Invasive shrubs differentially alter autumnal activity for three common small-mammal species

Area of Science:

• Ecology
• Invasive Species Biology
• Animal Behavior

Background:

• Seasonal activity patterns in animals are crucial for fitness and ecological interactions.
• Global change, including invasive plants, can disrupt these natural seasonal rhythms.
• The impact of invasive plants on animal seasonal activity, beyond daily patterns, is not well understood.

Purpose of the Study:

• To investigate the effects of invasive woody shrubs (Autumn olive and Amur honeysuckle) on the seasonal activity of three small mammal species.
• To understand how experimental removal of invasive shrubs influences animal foraging behavior and activity timing.
• To assess species-specific responses of small mammals to plant invasions and habitat changes.

Main Methods:

• Experimental removal of invasive shrubs (Autumn olive, Amur honeysuckle) at six paired forest sites.
• Utilized autumnal camera trapping over two consecutive years to monitor small mammal activity.
• Focused on three species: Eastern chipmunk (Tamias striatus), White-footed mouse (Peromyscus leucopus), and Fox squirrel (Sciurus niger).

Main Results:

• Eastern chipmunks exhibited extended foraging periods (20+ days) in shrub-invaded areas.
• White-footed mice showed increased foraging in invaded plots in one year, but no significant shift in activity timing.
• Fox squirrel activity demonstrated year-specific responses to shrub removal, influenced by intra-annual cues like temperature.

Conclusions:

• Invasive plants can cause species-specific alterations in small mammal seasonal activity patterns.
• These invasions may affect the timing of critical physiological processes, such as torpor, in small mammals.
• Altered seasonal activity due to plant invasions can modify animal-mediated ecological processes like seed dispersal and granivory.