Reindeer Lichen Productivity as A Function of Mat Thickness

Abstract

Reindeer lichens frequently grow in dense mats which vary in thickness. Chlorophyll a + b profiles of Alaskan populations of two species, Cladina stellaris and Cladonia rangiferina, show a concentration decrease with increased distance down from the thallus tip. This decrease is much steeper in C. stellaris than in C. rangiferina, dropping to a very low value 1.0 to 1.5 cm from the tip in the former and 4.0 to 5.0 cm from the tip in the latter. No size class difference was observed in chlorophyll a + b profiles of C. stellaris. A protein profile in C. stellaris exhibits a pattern closely matching that of chlorophyll a + b. Photosyntheis measurements of mats of different thicknesses (6, 9, 12, and 15 cm) of C. rangiferina showed that the thinnest mat had about twice as high a maximum rate and accumulated drying period carbon dioxide uptake as thicker mats. These patterns correlated with the biomass proportion of the top 1.5 cm of the lichen mat, and have potentially important implications in reindeer range evaluation and management.