1. Introduced Predators: The introduction of non-native predators, primarily dogs and to a lesser extent cats, posed a significant threat to the thylacine. These introduced species were more efficient hunters and often preyed on the thylacine's primary food sources, such as small marsupials, contributing to food shortages and population decline.
2. Habitat Loss and Fragmentation: The expansion of European settlements, agriculture, grazing, and forestry significantly reduced the thylacine's natural habitats. The destruction and fragmentation of its preferred forest and scrubland ecosystems compromised its survival and reproductive success.
3. Hunting and Extermination: The thylacine was often viewed as a threat to livestock, mainly sheep, and was subject to extensive hunting and persecution. Bounty systems incentivized hunters to eliminate thylacines, resulting in their systematic culling and further population declines.
4. Disease: It is believed that diseases brought by European settlers may have also contributed to the demise of the thylacine. Introduced diseases like canine distemper virus, which affects carnivorous species, could have had a significant impact on the already vulnerable thylacine population.
5. Loss of Genetic Diversity: Thylacines had a relatively small population size, making them more susceptible to genetic issues and inbreeding. This genetic vulnerability, coupled with the other factors mentioned above, potentially accelerated their decline and contributed to the species' inability to adapt to the changing environmental conditions.
The combination of these ecological and human-induced pressures eventually led to the catastrophic population decline and eventual extinction of the Tasmanian tiger in the wild, with the last known individual dying in captivity in the early 20th century.