RAPID: Critical transitions in at-risk Balinese subaks

自然界中通常的情况是种群围绕某种趋势或稳定的平均值波动。然而，偶尔，这种情况会被突然转变为一种截然不同的状态所打断，就像在开阔的海洋中，许多物种的种群突然同步地跳跃到不同的丰度。对自然界这种变化的明显直观解释是突然发生的巨大外部冲击。然而，理论家们一直强调，事实并非如此。如果超过被称为“灾难性分叉”的临界阈值，即使条件的微小增量变化也可能引发某些系统的巨大转变。直觉上，这就像一艘超载的船，当太多的人移到一边时，船就会倾覆。一个有趣的问题是，这种临界点是否也存在于积极管理的生态系统中，比如灌溉稻田。2011年春天，一项对印度尼西亚巴厘岛传统小规模灌溉系统（称为subaks）的试点研究首次提出了积极管理的社会生态系统中存在多种机制的经验证据。第一组的四个subak自信地应对经济和环境挑战，而第二组的四个经历了快速下降。自世纪以来，巴厘岛上就有苏巴克，但大多数现在都处于危险之中，去年有一千公顷的梯田停产。有迹象表明，苏巴克系统受到严重威胁，导致印度尼西亚政府提议创建一个教科文组织世界遗产文化景观，以支持苏巴克人。 为了使世界遗产获得成功，了解是什么原因导致苏巴克从一个政权转向另一个政权至关重要。该项目将培训印度尼西亚研究人员使用为试点研究开发的新的多尺度分析方法，调查23个subak的临界点。本研究还将评估新方法在其他社会生态系统中理解关键转变的潜力。

The usual state of affairs in nature is one of populations fluctuating around some trend or stable average. Occasionally, however, this scenario is interrupted by an abrupt shift to a dramatically different regime, as when the populations of many species suddenly jump to different abundances in synchrony in the open ocean. The obvious intuitive explanation for such changes in nature is the occurrence of a sudden large external impact. However, theoreticians have long stressed that this need not be the case. Even a tiny incremental change in conditions can trigger a large shift in some systems if a critical threshold known as "catastrophic bifurcation" is passed. Intuitively, this is like the tipping over of an overloaded boat when too many people move to one side. A question of interest is whether such tipping points also exist in actively managed ecosystems, like irrigated rice paddies.In spring 2011, a pilot study of traditional, small-scale irrigation systems (called subaks) on the Indonesian island of Bali produced the first empirical evidence for the presence of multiple regimes in an actively managed social-ecological system. One group of four subaks responded confidently to economic and environmental challenges, while a second group of four experienced a rapid decline. Subaks have existed on Bali since the eleventh century, but most are now at risk, and last year a thousand hectares of terraced fields went out of production. Signs that the subak system is under severe threat led to a proposal from the Government of Indonesia to create a UNESCO World Heritage Cultural Landscape to support the subaks. For the World Heritage to succeed, it is vital to understand what causes subaks to tip from one regime to another. This project will train Indonesian researchers to use the new multi-scale analytical methods developed for the pilot study, to investigate tipping points in 23 subaks. This study will also evaluate the potential of the new methods for understanding critical transitions in other social-ecological systems.