The following two categories are mainly related to habitat degradation. Species survival is dependant upon the presence of food host (i.e. the plants or ants upon which the larvae feed), in a suitable environment. These are often very specific. Should the food host habitat be destroyed then the butterfly will also perish. Loss of habitat is due to urbanisation and agricultural land use.
Presently within Australia, there is a Federal Endangered Species Protection Act (1992) which includes the criteria for a threatened species.
For the purposes of this Act, a species is ENDANGERED if:
(a) it is likely to become extinct unless the circumstances and factors threatening
its abundance, survival or evolutionary development cease to operate; or
(b) its numbers have been reduced to such a critical level, or its habitats have been so drastically reduced, that it is in immediate danger of extinction; or
(c) it might already be extinct, but is not presumed extinct.
A species is VULNERABLE if:
Within the next 25 years, the species is likely to become endangered unless the circumstances and factors threatening its abundance, survival or evolutionary development cease to operate.
At this point in time, none of the threatened butterfly species to be found in South Australia have been accepted by local government authorities for listing as protected fauna. At a federal level, only one species of butterfly is presently listed (1998) as threatened for the purposes of the above act.
RARE: Species are not currently threatened but are localized or patchy in distribution. They may be widespread in overall distribution, but are not always present near the food host, and usually occur in very few numbers.
LOCAL (UNCOMMON): Species are usually present wherever the food host occurs, but are rarely seen in high numbers.
COMMON: Species are usually present wherever the food host occurs, and are often seen in high numbers.
MIGRANT: These species either periodically or annually migrate in numbers within Australia, over short or long distances. Usually common near the food host in their normal environment.
VAGRANT: These species either periodically or annually, randomly migrate singly within Australia, over short or long distances. Many species have this tendency (especially the females), particularly during favourable seasons, it being used as a means of dispersal.
NORTHERN MIGRANT/VAGRANT: These species enter South Australia from the north or northeast, particularly during favourable monsoon seasons of combined wet, humid summers and autumns in inland areas. Most of these species are biologically unsuited to the cooler southern areas of South Australian and do not establish even if the food host is present.
INLAND FAUNA: These species are established in the Alice Springs area (Northern Territory). They have not as yet, been noted as being established in the adjacent northern areas of South Australia.
INTRODUCED: These species have been accidentally introduced to an area favourable to their continuing existence. This may be by natural causes such as violent uplifting storms or by rafting, but is usually by transportation of early stages on foodplant hosts or by adults sealed in transportation vehicles.