Trees Trigger Trouble - Landsliding by Biomass Surcharge and Wind Disturbance in Patagonian Rainforests (RETROGRESS)

沿海温带雨林是地球碳循环的全球参与者。它们经历不同幅度和频率的干扰。在巴塔哥尼亚的热带雨林，扰动包括火山爆发、暴雨和风暴；这些扰动导致浅层滑坡，从而释放出大量的c脉冲。沿海雨林易受气候变化和扰动机制的影响。这些变化正朝着相似的方向发展，但速度不同。因此，量化巴塔哥尼亚森林的干扰反应，例如，可以从有用的“蓝图”中为北美雨林的研究提供信息。多重干扰可以驱动C存储（净汇）或C消耗（净源），这取决于干扰期间C的相对减少、事件的平均频率和恢复时间。干扰频率高的地区和干扰频率低的地区分别由于生物量再生的事件间期有限或生产力降低而维持在相对较低的C状态。在这里，我们检验了中等扰动暴露区域形成相对最大C形成点的假设。生物过程被认为是地貌过程的重要控制因素。然而，因果关系并不总是单向的。例如，森林生物量的重量可能在通过树木转移到土壤的风力引发的滑动中达到顶峰。同时，滑坡疤痕为植被演替提供了新的场所。因此，山体滑坡也控制着被剥蚀的山坡上的生物量。下一步：我们通过实施生物质负荷和风的强迫，开发了一个基于模块化过程的滑坡模型。使用我们的模型，我们通过模拟植被-动力学-滑坡-反馈在几个干扰重复周期内测试了生物量附加和风力对滑坡触发的阈值。RETROGRESS采用基于物理的建模，结合实地工作、环境地震学和遥感。该研究旨在(1)利用激光雷达、森林清查图和统计数据，量化沿滑坡和风扰动暴露梯度在生物质和土壤中的碳储量；(2)模拟生物质负荷作为滑坡原因的敏感性；(3)风强迫作为滑坡触发因素的敏感性。我们选择的模型是Landlab。RETROGRESS汇集了来自生态学、建模学、地貌学、地质学的国际专家，并涉及当地环境保护当局。预期的成果是：(1)对巴塔哥尼亚雨林中c -种群及其与干扰的空间关系的前所未有的见解；(2)对基本干扰生态学理论的定量检验；(3)对滑坡的森林内在原因的新见解；(4)在地球上风最大、生物多样性最丰富的地区之一，潜在的重要滑坡触发因素。它有可能单独推动每个领域以及它们之间的综合，建立关于沿海雨林生物群系的新知识。

Coastal temperate rainforests are global players in Earth’s carbon cycle. They experience disturbances at different magnitudes and frequencies. In Patagonian rainforests, disturbances comprise volcanic eruptions, rain-, and windstorms; These disturbances result into shallow landslides, thus unleashing massive pulses of C. Coastal Rainforests are subject to shifts in the climate and disturbance regimes. Such changes are proceeding in similar directions but at different rates. Consequently, quantifying disturbance responses in Patagonian forests, for example, can from useful ‘blueprints’ informing research on rainforests of North America.Multiple disturbances can drive C-storage (net sink) or C-depletion (net source) depending on the relative reduction in C during the disturbance, the mean frequency of events, and the recovery time. Areas with high and low disturbance frequencies are maintain in a relatively lower C status due to limited inter-event periods for biomass regrowth or lowered productivity, respectively. Here, we test the hypothesis that areas of moderate disturbance exposure form spots of relative maximum C formation.Biotic processes are recognized as important controls of geomorphic processes. Yet cause and effect are not always unidirectional. For example, the weight of forest biomass may culminate in sliding triggered by wind forces transferred to the soil via trees. At the same time, landslide scars provide new spots for vegetation succession. Hence, landslides control biomass stocks on thus denuded hillslopes, too. Here we go the next step: We develop a modular process-based landslide model by implementing biomass burden and wind forcing. Using our model, we test for thresholds of biomass surcharge and wind forces on landslide triggering via simulating vegetation-dynamics–landslide-feedbacks over several disturbance recurrence intervals.RETROGRESS uses physics-based modelling coupled with field work, environmental seismology and remote sensing. It aims to (1) quantify C stored in biomass and soils along landslide and wind disturbance exposure gradients using LiDAR, forest inventory plots, and statistics, and (2) to simulate the sensitivity of biomass load as a landslide cause, and (3) wind forcing as a landslide trigger. The model of choice is Landlab.RETROGRESS brings together international experts from ecology, modelling, geomorphology, geology and involves local environment conservation authorities. The expected deliverables are (1) unprecedented insights into C-stocks and its spatial relation to disturbances in Patagonian rainforests, (2) a quantitative test for a fundamental disturbance ecology theory, (3) new insights into forest-intrinsic causes for landsliding, and (4) a potentially important landslide trigger in one of the windiest and most biodiverse spots on Earth. It has the potential to push each field individually as well as the synthesis between them, building new knowledge of the Coastal rainforest biome.