Khanzada, Tahir;
(2024)
Spatial and temporal patterns of aquatic macrophyte biodiversity at the river catchment scale: the River Glaven, north Norfolk.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Freshwater biodiversity has declined globally at an alarming rate over the last 200 years due to anthropogenic activities often involving agricultural expansion. Lowland agricultural catchments in the UK have been highly impacted by such activities resulting in habitat fragmentation and eutrophication, yet they still have high biodiversity value. The River Glaven catchment, north Norfolk, UK provides a unique opportunity to investigate biodiversity at the catchment scale using aquatic macrophytes as an indicator group due to an extensive dataset of 587 macrophyte surveys at 274 sites since the late 1990s. Analysis of historical and contemporary maps showed that the catchment has lost ~47% of its ponds since the late 19th century due to agricultural intensification. Analysis of contemporary macrophyte survey data for 268 sites revealed that lakes, ponds, river sections, ditches, and backwaters all made important contributions to catchment-scale diversity. Collectively, ponds harbour the greatest number of species, as well as the most unique and important species for conservation, with lakes individually containing the most species per site; these patterns hold true when a temporal element is included in analysis. Important and novel outputs recorded a 4% increase in catchment biodiversity due to pond restoration efforts over the last decade, and potential catchment-wide biodiversity loss of 5.6% due to predicted increases in saline intrusion. To incorporate a longer temporal dimension, palaeoecological analysis of two shallow lakes was performed at Selbrigg Pond and Bayfield Hall Lake to assess changes in biodiversity over the last century. The multi-indicator study revealed that both sites have a history of eutrophication but that restoration measures have improved the ecological quality of both sites, and this has continued to the present day as evidenced by contemporary surveys. Overall, this study demonstrates the value of understanding catchment-scale biodiversity patterns on multiple timescales to inform conservation and restoration strategies.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Spatial and temporal patterns of aquatic macrophyte biodiversity at the river catchment scale: the River Glaven, north Norfolk |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2024. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL SLASH UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS > Dept of Geography |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10191966 |
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