Investigating pollinator diversity, traits, and interaction networks among urban green spaces

Plant, Emma Louise (2026) Investigating pollinator diversity, traits, and interaction networks among urban green spaces. PhD thesis, University of Glasgow.

Abstract

Global urbanisation raises concerns for biodiversity due to the negative impact on a range of taxa including invertebrate pollinators. However, cities may be hotspots for certain species, including some species of conservation relevance. Urban areas are characterised by a mosaic of land use types that range in their value as pollinator habitats. Private green spaces, such as gardens and allotments, offer great conservation potential due to the proportionally large area they cover and their high floral abundance. Management of these privately owned spaces varies and therefore understanding how these green spaces support pollinator diversity, their interactions with plants, and their functional traits are knowledge gaps critical to informing their future management.

In this thesis I have assessed the environmental drivers of pollinator diversity, plant-pollinator interaction networks, and trait assembly within gardens and allotments across Glasgow, Scotland. I collected data in 18 gardens and 8 allotment sites across two years, where I used cameras and visual observations to record plant-flower visitor interactions by bees, hoverflies and butterflies. Alongside this I also collected local and landscape level environmental data.

Results showed no effect of green space type on pollinator diversity or plant-flower visitor network structure. However, I found four key patterns. 1) Greater floral richness supported higher pollinator diversity. 2) Native plants received more flower visits; however non-native plants were still important forage for flower visitors particularly later in the season. 3) Floral richness was positively associated with network specialisation. 4) No evidence of trait filtering was revealed at the urban green space scale but did occur at the regional-city interface. This regional-city filtering may be indicated by the high prevalence of Bombus pascuorum in the city which was responsible for 25% of all flower visits, suggesting that generalist species are dominant within Glasgow’s pollinator community.

Together, these results suggest that management interventions within gardens and allotments can support greater pollinator diversity through increases in floral richness. However, these strategies may only support greater taxonomic diversity, rather than directly increasing functional diversity. As such, I suggest management interventions should be implemented at broader spatial scales to facilitate the movement of pollinators surrounding cities into the core urban area. Gardens could offer the opportunity to scale up pollinator conservation interventions across urban environments, given that gardens contribute to approximately 30% of green space within cities.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: This research was part of the GALLANT project, funded by the Natural Environment Research Council as part of the Changing the Environment Programme [grant number NE/W005042/1].
• Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences; H Social Sciences > HD Industries. Land use. Labor; S Agriculture > SB Plant culture
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Funder's Name: Natural Environment Research Council (NERC), GALLANT
• Supervisor's Name: McCafferty, Dr. Dominic, Dominoni, Dr. Davide and Dunkley, Professor Ria
• Date of Award: 2026
• Depositing User: Theses Team
• Unique ID: glathesis:2026-86264
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 21 Oct 2026 15:39
• Last Modified: 22 Oct 2026 09:10
• URI: https://theses.gla.ac.uk/id/eprint/86264

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