Empirical evidence reveals the phase diagram of vegetation patterns in Mediterranean drylands [article]

Fernando Meloni, Gilberto Medeiros Nakamura, Cristiano Roberto Fabri Granzotti, Alexandre Souto Martinez
2017 bioRxiv   pre-print
Drylands are important ecosystems with limited water resources, often subject to desertification. Their ecological activities depend on spatial patterns formed by local vegetation, but the relation with vegetation growth remains unclear. Using satellite images of a typical semiarid shrubland in Southern Spain, we gather vegetation data and argue that vegetation cover can be interpreted by means of a percolation process. We use a static analysis that compares patch statistics in different
more » ... scales to study the various patch patterns that occurs in drylands. Our results indicate three distinct phases in the overall vegetation cover range. The spatial patterns of vegetation are separated by a first- and a second-order phase transition, in three different spatial scales. We measure the corresponding critical exponents and determine novel relations between scaling exponents. The results reconcile conflicting views about vegetation patterns in drylands and demonstrate that different phase transitions coexist in the phase diagram of dry shrublands in Southern Spain. In addition, our preliminary test with a distinct dryland supports the hypothesis of universality classes to sort different drylands.
doi:10.1101/171835 fatcat:bk4yj2snjfhxzcmpxemmr4laky