14C/C Measurements support Andreev's Internode Method to Determine Lichen Growth Rates in Cladina Stygia (Fr.) Ahti

摘要

Growth rates and the ability to date an organism can greatly contribute to understanding its population biology and community dynamics. 1n 1954, Andreev proposed a method to date Cladina, a fruticose lichen, using total thallus length and number of internodes. No research, however, has demonstrated the reliability of this technique or compared its estimates to those derived by other means. In this study, we demonstrate the utility of 14C/C ratios to determine lichen age and growth rate in Cladina stygia (Fr.) Ahti collected from northwestern Alaska, USA. The average growth rate using 14C/C ratios was 6.5 mmDTyr-1, which was not significantly different from growth rates derived by Andreevs internode method (average = 6.2 mmDTyr-1); thus, suggesting the reliability of Andreevs simple field method for dating lichens. In addition, we found lichen growth rates appeared to differ with geographic location, yet did not seem related to ambient temperature and total precipitation.