@article {KNZ00768,
	title = {Effects of ungulate grazers on arbuscular mycorrhizal symbiosis and fungal community structure in tallgrass prairie},
	journal = {Mycology},
	volume = {93},
	year = {2001},
	pages = {233 -242},
	abstract = {Complex interactions among mycorrhizal fungi, plants, and herbivores occur in grasslands. Grazing of aboveground vegetation may influence plants directly and indirectly through the alteration of mycorrhizal symbiosis and other below-ground processes, and mycorrhizae in turn can influence plant responses to defoliation. An understanding of these interactions is important to our understanding of the dynamics of plant and fungal communities and to the sound management and conservation of grass- land ecosystems. In this study, the effects of grazing in tallgrass prairie on mycorrhizal colonization of plant roots, fungal community composition, and ex- traradical mycorrhizal hyphal (EMH) development were examined. In October 1994 and 1995 rhizo- sphere samples were taken at different topographical positions in tallgrass prairie sites grazed for several years by cattle at varying intensities, in ungrazed sites, and inside and outside permanent 25-m2 exclosures at each site. Spores of 19 species of AM fungi were encountered in these sites, and Glomus heterosporum was the most abundant species present. Moderate and intense grazing increased root colonization by mycorrhizal fungi in both years of this study. Similar root colonization levels inside and outside permanent exclosures in the ungrazed sites indicated no confounding effects of the exclosure structure itself. In 1995, EMH development was also increased under intense grazing. AM fungal species diversity (based on AM fungal spores present) decreased with grazing under both moderate and high grazer densities in both years. Different fungal species varied in abun- dance with topographical position, however topography did not significantly affect AM fungal spore species diversity, mycorrhizal root colonization or EMH development in either year. Although overall total spore density was unaffected by grazing intensity or soil type, several individual species increased or decreased in response to these factors. These results suggest that defoliation alters plant resources which stimulates greater development of mycorrhizal symbiosis. The shifts in fungal species composition and decrease in diversity with grazing also indicates that defoliation, or alteration of the soil microenviron- ment by grazers, favors certain species of grazing- adapted AM fungi that increase under grazed conditions. The high mycorrhizal dependency of many tallgrass prairie grasses and these results together suggest significant interactions between plant-grazer and plant-fungal relationships in tallgrass prairie. In addition to direct effects of herbivory, our results indicate that grazers may influence grassland plants in- directly through alterations in soil communities and in mycorrhizal symbiosis.
},
	keywords = {LTER-KNZ, fungal communities, fungal diversity, Glomus, hyphal development, mycorrhizae},
	url = {http://www.jstor.org/stable/3761643?seq=1$\#$page_scan_tab_contents},
	author = {Eom, A.H. and G.T. Wilson and D.C. Hartnett}
}
@article {KNZ00732,
	title = {Host plant species effects on arbuscular mycorrhizal fungal communities in tallgrass prairie},
	journal = {Oecologia},
	volume = {122},
	year = {2000},
	pages = {435 -444},
	abstract = {Symbiotic associations between plants and arbuscular mycorrhizal (AM) fungi are ubiquitous in many herbaceous plant communities and can have large effects on these communities and ecosystem processes. The extent of species-specificity between these plant and fungal symbionts in nature is poorly known, yet reciprocal effects of the composition of plant and soil microbe communities is an important assumption of recent theoretical models of plant community structure. In grassland ecosystems, host plant species may have an important role in determining development and sporulation of AM fungi and patterns of fungal species composition and diversity. In this study, the effects of five different host plant species [Poa pratensis L., Sporobolus heterolepis (A. Gray) A. Gray, Panicum virgatum L., Baptisia bracteata Muhl. ex Ell., Solidago missouriensis Nutt.] on spore communities of AM fungi in tallgrass prairie were examined. Spore abundances and species composition of fungal communities of soil samples collected from patches within tallgrass prairie were significantly influenced by the host plant species that dominated the patch. The AM fungal spore community associated with B. bracteata showed the highest species diversity and the fungi associated with Pa. virgatum showed the lowest diversity. Results from sorghum trap cultures using soil collected from under different host plant species showed differential sporulations of AM fungal species. In addition, a greenhouse study was conducted in which different host plant species were grown in similar tallgrass prairie soil. After 4 months of growth, AM fungal species composition was significantly different beneath each host species. These results strongly suggest that AM fungi show some degree of host-specificity and are not randomly distributed in tallgrass prairie. The demonstration that host plant species composition influences AM fungal species composition provides support for current feedback models predicting strong regulatory effects of soil communities on plant community structure. Differential responses of AM fungi to host plant species may also play an important role in the regulation of species composition and diversity in AM fungal communities.},
	keywords = {LTER-KNZ, Arbuscular mycorrhizal fungi, fungal diversity, Grasslands, Host specificity, Soil communities},
	doi = {10.1007/s004420050050},
	author = {Eom, A.H. and D.C. Hartnett and G.T. Wilson}
}
@article {KNZ00685,
	title = {The Effects of fire, mowing, and fertilizer amendments on arbuscular mycorrhizas in tallgrass prairie},
	journal = {American Midland Naturalist},
	volume = {142},
	year = {1999},
	pages = {55 -69},
	abstract = {Tallgrass prairie sites subjected to 10 y of annual burning, mowing, nitrogen (N) fertilization or phosphorus (P) fertilization and untreated reference sites were studied to examine effects of these management practices on arbuscular mycorrhizal (AM) symbiosis. Spring burning of native prairie field plots significantly reduced AM fungal species diversity, while increasing spore abundance. This increase in total spore number was due to a general increase in most of the 17 fungal species present. In general, the management treatments had larger effects on the richness component of diversity than on the evenness of AM species abundances. Burning and mowing had no significant effects on AM fungal colonization of roots or extraradical mycorrhizal hyphae (EMH) development. However, nitrogen fertilization significantly increased root colonization and EMH development, and P amendment decreased EMH development. There was no significant effect of fertilizer amendment on AM spore abundance, fungal species diversity or richness, but N and P fertilization decreased fungal species evenness. Effects of management practices on AM fungi may be mediated through changes in soil resources or microclimate or through changes in their host plants. These effects on AM symbiosis and community structure are important because AM fungi strongly influence the growth, demography, competitive relationships, relative abundances and diversity of plants in grassland communities.},
	keywords = {LTER-KNZ, tallgrass prairie},
	doi = {10.1674/0003-0031(1999)142[0055:TEOFMA]2.0.CO;2},
	author = {Eom, A.H. and D.C. Hartnett and G.T. Wilson and Figge, D.A.}
}
@phdthesis {KNZ00949,
	title = {Ecology of arbuscular mycorrhizas in tallgrass prairie},
	volume = {PhD Dissertation},
	year = {1998},
	pages = {1 -129},
	school = {Kansas State University},
	type = {Ph.D. Thesis},
	address = {Manhattan, KS},
	keywords = {LTER-KNZ},
	author = {Eom, A.H.}
}
