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Apparent lack of sex ratio change due to anthropogenic pressures in Jersey grass snakes


The grass snake (Natrix helvetica), is Least Concern Europe-wide. However, it is rare on Jersey and is the island’s most threatened reptilian. A 2017 thesis studied the Jersey grass snake population, sampled in western Jersey. However, the sex ratio of the observed population- which previous research has established is relevant to reproductive output and which anthropogenic pressures may be altering- was not analysed. This analysis examined observed Jersey grass snake sex ratios to establish whether they resembled ratios of populations under size-dependent pressures. Moreover, variation in environmental conditions between Jersey detections was analysed. Sex ratio was found to be biologically relevant and significantly deviated from a 1:1 ratio. This may indicate a lack of size-dependent pressures. However, lack of historical data precludes definitive conclusions. Moreover, the potential absence of such trends would not negate other pressures. Samples did not cluster based on environmental conditions, which may have conservation relevance.

Categories Ecology, Island studies
Keywords Anthropogenic, Grass Snake, Natrix helvetica, Reproductive Biology, Sex Ratio
Author Anonymous
Date published 2023
Document type Report
Organisation Jersey International Centre for Advanced Studies
IRR Code IRR/JICAS/2023.43902
File Type pdf