Indirect Human Influences in Fear Landscapes: Varying Effects of Moonlight on Small Mammal Activity along Man-Made Gradients of Vegetation Structure

Abstract

Risk of predation is one of the main constraints of small mammal distribution and foraging activity. Aside from numerical effects on population size due to the presence and abundance of predators, indirect cues, such as vegetation structure and moonlight, determine patterns of activity and microhabitat use by small mammals. Indirect cues are expected to interact, as shading provided by vegetation can suppress the effects of changing moonlight. We analyzed the effects of moonlight levels on the activity patterns of three common small mammal species in Mediterranean habitats, and tested whether moonlight effects were modulated by shadowing associated with the development of tall vegetation due to spontaneous afforestation following land abandonment. A. sylvaticus, a strictly nocturnal species, decreased activity under moonlight with no interactive effects of vegetation cover. C. russula showed no activity change with moonlight levels and M. spretus increased activity, although activity in both species was mostly determined by vegetation cover, that favored it. The effects of moonlight on small mammal activity were not homogeneous among species, nor were the interactive effects of man-made gradients of habitat structure, a fact that will produce community changes along vegetation gradients mediated by varying fear landscapes.

The Abundance and Dynamics of Small Mammals and Their Predators: An Editorial

“…The aim of this editorial is to introduce the Special Issue "Abundance and Dynamics of Small Mammals and Their Predators", which included 10 papers in total (two reviews and eight research papers). Almost all studies were conducted in European countries, with four from Spain [7][8][9][10], two from Lithuania [11,12], one from Greece [13], and one from Latvia [14]. The remaining two studies were conducted in New Zealand [15] and Chile [16].…”

“…Through shading, vegetation mitigates the effects of changing moonlight levels, and this is important for the foraging of small mammals, as moonlight changes predation and anti-predator behavior. Pasquet et al [8] investigated the impact of moonlight levels on the activity patterns of three common small mammal species in Mediterranean habitats, examining whether the effects of moonlight were influenced by the presence of tall vegetation resulting from spontaneous afforestation after land abandonment. They found that responses to moonlight were species-specific.…”