A multi-scale biophysical model to inform regional management of coral reefs in the western Philippines and South China Sea J. Melbourne-Thomas a, * , C.R. Johnson a , P.M. Aliño b , R.C. Geronimo b , C.L. Villanoy b , G.G. Gurney a a School of Zoology, University of Tasmania, Hobart, Tasmania 7001, Australia b Marine Science Institute, University of the Philippines, Diliman, Quezon City 1101, Philippines article info Article history: Received 2 October 2009 Received in revised form 3 March 2010 Accepted 31 March 2010 Available online 4 May 2010 Keywords: CORSET Coral reef Regional scale Decision support Ecosystem model Management Connectivity Philippines South China Sea abstract The health and functioning of coral reef ecosystems worldwide is in decline, and in the face of increasing anthropogenic stress, the rate of decline of these important ecosystems is set to accelerate. Mitigation strategies at regional scales are costly, but nevertheless critical, as reef systems are highly connected across regions by ocean transport of both larval propagules and pollutants. It is essential that these strategies are informed by sound science, but the inherent complexity of coral reef systems confers significant challenges for scientists and managers. Models are useful tools for dealing with complexity and can inform decision making for coral reef management. We develop a spatially explicit biophysical model for a general coral reef system. The model couples dynamics from local (10 2 m) to regional (10 6 m) scales, and explicitly incorporates larval connectivity patterns derived from sophisticated larval dispersal models. Here, we instantiate and validate the model for coral reefs in the Philippines region of the South China Sea. We demonstrate how the model can be used in decision support for coral reef management by presenting two examples of regional-scale scenario projection relating to key management issues in the Philippines: (i) marine reserve design and the recovery of fish stocks; and (ii) synergistic effects between coral bleaching and poor water quality. These scenarios highlight the importance of considering multiple stressors to reef health and patterns of larval connectivity in regional-scale management decisions. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction 1.1. Models of complex coral reef systems Coral reefs provide essential ecosystem services to millions of people in coastal populations worldwide (Done et al., 1996; Moberg and Folke, 1999) and the demand for decision support tools to inform the management of these ecosystems is increasing. Coral reefs are inherently very complex, multi-scale and multi-process systems (Hatcher,1997; Hughes et al., 2005; Dizon and Yap, 2006), the behaviour of which is difficult to understand and predict. Conceptual models, analytical models and simulation models are effective tools to capture some of this complexity and to assess trade-offs that arise in the exploitation and protection of coral reef systems (Van Kouwen et al., 2008). However, ecosystem models for coral reefs have tended to focus on local-scale processes (e.g. McClanahan, 1992, 1995; McCook et al., 2001; Mumby, 2006b; Mumby et al., 2006, but see Gribble, 2003), despite that reefs are highly connected at regional scales by ocean currents, social structures and regional economies. Ocean circulation and particle tracking models have dramati- cally improved understanding of dispersal processes for the larvae of coral reef organisms (e.g. James et al., 2002; Bode et al., 2006; Cowen et al., 2006; Paris et al., 2005, 2007), terrestrially-derived suspended particles (Chérubin et al., 2008; Paris and Chérubin, 2008) and contaminants in coastal waters (Condie et al., 2005; Suh, 2006). Predictions from these models have important impli- cations for management, for example in assessing likely recovery trajectories of damaged reef localities. Cowen et al. (2000, 2006) and Paris et al. (2007) demonstrate the importance of considering both circulation patterns and larval behaviour (e.g. vertical migra- tion and attraction towards settlement habitats) in estimating connectivity strengths for coral reef organisms. However there have been limited attempts to incorporate connectivity information derived from sophisticated particle tracking simulations e that include both hydrodynamics and larval behaviour e into ecosystem models (Gray et al., 2006; Little et al., 2007). We present a spatially explicit regional-scale model of a coral reef system; CORSET (Coral Reef Scenario Evaluation Tool). CORSET captures multi-scale processes by coupling a local-scale ecosystem * Corresponding author. E-mail address: jessica.melbournethomas@utas.edu.au (J. Melbourne-Thomas). Contents lists available at ScienceDirect Environmental Modelling & Software journal homepage: www.elsevier.com/locate/envsoft 1364-8152/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.envsoft.2010.03.033 Environmental Modelling & Software 26 (2011) 66e82