Artificial light responsible for insect declines globally: Report

New Delhi (NVI): Artificial light at night is responsible for insect declines globally, as it affects insect movement, foraging, reproduction and predation, according to a United Nation Environment Programme (UNEP) report.

The report, based on a recent study ‘Light Pollution is a driver of insect declines’, says lighting disrupts photosynthesis and the activities of insects, birds and other animals.
Photosynthesis, the process by which plants grow, depends on light and dark. And all animals depend on plants for their survival.

A study said habitat loss, pesticide use, invasive species and climate change have all played a role in insect declines globally, but that artificial light at night is another important but often overlooked cause.

The light affects insect movement, foraging, reproduction and predation, says the study which, however, suggests that insect biodiversity loss can be mitigated with better-informed lighting practices.

“Artificial light at night is unique among anthropogenic habitat disturbances in that it is fairly easy to ameliorate and leaves behind no residual effects. Greater recognition of the ways in which (artificial light at night) affects insects can help conservationists reduce or eliminate one of the major drivers of insect declines,“ it says.

With artificial light increasing by around 2 per cent per year globally, light pollution has become a pertinent issue.

Artificial light not only impacts insects. Turtles, seabirds and shorebirds, and ecosystems at large, are being affected.

Artificial light at night can disorientate adult and hatchling sea turtles, so they are unable to find the ocean.

Birds are also known to become disorientated by lights, resulting in higher bird mortality due to collisions with artificial structures such as buildings. Migratory shorebirds may be exposed to increased predation where the lighting makes them visible. They may also abandon preferable roosting sites to avoid lights.

Here are some ways to manage the impact of artificial light

New proposed guidelines drafted by the government of Australia provide a framework for assessing and managing the impact of artificial light on susceptible wildlife, including migratory species.

For example, they consider wildlife-friendly lighting design and the management of light sources near protected wildlife.

The guidelines recognize the potential of conflicting requirements for wildlife conservation and human safety and the need for a balance between the two.

To prevent harm to migratory species, the guidelines propose a multi-step approach. If artificial light is visible outside, best practice light design should be applied so as not to impact nearby habitats of threatened species.

An environmental impact assessment should consider negative effects before artificial light sources are installed.