Alien predators are more dangerous than native predators to prey populations

Area of Science:

• Ecology
• Conservation Biology
• Invasive Species Research

Background:

• Alien predators are often assumed to be more detrimental to prey populations than native predators.
• Understanding the differential impact of predator origin is crucial for effective conservation strategies.

Purpose of the Study:

• To quantitatively assess the impact of alien versus native predators on vertebrate prey populations.
• To investigate how predator origin influences prey responses across different geographical locations (mainland vs. island).

Main Methods:

• Conducted a meta-analysis of 45 replicated and 35 unreplicated field experiments.
• Analyzed data from experiments manipulating population densities of mammalian and avian predators.
• Examined the effects of predator origin (native vs. alien) and location (mainland vs. island) on prey responses.

Main Results:

• Predator origin significantly affected prey responses, with alien predators showing double the impact of native predators.
• A significant interaction between location and predator origin was observed, with alien predators having the strongest effects in mainland areas.
• These findings were largely driven by the substantial impact of alien predators in Australian mainland ecosystems.

Conclusions:

• Introduced predators exert a more intense suppression on native prey populations compared to native predators.
• Alien predators can drive prey populations further from their predator-free densities than native predators.
• The findings underscore the significant ecological threat posed by invasive predators, particularly in mainland environments.