Maximum stem diameter predicts liana population demography

Abstract

Determining population demographic rates is fundamental to understanding differences in species life‐history strategies and their capacity to coexist. Calculating demographic rates, however, is challenging and requires long‐term, large‐scale censuses. Body size may serve as a simple predictor of demographic rate; can it act as a proxy for demographic rate when those data are unavailable? We tested the hypothesis that maximum body size predicts species' demographic rate using repeated censuses of the 77 most common liana species on the Barro Colorado Island, Panama (BCI) 50‐ha plot. We found that maximum stem diameter does predict species' population turnover and demography. We also found that lianas on BCI can grow to the enormous diameter of 635 mm, indicating that they can store large amounts of carbon and compete intensely with tropical canopy trees. This study is the first to show that maximum stem diameter can predict plant species' demographic rates and that lianas can attain extremely large diameters. Understanding liana demography is particularly timely because lianas are increasing rapidly in many tropical forests, yet their species‐level population dynamics remain chronically understudied. Determining per‐species maximum liana diameters in additional forests will enable systematic comparative analyses of liana demography and potential influence across forest types.This article is protected by copyright. All rights reserved.

Patterns and inferred causes of liana mortality in a tropical forest

“…It is possible that liana turnover rates are faster because of inherent differences in their anatomy, physiology and ecology, with lianas representing a more acquisitive but shorter-lived life-history strategy than a typical tree. Lianas are also smaller than trees, and metabolic theory shows smaller organisms have faster turnover rates [33,49]. However, the similar mortality rates of liana taxa and 'fast' tree species suggest that lianas could have similar life history strategies to a subset of tree species.…”

“…We repeated this census in 2017 by remeasuring all stems that were present in 2007, recording whether they died or survived, and adding new rooted liana stems ≥1 cm in diameter that were not present in the initial 2007 census (electronic supplementary material, figure S1) [2]. This second census allowed us to calculate mortality for the liana community [33]. We distinguished independent stems (i.e.…”