Offspring survival changes over generations of captive breeding

Area of Science:

• Conservation genetics
• Evolutionary biology
• Population genetics

Background:

• Conservation breeding programs, like zoos, are vital for preventing species extinction.
• Population genetic changes (neutral and adaptive) can threaten the long-term sustainability of these programs.
• Detecting these genetic changes within a single species or context is challenging, impacting global conservation strategies.

Purpose of the Study:

• To investigate the impact of increasing generations in captivity on offspring survival across multiple vertebrate species.
• To identify patterns and variability in population genetic changes during captive breeding.
• To determine if species' evolutionary relationships predict their response to captive breeding.

Main Methods:

• Analysis of pedigree data from over 30,000 individuals across 15 vertebrate species.
• Examination of offspring survival rates across successive generations of captive breeding.
• Statistical analysis accounting for inbreeding and differentiating between dam and sire effects.

Main Results:

• Offspring survival changes over generations in captivity were highly variable across species, with some showing significant increases or decreases.
• Dam and sire effects on survival differed between first-generation and multi-generational analyses.
• Species' phylogenetic relationships did not predict their responses to captive breeding.
• Generational fitness changes occurred that were not explained by known factors like inbreeding depression.

Conclusions:

• Captive breeding programs experience unpredictable generational fitness changes that challenge long-term sustainability.
• The variability in species' responses to captivity underscores the need for species-specific conservation management.
• Further research is needed to understand the drivers of these unexplained fitness changes in captive populations.