Invasive species can't cover their tracks: using microsatellites to assist management of starling (Sturnus vulgaris) populations in Western Australia

Abstract

Invasive species are known to cause environmental and economic damage, requiring management by control agencies worldwide. These species often become well established in new environments long before their detection, resulting in a lack of knowledge regarding their history and dynamics. When new invasions are discovered, information regarding the source and pathway of the invasion, and the degree of connectivity with other populations can greatly benefit management strategies. Here we use invasive common starling (Sturnus vulgaris) populations from Australia to demonstrate that genetic techniques can provide this information to aid management, even when applied to highly vagile species over continental scales. Analysis of data from 11 microsatellites in 662 individuals sampled at 17 localities across their introduced range in Australia revealed four populations. One population consisted of all sampling sites from the expansion front in Western Australia, where control efforts are focused. Despite evidence of genetic exchange over both contemporary and historical timescales, gene flow is low between this population and all three more easterly populations. This suggests that localized control of starlings on the expansion front may be an achievable goal and the long-standing practice of targeting select proximal eastern source populations may be ineffective on its own. However, even with low levels of gene flow, successful control of starlings on the expansion front will require vigilance, and genetic monitoring of this population can provide essential information to managers. The techniques used here are broadly applicable to invasive populations worldwide.

Ecological genetics of invasive alien species

“…If the invasive population clusters clearly with one of the potential source populations, this is considered to provide fairly conclusive information about the origin of the invasive population (e.g. Marrs et al 2008;Rollins et al 2009). A shared ancestry of the individuals of invading populations with various populations from the native area is sometimes interpreted as evidence for an admixture origin of the invasive population considered, although it may also reflect the presence of unsampled sources, drift, or insufficient numbers of markers (Darling et al 2008;Rosenthal et al 2008).…”

Genetic population structure of the invasive signal crayfish Pacifastacus leniusculus in Japan inferred from newly developed microsatellite markers

“…Recently, microsatellite analysis has also been used in studying the migration pathways and population structure of invasive species. Owing to recent advances in Bayesian analysis, microsatellite DNA has also been used in defining eradication units of invasive species (Robertson & Gemmell 2004, Abdelkrim et al 2005, Rollins et al 2009, Guillemaud et al 2010). …”

Patterns of genetic diversity reveal multiple introductions and recurrent founder effects during range expansion in invasive populations of Geranium carolinianum (Geraniaceae)

“…For example, such information can be used to test whether phenotypic and/or genetic differences between invasive and native populations are because of adaptive or neutral evolutionary processes (Keller and Taylor, 2008). From a management perspective, an understanding of invasion pathways and genetic connectivity among invasive populations can be useful in designing effective control programs (Rollins et al, 2009) and can help to prevent or limit the introduction and dispersal of similar species by identifying potential routes of introduction and dispersal.…”

“…A clear understanding of the introduction patterns, expansion and gene flow during biological invasions is crucial for making informed management decisions (see, for example, Rollins et al, 2009), especially for species that are transported accidentally via traffic or commerce. Genetic analyses are often the only way to disentangle invasion histories, as historical, observational records on the timing and location of introductions are often lacking and/or misleading (Estoup and Guillemaud, 2010).…”