While governments are meeting in Montreal these weeks about better protection of biodiversity, professor of plant ecology Hans de Kroon and PhD candidate Robin Lexmond show what has already been achieved over the past fifteen years in the countryside of the Ooijpolder, near Nijmegen. How butterflies flutter to and fro again. How orchids started to bloom.
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“But this is about the worst day to show that,” says De Kroon. On this Monday morning, late autumn, it is grey, gray and drizzly. Just as Lexmond jokingly says that biodiversity is “a long way off now,” a wren lands in a nearby bush and hops from branch to branch.
Modern, large-scale agriculture is one of the main causes of the decline in biodiversity. In the tropics, rainforest is being cleared and converted into farmland, especially pastures for livestock, or fields for growing animal feed. After the Second World War, biodiversity in Europe suffered mainly from the intensification of agriculture: the emergence of extensive monocultures with high inputs of (artificial) fertilizers and pesticides. According to inventories by the Netherlands Environmental Assessment Agency, the trend is declining in the Netherlands trend of biodiversity in natural areas meanwhile has come to a standstill. On the countryside sets the decline still going on though.
But not in the Ooijpolder. Many farmers signed contracts here about fifteen years ago to clear parts of their land for so-called landscape elements. We pass them during the walk between the meadows and fields. Rows of pollard willows, hawthorn hedges, herb-rich strips along the fields, pools, faded banks. In return, the farmers receive long-term compensation – for maintenance and lost income. “Especially that guaranteed compensation for 30 years is very important,” says De Kroon. In the distance, an egret perches in a puddle.
common blue
As we pass a row of pollard willows, and great tits chirping after us, Lexmond enthusiastically lists the types of butterflies she has already seen in the area last summer. “Icarus blues, tadpoles, brown sand eyes, small veined whites, and also more special species such as brown blue and orange alfalfa butterfly.”
The crown coordinates a project started last year that investigates how to restore biodiversity in rural areas. More than 4 million euros has been made available for this via the National Science Agenda of NWO. The project will take five years, he says. In addition to the Ooijpolder, the research is also being carried out in the bulb-growing region of the West Netherlands and in the peat meadow area of the Alblasserwaard. “Hey look,” says Lexmond. She points to a field of corn stubble. A hare darts away.
The project that De Kroon coordinates has a link with the Delta Plan for Biodiversity Restoration, set up in 2018, a partnership of nature organisations, farmers, governments, companies and knowledge institutions. Last September they handed over to Minister Van der Wal (VVD, Nature and Nitrogen) a plan for the next 30 years To design 10 percent of the countryside with landscape elements. Until 2030, 7.5 billion euros in long-term fees are required.
For this plan, Wageningen researchers have mapped out the usefulness and effect of landscape elements. Various functions have been investigated, Irene Bouwma says over the phone. Capturing CO2, better control of insect pests in the crops, water infiltration, air purification. “Especially those first two functions stand out clearly,” says Bouwma. That actually makes sense too. “A row of pollard willows stores more CO2 tighter than a barbed wire.” And all those landscape elements give all kinds of extra habitat, protection and nutrition, she says. “From those hawthorn hedges or herb-rich strips, they also move into the crops and suppress pests there.”
Skylark
For the Ooijpolder an initial analysis was made in 2014 of the changes in biodiversity, by the Bargerveen Foundation. Ecologist Marijn Nijssen co-wrote the report. He says that they made a comparison between areas where landscape elements have been deliberately created, and areas nearby without those elements. “Bird species such as warbler and skylark clearly fared better in areas with those elements.” That also applied to many insects, and a species such as the crested newt, says Nijssen. A combination of different landscape elements seemed to work best. Nijssen calls the initiative in the Ooijpolder “a great success”. It does matter, he says, how the elements are maintained. “Farmers tend to want to keep the landscape very tidy. We then say: it could be a bit messier.”
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De Kroon recognizes that image. His father was a farmer. “He always told me: a sloppy farmer is a bad farmer.” The construction and management of landscape elements requires a different approach mindset. “But many farmers really have a heart for nature.”
We walk past a field of rapeseed. There is a hawthorn hedge on the edge. The red berries are still here and there. Lexmond says she also wants to investigate how the landscape elements are used by the different species. “Do they only function as a transit route, or also as a habitat?”
We come to a pool with a reed collar on one side. The pool is dry. While autumn is almost over. The Crown is shocked. “I saw crested newts here a few years ago.” That drought is a sign of climate change, he says. The Rhine and its extension, the Waal, are changing from a river that is partly fed by melting snow, into a river that only receives rainwater. The summers become drier, and then the river drains water from its surroundings. “That will be a huge, additional challenge.”