What method can be used to reduce populations of muskrats and woodchucks?

Keeping earthen dams mowed is an effective method for reducing populations of muskrats and woodchucks as it disrupts their habitat and reduces the availability of cover. Muskrats typically burrow and nest in areas with dense vegetation near water bodies. By maintaining mowed areas, it makes it less appealing for these animals to establish their homes, as the open areas provide less shelter and foraging opportunities. This approach not only creates less ideal habitat for them but also allows for better management and monitoring of their populations.

The other options present alternatives that do not effectively reduce populations in the same manner. For instance, increasing water levels might actually enhance habitat suitability for muskrats, as they thrive in aquatic environments. Introducing natural predators could be effective in some ecosystems, but it might not be feasible or practical given the ecological balance required. Planting dense vegetation might provide additional cover, which could attract more muskrats and woodchucks rather than repel them. Therefore, keeping earthen dams mowed is a strategic and immediate approach to managing these pests.