The primary succession on the 50 year old volcanic island of Surtsey, Iceland, has been intensively
studied. Initial soil development and other belowground processes are important drivers of primary
succession but frequently overseen. A Leymus arenarius and Honckenya peploides dominated plant
community has formed a relatively stable successional sere on the island, where external inputs of nutrients
remain low. These plants have had a stable <10% aboveground surface cover during the past 20 years, but
less is known about their belowground development. We investigated the organic matter (carbon) output
and input processes (soil respiration, ecosystem respiration and photosynthesis) of the community and how
they were affected by soil temperature, soil water content, vegetation and age of L. arenarius dunes. We
found that both soil respiration and root stocks have increased substantially from 1987, when an earlier
study was conducted. The same pattern was found when different aged L. arenarius dunes were studied. L.
arenarius had a stronger effect on the soil respiration fluxes than its surface cover might indicate, through
its much higher photosynthesis rates than H. peploides. The study furthermore illustrated how water stress
may temporally limit belowground processes in this coastal community.
Linking Foliar Traits to Belowground Processes
