Cross-Continental Analysis Shows That Disturbance Effects on Reptile Body Condition Do Not Predict Abundance...

Area of Science:

• Ecology
• Conservation Biology
• Herpetology

Background:

• Ecological disturbances alter ecosystems, potentially causing animal population declines.
• The risk-disturbance hypothesis suggests declining body condition predicts population collapse, but empirical evidence is lacking.
• The general relationship between reptile body condition and abundance, especially in response to disturbance, remains understudied.

Purpose of the Study:

• To empirically test the relationship between reptile body condition and abundance across various studies and species.
• To investigate if population abundance and body condition show linked changes in response to ecological disturbances.
• To determine if environmental and species traits influence the body condition-abundance relationship and if there are time-lagged effects.

Main Methods:

• Utilized a combined dataset from 33 studies with over 42,000 observations of 75 reptile species.
• Analyzed the body condition-abundance relationship at the site level.
• Employed meta-analytical models to assess linked changes in abundance and body condition in response to disturbance.

Main Results:

• A positive relationship was observed between mean reptile body condition and abundance at the site level.
• This positive relationship was largely absent when examining population responses to disturbance.
• Results did not support the risk-disturbance hypothesis and offered limited support for the population collapse framework.

Conclusions:

• Disturbance impacts on reptile body condition do not necessarily reflect or predict changes in population abundance.
• Disturbances can decouple the relationship between abundance and body condition by altering factors like predation and resource availability.
• Monitoring programs should validate the body condition-abundance link within specific systems before using body condition as a proxy for population status.