# Ecological Effects of Solanum rostratum Invasion on the Diversity and Functional Traits of Native Plant Communities

## TL;DR

Solanum rostratum invasion initially boosts plant diversity but later causes ecosystem imbalance by outcompeting native plants and altering soil nutrients.

## Contribution

The study reveals stage-dependent ecological effects of S. rostratum invasion and supports three core ecological hypotheses.

## Key findings

- Low invasion levels increase community diversity and stability, while high levels cause sharp biodiversity decline.
- S. rostratum alters soil nutrient patterns and exhibits phase-specific disturbance characteristics.
- Functional traits shift from convergence to divergence as invasion progresses, reducing functional redundancy.

## Abstract

Severe invasion by invasive plants can reduce the diversity of native plants, thereby limiting the functional diversity of ecosystems and threatening their stability in the invaded areas. In this study, the invasion area of
Solanum rostratum
in Urumqi, Xinjiang, China, was analyzed to determine the impact of different degrees of invasion on the species and functional diversity of plant communities in desert steppe and the ecological effects and driving mechanisms of invasion. Community‐weighted mean trait values of invasive and coexisting local plants were also calculated to explore changes in species diversity and functional diversity at different degrees of invasion.
S. rostratum
invasion was associated with significant differences in soil nutrient patterns and exhibited phase‐specific disturbance characteristics. Compared with the non‐invaded quadrats, low and moderate invasion levels increased local community diversity and stability (p < 0.05), whereas high invasion significantly reduced local community diversity (p < 0.05). The community stability index dropped from 2.29 (light invasion) to 1.23 (severe invasion), representing a decrease of 46.21%. The invasibility index rose from 0.29 to 0.51, representing an increase of 73.86%. The
S. rostratum
invasion index increased from 0.64 to 1.95, representing an increase of 50.27%. Thus, plant species diversity was the primary factor affecting the stability and invasiveness of native plant communities. The weighted average character value of invasive plants was higher than that of native plants; the functional difference was < 0 for the low‐ and medium‐invasion quadrats and > 0 for the high‐invasion quadrat.
S. rostratum
invasion restructured soil nutrient regimes. The competitive strategy of
S. rostratum
is to promote and restrict local plant growth under low and high invasion levels, respectively, leading to a sharp decline in biodiversity and ecosystem imbalance. The results indicate that timely control measures should be implemented upon the initial invasion to prevent further spread and maintain ecological security, sustainable agriculture, and animal husbandry development.

The invasion of Solanum rostratum exerts stage‐dependent effects on native plant communities. The study found that at low invasion levels, it temporarily enhances native plant diversity and community stability through resource complementarity; whereas at high invasion levels, it shifts to strong competitive inhibition, leading to a sharp decline in species diversity and ecosystem imbalance. This process is accompanied by a functional trait shift from “convergence to divergence”: during early invasion, functional traits converge with those of native plants, while later stages achieve replacement through superior traits such as greater plant height and larger leaf area. Moreover, the decline in species diversity is not synchronized with changes in functional diversity, indicating a loss of functional redundancy under high invasion intensity. These findings support three core hypotheses—the “diversity‐stability threshold,” “functional trait replacement,” and “loss of functional redundancy”—and underscore the importance of implementing control measures during early invasion stages and maintaining native species diversity to resist invasion and ensure ecological security.