The carbon stable isotopic composition of mosses: A record of temperature variation

Samples of two moss species, Sphagnum and Polytrichum, were collected at 19 points selected along vertical transects in the Karkonosze Mts. (739-1393 m) and the Izerskie Mts. (500-1100 m), SW Poland. Continuous automatic monitoring of temperature and humidity at the sampling points was carried out (1 h intervals) through the entire growth season (2004). A strong correlation between δ13C value of plant tissue cellulose and mean air temperature was noted for both areas and sampling periods (R2 between 0.92 and 0.64). It was calculated that a 1 °C increase in air temperature during the growing season results in a −1.6‰ (Sphagnum) and a −1.5‰ (Polytrichum) decrease in δ13C. In contrast, it seems that humidity shows no clear influence on the carbon isotope composition of mosses.