Co-occurring predators increase biotic resistance against an invasive prey

Area of Science:

• Marine ecology
• Invasive species biology
• Predator-prey dynamics

Background:

• Biotic resistance from native predators is crucial for controlling invasive species.
• Studies often overlook how predator interactions alter prey risk.
• Understanding combined predator effects is vital for invasive species management.

Purpose of the Study:

• To compare prey selection of whelks and rock lobsters in isolation versus when co-occurring.
• To assess how predator interactions influence predation on native and invasive prey.
• To determine if co-occurring predators increase biotic resistance against invasive mussels.

Main Methods:

• Observed prey selection of whelks and rock lobsters foraging alone.
• Recorded prey selection when whelks and rock lobsters foraged together.
• Quantified predation risk on native (Choromytilus meridionalis) and invasive (Semimytilus algosus) mussels.

Main Results:

• In isolation, both predators preferred the native mussel, C. meridionalis.
• When co-occurring, predation risk increased for all prey, including the invasive S. algosus.
• Rock lobster prey selection became more variable in the presence of whelks, driving increased predation.

Conclusions:

• Co-occurring predators can exert greater predation pressure than when foraging alone.
• Predator interactions significantly enhance biotic resistance against invasive prey.
• Assessing predators in isolation underestimates their potential impact on invasive species.