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The unseen majority: soil microbes as drivers of plant diversity and productivity in terrestrial ecosystems
Author(s) -
Van Der Heijden Marcel G. A.,
Bardgett Richard D.,
Van Straalen Nico M.
Publication year - 2008
Publication title -
ecology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.852
H-Index - 265
eISSN - 1461-0248
pISSN - 1461-023X
DOI - 10.1111/j.1461-0248.2007.01139.x
Subject(s) - ecology , ecosystem , productivity , terrestrial ecosystem , diversity (politics) , biodiversity , ecosystem diversity , terrestrial plant , biology , geography , agroforestry , environmental resource management , environmental science , sociology , anthropology , economics , macroeconomics
Microbes are the unseen majority in soil and comprise a large portion of life’s genetic diversity. Despite their abundance, the impact of soil microbes on ecosystem processes is still poorly understood. Here we explore the various roles that soil microbes play in terrestrial ecosystems with special emphasis on their contribution to plant productivity and diversity. Soil microbes are important regulators of plant productivity, especially in nutrient poor ecosystems where plant symbionts are responsible for the acquisition of limiting nutrients. Mycorrhizal fungi and nitrogen‐fixing bacteria are responsible for c. 5–20% (grassland and savannah) to 80% (temperate and boreal forests) of all nitrogen, and up to 75% of phosphorus, that is acquired by plants annually. Free‐living microbes also strongly regulate plant productivity, through the mineralization of, and competition for, nutrients that sustain plant productivity. Soil microbes, including microbial pathogens, are also important regulators of plant community dynamics and plant diversity, determining plant abundance and, in some cases, facilitating invasion by exotic plants. Conservative estimates suggest that c. 20 000 plant species are completely dependent on microbial symbionts for growth and survival pointing to the importance of soil microbes as regulators of plant species richness on Earth. Overall, this review shows that soil microbes must be considered as important drivers of plant diversity and productivity in terrestrial ecosystems.