Temporal Changes in Tasmanian Devil Genetic Diversity at Sites With and Without Supplementation

Area of Science:

• Conservation Genetics
• Population Management
• Wildlife Biology

Background:

• Genetic data are crucial for threatened species management, yet in-situ actions like supplementation are often site-specific.
• The Tasmanian devil (Sarcophilus harrisii) conservation provides a model to study multi-site supplementation impacts versus natural fluctuations.

Purpose of the Study:

• To investigate the temporal genetic consequences of multi-site supplementation in Tasmanian devils.
• To compare genetic changes at supplemented sites with control sites lacking management interventions.

Main Methods:

• Analyzed 1,778 genome-wide SNPs from 1,546 Tasmanian devils over 9 years (2014-2022).
• Compared four wild-supplemented sites with four monitoring-only control sites.
• Utilized linear mixed-effects modelling with random slopes to assess temporal genetic variation.

Main Results:

• Genetic differentiation significantly decreased among supplemented sites compared to control sites.
• Three of four supplemented sites showed increased genetic diversity as predicted.
• One supplemented site exhibited decreased diversity and increased relatedness, contrary to predictions; control sites showed heterogeneous genetic changes.

Conclusions:

• Multi-site supplementation can reduce genetic differentiation, but outcomes vary.
• Long-term, multi-site monitoring, including controls, is essential to evaluate conservation intervention effectiveness.
• Tasmanian devil populations display significant heterogeneity, influenced by connectivity and genetic drift.