Hierarchical neighbor effects on mycorrhizal community structure and function

Area of Science:

• Ecology
• Microbiology
• Plant Science

Background:

• Neighboring communities can influence each other's composition and function through species exchange.
• Empirical evidence for the directionality and strength of these ecological neighbor effects is limited.

Purpose of the Study:

• To experimentally determine the directionality and strength of neighbor effects in a plant-fungal model system.
• To investigate how ecological history influences interactions between neighboring ectomycorrhizal fungal communities and their host plants.

Main Methods:

• Established distinct ectomycorrhizal fungal communities on Douglas-fir seedlings in three different soil environments.
• Utilized a fully factorial transplant experiment to quantify neighbor effects on fungal community composition and seedling growth.
• Analyzed changes in fungal species composition and seedling vigor as indicators of community function.

Main Results:

• Neighbor effects on community composition and function exhibit a dominance hierarchy.
• Mycorrhizal communities from Douglas-fir plantations were less sensitive to neighbor effects.
• These plantation-derived communities strongly influenced neighbors, promoting compositional convergence and enhancing seedling vigor.

Conclusions:

• Asymmetric neighbor effects, driven by ecological history, are critical in shaping both community composition and function.
• The findings highlight the significant role of past environmental conditions in mediating current ecological interactions.
• This study provides empirical support for theoretical predictions regarding community assembly and inter-community dynamics.