Determining the Appropriate Scale: Phytometer Analysis of A. breviligulata, J. balticus, and P. anserina in a Great Lakes Shoreline Environment
Over the past one-hundred years, there has been much debate as to whether niche differentiation or neutral drivers play a more important role in establishing plant communities. However, little research has been conducted to determine the smallest relevant scale at which environmental variation affects a plant’s fitness. To determine this scale within the Great Lakes shoreline plant community, I conducted a field experiment where I created phytometers along the shoreline of Beaver Island, Michigan, for three common clonal plant species: A. breviligulata, J. balticus, and P. anserina. By taking ramets from a clonal species, genetic variation between individuals was insignificant, allowing for the plants’ survivorship and growth to accurately reflect the environmental variation between individuals. I found that there was a significant difference in the plants’ survivorship when plants were approximately 80-320 cm apart, but below that scale there was not a significant difference. I also found change in the number of leaves over the course of the growth period in A. breviligulata was significantly different at 20-80 cm, but was not at scales larger than that. The other two species did not show significant differences in the number of leaves at any spatial scale. Collectively, these results suggest that the scale at which environmental variation affects plant fitness may be species-specific, especially in regard to growth indicators like the change in the number of leaves. Despite this, there is strong evidence that an overall shoreline plant’s fitness is sensitive to environmental variation on a scale as small as 80- 320 cm. This distance may be used by shoreline plant ecologists as a baseline sampling scale that accounts for the effects of environmental variation on plant fitness.