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Steve Ormerod

Professor Steve Ormerod


School of Biosciences

+44 29208 75871
Sir Martin Evans Building, Room Cardiff School of Biosciences, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, Museum Avenue, Cardiff, CF10 3AX
Media commentator


Research overview and external responsibilities

Complementing the perspectives of other members of the Organisms and Environment Division, my work is explicitly ecological and unified by the theme of ecosystem-scale perspective of rivers, lakes and wetlands.  Activities focus on:

  1. Global change effects on freshwater organisms and ecosystems
  2. Freshwater biodiversity 
  3. The ecology of river and wetland birds

Solutions to the problems of freshwater ecosystems through policy and management are also an important focus, and I co-direct the University’s Water Research Institute having been instrumental in its formation. I'm also involved in the application of ecology as Deputy Chairman of Natural Resources Wales (the largest Welsh Government sponsored body), a member of the UK Joint Nature Conservation Committee and Vice President of the RSPB (Europe's largest wildlife charity).

Each of these themes is expanded under 'Research', while my extensive involvement with NGOs, professional bodies, businesses and government organisations is outlined under 'Biography'.


Academic Team Leader

School of Biosciences Ethics Committee

European Languages

French (fluent)



























Book sections




I came to Cardiff in 1980 for the prestigious UWIST MSc in Applied Hydrobiology, from there completing a PhD on water quality and invertebrates in the Wye river-system. Simultaneously, I developed an interest in the ecology of river birds, showing for the first time how this group was affected by acid rain. These major themes — multiple global-scale pressures on freshwater ecosystems, river invertebrates and birds in aquatic habitats — have continued to provide my major research models.

From 1984, I led a post-doctoral group investigating the ecological effects of acidification in upland rivers using surveys, models and ecosystem-scale experiments at the Llyn Brianne Stream Observatory. These experiments have now run for almost 40 years, and my ecosystem-scale work has expanded to encompass global change effects on freshwaters ecosystems on three continents.  Most recent work with a wide range of colleagues continues to expand our evidence about the sensitivity of running waters to climate change while also telling the remarkable story of how the recovery of British rivers from gross sanitary problems has been tempered by the growing challenge of diffuse pollution from urban and rural sources.

So far, my career total of over 300 scientific publications have been cited over 25,000 times at H > 78 (Google Scholar).

Research areas

Global change effects on freshwater organisms and ecosystems

For almost four decades, prominent themes in my work have been large-scale, long term impacts of global change on freshwater ecosystems as well as ecosystem recovery where multiple stressors have been managed or removed (see ‘Publications’)

Our globally unique Llyn Brianne Stream Observatory, operational from 1981, has multiple experimental and reference streams that have figured prominently in understanding global change effects on freshwater ecosystems. The site also a suite of replicate, cascading experimental channels that figure increasingly in research work.

Freshwater Biodiversity

River biodiversity and ecosystem services have become an increasingly important focus in my work, in particular to understand how biodiversity supports services and how environmental stressors erode ecosystem functions and service delivery.

Examples include:

  • Co leadership of the freshwater sections of the National Ecosystem Assessment for Defra and the Devolved Administrations (Maltby & Ormerod 2011 )
  • Acting as Cardiff PI in the £3.1 million NERC BESS project, Duress (Diversity in Upland Rivers for Ecosystem Service Sustainability; from 2012)
  • Acting as Cardiff PI and co-leader of catchment studies in the €9 million EU-funded MARS project (Managing Aquatic ecosystems and water Resources under multiple Stress; from 2014)
  • The UK NEA assembled key data on the status and trends in ecosystem services delivered by British fresh waters.

My biodiversity work also includes significant focus on pollution

Long-standing interest in the effects of pollution on freshwaters - including acid rain, wastewater and xenobiotic substances - led in 2016 to some of the world's first assessments of microplastics in river food webs.  Investigation of the Wye, Usk and Taff revealed that around 50% of insects contained plastic fibres (Windsor et al. 2019).  Further work has since shown how this material is transferred to riverine predators (D'Souza et al. 2020_, also assessing its sources, fluxes, fate and effects in the river environment.  Current work also includes assessments of human and veterinary pharmaceutical compounds in rivers.

The ecology of river and wetland birds

I became interested in river-birds, and in particular dippers, while researching aquatic invertebrates for my PhD.  This interest led to some of the world's first evidence that birds could be affected by acid rain (eg Ormerod et al. 1991), and in turn some of the world's best known autecological bird research.  The concept of using dippers as indicators of acidity led to research into their role as indicators of broader aspects of water quality that currently includes legacy or emerging contaminants, diffuse pollution and microplastics. I collaborated recently with the Wildlife Institute of India in investigations into the effects of global change on Himalayan rivers – where the most diverse assemblage of river birds on Earth occupies one of its most rapidly changing regions.


