Backyard Biodiversity & Ecosystem Health; Protected by Beetle Banks

Are you looking to begin another project in the garden for the sake of wildlife? Or instead are you perhaps looking to defend your garden from the pests that munch on your flowers and crops?

Prepare to celebrate then, for you’re about to hit two birds with one stone!

As is implied by the featuring title above, this is a method that aims to host insects whilst being able to protect a certain something, and in this case it’s the greenery in your garden. Whilst on the topic I want to shoot down any uncertainties, the “beetles” in this title is purely for the sake of alliteration, and is really in reference to the general insect population.

With that out the way, I hear your next question coming;

How will introducing more insects into my garden stop insect pests? Surely it will increase my troubles..!

That’s an easy answer as just as there is a food chain amongst animals, there’s a food chain to insects within their own order, in which there are insects that predate other insects and are known as insectivores.

Going from here is intuitive! As we own habitats that’s inviting to your pest species (your crops & other greenery being their food source & shelter), we can introduce a habitat that is capable of hosting insectivores. There’s a bit of art & science to it, so I will explain in more detail in the next section.

But for now know that this is the origin of Beetle Banks, a practice often implemented by farmers seeking to encourage these predatory insect species and in doing so, reducing the time, effort & cost needed to employ other pest control methods such as pesticides.

And there’s the concept!

Now let’s move on to the practical element.

The Operation of a Beetle Bank

We’re starting with a bank, a long strip of (preferably) raised soil that resembles a speed bump, though the bank can be a fair bit taller. It’s the “raised” height feature that gives rise to a slight difference in the ground condition that effects the grasses that grow from it, creating a mosaic of freely draining soil, differing levels of sunlight exposure, wind buffering and so on, that encourages different grasses and other perennial plants to compete amongst each other to maintain a balance of various species.

Off of this bank we’ll be growing thick tussocks of grass and/or plants that can act as an insects ideal habitat, whilst allowing for safe residence and movement similar to a wildlife-corridor. These insects will do a lot for you, including acts that go unnoticed such as balancing soil nutrition, organic decomposition, or ground aeration, however the overarching goal that you can easily notice is controlling pest insect populations near you.

As a extra add-on, this bank that fosters an array of insects also provides a beneficial food resource to the fauna that prey on these insects, most importantly through the winter when food resource are thin. For any wildlife enthusiasts, you may be excited to hear that other wildlife such as hares, partridges, and harvest mice may also inhabit the banks on occasion.

There is a benefit to a balanced ecological system that will benefit your green space, which you read about here.

Fixing an Wildlife Issue, to Fix Yours!

We’re lacking in a number of habitats for certain wildlife currently, and whilst there are still dense grass zones and intact hedgerows, it is an issue of unconnected habitat corridors and the low quality & quantity of habitat area compared to the past. By providing a space for these insect species you can encourage a local population that in the Spring will move to hunt amongst your crops & flowers, and furthermore even allowing them to overwinter in dense numbers.

Modern dense grasslands typically lack the correct grass species mix, often dominated by other species, and don’t create that ideal habitat to host beneficial insects. Then there’s also the issue of overly-expansive fields in which these small of stature insects may takes weeks to cross if they aren’t able to fly. By correctly positioning a Beetle Bank, you can allow insects safe yet quick access to nearby resources.

The concept of mid-field refuges may also be of benefit to you, as they are akin to hedge-banks with no woody shrubs, available as refuge stepping stones during long distance travel in which predators can overwinter and spread to their hunting grounds in the Spring.

In these conditioned environments the insect population that inhabits these banks can be even higher than the traditional existing field boundaries. Which is exactly what you want.

Because of the low number of suitable habitats for these predatory insects, the beetle banks you create will become hugely dense with these sleepy mini-beasts during the winter, only to spread out during the Spring. This of course means that your garden receives the the healthiest does in the reduction of crop pest species by virtue of it’s proximity.

As a final additional benefit, this is a project with easy maintenance, requiring mowing only during the first year, and after which it is best left unmanaged! So after the hard work of creating it, all that’s left is letting it carry on doing as it likes.

Speaking of which, let’s get into it!

Building a Bank

  1. You’re aiming to create a raised bank of soil, whether it follows a straight line, fit’s into a corner, or shaped as a circular mound. You can raise for up to 40cm in height, with a width of your preference.
  2. September is the best time to hand sow your soil with a mixture of perennial grasses, but aim for a high percentage of “tussock-forming” and/or “mattock-forming” species (listed below), alongside a mix of fescues, bents, or even tall-growing wildflowers. If you can’t do September, then the following Spring is a good option.
  3. Up to three cuts in the first Summer can be helpful after the sward reaches a height of 10cm, one cut for every time it reaches this height. By doing so it controls the encroachment of annual weeds, and encourages new shoots of grass to grow to make dense, tussocky grass.
  4. At this point your beetle bank will have established itself and be largely self-maintaining! You will only need to cut the grassy strips to regenerate dead tussocks, which will likely be several years in-between.
  5. Two-to-three years after the initial sowing, these banks will have developed into a suitable habitat for your overwintering insects, benefitting your garden with a healthy food chain.

Ever-important Plants

Native plants that, once established, will create strong connections to the wildlife that is naturally present within it’s surroundings. These aren’t the only species of plants you have to use, and can eb taken as reference.

Grass mix containing tussock and mat-forming species;

  1. Cocksfoot
  2. Timothy
  3. Red Fescue
  4. Ribwort Plantain
  5. Crested Dogstail
  6. Tufted Hairgrass
  7. Tall Fescue
  8. Sheeps Fescue
  9. Fescues & Bents

Tall or mat-forming wildflowers;

  1. Sunflowers
  2. Coriander
  3. Borage
  4. Buckwheats
  5. Yarrow
  6. Tansy
  7. Oxeye Daisy
  8. Teasel
  9. Black Knapweed
  10. Red Campion
  11. Musk Mallow
  12. Wild Carrot

The added benefit of providing additional mixtures of wildflowers & grasses is providing food and further habitat for multiple species, including endangered or struggling species. With local native plants, the restoration of the surrounding ecology can be supported.

And there you have it!

Whilst they make take a while to get rolling, they are an interesting feature akin to shaggy green hills to have displayed in the garden, teeming with tiny critters who’s sole goal it’s to help you keep pests populations down.

I’m sure you can get creative with the design to create your own unique backdrop suitable for your personal garden designs. I’d be very interested to see the many outcomes from this.

If you’re craving more of a similar brand, feel free to read more on the Habitat Management section in my blog!

Happy Reading!

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