Abstract. The structure of stakeholder interaction is a critical precursor to the ability to solve complex environmental challenges. The structure relates not just of social interactions, but also of how social actors participate in key policy forums (working groups, technical committees etc.). Accordingly, multi-level networks provide a useful framework for the analysis of such problems – with social actors at one level, and policy forums at another. Networks based on stakeholder participation in institutional responses to agricultural pest and disease incursions are analysed. In such networks the spatial complexity of response is further challenged by the need to design and implement plans quickly in order to stop the spread pest and disease of incursions. Exponential random graph models were applied to multi-level networks collected from Australia’s institutional responses to the 2010 myrtle rust (trees) and 2001 black sigatoka (banana) incursions. Lessons from political theory suggest that, in these policy networks, where higher-level decisions are made interactions should be denser, with overlapping stakeholder interactions signifying collaboration (bonding-capital, high transaction-costs).  Where plans are implemented more-or-less at face value, networks should exhibit lower-transaction cost interactions associated with the socially cheaper task of coordination (bridging-capital, low transaction-costs). Both datasets give some support to these ideas.  More generally, methods to identify the mix of coordination and collaboration in networks for solving environmental problems can help target capacity building and institutional design.

Biography. Ryan is a behavioural economist and principal research scientist with CSIRO, exploring problems that require cooperation to solve. He has worked across the Australian rangelands, and extensively in urbanised, coastal communities. Between 2009 and 2012, he ran a major regional scale adaptation initiative, examining the distribution of the economic winners and losers from climate adaptations. More recently, he has been focusing on community participation in Australia’s biosecurity detection and response system. Previously, Ryan worked in statistical roles with the Australian and British governments, and with industry.