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Stone gardens - a threat to biodiversity in urban areas

We all know, biodiversity is under threat. In Germany, we experienced a reduction of ¾ of insects’ biomass in protected areas within a period of 27 years [1]. These numbers are threatening, as our ecosystems and agriculture strongly depend on insects and especially pollinators.

Action by a german supermarket in 2017. All products depending on bees were taken out of the shelf.

Here a short summary of some of the services that insects provide [1; 4]:

  • The pollination of wild growing and agricultural relevant plants

  • They are a very efficient pest and parasite control for plants and other animals

  • Providing a food source to other species – especially birds, reptiles and amphibians

  • They break down plants and other organic material (like dung of larger animals), which contributes to the soil cycle and its fertility

  • The provision of goods we use, like honey or silk

  • Recreational and intrinsic value (Fishing, Photography, Gardening etc.)

These services are provided for FREE, imagine! We have never thought about the value of these benefits and now the decline of species richness and abundance hits us noticeable. You can calculate the demand of fertilizer you need to replace beetles, which do the turnover by decomposing organic material into fertile soil. You can calculate the harvest loss of trees, which don´t get pollinated. You can calculate the decline of other animals and plants, which heavily depend on insects for their own survival. Our own future is currently jeopardized by further intensified agriculture, landscape changes and the climate crisis to name only few of the big ones.


What is needed now is space for insects, it sounds ironic, doesn’t it? And I don´t mean that we need more habitats for specialists such as xylophagous – wood eating - insects (which we need, too).


I am talking of urban areas, which can be designed to be suitable for insects. Natural habitats are becoming smaller and urban sites are increasing. Not all insects like it near human settlements, but some can be supported by proper gardens, or meadows and parks. This means, urban areas are of great importance for all types of insects and especially bees [3].


Let´s get to the point now, I want to speak about gardens, and especially about the latest trend in low effort gardening: Stone Gardens. By this, I don´t mean small sectors with a pile of stones for potential reptiles or little artsy stone-heaps. I speak of whole gardens covered with gravel, sometimes with one (often exotic) bush or tree and all other types of plants abandoned. People cover the soil with a plastic liner and then they add gravels because they think its practical, cheap and apparently pretty.

Here some negative examples:

These kinds of gardens are the worst, when it comes to nature conservation. There are many species, which have adapted to human settlements, they use urban areas as their all year habitat or settle for certain periods. This means, that by YOUR choice of garden substrate, YOU decide, how biodiversity and abundance in your area are evolving. Wild bees for instance will not accept to live in bee hotels, if there are not enough sufficient food sources in the nearby environment. In times, where we are told to eat less meat, reduce our waste and avoid cruise ships; that we are potentially able to contribute with conscious consume to make a better planet, why not also get active in our homes?


I understand that gardening can be a hassle sometimes, but the reward is worth it. To help you out, here a list with some reasons, why a stone garden is NOT as nice as you might think:

  • It is more effort to keep weeds out of such gardens as you may know

  • Conventional plants will serve your garden as air condition, which will be especially useful for hotter summers to come (hello climate change)

  • Without plants, there won´t be insects and neither other animals which prefer a green garden, like birds and hedgehogs and squirrels

  • Gardening is actually a hobby, which actively supports human wellbeing [2]

I had a little discourse with a dear friend about this topic, and after explaining the need for extensively managed gardens, she planned on creating a little meadow strip at her own garden. This was such a wonderful exchange and I hope that next year by this time she´ll send me her results.


To shape your garden insect-friendly is not too hard. There are endless amounts of blogs, homepages and people, who would love to show you how to make this happen.


There are a few things to consider:

  • Depending on the pre-existing soil conditions you might have to prepare it for the establishment of flower strips.

  • Make sure you use plant species which originate from your region!

  • There are a couple of plants which might look nice, but they don’t provide good or enough food for insects, so be careful with your selection.

  • If you add features to your garden, like a bee hotel or bricks and such, make sure you check the needed requirements for these gadgets.

  • Useful features would be for instance small water places and sports for insects to rest during winter like a bunch of leaves and some twigs in an unused corner of your garden

Most important: Be patient, sometimes it takes one or two years to successfully develop the insect friendly garden. Insects also need some time to find their new hot spot. Trust me, at the end you will feel, how much more live your garden contains and that you are contributing to nature conservation in urban areas for our maybe hardest working livestock and secret pets – insects.


If you come up with more ideas and reasons for insect friendly gardens, let me know!


Last but not least, here some images of one of the insect friendliest gardens I know. As you can see, it is beautiful and still well organized. There is no need for a gravel-only garden ;-)

Extra: Websites (in German), which can be usefull to read (Advertisement is not intended, but sometimes it´s shops and certain institutes, which provide proper information):

https://www.plantura.garden/gruenes-leben (Insekten freundliche Pflanzen)

https://www.wildbienen.info/ (Wildbienen Nisthilfen)

https://www.nabu.de/umwelt-und-ressourcen/oekologisch-leben/balkon-und-garten/tiere/insekten/index.html (verschiedene Artikel)

https://www.geo.de/natur/nachhaltigkeit/19701-rtkl-zeit-sparen-und-tiere-schuetzen-warum-sie-ihren-garten-jetzt-nicht (-aufräumen-sollten)


Here two more in English (it`s not that easy to find sources):

https://friendsoftheearth.uk/bees/beefriendly-plants-every-season

https://www.amentsoc.org/insects/insects-and-man/gardening-for-insects.html

[1] J. E. Losey and M. Vaughan, “The Economic Value of Ecological Services Provided by Insects,” Bioscience, vol. 56, no. 4, p. 311, 2006.

[2] K. C. R. Baldock et al., “Where is the UK’s pollinator biodiversity? The importance of urban areas for flower-visiting insects,” Proc. R. Soc. B Biol. Sci., vol. 282, no. 1803, pp. 20142849–20142849, 2015.

[3] R. Home et al., “Effects of garden management practices, by different types of gardeners, on human wellbeing and ecological and soil sustainability in Swiss cities,” Urban Ecosyst., vol. 22, no. 1, pp. 189–199, 2019.

[4] H. Sumser et al., “More than 75 percent decline over 27 years in total flying insect biomass in protected areas,” PLoS One, vol. 12, no. 10, p. e0185809, 2017.

© Cover image: NABU.de © First image: utopia.de © Image block: https://www.facebook.com/GaertenDesGrauens/

© Image block at the end: Provided by a wonderful granny that I happen to know

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