RAPID: Critical transitions in at-risk Balinese subaks

自然界中事物的通常状态是种群围绕某种趋势或稳定的平均值波动。然而，这种情况偶尔会被突然转变到一个截然不同的状态所打断，就像许多物种的种群突然在开阔的海洋中同步跳到不同的丰度一样。对于自然界的这种变化，显而易见的直观解释是发生了突然的巨大的外部冲击。然而，理论家们长期以来一直强调，事实并非如此。如果超过一个被称为“灾难性分叉”的临界阈值，即使是条件的微小增量变化也可能引发某些系统的巨大变化。直观地说，这就像一艘超载的船在太多人向一侧移动时倾覆一样。一个令人感兴趣的问题是，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，在印度尼西亚巴厘岛对传统的小规模灌溉系统（称为subaks）进行的一项试点研究首次提供了经验证据，证明在一个积极管理的社会生态系统中存在多种制度。其中一组由4只subak组成，对经济和环境挑战做出了自信的回应，而另一组由4只subak组成的小组则经历了迅速的衰退。自11世纪以来，苏巴克就在巴厘岛生存，但现在大多数都处于危险之中，去年，1000公顷的梯田停产。有迹象表明，亚豹系统正受到严重威胁，因此印度尼西亚政府提议创建一个联合国教科文组织世界遗产文化景观来支持亚豹。为了使世界遗产获得成功，了解是什么导致了亚克力从一个政权转向另一个政权是至关重要的。该项目将培训印度尼西亚的研究人员使用为试点研究开发的新的多尺度分析方法来调查23个亚种的临界点。这项研究还将评估新方法在理解其他社会生态系统关键转变方面的潜力。

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.