Abstract for presentation at Biodiversity Extinction Crisis Conference - A Pacific Response

Invasive species are considered to have a larger negative impact on threatened species than any factor other than habitat loss, particularly in Australasia where the largest number of introductions worldwide have occurred. Considered one the “world’s worst invasive species”, starlings (Sturnus vulgaris) were introduced to eastern Australia in the mid-19th Century and, other than the odd vagrant, were first seen in Western Australia (WA) in the 1970’s. Despite intensive control efforts, Western Australian populations have persisted and new areas of infestation have recently been identified. Combining genetic and ecological data, this study aims to provide information regarding population dynamics of starlings in Australia to management authorities in WA. Ecological data and tissue samples were taken from across the current range of starlings in Australia. Genetic data gathered from nuclear and mitochondrial markers indicate that multiple introductions from different source populations have occurred in Western Australia. Additionally, there appears to be a barrier to dispersal between these populations because they remain genetically discrete. The analysis of historical samples from incursions into WA during the late 20th Century suggests that the arrival of founding individuals may have been facilitated by human transport. Our results indicate that control operations focused on eastern source populations which are proximal to WA would not be sufficient to stem the flow of starlings into WA. However, because WA populations are not mixing, localized control efforts in WA may be effective at reducing population size. We also conclude that it may be advantageous for authorities to increase surveillance in areas such as shipping ports, which may act at entry points for new introductions. Starlings are unlikely to be eradicated from Australia, but effective and informed control can forestall the damage and may be able to protect important areas of conservation, such as WA’s internationally recognized biodiversity hotspot.