A matter of time: Temporal variation in the introduction history and population genetic structuring of an invasive lizard

Abstract

Invasive species are considered one of the greatest threats to native ecosystems, second only to habitat loss and fragmentation. Despite this, the temporal dynamics of invasions are poorly understood, with most studies focusing on a single time point, providing us with only a snapshot of the biology and genetics of the invader. We investigated the invasion of Lord Howe Island by the delicate skink Lampropholis delicata and assessed the introduction history and genetic structure of this species over a 5-year period. Using genetic data taken from 2007, and again in 2011/12, we examined changes in the population genetic structure (whether new haplotypes had been introduced to the island, and shifts in haplotype frequencies) of the species on the island between these two time points. No new haplotypes were introduced to the island between 2007 and 2011/12; however, significant shifts in haplotype frequencies across the island were detected. We conclude that the delicate skink is expanding its range into the southern regions of the island and that the haplotype frequencies on Lord Howe Island are still in a state of highly dynamic flux. Our study highlights the importance of considering invasions as dynamic and studying them in such a way that enable us to better manage their impacts.

Tracing the Invasion and Expansion Characteristics of the Flatid Planthopper, Metcalfa pruinosa (Hemiptera: Flatidae), in Korea Using Mitochondrial DNA Sequences

“…If this interpretation is accurate, MPBR02 might further expand to currently less occupied regions, such as the North-East and South-West regions, causing additional temporal changes in the haplotype frequency in Korea ( Figure 7 ). Temporal variation in haplotype frequency in the given regions has also been reported in diverse organisms, including invasive species [ 42 , 43 , 44 ]. In contrast, the role of M. pruinosa entering through the South-East region is not obvious in the current population genetic structure, along with the origin.…”

Sex‐specific shifts in morphology and colour pattern polymorphism during range expansion of an invasive lizard

“…Despite the presence of intraspecific hybridization in the central and southern regions of Lord Howe Island among individuals from different native‐range source regions (Chaplin, ; Chapple, Miller, et al., ; Chapple et al., ; Moule et al., ), no morphological shifts in shape were observed on the island. This result is in contrast to the invasive range of the brown anole ( Anolis sagrei ), where there was a positive relationship between the extent of morphological change and the degree of genetic admixture present within the invasive population (Kolbe, Larson, & Losos, ).…”

“…The Lord Howe Island population was treated as three separate invasive populations because each region of the island has different source clades. The northern portion of the island was colonized by the source Clade 5; the central region by Clades 3, 4, 5 and 9a; and the southern region by source Clades 4 and 9a (Chapple, Miller, et al., ; Chapple et al., ; Moule et al., ; Table ). Additionally, the density of historic sampling in Hawaii also allowed an examination of phenotypic changes over time.…”

Does geographical isolation influence group recognition and social preference in an invasive lizard?

“…The introduced populations have been shown to originate from five genetically distinct source regions (Brisbane, Tenterfield, Border Ranges, Yamba-Coffs Harbour, and Sydney) within the native range that are estimated to have been geographically isolated from each other for approximately two million years (Chapple et al, 2011a(Chapple et al, ,2011ba,b, 2013. High levels of genetic admixture (involving all five native-range source regions) within the introduced Lord Howe Island populations indicate that individuals from distinct populations are indeed coming into contact and interbreeding (Chapple et al, 2013;Moule et al, 2015). However, the mechanisms mediating the social interactions within the invaded regions have yet to be resolved.…”