| Abstract: | Abstract. Correlations between five floristic gradients at small spatial extents (10 - 20 m) and one successional gradient over a larger spatial extent (1.5 km) are analysed. Floristic data (62 taxa) were sampled on five terminal moraines of known age deposited after the ‘Little Ice Age’ (1750–1930). The floristic gradients on the moraine ridges were sampled by two or three transects on each moraine, and the successional gradient by 114 plots on all moraines. The sequential orders of species were determined by constrained and unconstrained Correspondence Analysis. The similarities between species order on the successional gradient and the exposure gradients at the same age were tested against the null hypothesis of no correlation. The null hypothesis was rejected using both Monte Carlo permutation tests and Spearman's rank correlations, except on the oldest moraine. Here a closed canopy has developed, which eliminates the environmental variability associated with ridge morphology. The similarity between the successional gradient and the moraine-ridge gradients is attributed to variation in environmental severity, mainly caused by glacier wind and related factors such as temperature and moisture. Similarity was highest on the moraines in the middle of the glacier foreland, which have many successional stages present and have a relatively exposed relief. The distribution of growth/life-forms along gradients of small spatial extent are comparable to the successional gradient, but lichens, herbs and graminoids differ in their behaviour. The resemblance between species gradients at a small spatial extent and species gradients on a larger spatial extent is interpreted as an ecological self-similar pattern, where young and old substrate are linked to exposed-xeric and protected-mesic habitats, respectively. |
