By Kathleen Berger
Spiders have a reputation for making some people’s skin crawl. Ecologist Amanda Koltz said she didn’t like spiders when she was a child, but she has a whole new outlook as a postdoctoral research associate at Washington University in St. Louis. Koltz now works closely with wolf spiders in the Arctic.
Koltz has a special interest in global warming. She said, “I’m interested in how climate change, and other forms of disturbance, is altering interactions between organisms. Arthropods seemed like a natural way to go because arthropods, insects and spiders, respond very rapidly to changes in temperature.”
Koltz chose to study Arctic wolf spiders because they are abundant in the Alaskan Arctic. In the tundra, wolf spiders outweigh gray wolves by several orders of magnitude. They are also fierce hunters making them one of the most important predators in the tundra.
“Wolf spiders, just like humans and other animals, respond to changes in their environment, but they also can alter their environment,” Koltz said.
Through her research, Koltz and her team discovered that Arctic wolf spiders may buffer some of the effects of global warming by helping to ‘keep it cool’. The field research is taking place at the Toolik Field Station in Northern Alaska.
The spider’s role with decomposition rates is a big part of the findings. Decomposition of dead plant matter in the Arctic contributes to global warming. Wolf spiders may play a role decreasing decomposition rates in a warming climate. It has to do with the spider’s diet. As the Arctic warms, research shows wolf spiders may dine differently initiating a cascade of food web interactions that could potentially alleviate some impacts of global warming.
Koltz and her team are manipulating the temperatures of some spider plots to show what may happen with global warming. Under warming conditions, the wolf spider’s tastes shifted away from collembola, or springtails, triggering a chain reaction. Springtails eat decaying plants and fungus. In a wet tundra, the fungus in the ground largely controls how quickly dead plant matter is decomposed. If the fungi-eating springtails (collembolla) are no longer getting eaten, they are more abundant to keep the fungus in check. When there is less fungal activity, there is slower decomposition and less carbon released from the permafrost.
On the other hand, Koltz said, “If more carbon is released from the Arctic ecosystem, it would increase the rate of global climate change.”
Next step is to see how widespread the effects can become by scaling up to having plots throughout the Arctic.