Table 3

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Table 3. Life Table for Known Cohort of 1600 Seeds in Field Germination Experiment.

We assumed that mortality occurred prior to germination each year and that annual seed survival (S) was constant.  To calculate S, we used a spreadsheet to iteratively match S3 to the observed proportion of seedlings surviving during the persistent seed bank portion of the experiment (4/367 = 0.011). This approach converged on a value of S = 0.22, the annual survival of seeds in the seed bank. Survival of fresh seeds before germination was calculated from S 0.5 = 0.4715 or germination 6 months after sowing. Germination percentages (g for fresh seeds, G for seeds from a persistent seed bank) were correspondingly calculated based on the predicted number of living seeds present at the start of the germination season.

Time    No. Alive at Beginning of x    Factor responsible for dx    Number of seeds    Term    Value   
0.5 1600 Six Month Survival 754 S1/2 0.475
0.5 754 Germination 387 g(1998) 0.513
1.0 367 Annual Survival 82 S 0.2223
1.5 82 Germination 2 G(1999) 0.0245
1.5 80 Annual Survival 18 S 0.2223
2.5 18 Germination 1 G(2000) 0.0565
2.5 17 Annual Survival 4 S 0.2223
3.5 4 Germination 1 G(2001) 0.2692
 
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Last modified: Monday May 12, 2008