Demographic evaluation of a herbivory-sensitive perennial bunchgrass: Does it possess an achilles heel?
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Authors: B. C. Hendon, and D. D. Briske
Date: 1997
Journal: Oikos
Volume: 80
Number: 1
Pages: 8-17
Summary of Methods: Hendon and Briske investigated the response of Texas cupgrass (Eriochloa sericea), a warm season perennial bunchgrass, to clipping of 75% of canopy volume prior-, during, and post- culm elongation, and in combination. After two years of treatment, mean basal area increased under April, May and June clipping, and the average number of tillers per plant decreased. Apical meristem elevation in vegetative tillers did not extend beyond 5 mm above the soil surface and the proportion of reproductive tillers did not exceed 10% of the total number of tillers. Low values for both morphological attributes indicate that they did not contribute to a meristematic limitation constraining leaf growth. Hendon and Briske were unable to identify a specific trait within this species that contributed to a meristematic limitation and herbivory-sensitivity. An alternative interpretation of herbivory-sensitivity is proposed which emphasizes the involvement of more subtle extrinsic mechanisms, including herbivore-mediated competitive interactions and drought-herbivory interactions. The authors conclude that the assessment of herbivory resistance based on the specific trait approach fails to recognize and address the importance of extrinsic mechanisms associated with herbivore-induced processes at higher ecological scales.
Article Summary / Main Points: None
Vegetation Types:
MLRA Ecoregions:
Agrovoc Control Words: Riparian zones Rangelands Wildlife
Article Review Type: Refereed
Article Type: Experimental Research
Keywords: perennial bunchgrass, texas cupgrass, eriochloa sericea, tiller demography, herbivory, defoliation, mortality, herbivory-sensitivity
Annotation: Defoliation was imposed at three phenological stages of plant development to assess plant and tiller responses. A portion of the plants were defoliated in the (1) pre-culm elongation stage (April), (2) culm elongation stage (May), (3) post-culm elongation stage (June), and (4) at all three phenological stages. Defoliation was implemented by hand clipping plants to a height of 6-cm above the soil surface which removed approximately 75% of the canopy volume.
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