The Effect of Urbanization on the Mycorrhizal Associations and Survival of Three Species of Eastern Hardwoods

mycorrhizae;forest ecology;urban forests;Natural Resources and Environment

Tonn, NatalieZak, Donald ;

University of Michigan

关键词: mycorrhizae;    forest ecology;    urban forests;    Natural Resources and Environment;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/122695/NTONNthesisFull2016.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Mycorrhizal fungi colonization can be a significant determinant of plant health andestablishment success. By protecting roots from pathogens and increasing plant uptake ofnutrients and water, mycorrhizal colonization can determine the outcome of competitiveinteractions between plants, thereby shaping plant community composition. Currently, inremnant forest patches, plants and their fungal symbionts are exposed to varied anthropomorphiceffects related to the encroachment of metropolitan areas into rural landscapes. However, little isknown about the impact of urbanization on the plant-mycorrhizal fungi association. To assess the effect of urbanization on mycorrhizal fungi root colonization and their role on seedlingestablishment, we investigated the relationship between mycorrhizal colonization of treeseedlings and seedling survival along an urbanization gradient typical of the mid-western regionof the USA. We planted three species of temperate tree seedlings (Acer rubrum, Carya ovata,and Quercus rubra) in each of three landscape types: urban, suburban, and rural forests. Wemeasured the percent of root length of the seedlings colonized by ectomycorrhizal (ECM) and arbuscular mycorrhizal fungi (AMF) and monitored seedling survival during their first growingseason. We analyzed the percent root length colonized by mycorrhizae as a function of landscapetype (urban-rural) and additional variables known to contribute mycorrhizal colonization (soilphosphorus, soil nitrogen, and initial plant height). We then analyzed seedling survival as afunction of the degree of mycorrhizal fungi colonization associated with the landscape gradientand of additional environmental factors (available light and soil moisture).Within a species, we found no changes in levels of mycorrhizal fungi colonization across theurban landscape gradient. Environmental variables (light, soil moisture, soil nutrients) did notsignificantly vary along the urban gradient, and differences in these variables did not have ameasureable effect upon mycorrhizal colonization or survival. Each seedling species hadmarkedly different levels of colonization and responded differently to increasing levels ofmycorrhizal colonization. For A. rubrum, survival was independent of mycorrhizal colonization,Q. rubra had a statistically non-significant rise in survival as colonization increased, and C.ovata had a significant positive survival response to more than 60 % colonization. These findingshighlight the resilience of mycorrhizal communities across the rural-urban gradient and thepotential sensitivity of some species to lower levels of mycorrhizal colonization.