Resampling a chronosequence of phytological succession after stand-replacing disturbance in a slow-growing environment (ReChron)

理解和预测生态系统动态是基础科学和生态系统管理的一个关键目标。在森林等以长寿生物为主的生态系统中，空间换时间替代（SFT），也称为时间序列，被广泛用作长期监测的替代方法，特别是用于了解林分替代干扰后的森林动态。然而，SFT替代的不确定性和挑战来自于违反基本假设，即除了时间之外，空间采样点之间的干扰是相同的。真正的时间序列和SFT替代之间的直接比较仍然令人惊讶地罕见。在这里，我建议检查SFT替代的有效性，预测植被动态后，取代干扰的主要亚高山针叶林，并从这种方法得出的结论，这些森林的管理前SFT替代研究后20年的restriatsites。这个案例研究是高度相关的，因为它是在一个紧张的环境中，导致植物生长缓慢和量化的植被动态后，皆伐，即一个主要的立场取代干扰，在以前的原始森林。20年和大约600平方公里的空间尺度使拟议的研究在空间和时间尺度上正确，其中很少有经验证据表明SFT替代的有效性。因此，本项目将提供一个正式的测试的有效性SFT替代在北方森林，并帮助了解他们的植被发展后，林分取代干扰，这对他们的管理有影响。

Understanding and projecting ecosystem dynamics is a key goal for both basic science and ecosystem management. In ecosystems dominated by long-lived organisms such as forests, space-for-time substitutions (SFT), also called chronosequences, are widely used as an alternative approach for longterm monitoring, in particular for understanding forest dynamics after stand-replacing disturbances. Uncertainties and challenges of SFT substitution, however, arise from violations of the underlying assumption that everything but time since disturbance is identical among the spatial sampling sites. Direct comparisons between true time series and SFT substitutions are still surprisingly rare. Here, I propose to check the validity of SFT substitution for projecting vegetation dynamics after stand-replacing disturbances in primary subalpine conifer forests and the conclusions drawn from this approach for management of these forests by resampling sites of a former SFT substitution study after 20 years. This case study is highly relevant as it is situated in a stressful environment leading to slow plant growth and the quantification of vegetation dynamics after clearcutting, i.e. a major stand-replacing disturbance, in formerly pristine forests. Two decades and a spatial scale of about 600 km² put the proposed study right at spatial and temporal scales for which little empirical evidence for the validity of SFT substitution exists. Thus, this project will provide a formal test of the validity of SFT-substitution in boreal forests and help understanding their vegetation development after stand-replacing disturbances, which has implications for their management.