title: Warming and fertilization alter the dilution effect of host diversity on disease severity.
abstract: An essential ecosystem service is the dilution effect of biodiversity on disease severity, yet we do not fully understand how this relationship might change with continued climate warming and ecosystem degradation. We designed removal experiments in natural assemblages of Tibetan alpine meadow vegetation by manipulating plot-level plant diversity to investigate the relationship between different plant biodiversity indices and foliar fungal pathogen infection, and how artificial fertilization and warming affect this relationship. Although pathogen group diversity increased with host species richness, disease severity decreased as host diversity rose (dilution effect). The dilution effect of phylogenetic diversity on disease held across different levels of host species richness (and equal abundances), meaning that the effect arises mainly in association with enhanced diversity itself rather than from shifting abundances. However, the dilution effect was weakened by fertilization. Among indices, phylogenetic diversity was the most parsimonious predictor of infection severity. Experimental warming and fertilization shifted species richness to the most supported predictor. Compared to planting experiments where artificial communities are constructed from scratch, our removal experiment in natural communities more realistically demonstrate that increasing perturbation adjusts natural community resistance to disease severity.
authors.affiliation: Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai, 200438, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Liu
authors.affiliation: Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai, 200438, China.
authors.forename: Shengman
authors.initials: S
authors.lastname: Lyu
authors.affiliation: Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai, 200438, China.
authors.forename: Shurong
authors.initials: S
authors.lastname: Zhou
authors.affiliation: School of Biological Sciences, University of Adelaide, South Australia, 5005, Australia.
authors.forename: Corey J A
authors.initials: CJ
authors.lastname: Bradshaw
mesh_terms: D044822:Biodiversity; D017753:Ecosystem; D005308:Fertilizers; D057232:Global Warming; D010802:Phylogeny; D010935:Plant Diseases / Q000706:statistics & numerical data; D010944:Plants; D018609:Tibet
chemical_list: D005308:Fertilizers
keywords: Tibetan Plateau; alpine meadow; biodiversity; community phylogeny; diversity-disease relationship; foliar fungal disease; species evenness; species richness