Effects of Clonal Integration and Architecture on Plant Growth in Natural Resource Landscapes: Test of a Multiple Level Hypothesis in Ecology

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Alpert 9507497 Clonal plants include some of the moat invasive, rapidly spreading, and persistent species known. They are also unique among plants in their capacities to place potentially independent units (ramets) non-randomly and to share resources among connected ramets. Two central hypotheses have been developed about clonal plants: (1) that integration among ramets confers significant advantages in habitats where resources are concentrated in small patches; and (2) differences in the degree of integration among clones reflect selection in response to different patterns of resource patchiness - i.e., clonal plants with a certain pattern of how ramets are placed and how they are integrated will be best adapted to an environment with a very specific distribution of light, water, nutrients, etc. Given the invasive potential of clonal plants, understanding the role of plant architecture in allowing the transfer of materials from patches where resources are abundant to patches where resources are limiting is critical in order to be able to predict and mitigate clonal plant invasions of natural or agricultural landscapes. The clonal herb, Fragaria Chiloensis, beach strawberry, is common in coastal sand dunes and grassland communities in Northern California where it plays an important ecological role. On dunes, the nitrogen fixing shrub, Lupinus arboreous, creates a landscape in which high light and soil nitrogen levels occur in different places. In grassland, Lupinus creates high soil nitrogen patches in a uniformly low light environment. In this study it will be determined whether: (1) connected ramets grow faster than unconnected ramets in the field due to resource sharing; and (2) differences in clonal architecture and the degree of sharing will vary between populations taken from dunes versus those from grasslands in a manner consistent with the patchiness of resources in those habitats..