Dark Matters: The Effects of Artificial Lighting on Bats

Abstract

While artificial lighting is a major component of global change, its biological impacts have only recently been recognised. Artificial lighting attracts and repels animals in taxon-specific ways and affects physiological processes. Being nocturnal, bats are likely to be strongly affected by artificial lighting. Moreover, many species of bats are insectivorous, and insects are also strongly influenced by lighting. Lighting technologies are changing rapidly, with the use of light-emitting diode (LED) lamps increasing. Impacts on bats and their prey depend on the light spectra produced by street lights; ultraviolet (UV) wavelengths attract more insects and consequently insectivorous bats. Bat responses to lighting are species-specific and reflect differences in flight morphology and performance; fast-flying aerial hawking species frequently feed around street lights, whereas relatively slowflying bats that forage in more confined spaces are often light-averse. Both highpressure sodium and LED lights reduce commuting activity by clutter-tolerant bats of the genera Myotis and Rhinolophus, and these bats still avoided LED lights when dimmed. Light-induced reductions in the activity of frugivorous bats may affect ecosystem services by reducing dispersal of the seeds of pioneer plants and hence reforestation. Rapid changes in street lighting offer the potential to explore

Out of the Dark: Establishing a Large-Scale Field Experiment to Assess the Effects of Artificial Light at Night on Species and Food Webs

“…Past studies have found both negative and positive consequences of artificial light for bats [55,56]. Our working hypothesis is that artificial light will change the bat assemblage foraging at the lit site compared with the assemblage foraging at the dark site.…”

“…In contrast, bats with a more rural distribution pattern, such as Pipistrellus nathusii should be less abundant at the lit than at the dark site since they are generally more light-averse. Similarly, species that usually forage in cluttered space should be less abundant at the lit site because they are adapted to the dark interior of their forest habitat and might be particularly light-averse [56,59].…”

Effects of artificial illumination on drinking bats: a field test in forest and desert habitats

“…a portable LED outdoor lamp emitting normal white light (produced by McMantom, Italy). The lamp's light spectrum had a bimodal pattern typical of LED lighting (Rowse et al, 2016) with two peaks of relative luminous flux at 450 nm and 590 nm (data provided by the producer). We powered the light with a 12V (35A) car battery switched on manually.…”

“…Besides repelling most bat species, ALAN at foraging sites may disrupt communities of prey insects (e.g. Moreover, illuminating the surroundings of feeding sites may sever bat commuting routes (Stone et al, 2009;Polak et al, 2011;Hale et al, 2015), or drive insects away from neighbouring habitats, exerting a sort of "vacuum cleaner" action that reduces food availability (Rowse et al, 2016). Moreover, illuminating the surroundings of feeding sites may sever bat commuting routes (Stone et al, 2009;Polak et al, 2011;Hale et al, 2015), or drive insects away from neighbouring habitats, exerting a sort of "vacuum cleaner" action that reduces food availability (Rowse et al, 2016).…”

Measuring Light Pollution with Fisheye Lens Imagery from A Moving Boat – A Proof of Concept

“…Several studies have investigated the impact of ALAN on the environment [5] and there is a growing concern that LP affects biodiversity [6,7]. Until recently, the main focus of studies about ecological LP was on terrestrial animals [5,[8][9][10] and plants [10,11]. However, because human settlements concentrate along freshwater reservoirs and coastlines, research on ecological LP has shifted towards aquatic systems [12][13][14][15][16].…”