E-Thesis 161 views 116 downloads
Role of intertidal seagrass (Zostera spp.) habitats in supporting wintering birds in two British estuaries / EMMA BUTTERWORTH
Swansea University Author: EMMA BUTTERWORTH
Abstract
Estuaries in Britain provide internationally important foraging resources for overwintering avian species. Seagrass, Zostera spp., in these estuaries provide significant benefits for epi- and infaunal invertebrates, yet little is known about the role of seagrass in supporting migratory invertivorous...
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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: | Unsworth, R. K. F., and Bertelli, C. M. |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa69937 |
| Abstract: |
Estuaries in Britain provide internationally important foraging resources for overwintering avian species. Seagrass, Zostera spp., in these estuaries provide significant benefits for epi- and infaunal invertebrates, yet little is known about the role of seagrass in supporting migratory invertivorous birds. Bird count surveys were conducted in Chichester Harbour (CH) and Milford Haven Waterway (MHW) in February and March respectively, in areas containing seagrass and unvegetated sediment. Densities of feeding birds were compared between seagrass and unvegetated habitats, as well as areas characterised by annual and perennial seagrass populations.Here I show that intertidal seagrass should be regarded as an important foraging resource for overwintering birds, including 18 species listed by the Convention on the Conservation of Migratory Species of Wild Animals (CMS); but that its role varies between species and regions.Evidence shows that coastal and estuarine species with broad dietary niches are largely unaffected by seagrass presence. However, evidence was found that seagrass across both regions mitigated the limiting effects of tidal changes in three species of wader (redshank Tringatotanus, oystercatcher Haematopus ostralegus, dunlin Calidris alpina). It also provided a stable environment which was used by corvids in MHW to exploit intertidal foraging resources, a previously unrecognised behaviour in this area. This study demonstrates that seagrass has a role in migratory avian ecology and provides a foundation for further research of its role as aforaging resource. It is anticipated to underpin the formation of an inventory of migratory avian species that use seagrass ecosystems, as encouraged by the CMS. |
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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: |
seagrass, zostera, shorebirds, estuarine, wintering birds, habitat use, wildfowl |
| College: |
Faculty of Science and Engineering |