Recruitment & Plant-Soil Feedback: The Effects of Mature Trees on Seedling Survival

Plant-soil Feedbacks;Fungal Communities;Tree Canopies;Natural Resources and Environment

Wolf, SamanthaZak, Donald ;

University of Michigan

关键词: Plant-soil Feedbacks;    Fungal Communities;    Tree Canopies;    Natural Resources and Environment;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/97363/Samantha%20Wolf%20Thesis%202013.pdf?sequence=1&isAllowed=y

瑞士|英语

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

【 摘 要 】

Plant-soil feedbacks (PSFs) are mechanisms by which plants alter the structure, chemistry,and biology of soil which then influences plant survival. Over time, PSFs have the abilityto alter forest composition because the soil biota associated with adult trees differentiallyaffects the establishment of conspecific or heterospecific seedlings. Greenhouse studieshave shown that host-preferred pathogens act as a type of PSF that can potentially infectdifferent species of seedlings. We conducted a field study over two summers comparingthe survival of four seedling species underneath three adult tree species in a temperateforest. We applied fungicide to the soil surrounding half of the seedlings in order toexclude the most common fungal pathogens. We found that initial stem height and soilmoisture significantly influenced seedling survival for all species. Possibly due tounusually extreme drought, we observed great variability in survival rates, and so wefound no statistically significant differences between our test and control groups.However, we were able to quantify the effects of the pathogenic fungal communityassociated with specific tree canopies on the survival of conspecific and heterospecificseedlings. We found indications of conspecific seedling-canopy species interaction whichaffected survival, although this varied among species. Prunus serotina seedlings treatedwith fungicide experienced a ~92% increase over the average survival of seedlings undercontrol conditions. Comparisons found that under control conditions, all seedling specieswere negatively affected by the fungal communities associated with P. serotina canopiesexcept for E. umbellata. Conversely, fungal communities associated with A. saccharumcanopies tended to have the weakest affect for all native species. Overall, we found that2seedlings treated with fungicide tended to experience increased survival, though therelative degree of effects varied. In summary we did not observe strong changes in PSFeffects between treatments of conspecific canopies on seedlings survival but we wereable to detect differential survival probabilities due to the fungal community which maycontribute to the coexistence of these species.