The ecology of Riparian Carabidae (Coleoptera) in a regulated river system

Sinnadurai, Paul ORCID: https://orcid.org/0000-0003-0179-188X 2014. The ecology of Riparian Carabidae (Coleoptera) in a regulated river system. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Rivers and riparian zones are among the most threatened ecosystems globally, with modification of their natural flow regime a major source of change. Exposed riverine sediments (ERS) are characteristic of unregulated rivers in their upper and middle reaches and among the few remaining natural riparian habitats. However, they are in decline across the UK and Europe as a result of widespread modifications to channel structure and flow regimes. Studies of ERS and their dependent carabid beetles can help to understand how environmental change is affecting river ecosystems more generally, but prolonged research is scarce. This thesis reports on a three year study of carabid beetles at multiple sites in the Usk river system, Wales, during an extended period of low river discharge. Plot-scale experimentation and reach-scale surveys showed consistently that carabid assemblage structure and distribution varied more strongly in response to time and across the reach than to within-patch habitat character. There was no evidence of carabid assemblage succession, though generalist species richness appeared to increase through the study as specialist species richness declined, and general conditions for specialist species may have declined. It is suggested that specialist carabids of high conservation importance could be squeezed as land use encroachment and river regulation causes a decline in the ERS resource. Management interventions at the reach- or catchment scale are advocated to maintain and restore the ephemerality of ERS. Being responsive to reach- and catchment scale events, exposed riverine sediments and their dependent fauna should be the focus of long term study to appraise rates of environmental change or resilience to anthropogenic stressors. In particular, long term studies may not only reveal trends on ERS towards homogenisation, indicative of environmental decline within the wider river system, but might also help to detect the effectiveness of river restoration.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Biosciences
Uncontrolled Keywords:	Anthropogenic, Beetles, Bembidion, Brecon Beacons National Park, Discharge, Exposed Riverine Sediment, Food Subsidy, Habitat Manipulation, Hand Search, Insects, Invertebrates, Leaf Litter, Mean Individual Biomass, Pitfall Trap, Rarefaction, Reach Scale, Regulation, Riparian Squeeze, River Usk, Scale, Sentinel, Stressors, Succession, Zone
Date of First Compliant Deposit:	30 March 2016
Last Modified:	10 Oct 2023 15:10
URI:	https://orca.cardiff.ac.uk/id/eprint/68179

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