Climate effects on nesting phenology in Nebraska turtles.

Area of Science:

• Ecology and evolutionary biology
• Climate change biology
• Herpetology

Background:

• Organisms often alter reproductive timing in response to climate change.
• Advancement of reproductive timing is a common response to warming in temperate regions.
• North American turtle species' nesting phenology responses to climate shifts require investigation.

Purpose of the Study:

• To investigate the impact of climate variables on the nesting phenology of two North American turtle species over three decades.
• To determine if warming temperatures lead to earlier nesting in Common Snapping Turtles (Chelydra serpentina) and Painted Turtles (Chrysemys picta).
• To explore the relationship between environmental factors, body size, and nesting timing in these turtle populations.

Main Methods:

• Analyzed three decades of nesting data for Common Snapping Turtles and Painted Turtles in Nebraska, USA.
• Correlated nesting timing (first and average dates) with various climate variables (temperature, precipitation) from preceding and current years.
• Assessed the relationship between nest deposition, female body size, and nesting phenology.

Main Results:

• Common Snapping Turtle nesting advanced with warmer December and May temperatures and previous July precipitation.
• Painted Turtle nesting showed a trend towards later nesting, correlated with warmer fall/winter temperatures and April precipitation, suggesting impeded vitellogenesis.
• Nest deposition was strongly correlated with female body size in both species, with larger females nesting earlier.

Conclusions:

• Nesting phenology responses to climate change vary significantly between turtle species.
• While Common Snapping Turtles showed some temperature-driven advancement, Painted Turtles exhibited a trend towards later nesting, potentially due to metabolic costs and precipitation.
• Future increases in spring temperatures may advance nesting for both species, contingent on body size variations and other environmental factors.