Lindsay A Turnbull, Christopher D Philipson, Drew W Purves, and AndOthers
Abstract Small-seeded plant species are often reported to have high relative growth rate
or RGR. However, because RGR declines as plants grow larger, small-seeded species could
achieve higher RGR simply by virtue of their small size. In contrast, size-standardized growth
rate or SGR factors out these size effects. Differences in SGR can thus only be due to
differences in morphology, allocation, or physiology. We used nonlinear regression to
calculate SGR for comparison with RGR for 10 groups of species spanning a wide range of
life forms. We found that RGR was negatively correlated with seed mass in nearly all groups,
but the relationship between SGR and seed mass was highly variable. We conclude that small seeded species only sometimes possess additional adaptations for rapid growth over and above
their general size advantage.
Publisher Ecological Society of America
2012 Ecological Society of America
C.E. Timothy Paine, Toby R Marthews, Deborah R Vogt, Drew Purves, Mark Rees, Andy Hector, and Lindsay A Turnbull. How to fit nonlinear plant growth models and calculate growth rates: an update for ecologists, Methods in Ecology and Evolution, British Ecological Society, September 2011.
Lindsay A Turnbull, Cloe Paul-Victor, Bernhard Schmid, and Drew W Purves. Growth rates, seed size and physiology - Do small-seeded species really grow faster?, Ecology, January 2008.
Lindsay A Turnbull, Mark Rees, and Drew W Purves. Why equalising trade-offs aren’t always neutral, Ecology Letters, October 2008.