Two research institutes, IRTA and CREAF, are working on the restoration of pollinator habitats in apple orchards in Catalonia, Spain. As part of this initiative, a Living Lab has been created, bringing together research institutes, apple farmers, fruit producers, farmer advisors, and fruit cooperatives.
The project is being carried out in 20 apple orchards managed under Integrated Pest Management (IPM). Twelve orchards are located in Lleida (Western Catalonia) and eight in Girona (Northeastern Catalonia).
Co-designing restoration measures
The restoration measures are co-designed with farmers, advisors, and cooperatives to enhance pollinator habitats and improve the availability of floral resources in apple orchards.
The co-designed restoration measures include:
- Plant cover management: Preserving field margins, improving ground cover strategies (e.g., reducing mowing frequency and using alternative machinery), and establishing flower strips with local plant species
- Nesting site preservation and creation: Maintaining or introducing nesting resources such as homemade bee hotels (e.g., bamboo straws) and straw bales
- Adjustment of plant protection practices: Reducing pesticide applications and/or modifying spraying schedules to avoid periods when bees are active, wherever possible
Fieldwork and monitoring
Surveys began in spring 2024 where plant cover management was improved, nesting sites were established, and plant protection spraying was reduced in the restored orchards. In autumn 2024, flower strips were sown in all the restored orchards. The selected species included local, drought-tolerant flowering plants that bloom at different times throughout the year (e.g., Eruca sativa, Calendula officinalis, Borago officinalis, Vicia villosa, etc.).
Pollinator and flower surveys
Fieldwork in apple orchards includes the assessment of apple flower visitation by pollinators, pollinator visitation to the plant cover, apple pollination experiments, fruit set and quality, flower cover, and the availability of nesting habitats. Surveys are carried out four times per year, covering key phenological periods:
- The apple flowering period (March-April)
- Post apple flowering period (May-June)
- Summer (July-August)
- Autumn (September-October)
During each sampling period, each orchard was surveyed for apple flower and other plant pollinators visitation to identify which and how many pollinators are visiting the local flower community, along with a flowering plant survey and a full botanical record to identify the flowering species and flower cover present.
Botanical and nesting surveys
Additionally, other surveys are conducted along the season, to monitoring the nesting structure occupation of pollinators and the pollination services and success. The number of occupied holes per diameter and the material used to construct the nest in bee hotels are recorded at the end of each season. Additionally, straw bale structures are surveyed twice per year to detect bee nests or nesting activity.
To assess the current level of pollination service and identify any possible pollination deficits, three pollination service measures will be measured on 12 trees per orchard, where one branch on each tree is assigned one of three treatments:
- Pollinator exclusion: Branches are bagged to prevent pollinator visits. This provides information about the self-pollination capacity.
- Open pollination: Branches remain unmanipulated throughout flowering to capture the ‘natural’ levels of pollination at that orchard.
- Supplementary pollination: During flowering, all open flowers receive supplementary pollination by hand, using compatible pollen. This provides information about the maximum pollination level.
This follows the RestPoll pollination monitoring protocol. Through this monitoring, we can measure the pollination success, including the apple yield and quality. For example, a few weeks after flowering, the number of fruit set on all treatment branches will be recorded to calculate the apple yield. Right before harvest the number of fruits on each experimental branch is recorded. At the laboratory, measurements of apple diameter, shape, pest damage, weight, sugar content, firmness and seed set are conducted to conclude the apply quality.
Preliminary results
Since 2024, we have observed an increase in both the richness and abundance of flowering species in the orchard alleyways. Notably, there is now continuous flowering throughout the season, a pattern not observed in non-restored orchards. Moreover, the bee hotels show an occupancy rate of over 50%. We recorded more than 100 pollinator morphospecies visiting apple flowers and over 100 visiting the flower strips within the apple orchards.
In the picture
To be continued
They are about to begin the fourth survey period of 2025 and start collecting apples at harvest, which in Catalonia takes place between July and November, depending on the apple variety. The data from the 2025 season will soon be processed, and it is planned to repeat all these surveys in 2026. Together with farmers and advisors, they will assess whether resowing flower strips, adding more nesting sites, or revising the application of plant protection products is necessary.
An important date is also marked on the calendar: November 18th, when the second Living Lab meeting will take place.
