Abrupt rise in atmospheric CO2 overestimates community response in a model plant-soil system

• Published in: Nature (London) 2005-02, Vol.433 (7026), p.621-624
• Main Authors: Klironomos, J.N, Allen, M.F, Rillig, M.C, Piotrowski, J, Makvandi-Nejad, S, Wolfe, B.E, Powell, J.R
• Format: Article
• Language: English
• Subjects: air pollution; Analysis of Variance; Animal, plant and microbial ecology; Applied ecology; Atmosphere - chemistry; Biological and medical sciences; Biomass; Biota; Bromus - metabolism; Bromus - microbiology; Bromus inermis; Carbon dioxide; Carbon Dioxide - analysis; Carbon Dioxide - metabolism; community ecology; Ecological effects; Ecosystem; Ecosystems; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; elevated atmospheric gases; Environmental changes; Fundamental and applied biological sciences. Psychology; Fungi - metabolism; Humanities and Social Sciences; letter; multidisciplinary; mycorrhizal fungi; Ontario; plant growth; plant physiology; Science; Science (multidisciplinary); Soil - analysis; species diversity; Species richness; symbiosis; vesicular arbuscular mycorrhizae
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature03268

Attempts to understand the ecological effect of increasing atmospheric CO2 concentration, [CO2], usually involve exposing today's ecosystems to expected future [CO2] levels. However, a major assumption of these approaches has not been testedthat exposing ecosystems to a single-step increase in [CO2] will yield similar responses to those of a gradual increase over several decades. We tested this assumption on a mycorrhizal fungal community over a period of six years. [CO2] was either increased abruptly, as is typical of most [CO2] experiments, or more gradually over 21 generations. The two approaches resulted in different structural and functional community responses to increased [CO2]. Some fungi were sensitive to the carbon pulse of the abrupt [CO2] treatment. This resulted in an immediate decline in fungal species richness and a significant change in mycorrhizal functioning. The magnitude of changes in fungal diversity and functioning in response to gradually increasing [CO2] was smaller, and not significantly different to those with ambient [CO2]. Our results suggest that studies may overestimate some community responses to increasing [CO2] because biota may be sensitive to ecosystem changes that occur as a result of abrupt increases.