Can foxes be controlled by reducing their fertility?

Area of Science:

• Ecology
• Wildlife Management
• Population Dynamics

Background:

• Fertility control is a potential method for managing invasive species populations.
• Environmental factors can significantly influence the success of wildlife management strategies.
• Foxes (Vulpes vulpes) are a significant pest species in many regions, impacting native wildlife and agriculture.

Purpose of the Study:

• To model the effectiveness of fertility control in reducing fox abundance.
• To investigate the influence of environmental variability on fertility control success.
• To compare different fertility control strategies, including baiting frequency and duration of infertility.

Main Methods:

• Development of a mathematical model incorporating age-specific recruitment and survival.
• Modeling resource availability using rainfall as an index.
• Simulation of fertility control effects on female pregnancy rates.
• Comparison of population growth rates between treated and untreated fox populations.

Main Results:

• Frequent baiting (every 1-2 years) is more effective than less frequent applications.
• Higher levels of fertility control lead to more rapid declines in fox abundance.
• Permanent sterility is more effective than temporary infertility due to accumulation of sterile individuals.
• Low-frequency baiting with temporary infertility agents results in highly variable outcomes.

Conclusions:

• Environmental variability is a critical factor influencing the success of fox fertility control.
• Strategic baiting frequency and the type of contraceptive agent (permanent vs. temporary) are key to effective population reduction.
• Models integrating ecological and management variables are crucial for optimizing wildlife control strategies.