title: Adult trees cause density-dependent mortality in conspecific seedlings by regulating the frequency of pathogenic soil fungi.
abstract: Negative density-dependent seedling mortality has been widely detected in tropical, subtropical and temperate forests, with soil pathogens as a major driver. Here we investigated how host density affects the composition of soil pathogen communities and consequently influences the strength of plant-soil feedbacks. In field censuses of six 1-ha permanent plots, we found that survival was much lower for newly germinated seedlings that were surrounded by more conspecific adults. The relative abundance of pathogenic fungi in soil increased with increasing conspecific tree density for five of nine tree species; more soil pathogens accumulated around roots where adult tree density was higher, and this greater pathogen frequency was associated with lower seedling survival. Our findings show how tree density influences populations of soil pathogens, which creates plant-soil feedbacks that contribute to community-level and population-level compensatory trends in seedling survival.
authors: Department of Ecology, School of Life Sciences/State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275, China.
authors: Minxia
authors: M
authors: Liang
authors: Department of Ecology, School of Life Sciences/State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275, China.
authors: Xubing
authors: X
authors: Liu
authors: Environmental Studies Department, University of California, 1156 High Street, Santa Cruz, CA, 95064, USA.|Smithsonian Tropical Research Institute, Balboa, Ancón, Panama.
authors: Gregory S
authors: GS
authors: Gilbert
authors: Department of Ecology, School of Life Sciences/State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275, China.
authors: Yi
authors: Y
authors: Zheng
authors: Department of Ecology, School of Life Sciences/State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275, China.
authors: Shan
authors: S
authors: Luo
authors: Department of Ecology, School of Life Sciences/State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275, China.
authors: Fengmin
authors: F
authors: Huang
authors: Department of Ecology, School of Life Sciences/State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275, China.
authors: Shixiao
authors: S
authors: Yu
mesh_terms: D005658:Fungi / Q000145:classification* / Q000502:physiology*; D010935:Plant Diseases / Q000382:microbiology*; D011156:Population Density; D036226:Seedlings / Q000382:microbiology*; D012988:Soil Microbiology; D014197:Trees / Q000382:microbiology*
keywords: Host density; Janzen-Connell effect; seedling survival; soil-borne plant pathogens; subtropical forest