How do plant community ecologists consider the complementarity of observational, experimental and theoretical approaches ?
Background and aims -- A panoply of methods are used by ecologists for studies at the plant community level. While early studies were mainly descriptive, more manipulative experiments are now being undertaken because they provide a more functional approach and greater insight into underlying mechanisms. Mathematical models are also being increasingly used for prediction of biodiversity change under global change. The aim of this study is to highlight the forces, limitations, and advantages of these three approaches, namely observational, experimental and theoretical modelling. Methods -- We assessed 156 papers published during the last four years in three specialized disciplinary journals (DJ) and 186 papers in three generalist high impact journals (HIJ) dealing with plant ecology, and checked the methods that were used. We asked participants of the ECOVEG7 meeting held in Lausanne (April 2011) whether observational, experimental and theoretical modelling approaches can, or should, be used alone or in combination when studying plant communities and ecosystem functioning in the context of global change. Key results -- About 50 % of articles published in both journal types used only a single approach. Papers in HIJ used the approaches in similar proportions, while articles in DJ had 8 times more observational than modelling studies. Combined approaches represented only 8 % in DJ, while this percentage was more than double in HIJ. Conclusion -- Plant community ecologists favour a combination of several approaches to their studies, but for practical reasons single-approach studies are generally preferred. Obstacles to a more comprehensive approach include difficulties in communicating among people using different approaches and publication strategies, as it is believed to be difficult to publish observational studies at least in HIJ. Papers that combine different approaches are more suitable for publication in HIJ.