Vegetation changes through time on islands of Lake Duparquet, Abitibi, Canada

Succession after fire has mainly been studied by chronosequence, which does not allow study of pre- and post-fire communities at the same site. By using palynology and anthracology, we recovered vegetation communities and fire histories through time on islands of Duparquet Lake, Canada. We show that succession after fire is dependent on interval between two fires (evaluated with depth of humus between subsequent fires). Sites with high fire occurrence show a cyclic succession (same species reappearing after fire), while sites with low fire occurrence show a directional succession. Different fire intervals lead to different pre- and post-fire pollen assemblages. During longer fire intervals, pollen assemblages change from Pinus banksiana Lamb. domination to Pinus strobus L. and Picea mariana (Mill.) BSP domination. When fire intervals are short, Pinus banksiana dominates both pre- and post-fire assemblages.