Researchers report links between warming and predator-prey interactions in the Arctic. Wolf spiders are one of the dominant predators in the Arctic tundra and are predicted to grow in size and abundance as the region warms. The spiders prey on herbivores, small soil animals, and other predators. Hence, changes in predator wolf spider abundances may shape tundra communities, ecosystem services influenced by soil animals, and carbon emissions from decomposition in the tundra. Amanda M. Koltz and colleagues set up experimental plots with low, normal, or high densities of wolf spiders either at ambient temperature or at temperatures increased by 1-2 °C. Under ambient temperature, high wolf spider densities were tied to decreased fungal-feeding Collembola and fast decomposition in soil. The effect was reversed under warm conditions; Collembola increased and decomposition slowed. Populations of intermediate predators also declined under warm conditions, suggesting that wolf spiders may have shifted their primary prey and released Collembola from predation, allowing Collembola to consume fungi and indirectly slow decomposition. According to the authors, the results suggest that predator activity can influence carbon and nitrogen dynamics in the Arctic but that warming may alter or reverse such effects.
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Article #18-08754: "Warming reverses top-down effects of predators on belowground ecosystem function in Arctic tundra," by Amanda M. Koltz, Aimée T. Classen, and Justin P. Wright.
MEDIA CONTACT: Amanda M. Koltz, Washington University in St. Louis, MO; tel: 314-935-8794, 607-423-8265; e-mail: akoltz@wustl.edu
Proceedings of the National Academy of Sciences