RESPIRATION OF THE BELOW-GROUND PARTS OF VASCULAR PLANTS - ITS CONTRIBUTION TO TOTAL SOIL RESPIRATION ON A SUCCESSIONAL GLACIER FORELAND INNY-ALESUND, SVALBARD

As a part of the study on soil carbon flow in a deglaciated area in Ny -Alesund, Svalbard (79 degrees N), we estimated the contribution of th e belowground respiration of vascular plants to total soil respiration in August 1996. Four study sites were set up along a primary successi onal series, ranging from newly deglaciated moraine to older moraine w ith well-developed vegetation cover. Respiratory activity of the below ground parts (roots + belowground stems) of three dominant species, Sa lix polaris, Saxifraga oppositifolia and Luzula confusa, was determine d under laboratory conditions. The respiratory activity and the Q(10) value of the respiration were higher in S. polaris than in the other t wo species. Total soil respiration rates measured in the field varied widely. The areas with dense vegetation cover tended to show high resp iration rates. Belowground respiration of vascular plants was estimate d based on the respiratory activity and biomass of the belowground par ts at each study site. The contribution to the belowground respiration to total soil respiration was negligible in the early stages of succe ssion. On the other hand, the respiration of the belowground parts con tributed to a significant proportion (similar to 29%) of the total soi l respiration in the latter stages of succession.