Lighting the Way
Balancing Wildlife Conservation and Preserving our Dark Skies with a Sensitive Garden Lighting Design - by Freyja Austin
Welcome to the final part of this series on dark skies and responsible artificial lighting. So far, we have looked at how light pollution from artificial light at night (ALAN) effects our view of the sky, and how ALAN at a residential scale can impact local wildlife. It may sound all doom and gloom, but in actual fact the effects of ALAN in your garden are quite easy to mitigate. This part will highlight some ways that you can install lighting in your garden responsibly.
Don’t be Scared of the Dark
Responsible outdoor lighting can meet your needs while also helping to protect your view of the night sky, conserving energy, and reducing your negative impact on wildlife.
Some of the actions we are told to take in order to protect the environment may seem fruitless at an individual scale. However, choosing your outdoor lighting carefully can have a real and visible positive impact on the wildlife on your doorstep. When planning on lighting your garden it is useful to think of the 4 W’s: why, where, when and what.
Why: Why are you installing lights? They should serve a purpose, like lighting a path or terrace, or for security.
Where: Lighting should be installed so it illuminates a specific target area. It should point down to reduce its spill into non-target areas and be situated away from established habitats.
When: Only light your garden when using it, consider timers and manual switches.
What: The colour and intensity of light can make a difference. Warm amber lighting is less impactful on wildlife, not to mention more pleasant than white light, and dimmers can lower light intensity.
Let’s take a closer look at these 4 points to show how thoughtful lighting design can benefit your garden ecosystem.
Keeping it Low
Low Lighting is Key: Lights that point down, are low light output (lumen) and low colour temperature (kelvin)
Why?
Increased private lighting of outdoor spaces is a cause for concern as it contributes to light pollution, harms wildlife, and increases energy consumption. The lighting in your garden should serve a purpose, you can limit the number of lights you install by thinking carefully about what you want to illuminate. Common reasons for lighting your garden include:
Safety and security: for example lighting your back or front door.
For access: such as having lights in a side alley, near outdoor bins, or to illuminate garden steps.
Functional lighting: that provides light for a terrace or an outdoor kitchen for example.
Feature lighting: that illuminates sculptures, shrubs, or trees.
If you take into consideration the reasons for installing outdoor lights you can balance your wants and needs for your garden with having a low impact on wildlife. Once you’ve decided ‘why’ you can think about ‘where’.
Where?
Once you have decided the reason for your garden lighting you can think about where to install it so that it serves its purpose and avoids light trespass into non-target areas. One of the easiest ways to achieve targeted lighting is to avoid up lighting. As a studio, one thing we have always committed to mitigate our effect on wildlife is to never up light existing trees. Your lights should shine below the horizontal plane, aiming down at a specific area or feature. If however, uplighting is non-negotiable, lighting experts like Hudson Lighting can provide advice on the location and angle of light fixtures to achieve minimal spill. It must be noted that any uplighting is not Dark Skies compliant.
As we know, ALAN can impede bats emergence from roosts and obstruct their commuting routes to feeding sites. Installing downward facing lighting minimises interference with their activity. Additionally, it creates minimal spill and therefore keeps areas of your garden dark for other nocturnal mammals. Although you may want to admire your garden at night as well as during the day, it is important to keep areas unlit as this maintains dark corridors for animals travelling between their homes and foraging areas at night. You should also avoid lighting near hedges and edges of woodland as lights will disturb these already established habitats. Furthermore, water should remain unlit as animals may be deterred from drinking and the activity of marine organisms could be effected.
Dark Skies Compliant Lighting
One of Hudson Lighting’s dark sky and wildlife friendly fixtures. Light shines downwards and has minimal glare.
When?
The ideal scenario for wildlife is for artificial light to absent at night. The next best thing is to reduce the duration your lights are on, thereby reducing the impact on wildlife. As beautiful as your garden may be, it is beneficial for plants and animals (and your electricity bill!) to turn off your lights if you are out of the house or not using the space. Timers can be set up so that your lights are on only when your household is active. Illumination may still overlap with the activity of nocturnal wildlife but using timers provides animals with longer periods of natural darkness. This can help to preserve essential dark and light cycles for animals which maintains their circadian rhythms and behavioural and physiological processes. Having manual control over your lighting is another way to protect wildlife. For example, leaving an outdoor dining area unlit unless it is in use will increase the number of dark places in your garden and with it the potential roaming space for nocturnal wildlife.
