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中的全球参与者。它们会经历不同程度和频率的干扰。在巴塔哥尼亚雨林，干扰包括火山喷发、降雨和风暴；这些干扰导致浅层山体滑坡，从而释放出巨大的C.C脉冲。沿海雨林受到气候和干扰制度变化的影响。这些变化正朝着相似的方向进行，但速度不同。因此，例如，量化巴塔哥尼亚森林的干扰响应可以从对北美热带雨林的研究提供有用的“蓝图”信息。多重干扰可以驱动C储存(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。高干扰频率区和低干扰频率区分别由于生物量再生或生产力降低的事件间期有限而维持在相对较低的C状态。在这里，我们检验了一个假设，即中等干扰暴露的区域形成了相对最大C形成的斑点。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会在通过树木传递到土壤的风力引发的滑动中达到顶峰。同时，滑坡伤痕为植被演替提供了新的斑点。因此，山体滑坡也控制着这样裸露的山坡上的生物质储量。现在我们开始下一步：通过实施生物质负荷和风力强迫，我们开发了一个基于模块过程的滑坡模型。利用我们的模型，我们通过模拟植被-动态-滑坡-反馈在几个扰动重复间隔上测试了生物量超载和风力对滑坡触发的阈值。RETROGRESS使用基于物理的建模结合野外工作、环境地震学和遥感。它的目的是(1)利用激光雷达、森林资源清查图和统计学方法，对滑坡和风扰暴露梯度上生物量和土壤中储存的碳进行量化，(2)模拟生物量负荷作为滑坡原因的敏感性，以及(3)风强迫作为滑坡触发因素的敏感性。RETROGRESS汇集了来自生态学、建模、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C-STOCKS及其与巴塔哥尼亚热带雨林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测试，(3)对森林导致滑坡的内在原因的新见解，以及(4)在地球上风最大和生物多样性最多的地区之一引发潜在的重要滑坡。它有可能推动每个领域的单独发展，以及它们之间的综合，建立关于沿海雨林生物群的新知识。

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.