Origin and expansion of feral cats in Australia

Spencer, P. B., Yurchenko, A. A., David, V. A., Scott, R., Koepfli, K. P., Driscoll, C., O’Brien, S.J. & Menotti-Raymond, M. (2015). The Population Origins and Expansion of Feral Cats in Australia. Journal of Heredity, esv095.

The historical literature suggests that in Australia, the domestic cat (Felis catus) had a European origin [~200 years before present (ybp)], but it is unclear if cats arrived from across the Asian land bridge contemporaneously with the dingo (4000 ybp), or perhaps immigrated ~40000 ybp in association with Aboriginal settlement from Asia. The origin of cats in Australia is important because the continent has a complex and ancient faunal assemblage that is dominated by endemic rodents and marsupials and lacks the large placental carnivores found on other large continents. Cats are now ubiquitous across the entire Australian continent and have been implicit in the range contraction or extinction of its small to medium sized (<3.5kg) mammals. We analyzed the population structure of 830 cats using 15 short tandem repeat (STR) genomic markers. Their origin appears to come exclusively from European founders. Feral cats in continental Australia exhibit high genetic diversity in comparison with the low diversity found in populations of feral cats living on islands. The genetic structure is consistent with a rapid westerly expansion from eastern Australia and a limited expansion in coastal Western Australia. Australian cats show modest if any population structure and a close genetic alignment with European feral cats as compared to cats from Asia, the Christmas and Cocos (Keeling) Islands (Indian Ocean), and European wildcats (F. silvestris silvestris).

Capter 3: A voyage to Terra Australis

Koch, K., Algar, D., Searle, J., Pfenninger, M., & Schwenk, K. (2014). A voyage to Terra Australis: human-mediated dispersal of cats. Genetic diversity and phylogeography of Australian feral cats, 56.

Domestic and ship cats have been transported as human commensals around the world, especially in the last 200 years. They have given rise to populations of feral cats in many places. The feral population in Australia is believed to have led to the decline and extinction of native mammal species, but until now the time and origin of the cat introduction into Australia is unclear. Here we investigate the history of arrival of cats to Australia, considering the possibility that this was pre- or post-European settlement, and the potential for admixture. We analyse the genetic structure and diversity of feral cats from six locations on mainland Australia and seven offshore islands as well as samples from Malaysia and Europe using microsatellite and mitochondrial DNA data. Our data suggest that cats in Australia originated from Europe with possible isolated cases of invasions from Asian locations. We find low genetic differentiation between samples from Dirk Hartog Island, Flinders Island, Tasman Island and Cocos (Keeling) Island (Australian Indian Ocean Territory). Historical records suggest that introduction of cats to these islands occurred at the time of exploration and in connection with the pearling, whaling and sealing trades at the beginning of the 19th century. On-going influx of domestic cats into the feral cat population is causing the Australian mainland populations to be genetically differentiated from those on Dirk Hartog, Tasman and Flinders Islands, which exhibit remnants of the historically introduced cat genotypes.

Ancient introductions of mammals in Mediterranean islands and their implications for conservation

Gippoliti, S., & Amori, G. (2006). Ancient introductions of mammals in the Mediterranean Basin and their implications for conservation. Mammal Review,36(1), 37-48.

1 The importance of taxonomy to the determination of conservation priorities and actions is widely accepted. It should be not surprising therefore that the taxonomic treatment of mammal species that have been subject to human actions in antiquity may well influence the contemporary assessment of conservation priorities at various levels.
2 As a result of early extinctions caused by humans and protohistoric and historic introductions, we suggest that the Mediterranean Basin and its islands are particularly prone to misdirection of efforts towards biodiversity conservation.
3 The two main risks associated with the failure to use an evolutionary and palaeoecological approach to conservation efforts are (i) an underestimation of the conservation importance of distinctive continental taxa vs. the apparent endemicity of island taxa; and (ii) a serious risk for native and endemic island species when anthropochorous mammals, especially ungulates, misguidedly become the focus of conservation actions, particularly inside protected areas.
4 Urgent measures, including refinement of mammal taxonomy, the exclusion of known anthropochorous taxa from conservation lists and implementation of protective legislation, are necessary to maintain the uniqueness and richness of the Mediterranean biodiversity hotspot.

Introduction and spread of cats in Australia

Abbott, I. (2002). Origin and spread of the cat, Felis catus, on mainland Australia, with a discussion of the magnitude of its early impact on native fauna.Wildlife Research, 29(1), 51-74.

A comprehensive search of historical sources found no evidence that the cat, Felis catus, was present on mainland Australia prior to settlement by Europeans. Nor were records of cats found in journals of expeditions of exploration beyond settled areas, undertaken in the period 1788–1883. Cats did not occupy Australia from the earliest point of entry (Sydney, 1788), but instead diffused and were spread from multiple coastal introductions in the period 1824–86. By 1890 nearly all of the continent had been colonised. This new chronology for the feline colonisation of Australia necessitates a re-appraisal of the early impact of the cat on native mammal and bird species. The evidence for early impacts of cats causing major and widespread declines in native fauna is considered tenuous and unconvincing.

Abbott, I. (2008). The spread of the cat, Felis catus, in Australia: re-examination of the current conceptual model with additional information.Conservation Science Western Australia, 7(1), 1-17.

This paper is an update of Abbott, I (2002) Origin and spread of the cat, Felis catus, on mainland Australia, with a discussion of the magnitude of its early impact on native fauna. Wildlife Research 29, 51–74. An additional 33 journals of expeditions of exploration or excursions beyond settled areas before 1895 were located, and as expected from the current conceptual model, none of these recorded cats. These accounts of travel through country as yet unsettled or sparsely settled by Europeans necessitate only one small modification (relating to north-east Queensland) to the conceptual model presented previously. In addition, nearly 150 new records of cats were located in other parts of Australia, and all are consistent with the chronology of spread hypothesized in the previous paper. For Tasmania, following their introduction in 1804, cats were first recorded there as feral in the 1840s. Incidental records were found indicating that in parts of Australia the spread of the cat was assisted by their release in regions experiencing their first outbreaks of rabbits, by flood-linked irruptions of the long-haired rat (Rattus villosissimus), and by their release to control rodents destroying sugar cane plantations in northern Queensland. Feral cats of large size were first detected in various regions of Australia some 10–30 years after local settlement.