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Dr Ian Vaughan

Dr Ian Vaughan


School of Biosciences

+44 (0)29 2087 4545
Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX

My research focuses on the processes that shape communities over ecological and evolutionary timescales, and how they respond to environmental change. Much of this focusses upon river systems, for their rich diversity, importance and because they are an excellent model system for asking general ecological questions. This encompasses processes acting across a wide range of scales, from individual trophic interactions and food resource dynamics, through management interventions, land cover and fluvial geomorphology, to large-scale climatic effects. A variety of approaches is used to address these questions, including novel field studies, analysis of large data sets, null models, network analysis, experiments and molecular analyses.


Deputy Module Leader: BI2133/4 Ecology and Conservation (including Field Course)

I read Biology at Bristol University (1997–2000) before making the trip over the Severn bridge to Cardiff to undertake a PhD (2000–4) with Prof. Steve Ormerod. The PhD focused on the methods used to predict animal and plant distribution patterns, with river birds as a model system. Two years of post-doctoral work in Cardiff followed, contributing to the understanding of how ecology interacts with physical habitat in rivers.

In September 2006, I was awarded a Research Councils UK fellowship allowing me to pursue my research interests in river systems and quantitative methods, before moving onto a lectureship in September 2011.
















My major research interests centre on how rivers respond to natural and anthropogenic change.

Current projects

Null model analysis of ecological networks

Null models are valuable tools for analysing community structure, and can help distinguish the roles of different processes in structuring ecological networks including food webs and pollinator networks. A fundamental question is the extent to which structure results from chance (e.g. interactions occur more frequently with common species cf. rare species) as opposed to choice (e.g. dietary preferences). In collaboration with Bill Symondson, we developed a null model for separating these two processes in prey choice and recently generalised this to whole network structure (Agusti et al. 2003; Pearson et al. 2018). This is now being applied in the research group to studies of diet, pollination and food web structure across a range of systems.

I wrote and maintain the econullnetr package for R (Vaughan  et al. 2018), available from the Comprehensive R Archive Network (, which makes it possible to run these analyses with a range of different data sets. My GitHub site hosts the most recent development version (

Long term changes in British rivers

Many UK rivers have changed greatly over recent decades. In and around urban areas, the news in generally good, with large scale-recovery from historical water quality problems, whilst elsewhere the news is less positive, with stressors such as fine sediments becoming increasingly important. Trying to understand the effects of a changing climate further complicates the mix. Work in this area has helped to elucidate the changes in river communities that have occurred, both nationally and more locally (e.g. Vaughan & Ormerod 2012, 2014), and continues to grapple with the challenge of determining the roles of different stressors.

Land use impacts on streams

Rivers reflect their catchments and land use can impact river ecosystems in manifold ways, including effects on the hydrology, water quality and availability of food resources. This opens up possibilities for managing the riparian zone and wider catchment for the benefit of river ecosystems. Combining large data sets, fieldwork and molecular analysis of predator diets, we are investigating the mechanisms by which land cover affects stream ecosystems, and the implications for long-term resilience (e.g. Pearson et al. 2016; 2018).

Current students

  • Jo James: 'Impacts of invasive crayfish in aquatic ecosystems' (Environment Agency/Natural Resources Wales and Cardiff University)
  • Caitlin Pearson: 'Impacts of intensifying pastoral agriculture on stream ecosystem functioning' (BBSRC)
  • Marian Pye: 'Catchment and riparian subsidy effects on upland stream ecosystems' (Cardiff University)
  • Danica Stark: 'Ranging behaviour of Proboscis Monkeys in the Kinabatangan Floodplain, Sabah' (Margot Marsh Biodiversity Foundation)
  • Rhodri Thomas: 'Predictions of river habitat response to climate change across the United Kingdom' (Cardiff University – President's Research Scholarship)
  • James Vafidis: 'The effect of climate change on wetland ecosystems' (Knowledge Economy Skills Scholarship)

Current/recent funding

NERC (including the recent £3.1m Diversity in upland rivers for ecosystem service sustainability (DURESS) project:

EU (including the €9m Managing aquatic ecosystems and water resources under multiple stressors (MARS) project)



Natural Resources Wales

Environment Agency


  • Prof. Steve Ormerod (Cardiff School of Biosciences) – long term changes in British rivers
  • Prof. Bill Symondson (Cardiff School of Biosciences) – analysis of trophic interactions
  • The Diversity of Upland Rivers for Ecosystem Service Sustainability (DURESS) – 28 researchers across nine universities and research institutions
  • Dr José Constantine (Cardiff School of Earth and Ocean Sciences) – river habitat response to climate change
  • Gwent Wildlife Trust, the Wildlife Trust of South and West Wales, and Drs Rob Thomas and Hefin Jones (Cardiff School of Biosciences) – long-term monitoring of wetland birds and their potential response to climate change