Anthropogenic resource subsidies decouple predator-prey relationships

Area of Science:

• Ecology
• Wildlife Biology
• Conservation Science

Background:

• Food web dynamics are poorly understood in human-altered landscapes.
• Resource subsidies can influence species interactions and predator-prey relationships.
• Urban development introduces anthropogenic resources that may affect wildlife.

Purpose of the Study:

• To investigate how resource subsidies in urban landscapes affect breeding birds and their nest predators.
• To test the hypothesis that subsidies decouple predator-prey relationships.
• To understand the impact of urbanization on species interactions.

Main Methods:

• Studied breeding birds and nest predators along a rural-to-urban gradient (2004-2009).
• Monitored 2942 nests of five songbird species in 19 forest stands.
• Surveyed nest predators and used video recordings to identify depredation events.

Main Results:

• Nest predator abundance increased with urban development, except for Brown-headed Cowbirds.
• Nest survival declined with predator detection in rural areas but not in urban areas.
• The interaction strength between breeding birds and nest predators diminished with increasing urbanization.

Conclusions:

• Resource subsidies in urban environments can decouple predator-prey relationships.
• Human drivers can significantly alter species interactions established in natural systems.
• Urbanization weakens ecological interactions, impacting native wildlife populations.