Katrine Turner, MSc, PhD

Biodiversity is one of the major global challenges that we face, as it is rapidly retreating across the entire planet. I believe that one of our most important tasks is to integrate nature into as many contexts as possible, and to alter our approach.

My motivation

My motivation for taking part in this project: Contribute to development of the design of urban furniture and multidisciplinary collaboration.

My best tips

Use native plants

The insects that live in towns and cities are adapted to the plants that grow locally, and many rare species in particular have found it difficult to find food in exotic garden plants.

Flowers all year round

It’s not just in the height of summer that insects need flowers. In the spring and autumn in particular, flowers can provide food for many insects.

Preserve old trees

Ancient crooked and hollow trees provide food and shelter to many fungi, insects, birds and mammals.

Living wattle fences

Garden waste, such as old branches and sticks, provides an excellent source of food for many insects, birds and fungi.

Life-giving water

Create a small pond of a size which suits your garden. Water is vital for all small garden animals. Whether as a source of water to drink or a place to live and/or breed.

Sunny warm spots

Many insects love south-facing slopes and warm nooks and crannies, and they need a little bare soil to make nests on for their eggs too.

Let the grass grow

Select a few areas where you can let the grass grow. Long grass provides shelter for many small animals.

Create habitats in your garden

Even if you don’t have much space, you can still help by building dwellings for bees, birds and bats. This will enable them to find shelter and space for their eggs.

Nature takes time

Once you have made some changes to encourage wildlife into your garden, give nature plenty of time to establish itself.

Take an interest in nature

Put names to species, follow all the wild things that are happening in your garden.


WINGS Bird box - entrance

By Katrine Turner.

Where would starlings build their nests if we didn't put up nesting boxes for them? Before humans came along and took control of the landscape, birds built their nests in old trees, in places hidden by tall grass, in bushes or on rocks, but many of these options have gradually disappeared as we have expanded, and birds often lack opportunities to breed. Most urban spaces would benefit greatly from putting up nest boxes for birds as a replacement for their lack of natural nesting places.

Different bird species have different preferences as regards where, when and how they want to build their nests. Swallows and swifts build under canopies, eaves and in old barns, where they are a pleasure to watch as they elegantly dash in and out—a sure sign that summer is on its way. Swallows mix mud with their saliva, and they are good at repairing old nests to keep using them. Blackbirds weave their nests out of twigs and moss and hide them in bushes, hedges or treetops. However, many of the birds we see in urban areas prefer to use spaces they could previously find in old trees. These birds would be happy to use nesting boxes. The size of both the nesting box and the entrance hole can be adapted to attract specific bird species. And maybe you didn’t know that it’s not only the classic garden bird species that benefit from man-made houses?

It's important to think about the size of the entrance hole and location when setting up bird boxes, as some species can be quite picky. Thought it’s always better to have a random or incorrect hole size than not put up a bird box at all. It’s a good idea to adapt the configuration to the species of bird you want to inhabit the box. Some species such as sparrows or starlings like to live close together in colonies, while others such as great tits and blue tits are territorial, so the boxes must be put up at a good distance from each other, or neighbourly disputes will occur. Similarly, some birds want to breed in the shelter of bushes, while others would prefer to be up high and have a good view, e.g. kestrels. We have gathered this information together in the table below.

You won’t necessarily have birds moving in right away, but they will eventually. It may be a good idea to put up the boxes in the autumn or winter, so that the birds can get used to them and the human smell can wear off. When the nest boxes are set up and birds have moved in, they should not be disturbed. Although the adult birds might not be home, they will probably be nearby and watching as you look for the small chirping chicks. This makes the birds stressed and in the worst-case scenario might even force them to find a new place to breed and leave the chicks in the box. You don’t need to clean bird boxes, the birds can do this for themselves, and if you don’t clean them, you might get lucky and have a colony of bumblebees move into the box the next year. This won't happen if you clean the box because they reuse the birds’ nesting material. As well as the nesting boxes themselves, it’s always a good idea to have a lot of scrub and brushwood and preferably native flowers nearby, where the birds can find shelter and peace, and insects they can eat, as not all species of birds eat seeds.


Retain old trees and make sure there is plenty of dead wood lying around

Gnarled old trees and dead wood, i.e. dead branches, cuttings and tall tree stumps, are important for encouraging more wild nature into your garden. Dead trees and brushwood are traditionally seen as litter which must be taken straight to the recycling centre, but disorder makes for thriving life. They form fantastic habitats and excellent sources of food for many insects, fungi, birds and mammals.

