Scale‐Dependent Inhibition Drives Regular Tussock Spacing in a Freshwater Marsh

Regular spatial patterning is common in nature, and various mechanisms of self‐organization have been proposed to explain regular patterning. We report on regular spatial patterning inCarex strictain a freshwater wetland and investigate the applicability of theoretical models that explain regular patterning based on inhibition, facilitation, or interaction between the two. Spectral analysis of aerial photographs revealed that tussocks were regularly spaced at an average distance of 60 cm. Photosynthetically active radiation varied significantly with distance from the tussock and was lowest at intermediate distance from the tussock center (15–40 cm). Using transplants to assay growth conditions, we found thatC. strictagrew well in all distance classes with and without naturalC. strictabiomass, except at intermediate distances when buried inC. strictawrack. Our experimental results reveal thatC. strictainhibits its growth in a scale‐dependent manner: inhibition was found to peak at intermediate distance from the tussock. We compared three alternative models to examine potential mechanisms driving regularity and found that, similar to our experimental results, scale‐dependent inhibition provides the best explanation for the observed regular tussock spacing. Our study underlines the importance of scale‐dependent feedback in the formation of regular spatial patterning in ecosystems.