Spatial pattern of intraspecific trait variability in Sphagnum fuscum

Abstract

Recent studies have shown that intraspecific variability is a mechanism by which species respond to environmental heterogeneity, and that intraspecific variation can have large implications for ecological processes. Here, we studied whether there is meaningful intraspecific variation in the ecohydrological traits, biomass allocation, and decomposability in Sphagnum moss, and if so, to explore the spatial pattern of variability. We implemented a hierarchical design in which we quantified traits of S. fuscum at three spatial scales: (i) between individuals within 8 cm2 patches; (ii) between replicate patches located within a single hummock or hollow location; and (iii) between hummocks. Although we focused on S. fuscum, we also compared the variability in some morphological features of S. fuscum and S. magellanicum. If growth is affected by density, we expected variability to be lowest at the patch level. Contrary to our expectation, most of the variability in both species occurred within-patch, which is our smallest sampling unit. Variability was generally higher in the traits for S. magellanicum compared with the variability in the traits for S. fuscum, which was generally negligible. Also, the pattern of variability observed for some of the traits such as the capitulum mass suggests that the mechanisms controlling different traits may be operating at different spatial scales.