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Dryad

Data for: Invasion history of Lycium ferocissimum in Australia – the impact of admixture on genetic diversity and differentiation

Data files

Apr 19, 2023 version files 21.83 MB

Abstract

Aim: We investigated the invasion history of Lycium ferocissimum, a spine-covered shrub native to South Africa that has developed into a damaging invasive plant of undisturbed landscapes and pastures across southern and eastern Australia. In addition to identifying the provenance of the Australian plants, we tested for evidence of admixture, and contrasted genetic diversity and structuring across the native and introduced ranges.

Location: Samples were collected across South Africa (24 localities) and Australia (26 localities).

Methods: We used genotyping-by-sequencing (3,130 SNPs across 381 individuals) to assess population genetic structuring in L. ferocissimum across Australia and South Africa. Coalescent analyses were used to explicitly test contrasting invasion scenarios.

Results: Clear geographic genetic structuring was detected across South Africa, with distinct clusters in the Eastern and Western Cape provinces. The L. ferocissimum plants in Australia form their own genetic cluster, with a similar level of genetic diversity as plants in South Africa. Coalescent analyses demonstrated that the lineage in Australia was formed by admixture between Eastern Cape and Western Cape plants, with analyses suggesting that plants from both African regions were originally introduced to South Australia. We detected little evidence of geographic genetic structure across Australia, although many of the populations were genetically distinct from one another.

Main conclusions: Our results illustrate how admixture can result in genetically diverse and distinct invasive populations. The complex invasion history of L. ferocissimum in Australia poses particular challenges for biological control. We suggest potential biological control agents should be screened against admixed plants (in addition to plants from the Eastern and Western Cape) to test whether they provide effective control of the genetically distinct invasive lineage.