Digging Deeper: What do moths think of agroforestry?
Through the Digging Deeper series, you can follow the developments and results of Inagro's own agroforestry plot from the front row. In this edition, you'll learn more about the leek yield on our plot, the battle against excess water, and the activities and other events on-site since the last update.
Agroforestry and Beneficial Biodiversity
Numerous benefits in terms of biodiversity are attributed to agroforestry. Is it justified or not? With our own agroforestry plot, we substantiate claims like these with experiences, observations, and practical data. Permanent wood elements such as trees and shrubs provide a habitat for birds, mammals, insects, earthworms, ... By sowing a perennial grass-herb mixture under the trees, we aim to strengthen this positive effect on biodiversity. From an agricultural perspective, we are particularly interested in the so-called 'beneficial biodiversity,' such as pollinators and natural pest controllers. Night moths also fall into this category.
Nocturnal Pollinators
Night moths are a large and species-rich group within the insects and a crucial link in a healthy (agricultural) ecosystem. They are the bulk food for many birds and bats, but in their quest for nectar, night moths also play a significant role as nocturnal pollinators. In an agricultural landscape with hedgerows, tree rows, and flower strips, we expect to find higher numbers and more species of these night moths.
We would like to guide you through the first summer in which we monitored these night moths. From this year onwards, we plan to repeat this monitoring annually.
Monitoring with LED Buckets
Using LED buckets, we monitored night moths in the tree row and the cultivation area of the agroforestry plot. We also included our demo plot agrinature, where hedges, flower strips, and other biodiversity measures are implemented, in this multi-year monitoring. On 8 different occasions from late May to September, we placed 5 LED buckets in the field for one night, distributed across these locations:
- Cultivation area of the agroforestry plot ('Cultivation AF'; leeks)
- Tree row of the agroforestry plot ('Tree row AF'; grass-herb mixture)
- Cultivation area of the agrinature demo plot ('Cultivation NBA'; leeks)
- Grass-herb strip along the hedge of the agrinature demo plot ('Grass-herb strip NBA')
- Reference in nearby cultivation
The LED buckets attract night moths at night with UV light, after which they get trapped in the bucket. And it's not just night moths that are drawn to these buckets, but also early birds! In the following mornings, our colleague Ruben was always up early to identify and count the species and numbers in each trap on-site.
Small remark, night moth monitoring typically starts earlier in spring, but due to a delayed delivery of the LED buckets, we started a bit later than usual this year.
One trapping location stands out
Most individuals and species were found in the - somewhat older - perennial grass and herb strip that runs alongside a mixed hedge on the demo plot agronature (NBA). From an ecological perspective, it’s always recommended to combine both elements in the landscape. Our initial observations seem to confirm that the hedge-grass and herb strip combination is also interesting for night moths. At this trapping location, we even found 2 species that are classified as "threatened" on the Flemish Red List (the Grass Emerald and the Small Rufous). One of these 2 species was also found in the adjacent cultivation (Cultivation NBA).
At locations other than the grass and herb strip of the demo plot agronature, the differences are less pronounced. The numbers in the reference crop seem slightly higher than at the two other trapping locations in the crops or the tree strip on the agroforestry plot. Possible explanations:
- The reference crop was a flowering crop (grain + legumes and potatoes).
- The leeks on the agroforestry plot and the demo plot agronature were only planted in mid-June.
- The leeks on the agroforestry plot received multiple treatments with low to non-selective insecticides during the monitoring period.
- The grassherbs in the tree strip on the agroforestry plot were well developed by the end of summer but struggled to get started in spring.
Hopeful for the years to come
Currently, we don’t see any impact of agroforestry with grass-herb strips on night moths. This was expected, given that it concerns a recently established agroforestry plot. The grass-herb strips are still developing, and the trees are young and small. Counts on Inagro's agronature demonstration plot however suggest that the combination of wood elements and grass-herb strips is valuable for moths in the longer term. In the coming years, we will continue to monitor our plots. Will our agroforestry plot follow the same path as the agrinature demonstration plot? Only time will tell, but these initial samplings are already promising.
Rewatch the report on plattelandsTV
Last summer, our agroforestry plot was featured on Tournée Provinciale on PlattelandsTV. Inagro researcher Willem Van Colen explains the broader research objectives and approach on the plot. Farmer Johan Delbeke also shares why agroforestry is a winner. Missed it? Below, you can rewatch the report.
What happened on the field since the last edition of 'Digging Deeper’?
