E-Thesis 159 views 172 downloads
Livestock grazing impacts bee (Apoidea) pollination networks in saltmarshes of South Wales / BENJAMIN LAM
Swansea University Author: BENJAMIN LAM
Abstract
Saltmarsh habitats serve as crucial connective terrain for wildlife, yet they are exploited for livestock pasture. Halophytic saltmarsh herbs provide abundant flower resources for pollinators such as bees (Hymenoptera: Apoidea) and maintain a supply of nectar resources late in the flowering season....
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Swansea University, Wales, UK
2025
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| Institution: | Swansea University |
| Degree level: | Master of Research |
| Degree name: | MRes |
| Supervisor: | Bull, J. C., and Harris, W. E. |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa69944 |
| Abstract: |
Saltmarsh habitats serve as crucial connective terrain for wildlife, yet they are exploited for livestock pasture. Halophytic saltmarsh herbs provide abundant flower resources for pollinators such as bees (Hymenoptera: Apoidea) and maintain a supply of nectar resources late in the flowering season. Several studies have demonstrated positive and negative impacts of grazing livestock management on grassland bee communities; however, the impacts of grazing on bees or the structure of their associated food plants in saltmarsh habitats is unknown.The study aimed to test the hypothesis that grazing impacts bee populations by (1)increasing habitat heterogeneity, (2) increasing flower diversity, (3) reducing forb biomass, and (4) consuming flowers.I compared mean values of bee populations and the structure of insect-pollinated plants in plots with different grazing intensities in Southwest Wales. Effects of grazing and insect-pollinated plant structure on bees were examined using GLMs.Flower richness varied across sites and tended to be higher in more intensively grazed plots, though no significant effect of grazing on flower richness was detected.Bee community composition was primarily driven by the abundance of two mass-flowering species: Tripolium pannonicum, which decreased in biomass with grazing, and Limonium vulgare, which was largely absent under high grazing disturbance.The results highlight the negative impact of grazing on dominant nectar-providing flowers, while also confronting the assumed value of saltmarsh flora for supporting local bee diversity. Significant reductions in grazing intensity and extensive rest periods on UK marshes are necessary for sustainable management of floral resources. |
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| Item Description: |
A selection of content is redacted or is partially redacted from this thesis to protect sensitive and personal information. |
| Keywords: |
Apis, Bombus, flower–pollinator interaction, halophytic community, biodiversity assessment, pasture management |
| College: |
Faculty of Science and Engineering |