Data from: Transition from conventional to light-emitting diode street lighting changes activity of urban bats

Light pollution is rapidly increasing and can have deleterious effects on biodiversity, yet light types differ in their effect on wildlife. Among the light types used for street lamps, light-emitting diodes (LEDs) are expected to become globally predominant within the next few years.
In a large-scale field experiment, we recorded bat activity at 46 street lights for 12 nights each and investigated how the widespread replacement of conventional illuminants by LEDs affects urban bats: we compared bat activity at municipal mercury vapour (MV) street lamps that were replaced by LEDs with control sites that were not changed.
Pipistrellus pipistrellus was the most frequently recorded species; it was 45% less active at LEDs than at MV street lamps, but the activity did not depend on illuminance level. Light type did not affect the activity of Pipistrellus nathusii, Pipistrellus pygmaeus or bats in the Nyctalus/Eptesicus/Vespertilio (NEV) group, yet the activity of P. nathusii increased with illuminance level. Bats of the genus Myotis increased activity 4·5-fold at LEDs compared with MV lights, but illuminance level had no effect.
Decreased activity of P. pipistrellus, which are considered light tolerant, probably paralleled insect densities around lights. Further, our results suggest that LEDs may be less repelling for light-averse Myotis spp. than MV lights. Accordingly, the transition from conventional lighting techniques to LEDs may greatly alter the anthropogenic impact of artificial light on urban bats and might eventually affect the resilience of urban bat populations.
Synthesis and applications. At light-emitting diodes (LEDs), the competitive advantage – the exclusive ability to forage on insect aggregations at lights – is reduced for light-tolerant bats. Thus, the global spread of LED street lamps might lead to a more natural level of competition between light-tolerant and light-averse bats. This effect could be reinforced if the potential advantages of LEDs over conventional illuminants are applied in practice: choice of spectra with relatively little energy in the short wavelength range; reduced spillover by precisely directing light; dimming during low human activity times; and control by motion sensors. Yet, the potential benefits of LEDs could be negated if low costs foster an overall increase in artificial lighting.

光污染正快速加剧，会对生物多样性造成有害影响，但不同光照类型对野生动物的影响存在差异。在用于路灯的各类光源中，发光二极管（light-emitting diodes，LED）预计将在未来数年内成为全球主流照明类型。
本研究通过大规模野外实验，在46盏路灯处各开展了12夜的蝙蝠活动监测，并探究了以LED替代传统照明光源这一普遍现象对城市蝙蝠的影响：我们对比了更换为LED的市政汞蒸气（mercury vapour，MV）路灯与未更换的对照样地的蝙蝠活动水平。
普通伏翼（Pipistrellus pipistrellus）是监测到的最常见物种；其在LED路灯处的活动水平较MV路灯低45%，但活动水平与照度并无关联。南佐治亚伏翼（Pipistrellus nathusii）、矮伏翼（Pipistrellus pygmaeus）以及夜蝠属/棕蝠属/普通蝙蝠属（Nyctalus/Eptesicus/Vespertilio，NEV）类群的蝙蝠活动不受光照类型影响，但南佐治亚伏翼的活动水平随照度升高而增加。鼠耳蝠属（Myotis）蝙蝠在LED路灯处的活动水平较MV路灯提升4.5倍，但其活动同样不受照度影响。
被认为具有耐光性的普通伏翼活动水平下降，这可能与灯光周围的昆虫密度变化相一致。此外，我们的研究结果表明，相较于MV路灯，发光二极管对畏光性鼠耳蝠属（Myotis）物种的驱避性更弱。据此，从传统照明技术向LED的转型可能会极大改变人工光对城市蝙蝠的人为影响，并最终可能影响城市蝙蝠种群的韧性。
研究综合与应用。在LED路灯下，耐光性蝙蝠原本具备的独有的在灯光处昆虫聚集区觅食的竞争优势被削弱。因此，全球LED路灯的普及可能会使耐光性蝙蝠与畏光性蝙蝠之间的竞争回归更自然的水平。如果在实践中充分发挥LED相较于传统照明光源的潜在优势，这一效应还会进一步增强：选择短波能量相对较低的光谱；通过精准控光减少光溢出；在人类活动较低的时段调暗灯光；以及通过运动传感器实现照明控制。然而，如果低成本促使人工照明整体规模扩大，LED的潜在益处可能会被抵消。