# Nutrient advantage of karst peaks cluster depressions and plant diversity in response

## TL;DR

This study explores how soil nutrients and plant diversity are linked in a fragile karst ecosystem, finding that shrublands have the highest diversity and soil nitrogen-to-phosphorus balance is key.

## Contribution

The study identifies shrublands as having the highest plant diversity and highlights the N:P ratio as a critical regulator of species composition in karst ecosystems.

## Key findings

- Shrublands have higher soil organic carbon and peak plant diversity indices compared to grasslands and forests.
- Soil nitrogen-to-phosphorus (N:P) ratio significantly influences plant species composition and spatial distribution.
- PLS-SEM modeling reveals interaction pathways between soil nutrients and plant diversity for ecological restoration.

## Abstract

The karst peak-cluster depression ecosystem is ecologically fragile, and the relationship between vegetation diversity and soil nutrients is a key scientific issue for ecological restoration. However, the relationships among soil chemical composition, nutrient elements, physicochemical properties, and plant diversity indices across different vegetation types, as well as the pathways through which key factors influence each other, remain unclear.

This study investigated grasslands, shrublands, and forests in Pingtang County, Qiannan Prefecture, Guizhou Province. Using correlation analysis and partial least squares structural equation modeling (PLS-SEM), we examined the associations and driving factors linking soil physicochemical properties, nutrient elements, mass ratios, and plant diversity.

We found that: (1) Shrubland vegetation exhibits significantly higher soil organic carbon (SOC) content than grasslands and forests, indicating greater carbon sequestration potential; total nitrogen (TN) was the primary limiting nutrient. (2) Shrubland communities reached peak values for Margalef, Shannon-Wiener, and Pielou indices, with SOC showing a significant positive correlation with the Pielou index. (3) Soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) content were core factors regulating plant species diversity. The soil nitrogen-to-phosphorus (N:P) ratio was a key regulator, significantly influencing species composition and spatial distribution. (4) The PLS-SEM model further quantified the interaction pathways among these factors, providing a theoretical basis for optimizing vegetation diversity and managing soil nutrients in regional rock desertification control.

Infographic illustrating relationships among vegetation types (grassland, shrubland, forest), soil properties, nutrient elements, and stoichiometric characteristics, showing that shrubland has the highest plant diversity indices and highlighting the influence of N:P balance and soil factors on plant diversity.