Effects of land use on the resilience of stream invertebrates to climate change

Joyce, Fiona 2023. Effects of land use on the resilience of stream invertebrates to climate change. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Climate change and land use are recognised as primary drivers of global biodiversity decline, and pose a significant threat to freshwater ecosystems. The ecological, economic, and aesthetic importance of freshwaters necessitate urgent action to enhance their resilience to accelerating environmental change. Riparian broadleaf woodlands have been increasingly promoted for this purpose, but evidence demonstrating their effectiveness is scarce. Using a 40-year macroinvertebrate dataset from 16 headwater streams in upland Wales, UK, this thesis aims to address the hypothesis that broadleaf woodlands enhance stream ecosystem resilience to climate change. Specifically, long-term community trends and multiple facets of ecological stability were assessed relative to water temperatures and discharge, water chemistry (acid versus circumneutral) and contrasting catchment character typical of upland management (sheep-grazed moorland, conifer plantations, and semi-natural broadleaf woodlands). Since the start of monitoring (1981), progressive structural and functional changes have occurred in these streams, with indications that detritivores were among the taxa underlying these trends. While enhanced resilience of population- and community-level properties in broadleaf streams was evident, it was also apparent that changes were far-reaching. Extreme conditions including high temperatures and complex effects of dry weather were commonly associated with community change, but a large amount of unexplained variation remained. Particularly deleterious effects of conifer forestry were highlighted, in addition to vulnerabilities of rare taxa. Despite the underlying complexities of stream communities and their dynamics, stream type remained the best predictor of taxonomic and functional diversity. Thus, coupled with their widely acknowledged benefits for biodiversity and stressor regulation, riparian broadleaves remain favoured candidates for climate adaptation. However, interventions may be required at broader scales than just riparian zones. Overall, this research provides sought-after evidence of climate and catchment character effects that enhances our understanding of ecological resilience, with important implications for river management in the face of global environmental change.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Biosciences
Subjects:	Q Science > Q Science (General)
Date of First Compliant Deposit:	10 October 2023
Last Modified:	10 Oct 2024 01:30
URI:	https://orca.cardiff.ac.uk/id/eprint/163117

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