Abstract Evidence suggests that seedlings of large-seeded species have an initial size advantage but also tend to have slower relative growth rates (RGR). In a 1-yr garden experiment in southern Chile, we address whether early size advantages or disadvantages shown by 3-month-old seedlings of three tree species differing markedly in seed size (Persea lingue > Peumus boldus > Drimys winteri) confer them with greater or lesser competitive abilities when grown in species mixtures in the following 12 months of development. Given the reported negative relationship between seed size and RGR, we predicted a negative relationship between seed size and competitive ability among these three species (i.e., D. winteri > P. boldus > P. lingue). Seedlings of D. winteri, the species producing the smallest seeds, had clear and strong negative effects on the growth of seedlings of both P. boldus and P. lingue. Likewise, P. boldus, the species producing medium-sized seeds, had strong negative effects on the growth of seedlings of the other two species. In addition, negative effects of D. winteri on P. boldus were generally greater than vice versa. Seedlings of P. lingue did not affect the growth of the other two species. Therefore, our results support the predicted hierarchy of competitive abilities, i.e., D. winteri > P. boldus > P. lingue.
Keywords competitive ability; final shoot length; plant interspecific competition; relative growth rate; seed size
B07011; Online publication date 27 November 2007; Received 20 April 2007; accepted 15 November 2007
New Zealand Journal of Botany, 2007, Vol. 45: 593–603
0028–825X/07/4504–0593 © The Royal Society of New Zealand 2007
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