The main aim of this study was to elucidate the roles of terrain age and spatial self-organisation as drivers of primary succession using high-resolution assessment of plant composition, functional traits and landscape metrics. We sampled 46 plots, 1m x 1m each, distributed along a 15-70 year range of terrain ages on the foreland of the Nardis glacier, located in the southern central Alps of Italy. From existing databases, we selected nine quantitative traits for the 16 plant species present, and we measured a set of seven landscape metrics, which described the spatial arrangement of the plant species patches on the study plots, at a 1cm x 1cm resolution. We applied linear models to study the relationships among plant communities, landscape metrics and terrain age. Furthermore, we used RLQ-analysis to examine trait-spatial configuration relations. To assess the effect of terrain age variation on trait performance, we applied a partial-RLQ analysis approach. Finally, we used the fourth-corner statistic to quantify and test relations between traits, landscape metrics and RLQ axes. Surprisingly, linear models revealed that neither the plant composition nor any of the landscape metrics differed among the three classes of terrain age distinguished, viz. 15-41 y, 41-57 y and 57-66 y, respectively. Further, no correlations were detected between trait patterns and terrain age, however, the floristically defined relevé clusters differed significantly with regard to several landscape metrics and suggestive relationships between increasing patch diversity and traits connected to growth rate were detected. We conclude that (i) terrain age below 70 years is not a good predictor for neither plant composition nor spatial configuration on the studied microhabitat and (ii) the small-scale configuration of the plant species patches correlates with certain functional traits and with plant composition, suggesting species-based spatial self-organisation.
Post-fire management and recovery of a pine forest in Greece