Are robotic lawn mowers a danger for biodiversity in gardens?

Between 2014 and 2018 sales of robotic lawn mowers nearly quadrupled! Although this trend proves the numerous qualities of robotic mowers and their ability to magically transform lawns, some people are concerned about possible loss of biodiversity, particularly following some articles in various media.

It is true that lawns and gardens, regardless of their location, are often the retreat of many small animals and countless insects that play their crucial roles in nature. Looking at an automatic lawn mower, it is only logical to fear the harmful consequences for hedgehogs. However, there are currently no real statistics on the danger of robotic mowers, and most articles often make general mention of ’gardening tools’ and ’brush cutters’.

At Belrobotics, we are convinced that, even if zero risk does not exist, a whole series of measures and gadgets greatly reduce the risk of wounding these small creatures.

 Robotic lawn mowers & hedgehogs: how to protect them?

To better protect hedgehogs it is first necessary to understand them. The hedgehog is essentially a nocturnal animal. It can sleep up to 18 hours a day under bushes, a pile of leaves or any other suitable place. It hunts at night and feeds on insects (slugs, snails, earthworms, etc.), but also on berries and fruit. This is one of the reasons why the hedgehog is now threatened. The massive use of pesticides poisons its food or makes it disappear. Another point, this little animal hunts mainly by hearing and smell, since its sight is far from perfect.

This behaviour explains why the robotic mower might be dangerous. It is able to cut automatically at night and be ’too’ silent for this little animal that, instead of fleeing, rolls itself up into a ball.

Don’t mow at night to save hedgehogs

To avoid any risk it is therefore preferable not to mow at night and to use a robotic mower suitable for surfaces larger than the real size of the lawn to be mown so as not to cut from dusk to dawn.

 Use robotic mowers with retractable blades

There are also two main categories of cutting heads in robotic mowers:

Those fitted with cutting blades similar to razor blades: they retract when they come up against resistance, not wounding animals at all or at least causing only very superficial injury – it’s the choice of our robots, used by lovers of beautiful lawns and for bigger professional sports surfaces. What is more our cutting heads are fitted with anti-friction discs and mounted on pantographs: it is a unique patented design that allows, for example, the cutting head to pass over the back of a hedgehog without injuring it, or at least touching only a superficial part of its skin.

The other cutting heads are made of long hard blades in the form of knives or stars: they are deadly if a hedgehog strays across their path.

New technologies in development to better protect biodiversity

Apart from the above advice – not mowing at night, using light blades instead of hard slicing knives -, Belrobotics has launched several other initiatives in order to guarantee better protection for hedgehogs:

For one thing we are constantly improving the active safety of our robots and are currently testing a technology that allows not only to detect but also to characterise obstacles. It can also detect for example the presence of an animal, teddy bear or child’s toy left out on the lawn and then manoeuvre round it.

Also, armed with our experience mowing golf courses, we have developed different models of cutting heads that avoid contact of the cutting blades with any object the size of, for example, a golf ball. We have planned tests this summer for these heads on dummies the size of hedgehogs: if the results are convincing we will offer this device as an option for our robots in 2021.

Finally, we are also testing protective devices installed on the front of the mower. First fitted to push aside small branches, waste or ducklings and thus to prevent the blocking of the heads. They could also push aside hedgehogs without injuring them.