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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Invasive Species and Pollinator Health » Research » Publications at this Location » Publication #165005
Title: SPATIAL AND TEMPORAL VARIATION IN RGR AND LEAF QUALITY OF A CLONAL RIPARIAN PLANT: ARUNDO DONAX

Author
item Spencer, David
item Ksander, Gregory
item Whitehand, Linda

Submitted to: Aquatic Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/2/2004
Publication Date: 1/1/2005
Citation: Spencer, D.F., Ksander, G.G., Whitehand, L.C. 2005. Spatial and temporal variation in rgr and leaf quality of a clonal riparian plant: arundo donax. Aquatic Botany. 81:27-36.

Interpretive Summary: Arundo donax L. is a tall perennial reed that has invaded riparian zones where it changes important ecosystem properties. Because plant growth and leaf quality influence the effectiveness of management techniques, we sought to determine if these characters varied over time and space in a northern California population. The concentration of carbon and nitrogen in the leaves varied during the growing season. Leaf nitrogen was higher in spring and in plants that grew closer to a stream. Plants near the stream produced taller stems with more leaves per stem than those more distant from the stream. Plant growth rate showed a similar pattern. Decline in growth rate coincided with the appearance of branches and flowers on stems less than 1 year old. Growth rate was related to the nitrogen content of leaves on mature stems. This implies that the decrease in stem growth reflected changes in nutrient availability within the entire A. donax clump and not just in the growing stems. These findings mean that the best time to apply some management techniques may be in spring. Plants growing more distant from a stream may need to be treated sooner than those growing near a stream.

Technical Abstract: Arundo donax L. is a tall perennial reed classified as an emergent aquatic plant. In California it has invaded riparian zones where it acts as a transformer species. Because plant growth and leaf quality influence the effectiveness of management techniques, we sought to determine if these characters varied temporally and spatially in a northern California population of A. donax. Tissue C and N content and C:N ratio varied during the growing season. Leaf N was higher in spring and in plants that were closer to a stream. It was significantly negatively related to the clump's distance from the stream but not related to its elevation relative to the stream. Plants near the stream produced taller stems with more leaves per stem than those more distant from the stream. RGR differed across time and space. It was highest in spring prior to the appearance of flowers on stems that were > 1 year old within the clumps. Decline in RGR as the growing season progressed coincided with the appearance of branches and flowers on stems < 1 year old on a few plants within the studied population. RGR was significantly related to the N content and C:N ratio of leaves on mature stems ( > 1 year old). This implies that the decrease in stem growth reflected changes in nutrient availability within the entire A. donax clump and not just in the growing stems (< 1 year old). These findings have implications for timing of management techniques.