Reevaluating the theory of gap dynamics using studies of typhoon disturbance at the fushan experimental forest, Northeastern Taiwan

The theory of gap dynamics generalizes disturbance-diversity-forest dynamics relationships but is hotly debated. Studies of interactions between tropical cyclones and forest dynamics at the Fushan Long-term Ecological Research Site in northeastern Taiwan, where typhoon disturbances occur on an annual basis, indicate that gaps created by disturbances do not always differ from the non-gap understory in important physical conditions such as light availability and variability. Therefore, shade-tolerant and -intolerant species can coexist in both gaps and the non-gap understory. In such forests, gaps are not indispensable for the establishment and growth of shade-intolerant species as postulated by the theory of gap dynamics. Thus, it is important to focus on specific environmental conditions rather than the gap versus non-gap status when discussing gap-biodiversity-forest dynamics relationships. In the era of climate change characterized by more-frequent climate extremes and natural disturbances, we should move beyond generalizations and directly address the processes leading to the observed relationships among disturbance, diversity, and forest dynamics.