Inferring community assembly processes from mangrove species–area relationships

The increasing species–area relationship (SAR) is a nearly universal ecological law. But recent theory has predicted that in systems with low large-scale diversity the law should be violated and the SAR should be nearly flat at intermediate scales, with species richness roughly constant at some value typically greater than one. We tested this prediction using a global dataset of mangrove trees—a species-poor group. We used a published global dataset of mangrove tree distributions to construct an SAR spanning local to global scales. We found that over a large range of scales (≈10^-4 to 10^6 km^2) the SAR was close to flat, in stark contrast to a classical power-law SAR, which would predict roughly a 300-fold change in species richness over these scales. Importantly, species richness was not simply equal to the minimum value of one or the maximum value of global mangrove richness over these scales, either of which possibilities would be reconcilable with the classical theory, but instead ..., We based our dataset on a recently compiled large field-based dataset on mangrove forest structure and biomass (Rovai et al. 2021, Rovai 2023). In its raw form, the dataset is a compilation of summary data for 3,497 mangrove plots distributed globally across 67 countries, synthesised from approximately 500 different sources (both published and unpublished). We removed 1,433 plots for which mangrove species identities and species richness were not available, leaving 2,064 plots. A total of 54 mangrove and mangrove-associated tree taxa were represented at these plots (i.e., roughly 74% of the global total).
Our goal was to construct SARs that are, as far as possible, based on accurate taxonomy, based on true mangrove tree species, and representative of natural conditions without anthropogenic influence. To this end we performed several data curation steps. We updated the name of Avicennia lanata to Avicennia rumphiana. We removed from the dataset species that are not considered true mangr..., , # Inferring community assembly processes from mangrove species–area relationships

[https://doi.org/10.5061/dryad.0zpc86788](https://doi.org/10.5061/dryad.0zpc86788)

## Description of the data and file structure

The data were existing published data comprising mangrove species diversity data from sites around the world. See the following references:

Rovai, A. S. 2023. Mangrove forest structure dataset associated to Rovai et al. 2021 in GEB. figshare: [https://doi.org/10.6084/m9.figshare.13570601.v1](https://doi.org/10.6084/m9.figshare.13570601.v1)

Rovai, A. S., R. R. Twilley, E. Castañeda-Moya, S. R. Midway, D. A. Friess, C. C. Trettin, J. J. Bukoski, A. E. L. Stovall, P. R. Pagliosa, A. L. Fonseca, R. A. Mackenzie, A. Aslan, S. D. Sasmito, M. Sillanpää, T. G. Cole, J. Purbopuspito, M. W. Warren, D. Murdiyarso, W. Mofu, S. Sharma, P. H. Tinh, and P. Riul. 2021. Macroecological patterns of forest structure and allometric scaling in mangrove forests. Global Ecology and Biogeography **...,