Consistency of demographic trade-offs across tropical forests

Abstract

All species must balance their allocation to growth, survival and recruitment. Among trees, evolution has resulted in different strategies of partitioning resources to these key demographic processes, i.e. demographic trade-offs. It is unclear whether the same demographic trade-offs structure tropical forests worldwide. Here, we used data from 13 large-scale and long-term tropical forest plots to estimate the principal trade-offs in growth, survival, recruitment, and tree stature at each site. For ten sites, two trade-offs appeared repeatedly. One trade-off showed a negative relationship between growth and survival, i.e. the well-known fast−slow continuum. The second trade-off distinguished between tall-statured species and species with high recruitment rates, i.e. a stature−recruitment trade-off. Thus, the fast-slow continuum and tree stature are two independent dimensions structuring most tropical tree communities. Our discovery of the consistency of demographic trade-offs and strategies across forest types in three continents substantially improves our ability to predict tropical forest dynamics worldwide.

Multiscale predictors of small tree survival across a heterogeneous tropical landscape

“…Differing here from past work is that these inventory data span dry to cloud forests, deep alluvial to shallow karst or serpentine soil substrates and a range of land-use histories, regional events and introduced species, all within the same species pool (excepting introduced species). Insofar as wood density and species stature both rank highly, the RF models are also consistent with the concept [131,134] that species stature has importance to survival that differs from a trade-off with traits characteristic of faster growth. That work used both a growthsurvival trade-off and a trade-off between tall stature and high recruitment to represent tree demography [131,134].…”

“…Insofar as wood density and species stature both rank highly, the RF models are also consistent with the concept [131,134] that species stature has importance to survival that differs from a trade-off with traits characteristic of faster growth. That work used both a growthsurvival trade-off and a trade-off between tall stature and high recruitment to represent tree demography [131,134]. If the tendency in these results for survival to increase with wood density (Fig 5) is reflecting a growth-survival trade-off, the high rank of species height in some of the models may reflect some independent importance of species height to survival even across this varied landscape.…”