Sinus mowing leads to more (flower-rich) vegetation
The nectar index is a useful method for determining whether and to what extent a roadside verge or grassland contributes to the conservation of insects, butterflies, and native plants. Research shows that the highest nectar score for HHNK is possible on nutrient-rich dikes.
HHNK has sown dozens of dike sections with flower seed mixtures and investigated whether the seed mixtures can be maintained with adapted management. Removing grass clippings leads to soil impoverishment and more vegetation. So that's good news. At more than half of the measuring points, the number of plant species exceeded the target of 30 species per m2, and almost half achieved the highest nectar score.
Nature Network Netherlands
The linear dike bodies are ideally suited for connecting nature areas, such as those in the Dutch Nature Network. That is why, in the spring of 2020, a number of dike sections were sown with a flower-rich mixture. And the results appear to be positive. Ecologist Richa Nanne: "We sow the flower sections on the dikes with native plant species to increase the supply of nectar, and the increase in insects at these locations will also increase the food supply for reptiles, amphibians, and birds, which in turn will benefit predators. So we are restoring the food chain. In addition, varied vegetation provides opportunities for reproduction and shelter."
The modified mowing policy therefore appears to have a demonstrable positive impact on the vegetative diversity of the selected flood defenses. Want to know more? Read the full report here.