To enter the contest, you can find details at the bottom of this post. “But I think it’s really neat to think about how these small animals have important impacts on the ecosystem as well.Welcome back to our Science Odyssey Contest event, where we're posting STEM articles from May 2 to May 17. “We tend to forget about the tiny animals because they’re not as visible as the bigger mammals,” says Koltz. Koltz says that the next step in this line of research would be to identify exactly how the spiders' diets changed. Or it might be that the higher temperature led them to find a different food source. It might be that with higher populations, the spiders shifted from eating springtails to competing with-and eating-each other. Koltz’s paper is that it shows not only is having direct impacts on these important ground dwelling animals but also on the complex ecological interactions between species on the tundra,” Joseph Bowden, an entomologist with the Canadian Forest Service who was not involved with Koltz’s research, says by email.īut it remains unclear why high-density spiders lose their appetite for springtails. The unexpected find has drawn praise from experts. (Also see: How Scientists Taught a Spider to Jump on Demand.) In a way, the spiders are helping to fight climate change in the arctic tundra. Among the hotter plots, the one with more spiders decomposed less than plots with almost no spiders. These larger springtail populations then ate more fungus, which lowered the rate of decomposition. In plots with more spiders, the spiders actually ate fewer springtails. In higher temperatures, decomposition occurs more quickly and wolf spiders are more active, so Koltz expected that when her mini-ecosystems got warmer, their wolf spiders would drastically reduce the springtail population. For two summers, she and her team monitored how temperature and the number of spiders changed the mix of organisms within these hemmed-off patches of permafrost. With all this in mind, Koltz set up some five-foot-wide experimental ecosystems in the Alaskan Arctic. If wolf spiders eat more or fewer springtails, how will the amount of Arctic fungus-and the resulting rate of fungal decomposition-vary? But one of their favorite foods is a fungus-eating arthropod called the springtail. Wolf spiders will eat most insects and spiders smaller than themselves, and they also dabble in cannibalism if their populations get too dense, they’ll eat each other. (Read expert advice on what to do if you find a spider in your home.) A 2009 study showed that a warmer Arctic with earlier springs and longer summers could make wolf spiders both larger and-because larger spiders can produce more offspring-more abundant. Scientists have known for almost a decade that climate change would impact spider populations. “I really felt like the animal element was potentially missing from this story,” she says. Louis, studies not only how a warming climate affects predator-prey relations, but also how changes in those relationships influence the broader ecosystem. Koltz, an Arctic ecologist at Washington University in St. Decomposition releases greenhouse gases like carbon dioxide and methane that further accelerate climate change. The Arctic's heat-up is particularly worrisome because as the region warms, permafrost-a frozen layer of soil and dead things-begins to melt, allowing fungi and bacteria to decompose it. Human activity, especially the release of heat-trapping greenhouse gases, is warming the planet-and the Arctic is getting hotter twice as fast as the rest of Earth. Her study reveals that at increased temperatures and population densities, arctic wolf spiders change their eating habits, starting an ecosystem-wide cascade that could change how quickly melting permafrost decomposes. The eye-popping calculation, published today in PNAS by National Geographic explorer Amanda Koltz, could shape our understanding of how the Arctic will respond to future climate change. The Arctic tundra is teeming with predators, just not the ones you might expect: By biomass, arctic wolf spiders outweigh arctic wolves by at least 80-to-1.
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