Data from: Mechanisms of resilience: empirically quantified positive feedbacks produce alternate stable states dynamics in a model of a tropical reef

Alternate stable states (ASS) theory is a dominant conceptual framework for understanding processes that support resilience of ecological communities in the face of multiple anthropogenic disturbances. For decades, coral reefs have been cited as a classic example of ASS, yet this position remains highly controversial, largely because convincing empirical evaluations have been elusive. Using a combination of empirical measurements of positive feedback processes and simulation modelling, we assessed ASS in coral reefs of the Eastern Tropical Pacific (ETP) by identifying the potential for multiple basins of attraction from a mechanistic perspective. Using bioassays of algal growth and consumption, we quantified two spatially localized positive feedback mechanisms on coral reefs: increasing herbivore activity associated with higher coral abundances and amelioration of nutrient limitation leading to higher algal growth in areas with higher algal abundance. Analysis of a model of benthic community dynamics incorporating these feedbacks showed they were central to producing hysteresis and bistability in the model, two hallmarks of ASS. Further, reefs simulated with conditions matching those measured at Isla Contadora, Panamá, displayed ASS dynamics while producing spatial patterns matching field observations. This provides model-derived support, based on empirically measured conditions of ETP reefs, for the presence of ASS. Synthesis. The combination of experimental bioassays to measure feedback strengths and simulation models to evaluate the influence of those feedbacks provides a novel, non-destructive approach to evaluating ASS dynamics that can be applied in threatened ecosystems where classic approaches are not viable.交替稳定态（Alternate Stable States, ASS）理论是理解生态群落在多重人为扰动下维持恢复力的主流概念框架。数十年来，珊瑚礁一直被视为ASS的典型范例，但这一观点仍颇具争议，核心原因在于始终缺乏令人信服的实证验证。 本研究结合正反馈过程的实证测量与模拟建模，从机制视角通过识别多吸引域的潜在可能性，评估了东热带太平洋（Eastern Tropical Pacific, ETP）珊瑚礁的ASS特征。 通过藻类生长与摄食的生物测定实验，我们量化了珊瑚礁上两种空间局域化的正反馈机制：一是珊瑚丰度升高伴随的植食动物活动增强，二是营养限制的缓解可提升高藻类丰度区域的藻类生长速率。 对纳入上述反馈机制的底栖群落动态模型的分析显示，这些反馈是模型中产生滞后现象与双稳态的核心驱动因素，而滞后与双稳态正是ASS的两大标志性特征。进一步模拟匹配巴拿马孔塔多拉岛（Isla Contadora）实测环境条件的珊瑚礁时，其呈现出ASS动态特征，且生成的空间格局与野外观测结果高度一致。这一基于东热带太平洋珊瑚礁实测条件的模型推导结果，为ASS的存在提供了有力支撑。 综上，结合量化反馈强度的实验生物测定与评估这些反馈影响的模拟建模，本研究提出了一种全新的非破坏性ASS动态评估方法，可应用于传统研究手段难以开展的受威胁生态系统中。