Simulating Growth and Competition on Wet and Waterlogged Soils in a Forest Landscape Model
Simulating Growth and Competition on Wet and Waterlogged Soils in a Forest Landscape Model
复制标题
DOI：
10.3389/fevo.2020.598775
复制
发表时间：
2020-12
期刊：
影响因子：
--
通讯作者：
E. Gustafson;Brian R. Miranda;A. Shvidenko;B. Sturtevant
中科院分区：
文献类型：
--
作者：
E. Gustafson;Brian R. Miranda;A. Shvidenko;B. Sturtevant
CO2浓度和气候的变化可能会改变树种之间的干扰机制和竞争结果，最终可能导致物种和生物群落边界的变化。这种变化在高纬度森林中已经很明显，在那里，地形、地表地质和永久冻土产生的积水土壤是森林动态的重要驱动力。要预测未来新条件下的这种影响，需要建立非生物驱动因素与增长和竞争之间存在直接和机械联系的模型。我们增强了这样一个森林景观模型（PnET-演替LANDIS-II），允许模拟积水土壤及其对树木生长和竞争的影响。我们正式测试了这些修改如何改变湿地和永久冻土区的水平衡，以及它们对树木生长和竞争的影响。我们应用该模型，以评估其承诺机械模拟物种范围的扩大和收缩下的气候变化在西伯利亚的纬度梯度。我们发现，更高的排放情景允许更快的范围扩张，并允许入侵物种的更大多样性，特别是在最高纬度地区，并且干扰通过克服已建立的生态群落的自然惯性来加速范围转移。山脉向北推进的主要驱动力是与冻土融化有关的水文变化，其次是温度对生长的影响。来自南方的范围收缩（灭绝）较慢，与排放或纬度的联系较少，并且是由于无法与入侵者竞争或干扰。一个重要的非直观的结果是，一些现存的物种被气候变化下预测的极端寒冷事件杀死，因为未来30年发生了更大的极端天气，这对随后的演替轨迹产生了重要影响。在这个森林景观模型中，气候和土壤水分动态之间的机械联系产生了紧密的联系，气候输入，植被生理和土壤在每月的时间步长。更新后的模拟系统可以产生高质量的预测气候对森林物种范围的变化的影响，占CO2浓度，气候（包括较长的生长季节），种子传播，干扰和土壤水文特性的相互作用。
Changes in CO2 concentration and climate are likely to alter disturbance regimes and competitive outcomes among tree species, which ultimately can result in shifts of species and biome boundaries. Such changes are already evident in high latitude forests, where waterlogged soils produced by topography, surficial geology, and permafrost are an important driver of forest dynamics. Predicting such effects under the novel conditions of the future requires models with direct and mechanistic links of abiotic drivers to growth and competition. We enhanced such a forest landscape model (PnET-Succession in LANDIS-II) to allow simulation of waterlogged soils and their effects on tree growth and competition. We formally tested how these modifications alter water balance on wetland and permafrost sites, and their effect on tree growth and competition. We applied the model to evaluate its promise for mechanistically simulating species range expansion and contraction under climate change across a latitudinal gradient in Siberian Russia. We found that higher emissions scenarios permitted range expansions that were quicker and allowed a greater diversity of invading species, especially at the highest latitudes, and that disturbance hastened range shifts by overcoming the natural inertia of established ecological communities. The primary driver of range advances to the north was altered hydrology related to thawing permafrost, followed by temperature effects on growth. Range contractions from the south (extirpations) were slower and less tied to emissions or latitude, and were driven by inability to compete with invaders, or disturbance. An important non-intuitive result was that some extant species were killed off by extreme cold events projected under climate change as greater weather extremes occurred over the next 30 years, and this had important effects on subsequent successional trajectories. The mechanistic linkages between climate and soil water dynamics in this forest landscape model produced tight links between climate inputs, physiology of vegetation, and soils at a monthly time step. The updated modeling system can produce high quality projections of climate impacts on forest species range shifts by accounting for the interacting effects of CO2 concentration, climate (including longer growing seasons), seed dispersal, disturbance, and soil hydrologic properties.