When the USA built the Panama Canal from 1904 to 1914, the army engineers created a humongous dam and the world’s largest artificial lake (at the time– Lake Mead, held back by the Hoover Dam in Nevada, is now larger). Lake Gatun, as it is known, submerged thousands of miles of tropical rainforests, flooded hundreds of farms, and required the relocation of several indigenous communities.
Sounds pretty bad, doesn’t it? I won’t argue the fact that creating this lake had several negative environmental and social aspects, but it does have some positive aspects for understanding how the natural world functions. Once the water stopped rising, the peaks of several mountains in the area became islands. We call the largest of these man-made islands Barro Colorado.
After the graduate course ended, six of us continued our journey at Barro Colorado Island, which is now a tropical research station run by the Smithsonian. As the huge container ships sail by on their way to the Atlantic or Pacific, hundreds of scientists work year-round on all kinds of interesting questions. We heard talks about ants in the forest canopy, chemicals in leaves that protect them from herbivores, and bats that eat fish (obligatory awesome photos here)!
You may have heard of habitat fragmentation– which is what happens when humans build farms or cities around forests or prairies. Well that’s exactly what happened when we “built” a lake around all these mountain tops and created a bunch of islands. Since Barro Colorado is an artificial island, it allows the scientists there to see what happens when humans isolate natural areas.
Sadly, the number of animals species has decreased on all the islands, ever since the lake formed. Birds that don’t like to fly in open areas (aka over lakes) died off, even on the largest islands, as their populations became small and inbred. The number of big cats seen on the islands decreased, too.
But, the big cats haven’t disappeared. Ocelots still live on Barro Colorado, the biggest island, and a jaguar will even swim over once and while! Also interesting, those freakin’ awesome fishing bats I told you about? They’re doing great on the large and small islands. For them, this type of habitat fragmentation wasn’t so much about isolation as it was about exciting new hunting grounds!
Now, most habitat fragmentation isn’t caused by lakes or water. So understanding how farms or cities impact natural processes and communities is important, too. The team of scientists at the Smithsonian and Barro Colorado is working on this, right on the Panamanian mainland. The Agua Salud project promises a lot of interesting advances– ones that I’ll be happy to follow, and maybe even participate in, in the future.