shark's belly? Or as turtle soup?

One day he got one of those lightning-bolt ideas: Maybe turtle would show on old restaurant menus? Over time, he collected 500 menus.
Turtles didn't show up on the menus, which went back as far as 1915.  However, he detected a shift from near-shore fish like snapper, flounder, and grouper before World War II to open-ocean fish like tuna and swordfish, along with lobster flown in from the east coast of the mainland.  His interpretation was that overfishing or pollution was affecting the selection on the menus as much or more than changing tastes of both the islanders and tourists.

Both articles demonstrate that one should look at all available sources of information, even the unexpected ones.  One never knows what will come in handy!

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