When the ‘native cat’ would ‘plague’: historical hyperabundance in the quoll (Marsupialia : Dasyuridae) and an assessment of the role of disease, cats and foxes in its curtailment

Abstract

Since the European settlement of Australia in 1788, 25 mainland terrestrial mammal species have become extinct, more than on any other continent during this period. To determine if the causal factors are still active, it is necessary to better understand the species and their status preceding these regional extirpations or extinctions, and examine the historical record for clues to the cause(s) of these declines. From an extensive review of historical material, primarily newspaper accounts, we collated >2700 accounts of quolls. We discovered 36 accounts that demonstrate the propensity for quolls to become hyperabundant. The geographical distribution of accounts implies that most refer to Dasyurus viverrinus, but an account from Normanton district (Queensland) likely applies to D. hallucatus. More than 110 accounts demonstrate that disease/parasite epizootics occurred in south-eastern Australia, commencing on mainland Australia possibly in the goldfields region of Victoria in the 1850s, or in south-eastern South Australia and south-western Victoria in the mid to late 1860s, and implicate these as the initial primary factor in the regional extirpation of Australia’s quolls. The loss of D. viverrinus populations in south-eastern Australia was reportedly from population abundances and densities that were sporadically extraordinarily high, hence their loss appears more pronounced than previously suspected. Accounts describing the widespread, rapid and major loss of quolls suggest the possible involvement of several pathogens. Ectoparasites such as Uropsylla tasmanica and ticks appear to be described in detail in some accounts. A few others state comortality of Felis catus and Canis lupus familiaris, suggestive of a disease of either or both of these species, such as Canine Distemper Virus, a morbillivirus with a propensity to be non-host specific, that may have caused the decline of the quolls, perhaps vectored by the reported ectoparasites. We also collated 23 presumed independent accounts of cats negatively impacting quolls, two of which describe significant mortality, and three presumed independent accounts of fox predation. These highlight the capacity of both of these introduced predators to have reduced quoll distribution and abundance.