Does pollution influence small mammal diet in the field? A metabarcoding approach in a generalist consumer

Abstract

Mammals are mainly exposed to trace metals (TMs) via consuming contaminated food. Several studies have demonstrated relationships between metal concentrations in food and in animal tissues. However, potential effects of TMs on feeding behaviour of wildlife have been poorly documented under field conditions, despite experimental evidence showing that food selection is impacted by resource contamination. Here, we test the hypothesis that the diet of a generalist rodent, the wood mouse (Apodemus sylvaticus), is altered by soil TM contamination in the field. Wood mice were sampled in spring and in autumn along a gradient of soil contamination in the surroundings of a former smelter located in northern France. Available resources in the field were inventoried, and the diet of the animals was analysed using DNA "metabarcoding." We demonstrated that (a) relationship between the resource richness in the diet and their richness in the field was altered by soil metal contamination. Wood mice specialized their diet along the gradient of soil metal contamination for both plant and invertebrate resources in spring. We also showed that (b) preference for Salicaceae, a plant family accumulating metals, decreased when soil contamination increased. These results suggest that environmental TM pollution could act as a force modulating trophic interactions in terrestrial food webs, thereby affecting wildlife exposure to contaminants by trophic route.

Comparable response of wild rodent gut microbiome to anthropogenic habitat contamination

“…These mice are typical granivorous rodents whose diets are largely dominated by mast seeds (e.g., acorns and other nuts) or weed seeds, but sometimes include vegetative plant material, invertebrates and/or fungi (Butet & Delettre, 2011). A. flavicollis and A. sylvaticus have similar ecology and diets (Knowles et al, 2019;Michaux et al, 2005;Ozaki et al, 2018), whereas despite overlapping habitats, soil-dwelling A. speciosus and tree-dwelling A. argenteus segregate vertically and differ in dietary preferences (specialist and generalist, respectively) (Oka, 1992;Sato et al, 2018).…”

Stable Isotopes Reveal the Dominant Species to Have the Widest Trophic Niche of Three Syntopic Microtus Voles

“…Our results are of interest for small mammal trophic ecology in general [ 5 , 18 , 59 , 65 , 66 ]. Due to agricultural activities, orchards and berry plantations are most possibly not places of abundant and diverse resources for herbivores.…”

DNA metabarcoding in diet studies: Unveiling ecological aspects in aquatic and terrestrial ecosystems

“…There have also been some studies focusing on the diets of reintroduced or recovering populations (Kowalczyk et al, ; Pansu et al, ; Pinho et al, ) and on the effects of hunting in niche partitioning between both herbivores (Pansu et al, ) and carnivores (Smith et al, ). Additionally, the effects of pollution have been addressed twice, with light pollution having species‐specific effects on bats' feeding habits (Cravens et al, ) and trace metal pollution modulating food preferences of the wood mouse Apodemus sylvaticus (Ozaki et al, ). So far, and to the best of our knowledge and based on our compilation, only one study focused on the effects of climate change on bats trophic niche, uncovering a profound impact on trophic webs (de Oliveira, ).…”