Preliminary Study of the Vegetation and Mycorrhizae of the Kalamazoo River Riparian Ecosystem
Foster, Sara D.
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Floodplain forests are linear strips of land parallel to an adjacent river that periodically floods the forest shaping the landscape and creating differences in elevation. Throughout a floodplain forest, zonation patterns in the vegetation exist. Three prevalent zones were characterized based on the vegetation, soil moisture, elevation and soil organic content differences; a low-lying, wet zone which was virtually vegetationless, a transitional zone consisting of a few herbaceous species, and an upland zone containing an abundance of diverse herbaceous species. The factors controlling distribution of vegetation in the floodplain forest were questioned. Due to the fact that nearly all vascular plants form symbioses with mycorrhizal fungi and that fungi generally do not survive under anoxic conditions (such as in saturated soil), it was hypothesized that mycorrhizae played a role in th3 vegetation distribution. Soil samples were collected from these zones at four different locations in the floodplain forest of the Kalamazoo River. From these samples, roots were extracted, stained, and assessed for abundance of mycorrhizal colonization. While the greatest abundance of mycorrhizae was located in the upland zones, additional colonization was found in the wet zone of the floodplain forest. These results suggest that mycorrhizae do not control whether a plant species could become established in wet zones. Instead, there must be other physiological reasons explaining why only certain plant species are found in the different zones.