Negative soil feedbacks accumulate over time for non-native plant species

Area of Science:

• Ecology
• Invasive Species Biology
• Plant-Soil Interactions

Background:

• The enemy release hypothesis (ERH) posits that invasive species thrive by escaping natural enemies.
• A dynamic ERH suggests this advantage diminishes over time as novel interactions develop.
• Understanding these evolving interactions is crucial for managing invasive species.

Purpose of the Study:

• To test if non-native plant species established longer ago exhibit stronger negative soil feedbacks.
• To investigate the relationship between soil feedbacks, species establishment time, and invasiveness.
• To explore how related species influence and respond to soil communities.

Main Methods:

• Assessed soil feedbacks for non-native plant species with varying establishment times in New Zealand.
• Correlated soil feedback strength with species' establishment duration, local abundance, and geographic spread.
• Examined impacts and responses of related plant species within soil microbial communities.

Main Results:

• Species established longer ago showed increasingly negative soil feedbacks.
• Negative soil feedbacks were stronger for more widespread species but weaker for locally abundant ones.
• Related species exhibited similar effects on and responses to soil communities, supporting phylogenetic assumptions.

Conclusions:

• Findings support a dynamic enemy release hypothesis, indicating that invasive species' advantages decrease over time.
• Negative soil feedbacks play a role in regulating invasive plant spread and local abundance.
• Novel plant-soil interactions evolve, highlighting the complex ecological consequences of species introductions.