Genetic adaptations to grazing and mowing in the unpalatable grass Cenchrus incertus
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Authors: K. K. McKinney, and N. L. Fowler
Date: 1991
Journal: Oecologia
Volume: 88
Number: 2
Pages: 238-242
Summary of Methods: To identify morphological and life history adaptations to grazing, mowing, and cultivation, authors collected seeds of the grass, Cenchrus incertus, from two populations in each of three types of sites: cemeteries (mown occasionally), pastures (grazed year-round), and orchards (plowed twice a year). Plants of the two cemetery sites on average produced the greatest number of leaves and had the greatest number of tillers per plant at each census. They were also, on average, the shortest in stature throughout the study. They tended on average to produce the greatest number of burs at each census, the greatest total number of burs, and the greatest total number of panicles per plant, but the fewest burs per panicle. Cemetery plants also had the lowest average dry weight of all plants. No consistent differences were apparent between the orchard and pasture plants. Some of the traits that distinguished the cemetery populations from the orchard and pasture populations, such as short stature, are probably direct adaptations to defoliation. Others may be secondary effects of these, or the result of allocation of trade-offs.
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: grazing, unpalatable plant, grass, cenchrus incertus, life history strategies, genetic differentiation of populations
Annotation: Mowing frequency had probably been about 4 to 6 times a year in recent years. Three censuses were conducted in April, June, and August of 1984. For each plant at each census, plant height, the number of tillers, green leaves, panicles, and new burs per plant were recorded.,Grazing intensity is not specified.
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