COS 134-1 - Evaluating the impact of local and landscape habitat variables on wild bee functional diversity for pollination ecosystem services management
Abstract: Insect pollinator declines have been reported globally for a range of taxonomic groups and may lead to pollination deficits. The abundance of pollinators is important for the delivery of pollination ecosystem services, but the functional divergence between species traits is also considered important and maintaining non-overlapping traits distributions could benefit crop pollination and yield. This research evaluates the influence of local and landscape habitat variables on honeybee abundance and wild bee functional group abundance and richness, and investigates the impact of high honeybee visitation on wild bee functional group abundance and richness. This study is carried out in Malta, a Central Mediterranean small island state, characterized by high agricultural (51%) and urban (30%) land use and a high honey bee hive density. In 2019, Malta had a hive density of 12.86 hives/Km2, which is significantly higher than the hive density recorded by Chauzat et al. (2013) for other European countries which had an average of 4.2±3 hives/Km2. Timed surveys of plant-bee interactions were carried out in belt transects (2 x 25m) between April and June for four years. For each specimen, functional traits associated with nesting type and pollen transport were identified based on literature (e.g. Danforth et al., 2019; Ropars et al., 2020). Preliminary results indicate that honeybees were strongly associated with agricultural habitats and used a wide range of floral resources that overlapped with those used by wild bees. Different functional groups were associated with different local habitat types, with agricultural, garden and roadside vegetation habitats being the most important habitats. At the landscape scale (r=250 and 500m) wild bee abundance was positively associated with arable, garrigue and grassland, orchard and urban but the abundance of different bee functional groups was influenced differently by landscape parameters. High honeybee visitation rate had a negative impact on wild bee abundance but no significant impact on functional group richness was recorded in this study. In conclusion, this study suggests the need for a more holistic approach that considers the effect of local and landscape habitat characteristics, and interspecific interactions when planning measures for conserving bee diversity and pollination ecosystem services. Finally, we present ongoing research in the BEEPOLL project which is combining remote sensing data to evaluate floral resource availability, bee hive monitoring and wild bee distribution modelling to inform pollinator and pollination ecosystem service management.
