The value of two agri-environment scheme habitats for pollinators: annually cultivated and floristically enhanced grass margins
Agriculture, Ecosystems and the Environment , 2022
We investigate the potential benefits to pollinators of two agri-environment scheme habitats, ann... more We investigate the potential benefits to pollinators of two agri-environment scheme habitats, annually cultivated
and floristically enhanced grass margins. The former encourages annual plant species whereas the latter targets
the provision of perennial plants, both may benefit foraging pollinators, many of which have declined in the UK
since the 1980s. We surveyed thirty cultivated margins and thirty floristically enhanced grass margins across the UK for pollinators, which included bumblebees Bombus spp., solitary bees and hoverflies Syrphidae. Pollinator abundance was then related to margin attributes such as age, width, soil fertility and adjacent habitat type. For cultivated margins we also investigated relationships with cultivation and rotation, and for floristically enhanced margins time cut. Plant preferences of foraging pollinators were recorded in 2019. On cultivated margins, target annual plants were frequently recorded on plots and were repeatedly visited by pollinators with management significantly influencing visitation rates. For example, plots which had been created with ploughing attracted fewer solitary bees and bees overall than those created with minimum tillage. Annually rotated cultivated margins were associated with lower flower abundance, broad leaved species cover and vegetation heights which resulted in lower total bee abundance. We therefore advise that cultivated margins be left in situ on farmland over longer periods. Older floristically enhanced grass margins became dominated by grass and contained fewer flowerheads to support foraging pollinators. Compared to those established via natural regeneration, sown margins were associated with increased bee and Syrphidae abundance, which is probably linked to the high flowerhead abundance and coverage of broad-leaved species on sown plots. Our pollinator foraging data from
2019 showed that tolerance of some agricultural weeds should be advocated. Our results highlight the complementary benefits of these agri-environment scheme habitats to pollinators. We suggest that where arable pollinator conservation is a priority both habitats be provided.
Uploads
Papers by John Holland
and floristically enhanced grass margins. The former encourages annual plant species whereas the latter targets
the provision of perennial plants, both may benefit foraging pollinators, many of which have declined in the UK
since the 1980s. We surveyed thirty cultivated margins and thirty floristically enhanced grass margins across the UK for pollinators, which included bumblebees Bombus spp., solitary bees and hoverflies Syrphidae. Pollinator abundance was then related to margin attributes such as age, width, soil fertility and adjacent habitat type. For cultivated margins we also investigated relationships with cultivation and rotation, and for floristically enhanced margins time cut. Plant preferences of foraging pollinators were recorded in 2019. On cultivated margins, target annual plants were frequently recorded on plots and were repeatedly visited by pollinators with management significantly influencing visitation rates. For example, plots which had been created with ploughing attracted fewer solitary bees and bees overall than those created with minimum tillage. Annually rotated cultivated margins were associated with lower flower abundance, broad leaved species cover and vegetation heights which resulted in lower total bee abundance. We therefore advise that cultivated margins be left in situ on farmland over longer periods. Older floristically enhanced grass margins became dominated by grass and contained fewer flowerheads to support foraging pollinators. Compared to those established via natural regeneration, sown margins were associated with increased bee and Syrphidae abundance, which is probably linked to the high flowerhead abundance and coverage of broad-leaved species on sown plots. Our pollinator foraging data from
2019 showed that tolerance of some agricultural weeds should be advocated. Our results highlight the complementary benefits of these agri-environment scheme habitats to pollinators. We suggest that where arable pollinator conservation is a priority both habitats be provided.
Neonicotinoid insecticide seed treatments were withdrawn from use on cereal crops in the European Union (EU) in 2018 exposing the crops to yellow dwarf viruses transmitted by cereal aphids. To reduce prophylactic pyrethroid sprays there is a need for easier, field‐specific monitoring techniques given that pest incidence is spatially and temporally highly sporadic.
A field‐specific monitoring method based on the use of yellow sticky traps mounted horizontally just above the crop was developed and evaluated to determine: (i) predictive capabilities of the sticky trap system, (ii) practicalities of use by farmers and agronomists, and (iii) whether landscape composition, boundary type and type of tillage affect immigration of aphid vectors.
RESULTS
Yellow sticky traps effectively sampled winged cereal aphids and identified spatial differences in immigration patterns within‐ and between fields. Farmers and agronomist's aphid identification skills need improving, although they could detect aphid trends with minimal training. At least three times more cereal aphids were captured in crop headlands, especially next to taller field boundaries indicating that wind currents determined aphid immigration patterns within fields. Considerable between field aphid immigration was detected (24% of fields had no aphid immigration) even on the same farm. Levels of immigrating grain aphids were positively related to the proportion of grassland in the landscape. Tillage type had no impact on levels of immigrating aphids.
CONCLUSION
Field‐based monitoring and different management of headland areas could be used to reduce insecticide usage when controlling of cereal/barley yellow dwarf virus.