David Raffaelli
Professor

Research

Overview

David Raffaelli has broad interests in food web, community and ecosystem ecology, in marine, freshwater and terrestrial systems. These include marine food web dynamics; the relationships between catchment land-use, water quality and impacts on coastal receiving systems; the application of manipulative field experiments to large-scale conservation and management issues, biodiversity, ecosystem functioning and ecosystem services; the influence of species body-size in community dynamics; the issues of communication in environmental debate; inter-disciplinary approaches to environmental management. He enjoys collaborative, multidisciplinary projects, working extensively with other European colleagues and in North America, New Zealand and Australia.

Projects

Biodiversity and ecosystem functioning

Species losses have increased dramatically world-wide over the last 50 years, but the consequences of these losses for the functioning of ecological systems are poorly understood. To date, much of the research surrounding this issue has been terrestrial and plant-based, but marine benthic systems offer great opportunities for this research area. The marine benthic environment covers more than 70% of the Earth’s surface and is the site of important biogeochemical fluxes (N,P) between the sediment and overlying water column. Experimental manipulation of invertebrate species richness in controlled mesocosms and the field have indicated that the effects of biodiversity on these fluxes are idiosyncratic, depending greatly on the identity of the species as well as on the water flow regime, and that there is no clear relationship between function and richness per se. Recently, this work has been extended to explore the effects of heterogeneity and of ocean acidification on these relationships.

Ecosystem Health and the sustained delivery of ecosystem services

Healthy ecosystems are those which whose underlying natural and social capital allow them to continue to deliver the range of ecosystem services on which society depends. Our group has been involved in devising tools and techniques for assessing and monitoring the ecological, environmental and social dimensions of an ecosystem, so that stakeholders and practitioners are able to make informed choices between competing land management policies. Such tools will be central to the implementation of an Ecosystems Approach to environmental management (Defra, 2007: Securing a healthy natural environment: an action plan for embedding an ecosystems approach).

Catchment processes

The long history of research on one particular estuary food web, the Ythan, Aberdeenshire Scotland, and its catchment has permitted a rigorous analysis of changes in ecological and environmental parameters relevant to eutrophication (nutrient enrichment). These include trends in catchment land-use, nutrients in river water, algal mats (Ulva), mudflat invertebrate populations and shorebirds. Analyses of these trends have allowed formulation of specific hypotheses concerning possible interactions between the different factors and these have been tested experimentally. The effects on water quality of changes in land-use and numbers of herbivorous wildfowl roosting on coastal lochs have also been evaluated for the Loch of Harray, Orkney and the Loch of Strathbeg, Aberdeenshire. The value of this work has recently been recognised within the context of the designation of Nitrogen Vulnerable Zones under the EC Nitrates Directive, and has become a test-bed for the implementation of management policy and its socio-economic consequences, as well as restoration and remediation techniques. The current focus on this system is the application of Discourse Analysis and related techniques from the social sciences to understand the dynamics of stakeholder dialogue in the NVZ debate and its eventual effects on policy formulation.

Food web dynamics

Over the last 15 years, Dave Raffaelli's research has focussed on the dynamics of food webs. This is a long-term project based mainly on coastal systems, particularly estuaries. The small scale of these systems offers opportunities for the formal description of web structure and for experimental manipulation of the component species, mainly shorebirds, fish and epibenthic crustaceans. This has allowed testing of current theory about food web patterns and the importance of predation in organising communities.

Grants

Supervision

Current students

• Zoe Austin (NERC) "The impact of deer on biodiversity in the east of England" (jointly supervised with Piran White)
• Hamida Bibi (Pakistan Govt) "Effects of pollution on body size relationships in aquatic invertebrate communities"
• Helen Laycock (NERC/ESRC) "Valuing biodiversity gains" (jointly with Piran White and Dominic Moran)
• Wei Lin (self-funded) "Spatial patterns and dynamics in shallow water marine systems"
• Roseliza Mat Alipiah (Malaysian Govt) "Valuation of ecosystem services" (jointly supervised with Jim Smart)
• Melanie Netherton (CSL/UoY) "The fate of human pharmaceuticals in the aquatic environment" (jointly supervised with Alistair Boxall)
• Sirapraha Premcharoen (Thai Govt) "An ecotrophic model of a tropical mangrove estuary in Thailand"
• Jessica Wiegand (ESRC) "Ecosystem approach to environmental management" (jointly supervised with Piran White and Jim Smart)
• Tsuyuko Yamanaka (self-funded) "Marine ecosystems and climate change" (jointly supervised with Piran White)

Recent students

• Simon Longonje (self-funded) "The Cameroon Forest ecosystem: ecological and environmental dimensions"
• Michael Townsend (NERC, jointly supervised with Plymouth Marine Laboratory) "Biodiversity and ecosystem function in coastal systems"
• Toyonobu Fujii (self-funded) "Impact of global change on shallow water assemblages"
• Sophie Avila Foucet (Mexican govt, jointly supervised with Charles Perrings) "Ecological-economic approaches to integrated catchment management in Mexico"
• Tim Hounsome (CSL, jointly supervised with Martyn Gorman, University of Aberdeen) "Effects of badger removals"
• Steve Kirkby (CSL, jointly supervised with Martyn Gorman, University of Aberdeen) "Badgers in food webs"
• Gary White (Aberdeen Harbour Board, jointly supervised with Graeme Paton and Ian Marr, University of Aberdeen) "Environmental Impact Assessment of Aberdeen Harbour Current". PhD Awarded 2003
• Catherine Biles (NERC, joint with David Paterson, University of St Andrews) "Marine Benthic System Function and Biodiversity" PhD Awarded 2002
• Mark Emmerson (NERC). "Biodiversity in food webs". PhD awarded 2001.
• Henrik Jensen (Danish Fisheries, jointly supervised with Peter Wright, Marine laboratory Aberdeen). "Sandeel fisheries ecology". PhD awarded 2001
• Rebecca Leaper (NERC). "Organism size in foodwebs". PhD awarded 2000
• Stefan Bolan (Napier University, jointly supervised with Teresa Fernades and Paul Reid, Napier University). "Spatial patterns in infauna". PhD awarded 1999
• Vanda Mendonca (JNICT, jointly supervised with Peter Boyle, University of Aberdeen). "Trophic interactions on shores". PhD awarded 1997
• Levent Bat (Turkish Govt, jointly supervised with Ian Marr, University of Aberdeen). "Eco-toxicology of sediments". PhD awarded 1996
• Joanna Maloney (SERC). "Biomass size spectra in sediments". PhD awarded 1996
• Stefan Ragnarsson (Icelandic Government). "Bioengineers on mudflats". PhD awarded 1996
• Martin Bailey (SOAEFD, jointly supervised with Mike Heath, Marine Laboratory Aberdeen). "Ecology of sandeels". PhD awarded 1996
• Sarah Lawrie (NERC, jointly supervised with Steve Hall, Marine Laboratory Aberdeen). "Spatial pattern in marine sediments". PhD awarded 1996
• Niall Bell (AURIS). "Multivariate analysis of benthic communities". PhD awarded 1996

External activities

Editorial duties

• 2003 - Editorial board, Journal of Sea Research
• 1998 - 2006 Editor, Journal of Animal Ecology
• 1992 - 2006 Editorial board, Journal of Experimental Marine Biology and Ecology
• 1996 - 1999 Editor, Advances in Ecological Research

Teaching

Undergraduate

• Applied Ecology and Environmental Management
• Ecological Principles for the Environment - I and II
• The Dynamics of Social-Ecological Systems

Postgraduate

• Population and Community Ecology for Environmental Management