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Invasive alien species are one of the greatest threats to biodiversity, ecosystems, human economy and human health. Future climate change may result in niche expansion, contraction or range shift leading to changes in their geographic distribution. The Giant African snail, Lissachatina fulica, is one of the 100 worst invaders. This study uses a species distribution modelling approach to assess current and future potential global distribution for this pest species under two climate change scenarios (SSP2 and SSP5). We tested the niche conservatism hypothesis for this pest species by comparing native niche versus invaded niche. We also quantified niche overlap and niche dynamics such as expansion, stable and unfilling between the native and introduced ranges using PCA-env. Our results show that potentially suitable niches in the present and future climate change scenarios increase significantly. The results suggest that Bio 13 and Annual Mean Temperature (Bio1) are the two most important drivers in determining the potential distribution of this invasive species. Furthermore, we found evidence for niche shifts due to niche expansion across the continents, thus occurring in climatically distinct regions. Finally, the study identified the areas of high invasibility which help in managing this invasive species. This study has implications for understanding the range dynamics of L. fulica across continents despite having low mitochondrial haplotype diversity in the invaded regions.

Isolation of high molecular weight DNA from gastropod molluscs and its subsequent PCR amplification is considered difficult due to excessive mucopolysaccharides secretion which co-precipitate with DNA and obstruct successful amplification. In an attempt to address this issue, we describe a modified CTAB DNA extraction method that proved to work significantly better with a number of freshwater and terrestrial gastropod taxa. We compared the performance of this method with Qiagen(®) DNeasy Blood and Tissue Kit. Reproducibility of amplification was verified using a set of taxon-specific primers, wherein modified CTAB extracted DNA could be replicated at least four out of five times but kit extracted DNA could not be replicated. In addition, sequence quality was significantly better with CTAB extracted DNA. This could be attributed to the removal of polyphenolic compounds by polyvinyl pyrrolidone which is the only difference between conventional and modified CTAB DNA extraction methods for animals. The genomic DNA isolated using modified CTAB protocol was of high quality (A260/280 ≥ 1.80) and could be used for downstream reactions even after long-term storage (more than 2 years). ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13205-020-2051-7) contains supplementary material, which is available to authorized users.