Cycles

In general, nutrient input is the main reason why plant biodiversity is declining so much in Central Europe because everything is fertilized like crazy—on the one hand by agriculture and on the other by industry and traffic. The nitrogen oxides that rain down with the rain are already enough to be considered basic agricultural fertilization.

But the beauty of the cemetery is that we have both low-growing plants—grass and shrub level—but we also have trees of different heights. And that of course gives many creatures the opportunity to settle there and then live in the different layers, like in an apartment building, and that works very well. You can see a small singing bird in the same corner, while a blackbird is looking for worms—and at the very top you can see a crow or a hawk. It's nice to see so many bird species so close together in such a relatively small place as the cemetery.

It's a very beautiful ecosystem—quite diverse, which is something we don't find so easily in the countryside nowadays—and unfortunately not so long-term in the city either. In the city there are biodiverse spaces, but not with such a long history.

There are many old trees that are already rotten and have hollows in them that are occupied by hollow breeders. There are over thirty bird species that have been recorded here on the site—for such an inner-city area, that's quite respectable, and there are also species that are strictly protected: Owls are here—at least as a hunting ground and some of them have their roosting trees here. The other day, for example, a goshawk was on the move here, they are also strictly protected. The entire bird population is in massive decline and areas like this one are of course extremely important in order to provide them with retreats in the cities.

So the birds that live in the garden all year round, that don't migrate south—let's take our house sparrow—it depends on finding something to eat all year round—also in winter. And these are usually seeds, that means any seeds and the like from plants. In other words, the more plants you have in an environment that provide such things, the better it is for them. On the other hand, in order to raise their young, they need proteins and insects, and the little sparrows eat insects. And that in turn means that we have to have a lot of plants that provide food for the insects. Be it in the form of pollen or nectar, or wood in general is also incredibly important for various types of beetles and the like. In other words, what we need is a good selection of plants.

The most important factor for the plant composition we have here is mowing. Depending on how often, in which places, in which way and how short the mowing is, different plants can assert themselves. All these early-flowering plants would not be in such conspicuously large stands if they were not mown regularly here, thereby eliminating the competition. In nature, it tends to be the case that one plant grows somewhere and says “I'll grow here” and then twenty others come along and say “let's see that first”. The plant that is best adapted to the location and is the most competitive will prevail. In Central Europe, this applies mostly for trees. If we didn't mow regularly here, it would all be a complete thicket, which would reduce the diversity of species.

What we need is biodiversity. Both we and the animals need that, and it's good for all ecosystems. And what does it take for that? In any case, we need to leave a bit to itself. There are areas here that are tilled—a lot happens here, but then there are many areas, for example this hedge back here: I bet nothing has happened there for years, which means that creatures definitely nest there, hedgehogs certainly feel at home there, there might be many insects and a layer of humus has already formed on the ground over many years—such corners that are simply left to themselves.

Up to now it has been like this in parks or in green areas around houses and apartment buildings, which are constantly mown. You always have this English lawn everywhere and it's terrible, it's hostile to life. It's not really good for anyone. We got used to it and we think it looks good—a well-kept lawn is a short lawn—but a well-kept lawn is ecologically dead. There's nothing in it, nothing lives in it, it's not good for anything or anyone.

We already have flowers actually blooming at a very early stage, often as early as February, for the first insects, which then slowly but surely wake up. Whereas I have to say that both the gardeners on site and I think that this year we have terribly few bumblebees. We don't have any data for this, we haven't caught any, but because we are often there and look around and observe, we got the impression that there are far fewer bumblebees this year than last year and I have also seen very few butterflies so far. So far I haven't seen a single peacock butterfly in the whole of Berlin.

Many creatures are also specialists: for example, they have a long proboscis that can only get into a certain flower shape and then they are not provided with a daisy. Or a butterfly that first has to look for the nearest black alder, which is kilometers away, may simply not make it. In other words, you ultimately need a habitat in which a variety of plants is available—otherwise you end up with no variety of anything.

Of course it is also fascinating to observe—which plants are now winners from climate change and which are the losers. The birch trees are all dying off because it's just too hot for them in the summer, but other species like the field garlic that used to be not so widespread here, now grow everywhere. Also walnuts: Young plants are relatively sensitive to frost and in the past there was always a hard winter that shaved the seedlings. That's not the case nowadays but the winters are actually all so mild that the walnuts get through and that's why you see young walnut trees coming up everywhere in the cemetery.

Just let things grow where you might say it looks overgrown, but that's usually much better for plants and animals than an English lawn.