Biodiversity on arable land – some treasures on cereal fields
Arable land often looks quite uniform. On the right side of the photo above, you can see a wheat field – with wheat and not much more. But it cereal fields can be much more colourful, as the left side shows. Many of us link cereal fields with poppies and cornflowers. In fact, one of my earliest memories is a cereal field full of poppies in front of the building we lived in. I was only three years old and this house and field was in Algeria, where we lived for a while after leaving Chile. Since then, I always associate poppies with that sight. But nowadays this has become quite rare. Usually, I see more poppies on road verges or gardens than on fields.
Poppies, cornflowers and many others are plant species that are typical for arable land. These two may be the best known, together with chamomile, field pansy or creeping thistle. Some less known species need fields, too, to thrive. As Klaus Weddeling from the biological ward in the Rhein-Sieg province (Germany) says: “These plants need fields to grow, they wouldn’t grow here without agriculture.”. He works on maintaining this typical flora on fields and grassland. When I called him to talk about the contract conservation work he does, I also asked to come with him one day. Last week, I had the chance to attend a control on different cereal fields in this program.
Three Red List species on the first field
The first field we check started well: it became part of the program only recently. But as it is strangely formed (with many angles and a long and narrow “tail”) the farmer dedicated the whole field to it. Farmers can participate with cereal fields (except maize) and have to leave a boarder stripe of 12m around the field without pesticide treatments. In this field, this would mean leaving only a tiny central part for “normal” management. Not worth the time and effort. At first sight, there’s plenty of windgrass on the field, which gives it a look of wearing a veil. But looking closer, we soon discover much rare plants: the first is a brome grass species, that is on the Red List.
From the three poppy species we find here, one is also on the Red List: the prickly poppy. My favourite so far. Later we find a rare buttercup: Ranunculus sardous, the hairy buttercup. As a new entry in the program, the field must have 15 typical species for arable land or one Red List species to qualify for it. We found more than that; and with three Red List species it’s on the safe side. Next are several fields from an organic farmer. He’s participating already three years, so here we have to find at least 20 species. All fields do fine, though the density of Red List species decreases a bit. but on one we find my personal highlight of the whole excursion: Knicksia elatine, the cancerwort.
Sowing wild flowers
Sometimes, it’s necessary to help nature a bit by sowing flowers that don’t appear naturally. This is the case in the field of the featured image above. Here, Weddeling not only sowed the flowers, but also the cereal on the strip designated to the program. “In these cases, I chose less common flowers, no field pansies or chamomile.”, Weddeling says. Instead, we see field larkspur and Venus’ looking glass. Both following close up to the cancerwort on my favourites list.
Sowing flowers isn’t first choice. Also because of the costs: the seeds are expensive, up to 30 € a kilogram. This is because it’s not enough to sow the typical species, the seeds must be regional. “The phenology of the plants is genetically fixed”, Weddeling told me on the phone some weeks ago. Phenology is the science of periodic events in the life-cycle of plants and animals. Like flowering or fruiting for plants or the flight season of solitary bee species. The same species flowers at different times if it grows in the mild Rhine area or in colder Northern Germany. If you sow seeds from the Rhine in the North, these plants would flower earlier than their native cousins. Because it’s in their “life-history program”. Therefore, all seeds used in this program are regional. That means that seeds have to be collected from natural sites, bred to produce more seeds and then sown on the designated sites.
Arable land as valuable habitat for insects
Though this was a day dedicated to plants, of course I looked for bees as well. It wasn’t easy, as it was a warm day and they were very mobile and didn’t stay for a photo. I was most lucky at the creeping thistles: these bee magnets attracted loads of bumblebees, but also some solitary bees.
The thistles were also very popular with butterflies, which aren’t any less mobile than the bees. Only a peacock was collaborative that day. We also saw swallow tails that day and marbled whites. One of the swallow tails was laying eggs, the others just passed by flying. Like saying “Oh, hi, but I’m sorry I can’t stay for longer!”. The chamomile was also popular with different bees. At least, I managed to get a photo of a masked bee. But there were also several halictids, a spider wasp and several hoverfly species.
Arable land is actually also a valuable habitat for a variety insects. They follow the plants and the structures within and around the fields. For instance, the song of great green bush-crickets is a typical summer sound. We heard and saw several of them in different fields.
With plenty of wildflowers and insects also the birds and other vertebrates follow. We didn’t pay that much attention to them this day. But nevertheless saw a red-backed shrike and a young sand lizard. All this shows: arable land can be a valuable habitat for a variety of plants and animals. It’s all a matter of proper management.