© Michigan Technological UniversityThe coastline of Isle Royale National Park is represented in two maps. Moose carcasses, like the ones on which wolves are feeding in lower map, produce pulses of nutrients that affect soil fertility, decomposition and the nutrition of nearby plants. Clustered hotspots of biogeochemical activity are seen in the yellow to white zones in upper map.
Moose eat plants; wolves kill moose. What difference does this classic predator-prey interaction make to biodiversity?
A large and unexpected one, say wildlife biologists from Michigan Technological University. Joseph Bump, Rolf Peterson and John Vucetich report in the November 2009 issue of the journal
Ecology that the carcasses of moose killed by wolves at Isle Royale National Park enrich the soil in "hot spots" of forest fertility around the kills, causing rapid microbial and fungal growth that provide increased nutrients for plants in the area.
"This study demonstrates an unforeseen link between the hunting behavior of a top predator -- the wolf -- and biochemical hot spots on the landscape," said Bump, an assistant professor in Michigan Tech's School of Forest Resources and Environmental Science and first author of the research paper. "It's important because it illuminates another contribution large predators make to the ecosystem they live in and illustrates what can be protected or lost when predators are preserved or exterminated."
Bump and his colleagues studied a 50-year record of more than 3,600 moose carcasses at Isle Royale. They measured the nitrogen, phosphorus and potassium levels in the soil at paired sites of wolf-killed moose carcasses and controls. They also analyzed the microbes and fungi in the soil and the leaf tissue of large-leaf aster, a common native plant eaten by moose in eastern and central North America.
