Slugs and snails, enemy of the gardener? Or vital member of the Ecosystem?

Slugs! Every year we hear about gardeners waging war with slugs complaining about losing half their garden to the slimy “pests”. But when was the last time you walked around a forest to find it destroyed by slugs or any other pest? So maybe we need to rethink our eternal struggle to control pests such as slugs and take a page out of Dr Frakenfurters book by looking at the cause, not the symptom.

Slugs munches down on his greens
Slugs munches down on his greens

Slugs have been living in the UK since the ice age, originating from the sea/coast and come from the second largest group of animals (Gastropods) just behind insects. An average garden is estimated to play home to 20,000 slugs with 200 slugs per square metre of which only 5% are active on the surface at any given time. Sadly in a vain attempt to combat these perceived “pests” British gardeners use an estimated 400,000 billion slug pellets per year! Sadly these slug pellets which are often touted as “safe” are anything but safe to the predators which feed upon poisoned slugs, as the toxins which kill slugs bio-accumulate within predator species until they themselves die from the “safe” slug pellets. A prime example of a predator which feeds on the dreaded slug is the much loved hedgehog, another animal which is in danger of extinction.

So how can we control slugs and similar pests I hear you asking? Well firstly we need to think about our gardens not just as isolated patches of land, but as part of a vast potential wildlife corridor, one which has more space than all our national parks combined! (See more about gardens as invaluable habitat in our previous blog post)

What can we do to balance out our gardens?

1. Create a pond – you will attract beneficial predators ranging from toads to insects with just a simple wildlife pond using native aquatic plants.
2. Create a beetle bank – attract beneficial predators with a beetle bank made from native tussock forming grasses.
3. Leave an area of your garden wild and create some log piles, sand banks or just bury a pot filled with bricks then topped with soil leaving an entry hole. This will create habitat for all manner of beneficial creatures.
4. Add some flat stones – these can be used by some bird species to aid in their hunt for prey such as snails.
5. Keep some/all of your grass long/longer. This will also create habitat for various other creatures.
6. Don’t go overboard on weeding – allow some “weeds” to grow, many of which are vital food for insects such as caterpillars (who doesn’t like a moth/butterfly?)
7. Plant some native pollen rich plants, including nighttime pollen producing plants.
8. Add bird/bat boxes
9. Plant a mixed hedge with native species including Rosa rugosa, Crataegus monogyna, Prunus avium, etc
10. When buying plants ask if they are treated with pesticides such as neonicotinoids (especially thiamethoxam)

Nematodes! Safe biological control?

Group of Nematodes
Group of nematodes under a microscope.

Nematode sales have skyrocketed as this biological slug/pest control is advertised as safe, natural and effective? But is it really a safe, viable method of controlling slugs and other pests in your garden? The sad truth is that peer reviewed research such as “A new threat to bees? Entomopathogenic nematodes used in biological pest control cause rapid mortality in Bombus terrestris” by Alexandrea Dutka, Alison McNulty, Sally M. Williamson, has shown that nematodes have a negative impact on insects such as bees and can potentially wipe out whole colonies.

Dangers of Metaldehyde and similar “pest” control chemicals

When people defend slug pellets and similar control methods you will hear the argument that they are safe and have been used for years, yet blind adherence to hearsay and folk wisdom about the safety of such chemicals is dangerous.

Chemicals within slug pellets have been found to be bio-accumulating within predator species and even drinking water, lakes, ponds and streams. Leading to fatal levels within slug predators such as hedgehogs!

Between 2009 and 2011 the environment agency reported high  levels of metaldehyde within 81 of 647 reservoirs, rivers and ground water. Metaldehyde can not be removed from water using standard water filtering techniques, so this chemical can potentially be found in drinking water around large agricultural facilities! You can read more about the environmental agency’s monitoring in the Guardians article “Slug poison found in one in eight of England’s drinking water sources.”

Snail climbing a plant
Snail climbing a plant