Responses of Dupontia fischeri to Simulated Lemming Grazing in an Alaskan Arctic Tundra

• Main Authors: MATTHEIS, P. J., TIESZEN, L. L., LEWIS, M. C.
• Format: Text
• Language: English
• Published: Oxford University Press 1976
• Subjects: Articles; Arctic; Barrow; Tundra; Alaska
• Online Access: http://aob.oxfordjournals.org/cgi/content/short/40/2/179

Preceding flowering, a Dupontia fischeri tiller at Barrow, Alaska, typically grows vegetatively for 3 or 4 years as a member of a system of interconnected tillers. Dynamics of such ‘tiller systems’ comprise the primary content of this study. Individual tiller responses are discussed according to the appropriate age classification. Leaf growth rates following each clipping regimen were similar to those of unclipped tillers. The primary effect of clipping on leaf growth appeared to be a shift toward the growth of younger leaves. Seasonal trends in the levels of stored carbohydrates were similar in clipped and unclipped tillers; though clipping appeared to effect a decrease in these levels. Reserves in chronically-clipped tillers dropped to 50 per cent of unclipped values. Experimental severance of rhizome connections indicated an apparent interdependence of tillers in a tiller system. Growth of younger tillers was inhibited by isolation, while segregation of older tillers resulted in stimulation of vegetative reproduction. Flowering tillers appear independent of connected tillers. These responses to clipping are discussed in the context of an environment which includes periodic extreme grazing pressure through the fluctuations in population density of the brown lemming.