Complex and Dynamic Effects of an Extreme Low Temperature Weather Event on Invasive Plant Populations and Resident...

Area of Science:

• Ecology
• Climate Change Biology
• Invasive Species Management

Background:

• Invasive species are often assumed to benefit from climate change.
• Empirical data on invasive species and community responses to extreme weather events (EWEs) is limited.

Purpose of the Study:

• To investigate the impact of a low-temperature EWE on the invasive plant Gunnera tinctoria and its invaded community.
• To assess the recovery of invasive populations and resident species following the EWE.

Main Methods:

• Monitoring of vegetative and reproductive growth of invasive G. tinctoria populations before and after a low-temperature EWE.
• Assessment of changes in the abundance and diversity of resident plant species in invaded areas.
• Analysis of historical climatic data to evaluate past exposure to EWEs.

Main Results:

• The low-temperature EWE significantly reduced vegetative and reproductive growth of mature G. tinctoria, impacting leaf expansion and inflorescence production.
• A 5-fold increase in resident species was observed, persisting even after G. tinctoria recovery.
• G. tinctoria seedlings showed resilience, with rapid growth resumption, while the resident community was largely unaffected.

Conclusions:

• EWEs can have complex, time-dependent effects on plant invasions, with greater impacts on established invasives than seedlings.
• Past exposure to similar EWEs has not limited G. tinctoria spread.
• Future low-temperature EWEs are unlikely to significantly restrict the growth of G. tinctoria and similar invasive species.