Pagnutti C, Anand M, Azzouz M
Department of Physics, Laurentian University, Ramsey Lake Road, Sudbury, Ont., Canada P3E 2C6.
J Theor Biol. 2005 Sep 7;236(1):79-87. doi: 10.1016/j.jtbi.2005.02.018. Epub 2005 Apr 7.
The geometry of the lattice used in ecological modeling is important because of the local nature of ecological interactions. The latter can generate complex behavior such as criticality (scale-invariance). In this work, we implement two slightly different forest disturbance models on three lattices, each with square, triangular and hexagonal symmetry, in order to study the effect of geometry. We calculate the density distribution of gaps in a forest and find bumps in the distribution at sizes that depend on lattice geometry. Similar bumps were observed in real data but remained unexplainable. We suggest that these bumps provide information about the geometry and scale of ecological interactions. We also found an effect of geometry on the conditions under which criticality appears in model forests. These conditions appear to be more biologically realistic, and also linked to the likelihood of local disturbance propagation. The scaling exponent of the gap-size distribution, however, was found to be independent of both model and geometry, a hallmark of universality.
由于生态相互作用具有局部性，生态建模中使用的晶格几何结构很重要。后者可以产生诸如临界性（尺度不变性）等复杂行为。在这项工作中，我们在三种晶格（分别具有正方形、三角形和六边形对称性）上实现了两个略有不同的森林干扰模型，以研究几何结构的影响。我们计算了森林中林窗的密度分布，并在取决于晶格几何结构的大小处发现了分布中的峰值。在实际数据中也观察到了类似的峰值，但仍无法解释。我们认为这些峰值提供了有关生态相互作用的几何结构和尺度的信息。我们还发现几何结构对模型森林中出现临界性的条件有影响。这些条件似乎更符合生物学实际情况，并且还与局部干扰传播的可能性有关。然而，林窗大小分布的标度指数被发现与模型和几何结构均无关，这是普遍性的一个标志。
