QUANTITATIVE CHARACTERIZATION OF SPATIAL PATTERNS IN DRYLAND VEGETATION

Vegetation in dryland ecosystems of Africa, America, Australia and Asia often forms remarkable spatial patterns. These range from regular bands of vegetation alternating with bare ground, to vegetated spots and labyrinths, to regular gaps of bare ground within an otherwise continuous expanse of vegetation. These remarkable patterns can be observed in satellite imagery and can be produced by activation–inhibition systems in computational models. However, descriptions of them are currently limited to qualitative descriptive nomenclature, Shannon entropy values and Fourier analysis. In order to address this, we have developed methods to quantify the complexity of these spatial patterns. We have analysed images of patterned vegetation produced by a computational model and a small set of satellite images from South Sudan in order to illustrate that our methods are applicable to both simulated and real-world data. Our methods may help to describe regime shifts in simulated dryland vegetation with greater accuracy, and could also be used to classify vegetation patterns in large-scale field surveys of dryland ecosystems using satellite imagery.