Plant functional ecologists have identified a series of functional traits that indicate where species fall along an ecological strategy spectrum from acquisitive to conservative species. Similarly, plant architecture and allometries are indicative of life-history strategies.
In a study published in Ecology and Evolution, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) and University of Notre Dame addressed the degree to which commonly measured functional traits predict tree architecture in a tropical forest. Specifically, they tested whether conservative functional trait values (i.e., dense wood, heavy seeds, slow leaf economics) are related to trees that are shorter in stature with larger crowns at a given stem diameter.
The researchers sought to elucidate whether coordination between tree allometries and functional traits exist. They focused on 14 dominant tree species in a tropical rain forest (in the El Yunque National Forest, Puerto Rico) that experiences repeated tropical storms and hurricanes that may select for species with coordinated trait axes and allometries.
They found that there was no interspecific variation in allometric slopes, but there was inter-specific variation in intercepts. Those intercepts were correlated with a leaf, stem, and wood traits with conservative values being related to species that have shorter heights and wider crowns for a given stem diameter.
Species varied in their allometric intercepts, but they did not vary in their allometric slopes for both height–trunk diameter and crown radius–trunk diameter relationships. The variation in allometric intercepts and not slopes indicated that interspecific differences in tree architecture in the forest were due to intercepts and not interspecific differences in the proportional increase in height or crown size for a given trunk diameter increase. Lastly, the interspecific variation in allometric intercepts and overall tree architecture across sizes could be predicted by a handful of functional traits.
"The results suggest that whole plant architecture and functional traits are correlated in the trees studied and their integration should provide insights into how integrated phenotypes are related to tree life histories and demography," said YANG Jie of XTBG.
YANG Jie Ph.D Principal Investigator
Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China