DISSERTATION RESEARCH: Can Predation Risk Limit Small Mammal Seed Predation in Novel Winter Habitats?

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

In northern forests, many plants and animals live at the interface between the snow and soil. In recent decades snowfall has declined across many parts of the northern United States and this decline is expected to continue into the future. This study focuses on how small mammals that live at the interface between the snow and the soil respond to the loss of this habitat. While deep snow allows small mammals, such as mice or voles, to hide from predators, these animals may benefit from leaving snow covered areas to search for food (seeds and seedlings). This study will remove snow in a small area to determine whether less snow leads small mammals to spend more time foraging and being susceptible to predators. Cameras will be used to record changes in the behavior of the small mammals. Seeds and seedlings will be monitored to determine how the changes in mammal behavior influence their survival. Understanding conditions that promote small mammal activity in areas with little snow could help in predicting seedling survival in future decades, ultimately leading to more effective forest management strategies. This study will support the training of a graduate and undergraduate student and will provide opportunities for outreach with K-12 students and with the general public. This research examines the importance of snow depth and predation risk on small mammal activity and seed predation in a northern temperate forest. The researchers will conduct an experiment that manipulates the predation refuge provided by the interface between the soil and snow (subnivium), and an alternative predation refuge (woody debris) from which most snow has been removed. Using a recently described technique, motion-sensor infrared cameras will be placed in each treatment combination to compare small mammal activity in areas with deep snow and shallow snow. Cameras will be focused on trays containing seeds and seedlings of four native tree species, allowing researchers to quantify how changes in small mammal activity can influence the relative survival rates of the plant species they consume. By combining camera traps in the subnivium with a seed removal assay, researchers will also be able to monitor the small mammal species consuming seeds. This research will help clarify the trade-offs small mammals face between foraging efficiency and predation risk during winter, providing a more thorough understanding of how environmental context might alter the relationship between snow depth, and small mammals and the seeds they consume.