Animals gone wild
It’s true that climate change is speeding the evolution of certain animals, but the longterm forecast looks grim.
Wed, Apr 08 2009 at 1:50 PM
CLIMATE CHANGE AND EVOLUTION: The current positive effects of climate change on species evolution won't last forever. (Photo: Joan MacKenzie/www.pikaworks.com)
Danish badger aggrandizements! Get your masked shrew bigger than you’ve ever seen it! Just take our CO2 supplements and watch the magic begin! Increase whale fertility with greenhouse gases! Larger Alaskan shrews, bird bounties, and more baby whales—the news from the wilderness these days would almost have you believe that global warming is doing wonders for the animal kingdom. But just as sure as those “RX MIRACLE PILLS - BETTER THAN VIAGRA” e-mails sing a false note, the good news about the warming situation will soon turn very dour indeed. It’s true that climate change is speeding the evolution of certain animals, but the long term forecast looks grim.
Shorter winters have helped the Arctic shrew grow bigger. Some birds in Europe are migrating sooner to hatch healthier chicks, and caterpillars are more abundant than ever. And temperature-sensitive species, such as mountain pine beetles, can creep into a widening range of inhabitable areas as mercury rises in higher-altitude forests up the mountains.
Other animals benefit from a warm-weather bounty of food sources. Israeli researchers discovered that their local blackbird has grown in body mass due to the screwy precipitation patterns that have coaxed more earthworms to the surface. Gray whales monitored in the San Francisco Bay area are reportedly birthing more calves, since their krill-hunting runs have grown larger as ice caps melt (although overall, krill is becoming scarcer as the seas heat up).
So what’s to keep an animal admirer from buying into what seem like warming as wonder drug claims? For starters, the nasty side effects. Most of the animals that benefit (certain species of insects, jellyfish, rodents, and caterpillars) are actually invasive species. They’re often called “cosmopolitan species” because they can adapt quickly to their surroundings, and although the nomenclature might evoke martini glass clinks, their evolution heralds anything but a party to the native species and ecosystems they encroach on. Take the innocuously named, filter-feeding sea squirt. Earlier warm seasons mean the squirts arrive earlier at prime rocky attachment areas. This leads to larger squirt colonies, which consequently edge out native mussels and oysters.
Professor Yoram Yom-Tov of Tel Aviv University, who studies how climate change affects evolution, points out that even a non-invasive, native species that has adapted can affect others in its guild (a group of animals that share an environment and food sources). “No conclusive research has been done yet, as one has to examine each guild separately,” says Yom-Tov, “but you can imagine that as small species become bigger, they’ll soon be competing with other species for bigger food items.”
Worse still is the unyielding fact that global warming is more likely to drive animals to their deaths than make their lives cushier. “The majority of the big picture work on climate change shows that there will be a greater rate of extinction,” says WWF Senior Scientist Lara Hansen. Most reports predict that animals that need cooler, secluded habitats will be global warming’s first victims-- the mountain-dwelling, hamster-esque American pika may be first to go.
“We’re working in three areas to help give species like the pika a little extra time,” says Hansen. “First, we need to protect adequate and appropriate space for them to live in. The second area is reducing non-climate stresses, such as habitat degradation and overharvesting, which can negatively interact with climate change, so that they can handle the heat a little longer. The last area we all need to work on is reducing greenhouse gas emissions.” The WWF calls theirs an “adaptive management” approach. Says Hansen, “We don’t have time to try out different techniques, so we have to correct our methods as we go with no regrets.” Scientists say that the pika is just the canary (or rodent, as it were) in the coal mine—in the coming years, they predict that more and more species will suffer as the climate heats up.
With many of nature’s most lovable ambassadors on the line, ignoring the warning signs will leave us with even more regrets than we have pieces of spam in our trash folders.
Story by Alice Shyy. This article originally appeared in "Plenty" in August 2006.
Copyright Environ Press 2006
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