Stormwater wetlands can function as ecological traps for urban frogs

Area of Science:

• Urban ecology
• Environmental toxicology
• Conservation biology

Background:

• Natural wetlands are declining in urban areas, replaced by constructed stormwater treatment wetlands.
• These constructed wetlands may pose risks to wildlife due to contaminant exposure.
• Ecological traps occur when animals prefer habitats with lower fitness outcomes.

Purpose of the Study:

• To investigate if urban stormwater wetlands function as ecological traps for frogs.
• To assess the impact of contaminant levels on frog survival, metamorphosis, and behavior.
• To determine frog breeding site selection in relation to wetland contaminant levels.

Main Methods:

• Mesocosm experiments simulating stormwater wetlands with varying contaminant levels.
• Testing frog survival, metamorphosis, and predator avoidance responses.
• Natural oviposition experiment to evaluate breeding site preference.

Main Results:

• Tadpoles in more polluted wetlands exhibited lower survival and reduced predator response.
• Frogs in polluted wetlands metamorphosed earlier and at a larger size.
• Breeding frogs did not avoid laying eggs in high-contaminant wetlands.

Conclusions:

• Urban stormwater wetlands can serve as ecological traps for frogs.
• Contaminants negatively impact frog survival and behavior, despite some compensatory growth.
• Management interventions are crucial to address the ecological costs of these artificial habitats.