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

1. 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. 2. Using a combination of empirical measurements of positive feedback processes and simulation modeling, 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. 3. Using bioassays of algal growth and consumption we quantified two spatially-localised 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. 4. 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. 5. 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.

1. 交替稳定态（Alternate stable states, ASS）理论是理解生态群落在多重人为干扰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的经典案例，但这一观点仍极具争议，核心原因在于始终难以开展令人信服的实证评估。2. 本研究结合正反馈过程的实证测量与模拟建模，从机制视角出发，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。3. 本研究通过藻类生长与摄食的生物测定实验，量化了珊瑚礁上两类空间局域化的正反馈机制：一是草食动物活动随珊瑚丰度升高而增强，二是养分限制得到缓解后，藻类丰度较高区域的藻类生长速率得以提升。4. 对纳入上述反馈机制的底栖群落动态（benthic community dynamics）模型进行分析后发现，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，而这二者正是ASS的两大标志性特征。进一步的模拟实验显示，当模型参数匹配巴拿马孔塔多拉岛（Isla Contadora）实地测量的环境条件时，模拟得到的珊瑚礁呈现出ASS动态特征，且其空间格局与野外观测结果一致。本研究基于东热带太平洋珊瑚礁的实测条件，通过模型推导为ASS的存在提供了支撑证据。5. 综合分析：本研究将测量反馈强度的实验生物测定法与评估这些反馈影响的模拟建模法相结合，提出了一种全新的非破坏性ASS动态评估方法，该方法可应用于经典研究手段难以开展的受威胁生态系统中。