In this blog post, author Kitti Révész and her team share their latest study exploring the effects of uncut refuge strips on the abundance and diversity of arthropods.
What is the best management practice of hay meadows from an arthropod conservation point of view?
Grassland arthropods are declining as a consequence of land-use change and intensive management. There are efforts to spread extensive management through agri-environmental schemes (AES), which include modifications like postponing first cut, omitting fertilisers and pesticides, and leaving uncut refuge strips.
Leaving refuge strips can be crucial for grassland arthropods’ survival during mowing. Besides providing shelter, the left vegetation also serves as a food source, oviposition site, and refuge from predators for the rest of the season. Refuge strips are becoming more and more popular, as part of AES across Europe. The typical minimum requirement and the most common practice is leaving 10% of the vegetation uncut. The width or arrangement of uncut areas is not standardised.
So what is the best way to leave uncut refuge strips? Do different details matter for arthropods? How do different groups of arthropods react to changes? We attempted to find the answers.
Testing different arrangements of refuge strips
We tested the effect of two different widths (3m and 9m) and proportions (10% and 25%) of refuge strips of total field area on local abundance and richness of arthropods. We conducted our large-scale experiment on Hungarian puszta grasslands (namely on Csanádi puszta) of Körös-Maros National Park. We studied five arthropod groups (grasshoppers, true bugs, carabids, ground-dwelling and vegetation-dwelling spiders), which we sampled by sweep-netting and pitfall traps, two weeks after the single mowing.
All studied groups were affected by uncut refuge strips but in different ways. We found higher abundance and species richness in the refuge strips than in mown areas for most groups, with up to eight times more individuals in refuges! This effect was stronger on vegetation-dwelling groups than on ground-dwelling ones. Furthermore, we found an interesting interaction effect: abundance of grasshoppers and species richness of ground-dwelling spiders and carabids benefitted more from the wide-10% or the narrow-25% combinations.
What kind of uncut refuge strips to leave, then?
First, we encourage all practitioners to leave some refuge strips for arthropods in their fields as it is clear how useful they are in arthropod conservation. If you want to choose an arrangement favouring more arthropods, we suggest choosing from the ‘wide strips with 10%’ or ‘narrow strips with 25%’ combinations! Nevertheless, our grasslands are less productive, and all protected by the national park. Thus, from an applied aspect, 10% uncut area with 9m wide strips might be suitable for more productive grasslands.
You can find more about our research group’s works at https://x.com/MTALACE or visit https://lace.ecolres.hu/ for our webpage.
Read the full article: “Supportive effect of uncut refuge strips on grassland arthropods may depends on the amount and width of strips” in Journal of Applied Ecology.