Gnarled old trees
Thousands of insect species thrive in old trees. Yet some of us humans are not very keen on them. As soon as an old tree gets a little fungus on it, puts the garden in shade or looks like it might fall over in the next storm, we start thinking about it as a danger and fell it. We have actually got to the situation where we simply do not have enough old trees across the entire country, especially those which have been allowed to grow in the sun and become beautiful and gnarled. Of course, it takes a ridiculously long time to produce an old tree and they are now in short supply. As a result, the many species that are linked to habitats in old trees are now also in decline. If you have an old tree in your garden or a communal area, take really good care of it. Instead of felling old trees, pollard and trim them, so that there is no risk of them falling over or dropping branches onto the heads of people below.

You can also help by creating good habitats in old trees by “veteranising” them, i.e. damaging them without destroying them, thereby creating cavities for use as natural bird’s nests and places where bats, ladybirds and small tortoiseshell butterflies can overwinter, and tree-dwelling beetles, fungi and bees can live.

However, if you do have to fell a tree, leave a 2 to 4 metre high stump and leave it to decay very slowly. Tree stumps form valuable habitats, especially in sunny spots. Climbing plants such as honeysuckle and ivy can be planted up against the stump, or bird boxes can be put up if you don’t think the stump is sufficiently attractive in itself.

Brushwood and firewood stacks
Piles of brushwood, leaves, garden waste and hedge clippings or a stack of old firewood logs can also be used to create important habitats around the garden. These are the most effective bug hotels around. They have many nooks and crannies which the animals can use to hide in, eat off and decompose. Piles of brushwood are a hedgehog's winter paradise and also act as nests for their young over the summer. These piles are easy to make, and the bigger the pile and the more piles you can create, the better. So, keep all your garden waste and leave it lying around the garden, both in sunny spots and under a hedge or bush, for example. This will maximise the variation in conditions in the stacks, enabling as many different species to live there as possible.

Once you have created your brushwood stack, it can just be left to look after itself. Do not disturb the stacks, but add new material from time to time. Then the animals will not have to move to a new stack every year. You can look inside the piles and admire the life in them if you do it carefully, just remember to put the branches and leaves back in place again.

Stacks of brushwood and firewood can be arranged in interesting or artistic piles, like attractive brushwood hedges, or placed in large piles. Small animals and fungi will not care what you do, so let your imagination run riot. If you want a stack of brushwood on your balcony, it is a good idea to create a bug hotel, so that it all fits together. You can also use some hollow pipes for bees to lay their eggs in. Just make sure they are at least 15 cm deep.

What you can do:

• Don’t fell old trees. Pollard or trim them
• If an old tree has to be felled, leave a 2 to 4 m stump in situ
• Veteranise trees by drilling holes in them
• Remember that stacks of brushwood and firewood form effective bug hotels


Arrange your garden according to the prevailing conditions

In order to create a wild garden teeming with life, it is important to consider the conditions in your garden and to them. There may be factors such as the amount of light and shade available, the amount of nutrients in the soil or the amount of moisture and water.

The vast majority of soils in Denmark are very rich in nutrients and full of nitrogen. The problem is that the Danish plant species which are most threatened are also those which thrive on nutrient-poor soils. They may well be able to grow in good quality soil, but they cannot compete with the species that grow rapidly. An important reason why many of them are declining is because, in many places, they have lost the battle with plant species which are able to make use of all the surplus nutrients in the well- and over-fertilised areas of Denmark.

No fertiliser
If you want to encourage nature and life into your garden, you must therefore remove nutrients, rather than add them. Remove grass clippings and plant material, and put them in your kitchen garden or in the compost bin. This will make room for plants which thrive in poor soils, improving the diversity of both plants and the animals that will use the sensitive herbaceous and other plants.

Exhausting the soil in this way can be easier said than done in gardens with a rich topsoil. The process can take many years, but it is also a process that is fun to follow, and there are ways of helping it along the way too. Imitate nature, where everything consists of many small niches, and use it to build up your garden. You could for example create an area of pasture with nutrient-poor sand, to compensate for a very rich topsoil. You could also create a woodland bed in the shade of shrubs, which is dark and damp and therefore utilises some of the conditions which occur naturally in the garden.

