Sown Wildflowers Enhance Habitats of Pollinators and Beneficial Arthropods in a Tomato Field Margin

Abstract

We evaluated the capacity of selected plants, sown along a processing tomato field margin in central Greece and natural vegetation, to attract beneficial and Hymenoptera pollinating insects and questioned whether they can distract pollinators from crop flowers. Measurements of flower cover and attracted pollinators and beneficial arthropods were recorded from early-May to mid-July, during the cultivation period of the crop. Flower cover was higher in the sown mixtures compared to natural vegetation and was positively correlated with the number of attracted pollinators. The sown Glebionis coronaria, Coriandrum sativum, Anethum graveolens, and Fagopyrum esculentum attracted mainly wild bees, which were the most abundant pollinating insects. In the natural vegetation, Rapistrum rugosum attracted mainly honeybees, while Asteraceae, Convolvulaceae, and Apiaceae species attracted wild bees. Beneficial arthropod abundance and diversity were higher in the sown mixture. Tomato flowers were visited by a small number of wild bees. Their number was not affected by the distance from the field margin, indicating no distraction effect from the sown or natural vegetation flowering plants. Our results suggest that selected flowering plants can improve the field margin habitats for pollinating insects and beneficial arthropods, but more work is needed to elucidate the effect on crop pollination.

Do Patches of Flowering Plants Enhance Insect Pollinators in Apple Orchards?

“…The introduction of sown flowering patches in the two following years increased pollinator visitation on the groundcover of the apple orchards compared to the wild plants, while at the same time it attracted pollinators of diverse taxa. While similar findings were reported before [ 62 , 63 ], most of the published studies compare the pollinator visits on the flowers of the sown plants to regularly mown grassy field patches or margins [ 60 , 63 ], practically with null flowering resources. Thus, in the present study, the comparison is more challenging, yet the higher records of pollinator visits on the flower resources of the sown flowering patches vs. of the wild plant patches in the apple orchards were evident and statistically significant.…”

“…General criteria in the mixtures’ composition included relative species growth and flowering characteristics, but also the cost and availability of the seed material. The seed weight for each species in the mixture (Ws) was calculated according to the equation by [ 63 ]:…”

“…The measurements were performed during the flowering period of the sown plants (from April to June), the wild plants in the control plots (from April to June), and the apple trees (mid to late April). The methodology was as described before [ 62 , 63 , 64 ] adapted for the experimental design of the current study. More specifically, the plant cover (total) and flower cover (total and per plant species) were visually estimated and expressed as percentage cover of the plot area (6.4 m 2 ), in all examined plots (sown and control (wild plants)).…”

“…Agri-environmental interventions for insect pollinator conservation typically focus on re-establishing floral resources [ 53 ], e.g., restoring species-rich grasslands, sowing field margins with nectar and pollen-rich mixes, and inclusion of flowering species such as legumes in rotations [ 54 , 55 ]. The use of sown flower strips in crops to provide resources for pollinators (mainly Hymenoptera: Apoidea and Diptera: Syrphidae) has been examined by several researchers [ 8 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 ].…”

Seed Dormancy and Seedling Ecophysiology Reveal the Ecological Amplitude of the Threatened Endemism Picris willkommii (Schultz Bip.) Nyman (Asteraceae)

“…In order to restore or extend the species, late winter or early spring planting would be preferable to late spring, for survival reasons and because of the time needed for plant development, since high temperatures accelerate plant maturation and shorten the vegetative growth period, as mentioned above. It was also observed that the presence of pollinating insects was scarcer at the later planting date, which could affect the fertilization of the flowers [ 56 ]. All this could be the reason why, naturally, any seed that germinates in spring does not usually prosper or compete successfully in the grassland.…”