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.