On balconies and terraces and in courtyards, it is easier to create the right conditions for plants. Here, you can put nutrient-poor soil in your planters and pots, so that the plants only have to compete with themselves, and they can be placed next to pots with species which thrive on rich soils and grow rapidly. It is a good idea to focus on plants which are rich in pollen and nectar resources, because the insects that pass by tend to be flying insects which need to refuel with food and drink.

What you can do:
• Create nutrient-poor soils, which are good for wild plants
• Create niches in the garden which promote different types of biotopes
• Exhaust the soil by removing grass clippings and plant material


Five simple steps to greater biodiversity on commercial land

Here at VILDSKAB, we have put together a little self-help guide to biodiversity on commercial land. It explains five easy steps you can follow on your land to encourage a little more biodiversity, which will produce results almost immediately.

1. Let the grass grow and cut it less often. An immaculate, carefully tended lawn is something many people dream of, yet for animals and plants, it is nothing but a desert. It also costs more to maintain and has a higher carbon footprint. Instead of a lawn, you could create a “grassland”, which could be home to many hundreds of species and provide food and hiding places for many animals. It’s incredibly easy to do, simply let everything grow a little, especially over the summer. If you’re afraid of complaints from customers or neighbours, put up a sign to explain what you are doing. It will help if other people know you are “cultivating a wilderness”. Cut the grass in the early spring and again in September or October, but remove the grass clippings each time!

2. An insect bank, ideally on a south-facing slope, is an excellent place to create better conditions for many wild species. South-facing slopes are particularly favourable, as they are really good places for many wild bee species to make their nests in. A south-facing bank, perhaps with a stone or two, will also trap the warmth of the spring or morning sun, which is perfect for many thermophilic (warmth-loving) animals, such as butterflies and lizards, which need to soak up the heat in order to move around. If the bank is created from a gravelly, nutrient-poor soil, it can also provide favourable conditions for many wild plant species which otherwise find it difficult to establish themselves in nutrient-rich topsoil and lawns. This includes bird’s-foot trefoil, thyme, field scabious and lady's bedstraw.

3. Gnarled old trees and dead wood, i.e. dead branches, cuttings and tall tree stumps, are important for creating more wild natural habitats. In fact, it is both easier and cheaper to preserve what is already of value! If there is an old tree on the plot, take really good care of it. Instead of felling old trees, they can be pollarded and cut back, so that there is no risk of them falling over or dropping branches onto the heads of people below. However, if you do have to fell a tree, leave a 2 to 4 metre high stump in situ to decay very slowly. Tree stumps form a valuable habitat, especially in sunny spots. Climbing plants such as honeysuckle and ivy can be planted up against the stump, or bird boxes can be put up if you don’t think the stump is sufficiently attractive in itself. Branches and cuttings can be stacked beneath trees and bushes and will become habitats for all manner of species. These are the most effective bug hotels around. They have many small nooks and crannies which the animals can use to hide in, eat off and decompose.

4. Flowering trees and bushes are the wildest biodiversity installations. If you plant willow, mirabelle plum, common hawthorn, bird cherry, wild apple, elderberry and guelder-rose, they will flower throughout the spring from March to June and provide food and shelter for insects and other animals. Most of these trees and bushes also produce berries and nuts, which provide food for birds and red squirrels in the autumn and long into the winter, enabling them to survive through to the spring. A tree is much easier to maintain than a flower meadow, and it produces many, many more flowers per square metre than a flower seed mix!

5. But, yes, there is no getting away from it. Everyone do want a flower meadow, even if they are difficult to manage successfully, particularly in the good quality loam soils used for lawns. If you want to use a seed mix, look for those with native species. The grass must be removed—completely—otherwise it won’t work properly. Look for mixtures with devil’s-bit scabious, field scabious, bird’s-foot trefoil, lady’s bedstraw, small scabious*, broad-leaved thyme, oregano, red clover, hemp agrimony and valerian. These species can compete with other species in powdery, nutrient-rich soils and produce beautiful flowers!

Remember to enjoy all the wonderful species you attract to the area and explain to your customers what you are trying to do. If you are looking for other simple ways to improve biodiversity, contact VILDSKAB at info@vildskab.nu and find out how we can help you. We design, hold courses, draw up biodiversity strategies and management plans, give talks and teach about Danish biodiversity and urban nature.

* Denmark