Abstract
Aim: Mangrove wetlands span broad geographical gradients, resulting in functionally diverse tree communities. We asked whether latitudinal variation, allometric scaling relationships and species composition influence mangrove forest structure and biomass allocation across biogeographical regions and distinct coastal morphologies.
Location: Global. Time period: Present. Major taxa studied: Mangrove ecosystems.
Methods: We built the largest field-based dataset on mangrove forest structure and biomass to date (c. 2,800 plots from 67 countries) to address macroecological questions pertaining to structural and functional diversity of mangroves spanning biogeographical and coastal morphology gradients. We used frequentist inference statistics and machine learning models to determine environmental drivers that control biomass allocation within and across mangrove communities globally.
Results: Allometric scaling relationships and forest structural complexity were consistent across biogeographical and coastal morphology gradients, suggesting that mangrove biomass is controlled by regional forcings rather than by latitude or species composition. For instance, nearly 40% of the global variation in biomass was explained by regional climate and hydroperiod, revealing nonlinear thresholds that control biomass accumulation across broad geographical gradients. Furthermore, we found that ecosystem-level carbon stocks (average 401 ± 48 MgC/ha, covering biomass and the top 1 m of soil) varied little across diverse coastal morphologies, reflecting regional bottom-up geomorphic controls that shape global patterns in mangrove biomass apportioning.
Main conclusions: Our findings reconcile views of wetland and terrestrial forest macroecology. Similarities in stand structural complexity and cross-site size–density relationships across multiscale environmental gradients show that resource allocation in mangrove ecosystems is independent of tree size and invariant to species composition or latitude. Mangroves follow a universal fractal-based scaling relationship that describes biomass allocation for several other terrestrial tree-dominated communities. Understanding how mangroves adhere to these universal allometric rules can improve our ability to account for biomass apportioning and carbon stocks in response to broad geographical gradients.
| Original language | English |
|---|---|
| Pages (from-to) | 1000-1013 |
| Number of pages | 14 |
| Journal | Global Ecology and Biogeography |
| Volume | 30 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - May 2021 |
Bibliographical note
Funding Information:The authors are thankful to all scientists and field crew who collected and processed the vast amount of data used in this paper. Louisiana Sea Grant College partially funded A.S.R. and R.R.T. The Coordena??o de Aperfei?oamento de Pesssoal de N?vel Superior (CAPES) and the Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq), through the Science without Borders and Post-doctoral Senior program, provided fellowships for A.S.R. (BEX1930/13-3), P.R.P. (BEX18379/12-5) and A.L.F. (BEX209666/13-7). Partial funding for E.C.-M. was provided by the National Science Foundation (NSF) through the Florida Coastal Everglades Long-Term Ecological Research Program (grant no. DEB-1832229). A.A. was supported by the USAID Indonesia Forest and Climate Supports (IFACS; contract no. AG-3187-C-13-0010). P.H.T. is thankful to the U.S. Forest Service International Programs (USFS/IP) for funding data collection. This is contribution number #1002 from the Southeast Environmental Research Center in the Institute of Environment at Florida International University.
Publisher Copyright:
© 2021 John Wiley & Sons Ltd
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.