Willow encroachment into the naturally mixed landscape of vegetation types in the Upper St. Johns River Basin in Florida, USA, impacts upon biodiversity, aesthetic and recreational values. To control the ex- Tent of willows and their rate of expansion into other extant wetlands, spatial context is critical to decision making. Modelling the spread of willows requires spatially ex- plicit data on occupancy, an understanding of seed production, dispersal and how the key life-history stages respond to environmental factors and management actions. Nichol- son et al. (2012) outlined the architecture of a management tool to integrate GIS spa- Tial data, an external seed dispersal model and a state-transition dynamic Bayesian net- work (ST-DBN) for modelling the inuence of environmental and management factors on temporal changes in willow stages. That paper concentrated on the knowledge en- gineering and expert elicitation process for the construction and scenario-based evalua- Tion of the prototype ST-DBN. This paper extends that work by using object-oriented techniques to generalise the knowledge or- ganisational structure of the willow ST-DBN and to construct an object-oriented spatial Bayesian network (OOSBN) for modelling the neighbourhood spatial interactions that underlie seed dispersal processes. We present an updated architecture for the management tool together with algorithms for implement- ing the dispersal OOSBN and for combining all components into an integrated tool
