Leaf litter decomposition and its drivers differ between an invasive and a native plant: Management implications

Area of Science:

• Ecology
• Biogeochemistry
• Plant Biology

Background:

• Litter decomposition is crucial for the carbon cycle.
• Environmental conditions, litter traits, and decomposer composition are assumed to control decomposition hierarchically.
• It is unknown if this hierarchy differs for invasive versus native plant species.

Purpose of the Study:

• To investigate if the hierarchy of factors controlling litter decomposition differs between invasive and native plant species.
• To compare litter decomposition rates and controlling factors of invasive Spartina alterniflora and native Phragmites australis across a latitudinal gradient.

Main Methods:

• Collected leaf litter of S. alterniflora and P. australis across a wide latitudinal range.
• Incubated litter in saltmarshes at different latitudes using varying mesh sizes to alter decomposer composition.
• Analyzed litter decomposition rates (k) after 90 days.

Main Results:

• Litter decomposition rates (k) showed a parallel latitudinal pattern for both species.
• S. alterniflora decomposed 2.2 times faster than P. australis.
• The hierarchy of controlling factors shifted: environmental conditions dominated for P. australis, while litter traits were more influential for S. alterniflora.

Conclusions:

• Plant invasions can alter litter decomposition dynamics and the relative importance of controlling factors.
• Findings have implications for managing invasive plants and conserving coastal blue carbon.