Long-term trends in aquatic invertebrates indicate river health in England and Wales

Pharaoh, Emma 2023. Long-term trends in aquatic invertebrates indicate river health in England and Wales. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Rivers are highly associated with human actvities within the river and their surrounding catchments. Such as, hydrological alteration, land use activities and their implications on water quality. These impacts vary across space and through time. It is important that the ecological consequences of these stressors are understood to inform policy and management decisions. River invertebrate data is abundant across the UK, with invertebrate communities responsive to changes in environmental conditions. Therefore, invertebrate data is a valuable tool for assessing changes in the ecological status of rivers, investigatng how communitiees are responding to changing conditions and inferring the overall status of rivers. This thesis looked to identify how river invertebrate communities have changed over the last three decades (1991-2019) across England and Wales, using national monitoring data of invertebrates collected by the Environment Agency and Natural Resources Wales. This also aimed to clarify the roles played by water quality, catchment land use, climate, and hydrology in driving these changes. Analyses explored multiple facets of invertebrate diversity (e.g. community composition, family richness, functional diversity) and spatial scales, ranging from national (England and Wales) to a single catchment (river Wye). The results of this thesis confirmed that river invertebrate communities have been changing through time, with an overall recovery throughout the time series both nationally and within the Wye. Recovery occurred in both urban and agricultural areas, with the greatest recovery occurring in urban areas. Spatially, these trends varied, with some notable areas of decline, including within the uplands. The role that environmental variables (e.g. water quality, land use) played in these trends also varied spatially, whilst interactions between water quality, hydrology and catchment variables were identified. These results highlighted the complexity and difficulty in attributing changes in invertebrate communities to environmental variables nationally and at the catchment scale.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Schools > Biosciences
Subjects:	Q Science > Q Science (General)
Date of First Compliant Deposit:	10 December 2024
Last Modified:	18 Feb 2025 14:24
URI:	https://orca.cardiff.ac.uk/id/eprint/174652

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