An exotic plant successfully invaded as a passenger driven by light availability

Area of Science:

• Ecology
• Invasive Species Biology
• Plant Community Dynamics

Background:

• Invasive exotic plant species (IEPs) impact global ecosystems, but their role as drivers or passengers of habitat change is debated.
• Understanding the ecological mechanisms of invasion is crucial for effective management strategies.

Purpose of the Study:

• To determine if the invasive annual *Pedicularis kansuensis* acts as a driver or passenger of habitat change.
• To investigate the influence of light competition and soil nutrients on the invasion success of *P. kansuensis*.
• To assess the impact of *P. kansuensis* invasion on native plant community structure and soil properties.

Main Methods:

• Vegetation and soil surveys conducted in 2018.
• Field experiments including *P. kansuensis* removal (2014-2015) and fertilization (since 2012).
• Analysis of light competition, species richness, plant community coverage, productivity, and soil nutrients.

Main Results:

• *P. kansuensis* is disadvantaged in light competition with native grasses but invades successfully due to reduced native coverage.
• Nitrogen enrichment inhibits *P. kansuensis* by enhancing native species' light competition.
• *P. kansuensis* invasion increased community coverage, productivity, and soil nutrients without reducing species richness.
• Removal of *P. kansuensis* had minimal impact on community structure and soil properties.

Conclusions:

• The passenger model accurately describes the benign invasive mechanism of *P. kansuensis*.
• Invasion is facilitated by available light niches created by overgrazing.
• Nitrogen availability is a key factor regulating the success of *P. kansuensis* invasion.