日時 8月8日(水) 16:00

場所 北大地球環境c棟104

Life history variation and costs of reproduction in Abies balsamea

Jonathan Silvertown and Mike Dodd
(The Open University, UK.)

Fir waves, which occur only in E.N.America and Japan, provide a unique opportunity to study the entire life cycle of a tree within a short period of time. Among other uses, the system can be used to test life history theory. Initially, we tested the idea that wave regeneration should select for delayed reproduction or even semelparity in wave populations. Fieldwork at Whiteface Mt. In upstate New York has shown this hypothesis to be wrong and our subsequent work has been directed at discovering why. We will present a graphical model of age/size-specific variation in the costs and benefits of starting reproduction at any given time. This model can explain the observed reproductive behaviour of firs in wave forests if the cost- and benefit-curves have certain specific shapes. We report field-derived estimates of these curves which support the model.


Silvertown, J. (1996). Are sub-alpine firs evolving towards semelparity? Evolutionary Ecology, 10, 77-80.

Silvertown, J. and Dodd, M. E. (1999). The demographic cost of reproduction and its consequences in balsam fir (Abies balsamea). American Naturalist, 154, 321-332.

Silvertown, J. and Dodd, M. E. (1999). Evolution of life history in balsam fir (Abies balsamea) in sub-alpine forests. Proceedings of the Royal Society of London B, 266, 729-733.

Dodd, M. E. and Silvertown, J. (2000). Size-specific fecundity and the influence of lifetime size variation upon effective population size in Abies balsamea. Heredity, 85, 604-609.


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