Current and recent sponsors include:

    • Natural Environment Research Council (including the £3.1 million Duress Project and the FRESH Centre for Doctoral Training)
    • European Union (where we co-led catchment-scale in the €9 million MARS project)
    • Esmée Fairbairn Foundation (who have funded the Llyn Brianne Stream Observatory)
    • Defra
    • Natural Resources Wales
    • Knowledge Exchange Studentship Scheme
    • Leverhulme Trust
    • BBSRC
    • ESRC
    • Daphne Jackson Trust
    • The Royal Society
    • RCUK
    • Wessex Water
    • Countryside Council for Wales
    • LWEC
    • Swiss Foundation for Scientific Research
    • The Welsh Government
    • The Environment Agency
    • Freshwater Biological Association
    • Royal Geographical Society
    • National Geographic Society (USA)
    • National Museum of Wales
    • Wye and Usk Foundation
    • Scottish Environmental Protection Agency
    • Cardiff City Council
    • Forestry Commission
    • SMEs (Shawater Ltd, Ambient Hydro, APEM Ltd, ENSIS Ltd, Cascade Consulting)

Successfully completed PhD students

    • Dr Sarah Lee (Joint wth Dr Rupert Perkins) Controls on algal dynamics in Cardiff Bay
    • Dr Ankita Sinha (Joint with Wildlife Institute of India) Himalayan River Birds
    • Dr Liz Davidson (Joint with UK CEH) Resolving freshwater communities and interactions using DNA
    • Dr Fiona Joyce (Joint with Dr Ian Vaughan) Stability and persistence in upland stream ecosystems
    • Dr Ankita Sinha (Joint with the Wildlife Institute of India) The ecology of Himalayan River Birds
    • Dr Liz Davidson (Joint with UK CEH) Resolving freshwater communities and interactions using DNA
    • Dr Sarah Lee (Joint with Dr Rupert Perkins) Controls on algal dynamics in Cardiff Bay
    • Dr Fred Windsor (Joint with Prof Charles Tyler, Exeter) The transfer and ecological effects of xenobiotic pollution in freshwater ecosystems
    • Dr Rhodri Thomas (President's Studentship with Ian Vaughan and Jose Constantine)  Predicting river habitat response to climate change
    • Dr Norhisham Ahmad Razi (Joint with the late Mark Jervis and Hefin Jones) Insect life-history response to global change
    • Dr Rhian Newman (Joint with Sian Griffiths and Bill Riley CEFAS)  Artificial light and predator-prey dynamics in freshwaters
    • Dr Marian Pye (Joint with Isabelle Durance and Ian Vaughan) Catchment and riparian subsidy effects on upland stream ecosystems
    • Dr Hannah Burton (President's Studentship joint with Mike Bruford and Hefin Jones)
    • Dr Caitlin Pearson (BBSRC studentship with Ian Vaughan and Bill Symondson) Agricultural effects on upland rivers
    • Dr Matt Dray (Presidents Studentship joint with Hefin Jones, Sue Hartley (York) and Rupert Perkins) Effect of elevated CO2 on tree litter chemistry and decomposition
    • Dr Kate Walker-Springett (ESRC/NERC Studentship joint with Jose Constantine and Lorraine Whitmarsh) Public perception of habitat management for pearl mussel in response to climate change
    • Dr Paul Sinnadurai (Jointly supervised with Dr Hefin Jones) Dispersal and distribution in riparian Coleoptera
    • Dr Stephen Thomas (KESS Studentship joint with Sian Griffiths) Riparian management effects on macroinvertebates and salmonids in upland streams affected by climate change
    • Dr Alisa Watson (NERC CASE studentship with WWT) The ecology of scarce wetland molluscs
    • Dr Beth Lewis (Wye and Usk Foundation; co-supervised with Dr Brian Reynbolds, CEH Bangor) The effects of liming on invertebrate recovery from acidification
    • Dr Clare Bale (NERC; jointly supervised with Dr Sian Griffiths) Behavioural avoidance and sheltering behaviour of salmonids during acid episodes
    • Dr Dave Bradley (PhD studentship funded by Defra) Dynamic processes in acid senstitive streams
    • Dr Emma Durward (Cardiff University/Llysdinam Trust; co-supervised with Dr Fred Slater)
    • Dr Esther Clews (Wye and Usk Foundation) The effects of hydrochemical restoration on river organisms
    • Dr Fabio Lepori (PhD studentship funded by the Swiss Foundation for Scientific Research) The ecological effects of acid episodes in the Swiss Italian Alps
    • Dr Faye Merrix (Cardiff City Council; Jointly supervised by Dr Steve Thackaeray, CEH Lancaster) Zooplankton ecology in Cardiff Bay
    • Dr H. Ceri Williams (NERC studentship; co-supervised with Prof Mike Bruford) Dispersal and genetic variation in Baetis mayflies
    • Dr Heike Hirst Ecological influences on diatom responses to water quality
    • Dr Hem Sagar Bharal (Joint with the University of Amsterdam) Community structure and habitat associations of lowland grassland birds of Nepal.
    • Dr Ian Vaughan (PhD Studentship funded by the Environment Agency) Modelling the distribution of river birds using habitat data
    • Dr Jacqui Barnes (NERC; joint supervision with Dr Ian Vaughan) Habitat complexity and river biodiversity
    • Dr Laura Trodden (Cardiff School of Engineering; jointly supervised with Dr Catherine Wilson) Climate change, stream hydraulics and stream invertebrates
    • Dr Liz Chadwick (Cardiff University/Llysdinam Trust; co-supervised with Dr Fred Slater) The influence of climatic variation on the ecology of common toads
    • Dr Muriel Alix (Cardiff City Council) The ecology of invasive zebra mussels in Cardiff Bay
    • Dr Renata Kowalik (PhD studentship funded by Defra) Detecting and modelling the effects of acid episodes on stream fauna
    • Dr Richard Jenkins The ecology of Water Rail Rallus aquaticus
    • Dr Seb Buckton The ecology of Himalayan River Birds
    • Dr Stefano Larsen (Wye and Usk Foundation) Effects of sediment deposition on upland stream organisms
    • Dr Zoe Masters (FBA/Cardiff University Ray Beverton Memorial Studentship) The effects of geographical isolation on stream recovery from acidification


Current responsibilities

Past responsibilities

Honours and awards