The following is some information on the conservation of South Australian butterflies and their habitat. There have been entire books dedicated to the subject, New 1997 (Butterfly Conservation, 272 pp, Oxford University Press).

Butterflies have evolved in unison with the evolution of flowering plants (angiosperms), and the larval stages of butterflies are almost entirely dependent on flowering plants as a food source. Therefore, the conservation or restoration of vegetation habitat is also of primary concern for the survival of butterflies.

Butterflies are good survivors and are extremely tolerant of environmental abuse. If they are not present in an area, where they are expected to be, then it is a good indication that some environmental catastrophe has either happened historically or is presently occurring. The obvious and usual catastrophe is the loss of their food host due to eradication, or overgrazing and trampling by feral or domestic animals. Fires are also catastrophic, especially when major, and particularly at the present time due to the fragmentation of regional habitat preventing species replenishment. Another major catastrophe, also particularly noticeable at present within intensive-use agricultural areas is the massive use of sprays (dipel and dioxin containing insecticides and weedicides etc), especially those distributed by aerial means, to protect legume, canola (mustard) and other cash crops. Agricultural and urban toxic waste invariably ends up in wetland systems and are therefore likely to have long term effects on butterfly populations in those areas.

There have been sporadic attempts to conserve colonies of threatened butterflies in Australia, notably jewel and birdwing butterflies in Queensland, coppers and ant-blues in New South Wales and Victoria, and the Ptunarra Xenica in Tasmania. Several attempts have been made to conserve threatened butterflies in South Australia, which have met with government indifference. The last remaining extensive habitat for endangered Hesperilla flavescens flavia within its original type-range on the Adelaide Plains, was recently bulldozed by the Federal Defence Department (in contravention to State law), so that the land could be sold off for urban and agricultural use. At this point in time, none of the threatened butterfly species to be found in South Australia have been accepted by government authorities for listing as protected fauna.

People often mention, "What happened to the butterflies that we saw when we were children?" In most cases this was either a reference to common urban butterflies or to the periodic migrations of butterflies through their gardens in spring. The urban butterflies are still present, but the reason those people do not see them now is largely because garden layouts have changed. The mass use of nectar laden, old-fashioned, cottage flowering plants has been replaced by lawns, non-nectar producing hybrid plants and specialist shrubs. Mass butterfly migrations in South Australia have certainly reduced, and this can only be put down to the disruption of the environment due to agricultural and urban developments, as outlined above, global warming, and perhaps to an increase in UV radiation due to disturbances of the ozone layer in the upper atmosphere caused by global warming.

Read More About the Story of Butterfly Gardening

As time progresses the insatiable demands of human urbanisation and development places increasing pressure on the conservation of bio-diversity. What may have been adequately preserved yesterday is put under stress tomorrow by urban encroachment and development. It is very easy to clear a pristine 1/2 hectare (~1 acre) area and remove totally its flora and fauna, and it can be done within the hour at very little cost, but it is virtually impossible to reinstate that area to its original condition once the original seed-base has been lost.

Unlike much of the eastern areas of Australia, where vegetation is very easy to re-establish due to the higher rainfall, it is very difficult to re-establish vegetation in South Australia on a broad acre basis because of the lack of rainfall and high evaporation rates.

In most dryland areas it would take 10 - 20 years just to establish some semblance of upper storey flora, and probably another 10 years to establish an understorey free of weeds. The cost in plants alone at a minimum density of 1 per square meter at A$1.00 per plant would equate to A$10,000 per hectare. It might also be mentioned that millions of dollars have been spent on Government funded re-greening projects in Australia over recent years, but very little of the vegetation planted in South Australia has any use as foodplant for threatened and rare butterflies.

In some specialist plant communities the floral dynamics probably take hundreds of years to fully develop. Many of the dryland Gahnia sedges including the butterfly foodplants Gahnia filum and Gahnia lanigera fall into this category. In fact, Kangaroo Island presently separated from the mainland Fleurieu Peninsula, was actually joined to the peninsula during the Pleistocene ice-ages (by lowering of the sea level), yet many peninsula plants did not make it across the 20 km gap to the island during periods of thousands of years!

