Resource-use-related traits correlate with population turnover rates, but not stem diameter growth rates, in 29 subtropical montane tree species

Abstract

The relationships between species’ functional traits and their demographic life histories are central to understanding the causes of life-history diversity. A previous study identified three independent demographic axes amongst 29 broadleaved tree species: a light-demand axis, a population turnover rate (r–K) axis, and one discriminating substrate requirements for recruitment. This study evaluates the basis of life-history variation amongst the 29 species by assessing the correlation between the three demographic axes above and 14 morphological, phenological, architectural and biomass-partitioning traits. A principal components analysis of the 14 traits revealed two main axes: (1) a ‘resource capture versus conservation’ axis separated species with large and thin leaf laminas, high leaf K, P and N concentrations, light wood and small seeds from species with opposite attributes, and (2) a ‘physiognomic’ axis separated species with compound leaves, high leaf/above-ground mass ratio, and tall first branch in saplings from species with opposite attributes. Subsequent paired correlations and a Procrustes superimposition analysis showed that species with attributes typical of high capture and low conservation of resources, small seeds and short stature had faster population turnover rates (short longevity, and high mortality and recruitment rates) than species with opposite attributes. Species with compound leaves, high leaf/above-ground mass ratio, and tall first branch as saplings (physiognomic axis) tended to be more light-demanding and to have fast diameter growth rates of stems ⩾10 cm diameter. The independence between attributes typical of resource capture or conservation and stem diameter growth rate is noteworthy; it differs from correlations often reported for saplings and could be attributed to ontogenetic changes in plant function. In addition, the clear link between attributes typical of resource capture or conservation and plant recruitment, survivorship and longevity is consistent with r–K theory and brings to light an important connection between a leading axis of plant evolutionary diversification (resource capture versus conservation) and rates of population turnover.