MYCORRHIZAL COMMUNITY DYNAMICS FOLLOWING NITROGEN FERTILIZATION: A CROSS-SITE TEST IN FIVE GRASSLANDS

Ecological MonographsVolume 77, Issue 4 p. 527-544 Article MYCORRHIZAL COMMUNITY DYNAMICS FOLLOWING NITROGEN FERTILIZATION: A CROSS-SITE TEST IN FIVE GRASSLANDS Louise M. Egerton-Warburton, Corresponding Author Louise M. Egerton-Warburton l-egerton@northwestern.edu Department of Botany and Plant Sciences, University of California, Riverside, California 92521-0124 USA Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, Illinois 60022 USA Weinberg College of Arts and Sciences, Northwestern University, Evanston, Illinois 60201 USA E-mail: l-egerton@northwestern.eduSearch for more papers by this authorNancy Collins Johnson, Nancy Collins Johnson Environmental and Biological Sciences and the Merriam-Powell Center for Environmental Research, Northern Arizona University, Flagstaff, Arizona 86011-5694 USASearch for more papers by this authorEdith B. Allen, Edith B. Allen Department of Botany and Plant Sciences, University of California, Riverside, California 92521-0124 USASearch for more papers by this author Louise M. Egerton-Warburton, Corresponding Author Louise M. Egerton-Warburton l-egerton@northwestern.edu Department of Botany and Plant Sciences, University of California, Riverside, California 92521-0124 USA Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, Illinois 60022 USA Weinberg College of Arts and Sciences, Northwestern University, Evanston, Illinois 60201 USA E-mail: l-egerton@northwestern.eduSearch for more papers by this authorNancy Collins Johnson, Nancy Collins Johnson Environmental and Biological Sciences and the Merriam-Powell Center for Environmental Research, Northern Arizona University, Flagstaff, Arizona 86011-5694 USASearch for more papers by this authorEdith B. Allen, Edith B. Allen Department of Botany and Plant Sciences, University of California, Riverside, California 92521-0124 USASearch for more papers by this author First published: 01 November 2007 https://doi.org/10.1890/06-1772.1Citations: 210 Corresponding Editor: J. N. Klironomos. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract Arbuscular mycorrhizal fungi (AMF) are considered both ecologically and physiologically important to many plant communities. As a result, any alteration in AMF community structure following soil nitrogen (N) enrichment may impact plant community function and contribute to widespread changes in grassland productivity. We evaluated the responses of AMF communities to N fertilization (≥100 kg N·ha−1·yr−1) in five perennial grasslands within the Long-Term Ecological Research network to generate a broader understanding of the drivers contributing to AMF species richness and diversity with increasing soil N fertility, and subsequent effects to host-plant communities. AMF spore and hyphal community data at three mesic sites (Cedar Creek, Kellogg Biological Station, Konza Prairie) and two semiarid sites (Sevilleta, Shortgrass Steppe) were collected over two consecutive years and used to test four hypotheses about AMF responses to N fertilization. Under ambient soil N, plant annual net primary productivity and soil phosphorus (P) were strongly related to climatic differences in AMF communities (semiarid vs. mesic). Following N fertilization, the drivers of AMF community structure were soil N availability, N:P supply ratio, and host-plant photosynthetic strategy (C3 vs. C4) but not climate. In P-rich soils (low N:P), N fertilization reduced AMF productivity, species richness, and diversity and intensified AMF community convergence due to the loss of rare AMF species and the increased abundance of Glomus species. In P-limited soils (high N:P), AMF productivity, species richness, and diversity increased with N fertilization; the most responsive AMF taxa were Acaulospora, Scutellospora, and Gigaspora. Soil N or N:P × host-plant (C3, C4) interactions further modified these responses: AMF hyphae (primarily Gigasporaceae) associated with C3 plants increased in abundance with N fertilization, whereas C4 plants hosted nitrophilous Glomus species. Such responses were independent of the duration or quantity of N fertilization, or the time since cessation of N fertilization. This synthesis provides a new understanding of AMF community patterns and processes, and it identifies three key drivers (soil N, N:P, host plant) of AMF community structure that may be tested in other communities. Citing Literature Supporting Information Filename Description https://dx.doi.org/10.6084/m9.figshare.c.3309309 Research data pertaining to this article is located at figshare.com: Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. Volume77, Issue4November 2007Pages 527-544 RelatedInformation