US-IALE 2018

AUTHORS: Insu Jo*, Purdue University; Kevin Potter, North Carolina State University; Grant Domke, USDA Forest Service; Songlin Fei, Purdue University

ABSTRACT: Plant-fungal interactions play an important role in forest community structure and functions; however, the dominant tree-fungal interactions that affect species invasions in forest understories remain largely unexplored. Using Forest Inventory Analysis program data from the US Forest Service, we examined how dominant tree mycorrhizal type affects forest soil properties, and in turn, how the altered forest soil properties and forest structure affect understory plant invasions in eastern US forests. We found that understory invaders were more abundant in arbuscular mycorrhizal (AM) dominant forests than ectomycorrhizal (ECM) dominant forests, whereas native species cover and richness had no strong associations with AM tree dominance. Among the soil attributes that were significantly influenced by AM tree dominance, forest floor thickness and soil carbon:nitrogen ratio were significantly associated with invader richness and cover. Our results suggest that forest structure and dominant mycorrhizal type are closely linked with understory plant invasions. The increased invader abundance in AM dominant forests can further facilitate nutrient cycling, such as nitrogen cycling, altering ecosystem structure and functions in forest ecosystems.