Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1073/pnas.1522130113
Title (Primary) Discovery of fairy circles in Australia supports self-organization theory
Author Getzin, S.; Yizhaq, H.; Bell, B.; Erickson, T.E.; Postle, A.C.; Katra, I.; Tzuk, O.; Zelnik, Y.R.; Wiegand, K.; Wiegand, T.; Meron, E.
Source Titel Proceedings of the National Academy of Sciences of the United States of America
Year 2016
Department OESA; iDiv
Volume 113
Issue 13
Page From 3551
Page To 3556
Language englisch
Keywords drylands; spatial pattern; Triodia grass; Turing instability; vegetation gap
UFZ wide themes RU5;
Abstract Vegetation gap patterns in arid grasslands, such as the “fairy circles” of Namibia, are one of nature’s greatest mysteries and subject to a lively debate on their origin. They are characterized by small-scale hexagonal ordering of circular bare-soil gaps that persists uniformly in the landscape scale to form a homogeneous distribution. Pattern-formation theory predicts that such highly ordered gap patterns should be found also in other water-limited systems across the globe, even if the mechanisms of their formation are different. Here we report that so far unknown fairy circles with the same spatial structure exist 10,000 km away from Namibia in the remote outback of Australia. Combining fieldwork, remote sensing, spatial pattern analysis, and process-based mathematical modeling, we demonstrate that these patterns emerge by self-organization, with no correlation with termite activity; the driving mechanism is a positive biomass–water feedback associated with water runoff and biomass-dependent infiltration rates. The remarkable match between the patterns of Australian and Namibian fairy circles and model results indicate that both patterns emerge from a nonuniform stationary instability, supporting a central universality principle of pattern-formation theory. Applied to the context of dryland vegetation, this principle predicts that different systems that go through the same instability type will show similar vegetation patterns even if the feedback mechanisms and resulting soil–water distributions are different, as we indeed found by comparing the Australian and the Namibian fairy-circle ecosystems. These results suggest that biomass–water feedbacks and resultant vegetation gap patterns are likely more common in remote drylands than is currently known.
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=17351
Getzin, S., Yizhaq, H., Bell, B., Erickson, T.E., Postle, A.C., Katra, I., Tzuk, O., Zelnik, Y.R., Wiegand, K., Wiegand, T., Meron, E. (2016):
Discovery of fairy circles in Australia supports self-organization theory
Proc. Natl. Acad. Sci. U.S.A. 113 (13), 3551 - 3556 10.1073/pnas.1522130113