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Risk induced by a native top predator reduces alien mink movements
Pälvi Salo1, Mikael Nordström, Robert L Thomson
1Section of Ecology, Department of Biology, University of Turku, Turku, Finland. pakisa@utu.fi
The Journal of Animal Ecology
|July 16, 2008
Summary
Alien predators like American mink alter their behavior to avoid native predators such as white-tailed sea eagles. This risk-sensitive behavior by mink may impact their population growth and affect native species in the Baltic Sea archipelago.
Area of Science:
- Ecology
- Behavioral Ecology
- Conservation Biology
Background:
- Nonlethal predation effects can significantly impact prey populations, especially in intraguild interactions involving invasive species.
- Invasive predators, such as the American mink (Mustela vison) in Europe, can have detrimental effects on native ecosystems.
- Re-colonizing native predators, like the white-tailed sea eagle (Haliaeetus albicilla), can influence the behavior of invasive species.
Purpose of the Study:
- To investigate the impact of predation risk from a native top predator (white-tailed sea eagle) on the movement behavior of an invasive predator (American mink).
- To understand how environmental factors, including proximity to eagle nests and observed eagle activity, influence mink swimming behavior.
- To assess potential cascading effects of altered invasive predator behavior on lower trophic levels.
Main Methods:
- Radiocollaring of 20 American mink in the Baltic Sea archipelago, Finland.
- Analysis of mink swimming distances in relation to proximity to white-tailed eagle nests and observed eagle activity.
- Comparison of observed mink swimming distances with random movement expectations.
Main Results:
- Mink, particularly females, reduced their swimming distances in response to increased predation risk from white-tailed sea eagles.
- A 10% reduction in swimming distance was observed for every 10 additional eagle observations, and a 5% reduction per kilometer closer to an eagle nest.
- Male mink behavior conclusions were limited due to a smaller sample size.
Conclusions:
- Female American mink exhibit risk-sensitive behavior, modifying movements to avoid native predators.
- Altered behavior of invasive mink may lead to reduced population growth and cascading effects on native prey populations (birds, mammals, amphibians).
- Reintroduction of top predators can be a strategy to mitigate the impacts of invasive alien species on native biota.
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