Intraguild predation reduces redundancy of predator species in multiple predator assemblage

Area of Science:

• Ecology
• Marine Biology
• Invasive Species Research

Background:

• Predator interference often reduces predation rates, benefiting shared prey.
• Such interference can also occur between predators of the same species (conspecifics).
• Understanding predator interactions is crucial for assessing biodiversity and functional redundancy.

Purpose of the Study:

• To determine the additivity and redundancy of predators in multiple- and single-species combinations.
• To investigate how predator biodiversity impacts predation rates and prey risk.
• To assess the functional interchangeability of different predator species.

Main Methods:

• Examined interactions between two invasive predatory crab species: *Carcinus maenas* and *Hemigrapsus sanguineus*.
• Assessed predation rates on shared amphipod prey in single- and multiple-species predator combinations.
• Quantified predator interference and per capita effects.

Main Results:

• Interference between *C. maenas* and *H. sanguineus* reduced predation risk for amphipod prey.
• Predators exhibited redundant per capita effects in most single- and multiple-species combinations.
• Intraguild predation scenarios increased predator interference and decreased predator redundancy.

Conclusions:

• Trophic structure significantly influences how the combined effects of predator species manifest.
• Assessing both redundancy and additivity is essential for understanding multiple predator species.
• Predator biodiversity's impact on prey risk is modulated by interspecific and intraspecific interactions.