Heterogeneous Stress Driven by Environmental Filtering Maintains Plant Diversity Along an Arid Riparian Gradient.

Area of Science:

• Ecology
• Environmental Science
• Botany

Background:

• Environmental stress typically reduces biodiversity.
• The role of heterogeneous environmental filtering in arid riparian ecosystems is not well understood.
• Understanding plant community assembly under stress is crucial for conservation.

Purpose of the Study:

• Investigate how heterogeneous environmental filtering affects plant community assembly in arid riparian ecosystems.
• Assess if severe, spatially heterogeneous stress can maintain high local plant diversity.
• Identify key environmental factors and species traits driving diversity patterns.

Main Methods:

• Studied herbaceous plant communities and soil factors along the Ulungur River riparian gradient.
• Utilized Non-metric multidimensional scaling (NMDS) for species turnover analysis.
• Employed generalized linear models (GLM) and random forest regression to determine factors influencing diversity.

Main Results:

• Local plant alpha diversity peaked in downstream areas with severe salinization-alkalization and phosphorus limitation.
• Elevation was a significant negative factor for all diversity metrics; soil organic carbon (SOC) and cation exchange capacity (CEC) positively affected halophyte richness.
• Species turnover was pronounced along the gradient, with high habitat heterogeneity in upstream plots.

Conclusions:

• Multidimensional and spatially heterogeneous stress landscapes can sustain high local plant diversity.
• Environmental filtering selects for stress-tolerant species, enhancing spatial species turnover.
• This study provides insights into community assembly in arid riparian ecosystems under stress.