Wild mice in an urbanized world: Effects of light at night under natural and laboratory conditions in the single-striped grass mouse (Lemniscomys rosalia)

ABSTRACT

Urbanization, and the accompanying artificial light at night (ALAN), can disrupt the activity of animals. Such disruptions at the base of a food web can ripple through the ecosystem. Most studies of ALAN are performed in the laboratory. Thus, we lack basic information about the circadian responses of animals under natural environmental conditions to fully evaluate the impact of ALAN. We studied the behaviour and activity of wild-caught, peri-urban single-striped grass mice (Lemniscomys rosalia) under a natural treatment and in a standard laboratory treatment, including dim light at night to mimic conditions that they could experience. The species exhibited predominantly crepuscular activity under all experimental treatments. It showed the highest level of activity under the natural treatment, whereas ALAN significantly suppressed its activity. Males were more active than females under all experimental treatments. The marked changes in activity under ALAN is of particular concern since global change in combination with urbanization can lead to a change in vegetation density and composition that will decrease the number of suitable microhabitats and expose small mammals to novel habitat changes. We suggest that the single-striped mice could become vulnerable because of urbanization, leading to impacts on its ecosystem broadly.

KEYWORDS:

• Activity
• laboratory
• rodent
• natural environmental conditions
• urbanization
• artificial light at night

Acknowledgments

We would like to thank Tim Nash and the staff of the Cradle Nature Reserve for allowing us to catch animals and conduct research on their premises. We are grateful for the funding received from the Lee R Berger Foundation and all the volunteers who helped catch and care for the experimental animals.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/07420528.2024.2317284.

Additional information

Funding

Our study was supported by the following organizations that provided financial support: University of Witwatersrand, Tim Nash Foundation and Lee Berger Foundation.