Rapid formation and storm-forced cyclicity of Sesuvium portulacastrum nebkhas on a tropical coastal island, South China

Description
This dataset contains morphometric, sedimentological, and chronological data of coastal nebkhas formed by Sesuvium portulacastrum on Nansan Island, South China. The data was collected to investigate the formation dynamics and spatial patterns of these vegetated aeolian landforms in a typhoon-prone tropical environment.
The study introduces a novel artifact-based dating approach, utilizing buried anthropogenic items with legible production dates to determine the age of nebkhas, thereby overcoming the limitations of OSL or 14C in frequently reset coastal systems. The findings support a “disturbance–reset–renewal” cyclic model, suggesting that extreme storm events dominate the evolution of these dunes by periodically resetting their growth.
Data Content
The dataset is organized into the following three primary files (as shown in the file list):
Spatial location data (based on total station).xlsx: Contains the high-precision geographical coordinates and spatial distribution metrics of 62 surveyed nebkhas. This file includes data used for Nearest Neighbor Index (NNI), Ripley’s K function, and Moran’s I analysis to evaluate clustering and spatial autocorrelation.
Grain size data.xlsx: Includes results from laser particle size analysis of sediment samples. It details the grain-size distribution, sorting, and downwind fining characteristics across the nebkhas and adjacent foredunes.
Morphological parameter data.xlsx: Provides quantitative geometric measurements of the nebkhas, including height, length, and width. It also contains the chronological data derived from buried artifacts, showing maximum possible ages (MPA) for specific dune heights.
Methods
Field Survey: Morphological parameters and spatial positions were captured using a total station.
Laboratory Analysis: Sediment characteristics were determined via laser particle size analysis.
Dating: Age determination was performed by identifying and recording the production dates of human-made artifacts excavated from within the nebkha structures.
Statistical Analysis: Spatial patterns were assessed using NNI, Ripley’s K, and Moran’s I (yielding a height autocorrelation of 0.45).
Key Finding Note: The data demonstrates that nebkhas measuring 0.7–0.95 m in height can form in as little as 1.13–3.15 years, highlighting the rapid recovery and dynamic nature of coastal systems following storm-induced resets.