How Might The Presence Of Invasive American Bullfrogs (Lithobates Catesbeianus) In Beaver-impacted Wetlands Influence The Population Dynamics Of Native Pacific Chorus Frogs (Pseudacris Regilla), And What Are The Implications For Beaver-mediated Nutrient Cycling And Water Quality In These Systems?

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The presence of invasive American bullfrogs in beaver-altered wetlands significantly impacts native Pacific chorus frogs and ecosystem dynamics. Here's a structured summary of the key points and implications:

  1. Impact on Native Pacific Chorus Frogs:

    • Predation and Competition: American bullfrogs predate on Pacific chorus frogs and their tadpoles, directly reducing their populations. They also compete for breeding and living habitats, displacing the native frogs.
    • Habitat Alteration: Beaver-created wetlands, with still water and abundant vegetation, favor bullfrog populations, exacerbating the decline of chorus frogs.

  2. Ecosystem Engineering by Beavers:

    • Beavers alter wetlands through dam-building, creating pond-like environments that inadvertently support invasive bullfrogs, enhancing their invasive success.

  3. Nutrient Cycling and Water Quality:

    • Nutrient Dynamics: Increased nutrients from beaver activity (e.g., added organic matter) can lead to eutrophication. Bullfrogs may contribute to this by affecting algae growth through predator-prey interactions.
    • Water Quality: The decline of chorus frogs and rise of bullfrogs can alter nutrient processing, potentially degrading water quality by increasing turbidity and nutrient levels.

  4. Ecosystem Implications:

    • Food Web Disruption: Loss of chorus frogs affects the food web, as they are both predators and prey, leading to broader ecosystem changes.
    • Management Considerations: Balancing the ecological benefits of beavers with the need to control invasive species is crucial. Restoration efforts may be necessary to protect native species while preserving beaver roles.

  5. Species-Specific Tolerances:

    • Differences in water preference and diet between bullfrogs and chorus frogs influence their success in altered wetlands, with bullfrogs thriving in still conditions and having a broader dietary impact.

In conclusion, invasive bullfrogs in beaver-impacted wetlands threaten native chorus frogs, disrupting nutrient cycles and water quality. Management strategies should address invasive species and consider the ecological role of beavers to maintain balanced and healthy wetland ecosystems.