How artificial light at night may rewire ecological networks: concepts and models

Abstract

Artificial light at night (ALAN) is eroding natural light cycles and thereby changing species distributions and activity patterns. Yet little is known about how ecological interaction networks respond to this global change driver. Here, we assess the scientific basis of the current understanding of community-wide ALAN impacts. Based on current knowledge, we conceptualize and review four major pathways by which ALAN may affect ecological interaction networks by (i) impacting primary production, (ii) acting as an environmental filter affecting species survival, (iii) driving the movement and distribution of species, and (iv) changing functional roles and niches by affecting activity patterns. Using an allometric–trophic network model, we then test how a shift in temporal activity patterns for diurnal, nocturnal and crepuscular species impacts food web stability. The results indicate that diel niche shifts can severely impact community persistence by altering the temporal overlap between species, which leads to changes in interaction strengths and rewiring of networks. ALAN can thereby lead to biodiversity loss through the homogenization of temporal niches. This integrative framework aims to advance a predictive understanding of community-level and ecological-network consequences of ALAN and their cascading effects on ecosystem functioning. This article is part of the theme issue ‘Light pollution in complex ecological systems’.

Light pollution in complex ecological systems

“…Such changes in species interactions have far-reaching implications for ecological networks and their stability, determining which species can coexist and form communities within and across ecosystems (figure 2). In this issue, Sanders et al [55] model pathways through which ALAN may alter species interactions, indicating that temporal niche shifts owing to the introduction of ALAN may rewire species networks and ecosystems, causing biodiversity change. Moreover, Bucher et al [34] show a significant decrease in plant diversity.…”

“…In this issue, Sanders et al . [ 55 ] model pathways through which ALAN may alter species interactions, indicating that temporal niche shifts owing to the introduction of ALAN may rewire species networks and ecosystems, causing biodiversity change. Moreover, Bucher et al .…”

“…In this issue, Sanders et al . [ 55 ] integrated a complex food web model with potential temporal niche shifts of diurnal, nocturnal and crepuscular species in response to ALAN. They show that the homogenization of temporal niches in particular can rewire species networks with varying consequences for species persistence.…”

Bats in the spotlight : Spatiotemporal response of foraging and commuting bats to anthropogenic light at night

“…Artificial light at night may therefore reshape the landscape of fear both spatially (Shier et al, 2020;Spoelstra et al, 2015) and temporally (Henke et al, 2022;Mariton et al, 2022). It also generates asynchronies inducing mismatches in prey-predator interactions if the two groups respond differently to light (Sanders et al, 2023) and thus reduces the quality of food patches.…”

“…Besides foraging (Lewanzik and Voigt, 2014;Polak et al, 2011), other behaviours are also altered due to artificial light, such as commuting (Hale et al, 2015;Kuijper et al, 2008;Stone et al, 2009;Zeale et al, 2018), roosting (Boldogh et al, 2007;Straka et al, 2020), drinking (Russo et al, 2017) and migrating (Voigt et al, 2018). In addition to the effects on the individual level, artificial light has an impact at the community level (Cravens and Boyles, 2019) and in food webs (Sanders et al, 2023). Different bat species might respond differently, lighttolerant or synanthropic bats showing positive phototaxis while light-averse species avoid lit areas (Azam et al, 2018;Lewanzik and Voigt, 2017;Spoelstra et al, 2017).…”