Impacts of local and landscape habitat variables and honeybee visitation on wild bee diversity in the Maltese Islands

Authors: Balzan Mario V , Leticia De Santis

Corresponding: Balzan Mario V (mario.balzan@mcast.edu.mt)

Keywords: Apoidea, Ecosystem Services, Floral Resources, Honeybee abundance, Pollination, Plant-bee networks

Doi: 10.7423/XJENZA.2023.1.09

Issue: Xjenza Online Vol. 11 Special Issue (Top Scientists)

Abstract:
Bees are important pollinators in several ecosystems, and losses of bee diversity can impact on crop and wild plants pollination, and associated ecosystem services. Here, we explore how landscape and local habitat variables influence honeybee and wild bee functional group abundance and richness. Within the context of high hive densities in the Maltese Islands, we explore how high honeybee visitation impacts on wild bee functional richness and abundance using a dataset of plant-bee networks from 78 sites surveyed in spring 2019. Honeybees were strongly associated with agricultural habitats and used a wide range of floral resources that overlapped with those used by wild bees. While no significant impact of local habitat type on functional group richness was recorded, different functional groups were associated with different local habitat types, with agricultural, garden and roadside vegetation habitats being the most important habitats. We assessed the influence of landscape context on wild bees in two radii (250 and 500m). At these scales, the land cover that influenced wild bee abundance positively were arable, garrigue and grassland, orchard and urban, and the abundance of different bee 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. These results are used to provide recommendations for habitat management for bee conservation, as we stress the need for a more holistic approach that considers the effect of local and landscape habitat characteristics, and interspecific interactions when planning measures for the conservation of bee diversity and pollination ecosystem services in the Maltese Islands.

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