Date of Award


Degree Type


Degree Name

Doctor of Philosophy


The effects of sand accretion on the lacustrine sand dune vegetation of Lakes Huron and Erie were studied. The tolerance and response to burial in sand of several dune species, namely, Ammophila breviligulata, Adropogon scoparious, Agropyron psammophilum, Artemisia campestris, Calamovilfa longifolia, Cakile edentula, Cirsium pitcheri, Corispermum hyssopifolium, Elymus canadensis, Equisetum arvense, Euphorbia polygonifolia, Lithospermum caroliniense, Melilotus alba, Oenothera biennis, Panicum virgatum, Poa compressa, Strophostyles helvola, Tusilago farfara, Populas balsamifera and Xanthium strumarium were examined under controlled (greenhouse and growth chamber) and natural (field) conditions. This study clearly showed that the amount of sand deposition was variable in different microsites and depended on the amount of sand brought up by the waves, the wind velocity, the distance from the lake, type of vegetation, and the time of year. The distribution of plants in the dunes was correlated with the extent of sand accretion and tolerance limits of species. For example, Ammophila breviligulata was present in areas where there was more than 50 cm of sand movement (erosion and accretion) in two growing seasons. Simulated burial experiments in the field showed that although there were significant differences between species in their tolerance limits, all dune species exhibited stimulation of the net CO{dollar}\sb2{dollar} uptake, leaf area, and biomass per plant at varying levels of burial in sand. The positive effects of burial were much more pronounced in the perennials, Agropyron psammophilum and Panicum virgatum, than in the annuals or biennials. Similar stimulation in growth following burial was also observed under controlled greenhouse and growth chamber conditions in all the species investigated. For example, in the greenhouse burial experiment Elymus canadensis plants buried to one third of their height had a CO{dollar}\sb2{dollar} exchange rate of 28 {dollar}\mu{dollar}mol m{dollar}\sp{lcub}-2{rcub}{dollar} s{dollar}\sp{lcub}-1{rcub}{dollar} as compared to 18 {dollar}\mu{dollar}mol m{dollar}\sp{lcub}-2{rcub}{dollar} s{dollar}\sp{lcub}-1{rcub}{dollar} for control plants. There were marked differences between species in their response to the different depths of burial and the length of time after the burial treatment. Light intensities and temperature regimes also made significant differences in the carbon dioxide exchange rate under growth chamber conditions. Another well recognized aspect in plant communities is the occurrence of mutualistic association with soil fungi to form mycorrhizae. A field survey of the dune plant community along Lake Erie, revealed that a large majority of plant species were colonized by vesicular-arbuscular mycorrhizal (VA-Mycorrhizae) fungi. With the exception of Equisetum arvense all 11 species had variable percentages of vesicular, arbuscular and hyphal colonization. Greenhouse experiments showed that although VA-Mycorrhizae enhanced the morphological and physiological responses in dune plants, there were not solely responsible for the enhanced growth exhibited by buried plants. Agropyron psammophilum had a CER value of 15 {dollar}\mu{dollar}mol m{dollar}\sp{lcub}-2{rcub}{dollar} s{dollar}\sp{lcub}-1{rcub}{dollar} for unburied plants containing VA-Mycorrhizae and 18 {dollar}\mu{dollar}mol m{dollar}\sp{lcub}-2{rcub}{dollar} s{dollar}\sp{lcub}-1{rcub}{dollar} for VA-Mycorrhizae-free plants that were buried and 25 {dollar}\mu{dollar}mol m{dollar}\sp{lcub}-2{rcub}{dollar} s{dollar}\sp{lcub}-1{rcub}{dollar} for buried VA-Mycorrhizae containing plants.



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