Epixylic vegetation abundance, diversity and composition vary with coarse woody debris decay class and substrate species in boreal forest

Although the importance of coarse woody debris(CWD) to understorey species diversityhas been recognized, the combined effects of CWD decay and substrate species on abundance and species diversityof epixylic vegetation have received little attention. We sampled a wide range of CWD substrate species and decay classes as well as forest floorin fire-origin boreal forest stands. Percent cover, species richnessand evenness of epixylic vegetation differed significantly with both CWD decay class and substrate species. Trends in cover, species richnessand evenness differed significantly between non-vascular and vascular taxa. Cover, species richnessand species evennessof non-vascular species were higher on CWD, whereas those of vascular plantswere higher on the forest floor. Epixylic species composition also varied significantly with stand ages, overstorey compositions, decay classes, substrate species and their interactions. Our findings highlight strong interactive influences of decay class and substrat...