Impacts of artificial light on food intake in invasive toads

Hirotaka Komine,Lin Schwarzkopf,Shinsuke Koike

doi:10.1038/s41598-020-63503-9

Hirotaka Komine, Lin Schwarzkopf + Show 1 more

Open Access

https://doi.org/10.1038/s41598-020-63503-9

Copy DOI

Abstract

Artificial light at night (ALAN) is a major form of anthropogenic disturbance. ALAN attracts nocturnal invertebrates, which are a food source for nocturnal predators, including invasive species. Few studies quantify the effects of increased food availablity by ALAN on invasive vertebrate predators, and enhancement of food intake caused by ALAN may also be influenced by various environmental factors, such as proximitity to cities, moon phase, temperature, rainfall and wind speed. Revealing the potential impacts on invasive predators of ALAN-attracted invertebrates, and the influence of other factors on these effects, could provide important insights for the management of these predators. We constructed and supplied with artificial light field enclosures for invasive toads, and placed them at locations with different levels of ambient light pollution, in northeastern Australia. In addition, we determined the effect of rainfall, temperature, wind speed, and lunar phase on food intake in toads. We found that ALAN greatly increased the mass of gut contents of invasive toads compared to controls, but that the effect was increased in dark lunar phases, and when there were low ambient light pollution levels. Effects of rainfall, temperature and wind speed on food intake were comparatively weak. To avoid providing food resources to toads, management of ALAN in rural areas, and during dark lunar phases may be advisable. On the contrary, to effectively capture toads, trapping using lights as lures at such times and places should be more successful.

Highlights

Artificial light at night (ALAN) is a major form of anthropogenic disturbance
Model comparisons showed that the experimental artificial light treatment, ambient light pollution levels, lunar phase, and the interactions between experimental artificial light treatment and ambient light pollution level, and between the experimental artificial light treatment and lunar phase were selected in all models with delta AIC < 2 (Table 1)
We found that the presence of artificial light in our experiment greatly increased the mass of gut contents of invasive toads, and that this effect was reduced when there was more ambient light, either from urban light pollution or natural moonlight

Summary

Introduction

Artificial light at night (ALAN) is a major form of anthropogenic disturbance. ALAN attracts nocturnal invertebrates, which are a food source for nocturnal predators, including invasive species. Few studies quantify the effects of increased food availablity by ALAN on invasive vertebrate predators, and enhancement of food intake caused by ALAN may be influenced by various environmental factors, such as proximitity to cities, moon phase, temperature, rainfall and wind speed. Revealing the potential impacts on invasive predators of ALAN-attracted invertebrates, and the influence of other factors on these effects, could provide important insights for the management of these predators. In addition attracted invertebrates are a food source for nocturnal predators of invertebrates, such as geckos, anurans, bats, and birds[21,22,23] Such phenomena are well documented[21,23], few studies quantify the effect of increased food availablity on predators, they may be among the strongest impacts of ALAN. Revealing the potential impact on invasive species of ALAN could provide important insights for the management of invasive species

Methods

Results

Conclusion