The northernmost populations of the European pond turtle (Emys orbicularis) are found in southern Lithuania. Once widespread, the species has declined dramatically due to habitat loss, pollution, the pet trade, invasive species, accidental mortality, and climate change. The earliest life stages—eggs and hatchlings—are especially vulnerable to predation and environmental stressors, making their protection a critical factor in population recovery.

Female turtles in Lithuania show a strong preference for open habitats when laying eggs. Unfortunately, these areas are often distant from water bodies and are typically located in human-disturbed environments. As a result, egg destruction and juvenile mortality are exceptionally high, threatening the viability of smaller, isolated populations. Reducing mortality during the first year after hatching is thus essential for ensuring long-term survival.

In a recent study published in Acta Herpetologica, Dr. Rakauskas and colleagues explored the potential of artificial incubation to enhance egg and hatchling survival. The research identified best practices for artificial incubation and early-life rearing. The study found that natural egg and hatchling viability was approximately 75%, though this varied by year, and was negatively influenced by nest depth and dense herbaceous cover. Wire mesh nest protectors significantly reduced predation, proving effective for in-situ conservation. 

Interestingly, clutch size and turtle size in Lithuanian populations were larger than those recorded in Southern Europe. Hatchling size was influenced by sex (with females being larger), clutch characteristics, and individual differences.

Laboratory incubation yielded a hatching success rate of approximately 97%, although incubation temperatures resulted in a strongly female-biased sex ratio. Artificial rearing over the first winter achieved a 75% survival rate. These findings underscore the value of targeted conservation actions—especially artificial incubation and overwintering care—in safeguarding vulnerable northern populations of Emys orbicularis, particularly at the edge of their range.

Read the full paper here to find out more.

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