Data from: Cross-continental analysis shows that disturbance effects on reptile body condition do not predict abundance responses

Ecological disturbances are discrete events that alter or transform the
physical, chemical, or biological characteristics of ecosystems. Animal
populations are vulnerable to disturbance, and the risk-disturbance
hypothesis and population collapse framework propose that population
declines can be predicted by declines in animal body condition. However,
no research has empirically examined the general relationship between body
condition and abundance, nor their relationship in response to
disturbance. We used a combined dataset representing 33 studies and
>42,000 observations of 75 species from Australia, New Zealand,
Spain, and the United States to test predictions relating to the
relationship between reptile body condition and abundance. We first
investigated the relationship at the site level and then used
meta-analytical models to test whether populations showed linked changes
in abundance and body condition in response to disturbance. We further
tested whether key environmental and species traits influenced this
relationship and whether there was a time-lagged effect of body condition
responses on abundance. Our results provided no strong support for the
risk-disturbance hypothesis or population collapse framework. We found a
positive relationship between mean reptile body condition and abundance at
the site level. However, the relationship was largely lost when
investigating population responses to disturbance. We provide a new
conceptual framework that shows how disturbances can modify or uncouple
the relationship between abundance and body condition by influencing
underlying drivers, such as predation, competition, and resource
availability. As such, the impacts of disturbance on reptile body
condition cannot be assumed to reflect or predict abundance responses.
Monitoring programs that infer population impacts based on changes in body
condition should confirm the relationship between these two variables in
the relevant study system.