A trait‐based trade‐off between growth and mortality: evidence from 15 tropical tree species using size‐specific relative growth rates

Abstract

A life-history trade-off between low mortality in the dark and rapid growth in the light is one of the most widely accepted mechanisms underlying plant ecological strategies in tropical forests. Differences in plant functional traits are thought to underlie these distinct ecological strategies; however, very few studies have shown relationships between functional traits and demographic rates within a functional group. We present 8 years of growth and mortality data from saplings of 15 species of Dipterocarpaceae planted into logged-over forest in Malaysian Borneo, and the relationships between these demographic rates and four key functional traits: wood density, specific leaf area (SLA), seed mass, and leaf C:N ratio. Species-specific differences in growth rates were separated from seedling size effects by fitting nonlinear mixed-effects models, to repeated measurements taken on individuals at multiple time points. Mortality data were analyzed using binary logistic regressions in a mixed-effects models framework. Growth increased and mortality decreased with increasing light availability. Species differed in both their growth and mortality rates, yet there was little evidence for a statistical interaction between species and light for either response. There was a positive relationship between growth rate and the predicted probability of mortality regardless of light environment, suggesting that this relationship may be driven by a general trade-off between traits that maximize growth and traits that minimize mortality, rather than through differential species responses to light. Our results indicate that wood density is an important trait that indicates both the ability of species to grow and resistance to mortality, but no other trait was correlated with either growth or mortality. Therefore, the growth mortality trade-off among species of dipterocarp appears to be general in being independent of species crossovers in performance in different light environments.

The value of biodiversity for the functioning of tropical forests: insurance effects during the first decade of the Sabah biodiversity experiment

“…We correlated survival and growth after 10 years with some traits that have been found to link to ecological strategies including in some of our previous work [26,37,46,47]. Wood densities for all species (excluding H. ferruginea whose high mortality prevented trait estimation) positively correlated with survival after 10 years ( r = 0.78) and negatively correlated with growth ( r = −0.50).…”

Leaf traits of dipterocarp species with contrasting distributions across a gradient of nutrient and light availability

“…LMA and leaf lifespan). Instead, variation in LMA and leaf lifespan among species is indicative of specialisation to distinct light environments in the forest understory (Baltzer and Thomas 2007;Philipson et al 2012Philipson et al , 2014.…”

Performance of Seedlings of a Shade-Tolerant Tropical Tree Species after Moderate Addition of N and P

“…There is a strong trade-off between high leaf lifespan, high leaf toughness and low herbivory and low mortality on the one hand, and high foliar nutrient concentrations and fast growth rates on the other hand (e.g., Poorter and Bongers, 2006;Wright et al, 2010;Kitajima et al, 2013;Philipson et al, 2014).…”