Editor's Summary
20 July 2006
Ecological complexity untangled
Food webs map which organisms eat which other organisms, and help to visualize community organization. They are complex, as Darwin recognized in his metaphor of a "tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth". The cover (by Sergi Valverde using Netlab software) illustrates complexity in an empirical food web — here it's species associated with Scotch broom at Silwood Park, UK. Montoya et al. review recent work on ecological networks and consider a paradox: theory predicts that complex networks will be fragile, yet complexity evolves and persists. Yes, these networks are complex, they conclude, but not so complex that we can't understand them. There are simplifying patterns in maps of feeding relationships, and parts of the 'tangled bank' are less tangled than others. As simulations grow more realistic, factors influencing ecological fragility should become clearer, with benefits for work on ecological impact and conservation. Ecology features elsewhere this week. In a contribution to the debate on ecosystem biodiversity, Rooney et al. identify a recurring pattern in real food webs: the top predators couple distinct 'fast' and 'slow' energy channels that differ in both productivity and turnover rate. Theory suggests that such coupling is critical to food-web stability. Alarmingly, human actions that reduce biodiversity also erode structures that provide that stability. So it may be time to stop focusing exclusively on ecosystem biodiversity, and to look more closely at the factors that create food-web stability. All agree: matters ecological are complex. But policymakers do not have a recognized international body of experts to turn to. Climate change has the IPCC. Now ecologists present the case for IMoSEB, the International Mechanism of Scientific Expertise on Biodiversity.
Commentary: Diversity without representation
For policymakers, biodiversity can present more complex challenges than climate change, argue Michel Loreau, Alfred Oteng-Yeboah and their co-authors. So why isn't there an international panel of experts for biodiversity?
doi:10.1038/442245a
News and Views: Ecology: Asymmetry and stability
Ecological communities are dauntingly complex. Nonetheless, ecologists gallantly persevere in eliciting insights about the factors that govern the behaviour and persistence of these messy, tangled webs.
doi:10.1038/442252a
Review: Ecological networks and their fragility
doi:10.1038/nature04927
Abstract | Full Text | PDF (324K)
Article: Structural asymmetry and the stability of diverse food webs
doi:10.1038/nature04887
Abstract | Full Text | PDF (245K) | Supplementary information
