Gayler S, Grams T E E, Kozovits A R, Winkler J B, Luedemann G, Priesack E
Institute of Soil Ecology, GSF--National Research Center for Environment and Health, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
Plant Biol (Stuttg). 2006 Jul;8(4):503-14. doi: 10.1055/s-2006-923979.
Inter- and intra-specific competition between plants for external resources is a critical process for plant growth in natural and managed ecosystems. We present a new approach to simulate competition for the resources light, water, and nitrogen between individual plants within a canopy. This approach was incorporated in a process-oriented plant growth simulation model. The concept of modelling competition is based on competition coefficients calculated from the overlap of occupied crown and soil volumes of each plant individual with the occupied volumes of its four nearest neighbours. The model was parameterised with data from a two-year phytotron experiment with juvenile beech and spruce trees growing in mono- and mixed cultures. For testing the model, an independent data set from this experiment and data from a second phytotron experiment with mixed cultures were used. The model was applied to analyse the consequences of start conditions and plant density on plant-plant competition. In both experiments, spruce dominated beech in mixed cultures. Based on model simulations, we postulate a large influence of start conditions and stand density on the outcome of the competition between the species. When both species have similar heights at the time of canopy closure, the model suggests a greater morphological plasticity of beech compared with spruce to be the crucial mechanism for competitiveness in mixed canopies. Similar to the experiment, in the model greater plasticity was a disadvantage for beech leading to it being outcompeted by the more persistent spruce.
植物间为获取外部资源而进行的种间和种内竞争，是自然和人工管理生态系统中植物生长的关键过程。我们提出了一种新方法，用于模拟树冠层内单株植物之间对光、水和氮等资源的竞争。该方法被纳入了一个面向过程的植物生长模拟模型。竞争建模的概念基于竞争系数，该系数根据每株植物占据的树冠和土壤体积与其四个最近邻株的占据体积的重叠情况计算得出。该模型用来自一个为期两年的植物人工气候室实验的数据进行了参数化，实验中幼年山毛榉和云杉以单作和混作方式生长。为了测试该模型，使用了来自该实验的一个独立数据集以及来自第二个植物人工气候室混作实验的数据。该模型被用于分析起始条件和种植密度对植物间竞争的影响。在这两个实验中，混作时云杉占优势。基于模型模拟，我们推测起始条件和林分密度对物种间竞争结果有很大影响。当两个物种在树冠郁闭时高度相似，模型表明与云杉相比，山毛榉具有更大的形态可塑性，这是其在混交树冠中具有竞争力的关键机制。与实验类似，在模型中更大的可塑性对山毛榉来说是一个劣势，导致它被更具持久性的云杉竞争淘汰。
