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Energy Allocation Patterns of a Sprouting and a Nonsprouting Species of Arctostaphylos in the California Chaparral

1977; University of Notre Dame; Volume: 98; Issue: 1 Linguagem: Inglês

10.2307/2424710

1938-4238

Jon E. Keeley, Sterling C. Keeley,

Plant and animal studies

The r- and K-selection theory was used to generate test- able hypotheses about patterns of energy allocation in two chaparral shrubs of different reproductive strategies. Terminal-branchlet vegeta- tive and reproductive biomass of the nonsprouting Arctostaphylos glauca and the sprouting A. glandulosa were sampled in a 23-year-old and a 90-year-old stand of chaparral to test the predictions that: (1) the ter- minal vegetative growth (g dry weight/m2 of areal coverage) would be equal in the two species, in both stands; (2) oven dry weight (g) of reproductive parts/m2 of areal coverage would be greater in A. glauca than in A. glandulosa in both aged populations; (3) allocation to repro- ductive parts by the shrubs in the 23-year-old stand would be greater than (or equal to) that of the 90-year-old shrubs. The amount of ter- minal vegetative growth was equal for both species in the 23-year-old and the 90-year-old stands. There was no statistically significant differ- ence in the weight of fruits produced by the two species in the 23-year- old stand. However, fruit production by A. glauca was significantly greater than by A. glandulosa in the 90-year-old stand. Fruit produc- tion was also significantly greater for the older A. glauca shrubs than for those in the 23-year-old stand. The relationships of rainfall pattern and age of shrubs to fruit production are discussed.