Research Interests

My primary research interest is in the methodology of research synthesis. How do we combine data to answer questions especially when the data reports a range of outcomes and is of variable quality?

I am particularly interested in Meta-analysis, systematic review and bayesian statistics. I apply these tools to addressing current problems in applied ecology and conservation.

Politicians, policy makers, NGO policy advocates, the general public and ecologists are inundated with unmanageable amounts of information. In medicine systematic reviews are used to integrate information and provide a basis for rational evidence-informed decision making. I am pioneering the use of systematic reviews in ecology. Systematic reviews establish where the effects of a management intervention or impact are consistent and where they vary. Consistent research results can be applied across species, sites, ecological settings, and small differences in treatment (e.g. intensity). The use of explicit, systematic methods in reviews limits bias (systematic errors) and reduces chance effects, providing more reliable results upon which to draw conclusions and make decisions. Meta-analysis, the use of statistical methods to summarise the results of independent studies, can provide more precise estimates of effects than those derived from the individual studies included in a review and allows decisions that are based on all available evidence…but it is easy to get it wrong using meta-analysis. I am interested in developing methods to make meta-analysis more repeatable, transparent and reliable especially when the data is not easy to analyse.

My other research interest is in plant ecology. I spent a long time learning how to identify plants early in my career and retain a strong interest in plant ecology, particulary in relation to vegetation dynamics and upland habitat management.  

 

 

 

 

 

 

 Friends 

My meta-analysis friends are mostly members of the NCEAS methods group on research synthesis. We have formed a meta-analysis in ecology group and continue to argue about the best ways of sticking stuff together which is what meta-analysis is all about. Khalid Khan, Ari Coomarasamy and Rod Taylor helped me with my first forays into research synthesis. Adrian Newton and Rob Marrs are other ecological friends who have done meta-analyses with me- in fact Adrian introduced me to the world of bayesian statistics which is where its really at if you want to meta-analyse messy diverse data.

My other meta-analysis friends are members of the Society for Research Synthesis Methodology. This is a group of medical, ecological and social scientists with an interest in evidence synthesis. Most members of the group are applied statisticians or biostatisticians of variable taxonomies. We have a shared interest in methods of sticking data together to answer policy questions. 

Recent Publications

Stewart, G.B. & Pullin, A.S. (2008) The relative importance of grazing stock type and grazing intensity for conservation of mesotrophic pasture. Journal of Nature Conservation. In press.

Stewart, G.B. Bayliss, H.R. Showler, D.A. Sutherland, W.J. and Pullin, A.S. (2008) Effectiveness of engineered in-stream structure mitigation measures for increasing salmonid abundance: a systematic review. Ecological Applications. In press.

Martinez-Abrain, A., Crespo, J., Jimenez, J., Pullin, A.S., Stewart, G.B. & Oro. D. (2008) Friend or foe: societal shifts from intense persecution to active conservation of top predators. Ardeola 55(1): 111-119.

Stewart, G.B., Cox, E.S., Le Duc, M.G., Pakeman, R.J., Pullin, A.S., & Marrs, R.H. (2008) Control of bracken across the UK: meta-analysis of a multi-site study. Annals of Botany. In press.

Davies, Z.G., Tyler, C., Stewart, G.B., & Pullin, A.S. (2007) Are current management recommendations for saproxylic invertebrates effective? A systematic review. Biodiversity and conservation. 17: 209-234 

Newton, A., Stewart, G.B., Diaz, A., Golicher, D., & Pullin, A.S. (2007) Bayesian Belief Networks as a tool for evidence-based conservation management. Journal of Nature Conservation. 15: 144-160.

Stewart, G.B., Pullin, A.S., & Tyler, C. (2007) The effectiveness of asulam for Bracken (Pteridium aquilinum) control in the U.K: A meta-analysis. Environmental Management 40 (5): 747-760. 

Stewart, G.B., Pullin, A.S. & Coles, C.F. (2007) Poor evidence-base for assessment of windfarm impacts on birds. Environmental Conservation. in press 

Roberts, P.D., Stewart, G.B., & Pullin, A.S. (2006) Are review articles a reliable source of evidence to support conservation and environmental management? A comparison with medicine. Biological Conservation 132 (4): 409-423.

Pullin, A.S., & Stewart, G.B. (2006) Guidelines for Systematic Review in Conservation and Environmental Management. Conservation Biology 20 (6): 1647–1656.

Tyler, C., Pullin, A.S., & Stewart, G.B. (2006) Effectiveness of management interventions to control invasion by Rhododendron ponticum. Environmental Management 37 (4): 513-522. 

Stewart, G.B., Coles, C.F., & Pullin, A.S. (2005) Applying evidence-based practice in conservation management: Lessons from the first systematic review and dissemination projects. Biological Conservation 126 (2): 270-278.

Fell Running

When I’m not working I can usually be found running in the hills (http://www.runfurther.com, http://www.fellrunner.org.uk).

 I am training more regularly with my Eryri clubmates having defected from Merica and am slowly regaining fitness. I hope to get fitter than i was in early 90s when I ran with Carnethy. Say Hi if you pass me at a local north wales race! I also run the odd British champs race (near the back with the other fat sods) and enjoy ultras. This year I am threatening the cream of the ultra-running world in the Vasque ultra-running championship alongside my Mucking Fuddler team mates.

 

I'm hoping to get fit enough to complete the paddy buckley round in the next few years but this will require a reduction in curry consumption and lots of long recce runs

Other stuff

 When i'm not meta-analysing data or rolling down hills like an out of control cannonball, i like gardening. I have a special fondness of Rhododendrons- and want to do an evolutionary meta-analysis of this genera at some point. I currently have 33 rhododendron in my garden but hope to increase this number over the years.

 

 

I also spend time looking after my ferrets (http://www.britishferretclub.co.uk). They are great beasts and don't bite that often. Rocky is a great fan of Cooper and Hedges but has a strong prior belief that raisins or other treats should be involved.

 

 

 

 

 

 

I spend a lot of time moaning about politicians (http://www.anarchist-studies-network.org.uk). i love the George Bernard-Shaw Quote: "He knows nothing and thinks he knows everything. That points clearly to a political career." Fortunately, Emma is a political scientist and spends her time proving that politicians lie! We're thinking of running some meta-analyses to show that too!