Additionally, access lighting for side alleys, sheds, or outdoor bins for example, could be motion activated. Passive infrared sensor (PIR) lights can be installed when access is needed to an area for a short amount of time. There are brands of PIR that will be activated by large moving objects (like us) but will not be triggered by animals. This means that areas of your garden will remain unlit unless you are moving through them, creating more naturally dark areas of your garden. PIR lighting or lower levels of uniform light (reducing glare and light/shadow contrast, which reduces visibility) may also increase home security.
Warmth
This low intensity, warm, amber bulb is creating little glare and minimal upward spill.
What?
The last important decision to make involves the colour and intensity of your lights. Lights have become whiter with the introduction of LEDs and other modern lighting; these are contributing to the brightening of the sky. Furthermore, as animals see light differently than we do, they are more sensitive to these short wavelengths of unnatural white light. Bright white lights, with blue wavelengths in, and lights that produce UV, should be avoided. Swap these out for more natural (and more pleasant) warmer toned lights.
All light in your garden at night will have an effect on wildlife, and there is not one colour that we can be certain has the lowest impact on the highest number of species. However, lights that are 2700k or lower (a warm, inviting tone) are estimated to cause the least disturbance. Even better is something called amber optics. This warm light is energy efficient and interferes even less with wildlife. Additionally, bulbs themselves should be hidden, lamp shade style fixtures or glare guards can be used to prevent light spill. We can find Dark Sky approved product lists , or we can use lighting companies like Hudson Lighting who aim to create a range of lights that maintain dark skies and have a minimal impact on wildlife, while also providing installation advice.
Creating a Barrier
In rural areas especially, hedgerows and woodlands are great at preventing light spilling out of your garden into surrounding areas.
Aside from the specifics of what lights to install and where to install them, there are some other things that can be factored into garden design to mitigate the effects of ALAN on sky visibility and wildlife. Building materials scatter light in different ways so you should:
Use non-reflective dark surfaces near lights so light isn’t needlessly scattered.
Avoid shiny surfaces that can polarise light causing it to look like water and confuse animals.
Opt for brighter paving materials that can reflect the moonlight and therefore reduce the need for artificial lighting.
Additionally, a natural way of mitigating the effects of ALAN, especially of light trespass, is to use hedgerows to prevent light spilling outside of your garden. This is particularly effective in rural areas to prevent light shining into surrounding countryside.
As a studio, our aim is to design all our schemes to be Dark Skies Compliant. We all have a duty of care to protect and enhance our natural world, and as designers, we are key in educating and facilitating this through our design process. Our client’s are all open to understanding the importance of Dark Skies Compliant Lighting to protect our night skies and support our wildlife, and they keen to make a difference and willing to adapt their initial desires for highly lit gardens. Sharing our lives with wildlife is a privilege we all feel when we experience it first hand, and those long warm evenings sitting in the garden staring in awe at Jupiter and how significant that planet was in our own evolution is just simply mind-blowing. It is something we should all be actively protecting. Bo Cook – Lead Designer.
Written by Guest Blogger Freyja Austin, Feb 2024
References:
https://darksky.org/what-we-do/darksky-approved/products-companies/
https://darksky.org/app/uploads/2022/06/IDA-State-of-the-Science-2022-EN.pdf
https://royalsocietypublishing.org/doi/10.1098/rstb.2014.0124
https://assets.publishing.service.gov.uk/media/5a7c47f8ed915d76e2ebc4e1/9780108508547.pdf.pdf
https://www.gov.uk/guidance/light-pollution#possible-ecological-impact
https://hudsonlighting.co.uk/darksky.php
https://cdn.buglife.org.uk/2023/06/Buglife-Nurture-the-Night-Shift-Bug-friendly-Lighting.pdf
https://www.dcceew.gov.au/campaign/light-pollution
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