Population structure and reproductive status of twoBanksiashrubs at various times after fire
✍ Scribed by Charles Zammit; Mark Westoby
- Publisher
- Springer Netherlands
- Year
- 1987
- Tongue
- English
- Weight
- 744 KB
- Volume
- 70
- Category
- Article
- ISSN
- 1385-0237
No coin nor oath required. For personal study only.
✦ Synopsis
Populations of the obligate-seeder, Banksia ericifolia, were even-aged. Seedling recruitment occurred only after fire. Mean genet size (height + canopy diameter; H + D) increased progressively with elapsed time since fire in stands last burnt 2-23 years before 1981. Populations of a co-occurring resprouter, B. oblongifolia, were mixed-aged. Genet size varied significantly between stands, but this variation was not explained by regressions of H + D on years since fire. In addition B. oblongifolia seedlings were recruited both after fire and in patches of heath unburnt for 16 years.
Most flower and seed production in B. oblongifolia occurred in the stands last burnt less than 10 years previously. More than 30% of genets had not produced cones since the last fire, irrespective of how many years had elapsed. In contrast, few B. ericifolia genets had produced cones five years after fire, but by 16 years after fire nearly 100070 had. Overall, about 51°/0 of B. ericifolia inflorescences and about 28o7o of B. oblongifolia inflorescences set seed. The number of seeds in seed-bearing cones was not significantly different between species.
Resprouting B. oblongifolia genets began flowering sooner after fire, but B. ericifolia subsequently overtook them in accumulating a bank of serotinous seeds. In the stand unburnt for 23 years the largest B. ericifolia genets had more than twice as many cones as the largest co-occurring B. oblongifolia. However, when accumulated cone production was compared for genets of equal H + D over all stands, there was no difference between species.