Technical Yearbook 2024

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FIGURE 4. Effect plots showing the influence of flowering plant functional richness on a) wild bee taxonomic richness, and b) wild bee functional richness. The shaded area indicates 95% confidence intervals.

functional richness promoted wild bee taxonomic and functional richness across management regimes and regions (Figure 4). This means that a wide range of flowering plant species that vary in their traits best promote a wide variety of wild bee species and traits. This positive relationship may be explained by the fact that individual bee traits were associated with distinct plant traits. For example, in Austrian vineyards, short-tongued bees benefited from yellow flowers with radial symmetry and hidden nectar, likely because their mouthpart morphology allows them to easily access hidden nectar compared to other insects such as flies (Figure 4). This type of trait matching between flowering plants and flower-visiting insects is important for effective pollination of the plant, and for the insect to access its food resource, pollen and/or nectar (Figure 5). 2 Management implications Increasing the functional diversity of flowering plants in and around vineyards promotes wild bee diversity. This could be done by selecting cover crop mixtures with diverse floral traits (e.g., by selecting plants from different plant families) and by reducing tillage that favours a wide variety of plant traits. This work shows potential to fine-tune vineyard practices to enhance pollinator diversity and plant-pollinator networks in viticultural landscapes. It would be supported by further research on how this could be optimised for different conditions in the South African context. 

FIGURE 5. An example of trait matching between pollinators and flowering plants: Short-tongued bees are effective pollinators of radial, yellow flowers with hidden nectar, which often belong to the Asteraceae family. traits. Additional factors were considered in the analyses, including vineyard management approach (organic vs non-organic), total vegetation cover in vineyards, amount of semi-natural vegetation in a 500 m radius around the sites, and number of woody structures (woodland patches, tree lines and solitary trees) in the surrounding landscape. The most prominent result was that high flowering plant

References https://www.wineland.co.za/promotion-of-wild-bees-in-south-african-and-austrian-vineyards/

For more information, contact René Gaigher at reneg@sun.ac.za.

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TECHNICAL YEARBOOK 2024