Inspired by Paul Nurse’s assertion that ‘our future is tied to insect species’, Julie Clark shares some insight into the importance of incorporating ecological ideas and research in landscape design

    Brian Tomlinson from Milton Keynes, UK, CC BY 2.0, via Wikimedia Commons

    It’s easy to say that to respond to the Biodiversity and Climate Emergency, we need to design differently. Deciding what to do is much harder. There’s a lot of science out there, and it’s impossible to grasp it all and keep up. We might work with ecologists, but we probably think with different assumptions and frameworks.

    I decided to look at insects as a ‘thinking tool’, because once upon a time I was a biologist looking at insect evolutionary genetics.

    The more varied our designed environments, the more opportunities we give for different species to survive and reproduce

    The Royal Entomological Society refers to insects as ‘The little things that run the world’, and in land-based systems, they are super important. Add to this two key papers published in 2020 (Moreno-Mateos et al., 2020 and Lambert and Donihue, 2020) which, respectively, demonstrate the need for more ‘network’ and ‘evolutionary’ thinking for biodiversity restoration. Insects are key on both counts. They are vital, and many sitting at the hub of networks makes them work. Yet we hardly notice them or cater for them in our designs.

    Place-making is an intervention in the evolutionary process. In the case of insects, evolution can be fast, and they make an impact. The insect ‘network hub species’ stand the best chance of helping everything on land through climate change.

    The environmental changes due to climate could be pacey. All life will need to adapt or perish. But the nature of the changes made by living things in response (as they change behaviour and/or evolve) is uncertain. The more varied our designed environments within and between sites, the more opportunities we give for different species to find the means to survive and reproduce. We might never know the worth of each design decision, but the more options we use, the more informed our thinking, the more likely it is we will design a winner sometime. Variety is value.

    In a preliminary study, I asked some entomologists to describe their favourite ‘Ento-diversity rich’ sites in terms of physical form and planting.

    They often mentioned the prevalence of water, trees, and veteran trees, as we would expect. Diversity of habitat types in each site was common – up to five, and often more. Generally, the sites contained areas of low footfall. There was also frequent mention of hills and ‘holes’ (old walls, spoil heaps etc). The sites were all old, as if to demonstrate the point that networks take a long time to build. Add to this the working knowledge of bee-keepers and the just-published design of a specialist ‘Ento’ garden (Harper and Reynolds, 2020) and some design thoughts emerge.

    We need mutualism in our design… an appreciation of the insect world and the needs of insects could take us a long way towards meeting that ideal

    Given the uncertainty, recipes for ‘what to include’ help. But it would be equally useful, if not more so, to support insects by the way we think in the design process and in the tools we use.

    As Xiang (2016) puts it, we need the value of mutualism in our design. This isn’t a shift in thinking for most of us. However, a general appreciation of the insect world and the needs of insects could take us a long way in meeting that ideal. Perhaps the thinking we need is almost the same as we do for the human aspects of a site. We add in insect need and scale to overall guiding principles, food sources, ‘homes’, transit, climatic conditions and exposure. The exception to this is that for humans, we never set traps! So we need to add ‘no traps’.

    Overall principles

    • The more habitats, the more species we will support.
    • Old plants and structures might be home to network species.

    Insect scale and need

    • Pollinators: A new insect-scale measurement here: it takes 2 million flower visits to make a 1lb pot of honey, not 2 million flowers. But that’s still a lot of flowers. A hive needs roughly 60lb a year to keep going; how many hives has your design supported? Where do the night-time pollinators feed? Where do the herbivores, dead wood and debris eaters feed? Is there water to drink?
    • Shelter/homes: Insect-scale holes and caverns can be in stone, live and dead wood, plant litter and earth. Is anywhere in the design ‘burrowable’? Is there water for aquatic insects?
    • Climate and exposure: Another new insect-scale measurement: There can be a 10 ̊C temperature gradient along a wheat stem. If you are 4mm tall, then a 2m mound is to you as Mount Snowdon is to a human, with the associated wind, rain, dryness and shadiness changes. Micro-micro-climate matters.
    • Transit: Insects perceive the landscape very differently to us. (Heinze (2017) nicely illustrates how they navigate it). Quite a lot of their perception is outside the design domain – no-one changes the magnetic field, for example! But we can see that access to starlight is needed.

    The traps

    There are some ecologically demonstrated pitfalls: notably, homogeneity of planting and form as urbanisation grows. There are myriad planting choices – don’t forever rely on your old favourites and repeat the same habitat time and time again. It might not suit the variety of options we need for the uncertain future.

    We know some things are actual traps; they attract insects and stop them thriving and reproducing. Examples are light and hard surfaces, and green roofs that are too high. These, among others, cause harm to that important network. Let’s not set traps unless they are vital in other ways.

    Tools

    We are using ever-more sophisticated design software containing pre-defined and user-defined plant and hardscape information. We work on the basis of case studies. This is not unlike the medical world. It seems to me there is scope to look at design software in the same way.

    The information about plants could include data such as the diversity of insect species supported by different trees, or the ‘nectar value’ and ‘nectar time’ of plants. This is not impossible if added on a user-wiki basis, with everybody – designers and ecologists – involved in updating it. Individual designers could then see if their design looked like it was producing ‘diversity value’. Put together, a collection of design details and planting schedules could make ‘big data’. It would be possible to see if there was ‘creeping homogeneity’ in our city developments. A designer could check if their own diversity support was increasing as they went along, or whether they were accidentally producing homogeneity over their careers. At last, there would be the beginnings of an accessible means to measure the impact of designs over time and different spatial scales.

    Julie Clark (with thanks to the Royal Entomological Society and in particular, the Outreach Special Interest Group)


    References

    • Harper, P. and Reynolds, S. (2020) ‘Garden’, Royal Entomological Society. Available at:
    • https://www.royensoc.co.uk/garden
    • Heinze, S. (2017) ‘Unraveling the neural basis of insect navigation’, Current Opinion in Insect Science.
    • Elsevier Inc., 24, pp. 58–67. doi: 10.1016/j.cois.2017.09.001.
    • Lambert, M. R. and Donihue, C. M. (2020) ‘Urban biodiversity management using evolutionary tools’,
    • Nature Ecology and Evolution. Nature Research, pp. 1–8. doi: 10.1038/s41559-020-1193-7.
    • Moreno-Mateos, D. et al. (2020) ‘The long-term restoration of ecosystem complexity’, Nature EcologY and Evolution. Nature Research, pp. 676–685. doi: 10.1038/s41559-020-1154-1.
    • Nurse, P. (2020) What is Life? Oxford, David Fickling Books
    • Xiang, W.-N. (2016) ‘Ecophronesis: The ecological practical wisdom for and from ecological practice’,
    • Landscape and Urban Planning, 155, pp. 53–60. doi: 10.1016/j.landurbplan.2016.07.005.

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