Mow whoever can!

The Regional Natural Park is currently contributing to a study conducted by the National Museum of Natural History to assess the effectiveness of "late mowing" practices on biodiversity.

The advantages of late mowing

By delaying the cutting of meadows beyond the usual period, late mowing allows plant and animal species dependent on grassy environments to complete their reproductive cycle. This delay particularly encourages plant fruiting and bird nesting.

As part of a national study coordinated by the French Office for Biodiversity and the PatriNat Joint Service Unit, monitoring is being carried out across the entire territory to better measure the benefits of these practices. The Park, already involved between 2020 and 2024, has been selected to continue this monitoring on new plots.

Structured local monitoring

At the local level, the "traditional" mowing date is estimated to be around May 15. On the Natura 2000 sites of the Nizonne Valley and the upper Dronne, several farmers have voluntarily committed to Agro-Environmental and Climate Measures (MAEC), thus pushing back the mowing date to June 19 or 29.

To assess the effectiveness of this system, six plots are being monitored by the Park from spring 2025 until 2029. The objective is to compare three meadows subject to delayed mowing with three others not affected. An initial characterization of the sites (geology, topography, management history) was carried out, and botanical, ornithological and entomological surveys will be carried out annually for five years to assess the state of biodiversity.

At the same time, between mid-May and early July, the Park's teams will conduct four rounds to record the actual mowing dates within a one-kilometer radius of the six plots studied. This data will help better contextualize the results obtained, taking into account the immediate environment.

First observations

During this first year of monitoring, two remarkable butterfly species were observed in meadows benefiting from delayed mowing. The Succisa Fritillary and the Marsh Copper, both protected, are species that frequent wet meadows with diverse flora. Since late mowing is one of the factors promoting the floristic diversity of plots, the presence of these species therefore seems to confirm the usefulness of the approach. However, reliable conclusions will have to wait until the end of the study.

By mid-June, only a quarter of the monitored meadows on the upper Dronne had been mown. While the May rains may explain this relatively low mowing rate, only continued monitoring over several years will provide sufficient perspective to assess this.

Local observations will enrich national data, contributing to a better understanding of the effects of late mowing. Ultimately, the results could encourage wider adoption of these biodiversity-friendly practices.