In the pastoral areas of South Australia, butterfly populations are mostly stable, but suffer from the effects of overgrazing from feral (goats and rabbits) and domestic animals. The intensive oil and gas exploration activities in the northeast of the state have also made a major contribution to the degradation. In some areas there has been very little self generation of (non-poisonous) woody flora since the coming of European habitation (1836), due to overgrazing by the animals. Existing woody flora in such areas are as old or older than this habitation!

In the southern agricultural and urban belt,it is estimated that 90% of this region has been cleared. About 60% of the state's butterflies are largely endemic to this region.

Butterflies in South Australia can be grouped into three general categories for conservation and restoration purposes.

Firstly, there are the migrants and vagrants, which are generally common butterflies where they breed and usually no conservation measures are required.

Secondly, there are the urban butterflies and again these are generally common butterflies which can be easily attracted to one's garden.

In the third group are the remaining butterflies into which all of the rare and threatened butterflies belong. These butterflies are rarely found in urban gardens, usually because of the specialist nature of their foodhost or because they have certain biological requirements which cannot be found in the urban garden. Many of these species are also dependent on hill tops for mating purposes.

All of the urban butterflies can be established by the simple method of introducing their foodplants to an appropriate area. These butterflies usually have a wide range of larval foodplants and therefore they can survive in diverse ecosystems. Larvae of the third group of butterflies are usually dependent on a narrow range of foodplants, often requiring a specialised ecosystem, and on top of which the adult butterfly may require its own ecosystem, and quite likely the ecosystem of the larvae may differ from that of the flying adult, so the restoration of these butterflies to an area is not always a simple matter of planting a few foodplants.

In South Australia, skippers and some satyrid butterflies favour sedges and certain grasses as foodplants, and are especially vulnerable to the effects of agriculture and urbanisation. Skippers have suffered the most among the butterflies with most of the species in South Australia now either threatened or rare. On the other hand, these butterflies would be the easiest to re-establish and conserve due to their simple requirements.

Many species of the Lycaenidae (blues and coppers) have also suffered in South Australia, due to their particular requirements of either a very narrow range of foodhosts or larval dependence on certain ants which also have particular requirements. Most of the threatened species of this group are now confined to large conservation parks. The same butterflies would be very difficult to re-establish and conserve due to their exacting requirements. For example, in urban Adelaide, 120 eggs and young larvae of the Amaryllis Azure (Ogyris amaryllis meridionalis) were experimentally placed on its mistletoe foodhost, and shelter was provided for the larvae as loose bark tied around the tree bough hosting the mistletoe. Its usual attendant ants were present in the area but were not actively foraging on the mistletoe. It was later observed that not one of the eggs or larvae fully matured to the adult stage, having been decimated by predators. The ants which should have protected the larvae, did not make the necessary adjustment to their regimen.

The habitat restoration checklist gives simplistic guidelines for those people wishing information on the re-establishing of butterflies to an area. It should be used in conjunction with the foodhost and regional checklist tables. It can be a complex undertaking. People undertaking large scale revegetation projects under Landcare or Greening Australia grants are encouraged to contact the society for Butterfly Conservation in South Australia which may be able to provide further expertise. Some butterflies which are common do not require conservation effort.

Suitable summer flowering plants also need to be grown to provide nectar for the adult butterflies. In the bush this can be partly provided by Bursaria spinosa (Christmas bush), Callistemon spp (Bottlebrushes - for wetlands), small Eucalyptus spp, Goodenia spp, Leptospermum spp (tea-tree), Melaleuca spp, and some Compositae and Leguminosae. In revegetation projects, large quantities of food and nectar plants need to be strategically planted so that colonies of the butterflies going to use the larval foodplant can easily establish.

Obviously there is no point undertaking rehab work for a butterfly if it does not occur in your area, and the planting of butterfly foodplant does not guarantee that the butterfly will find and utilise the plant. A further complication is that butterflies with a wide range of foodplants (particularly the rarer species), often tend to specialise on only one of these foodplants in any given locality. For example, the blue Jalmenus icilius uses Acacia spp as a foodplant in the southern parts of its range, yet in northern pastoral areas it uses Senna as a foodplant, even though the same Acacia spp that are foodplant in the south are actually growing adjacent to the Senna. The same specialisation can even occur within the Acacia foodplants within different areas.

It is always best to let the adult female butterfly find the foodplant, as she has remarkable sensory powers for this purpose and she knows exactly whether the foodplant is suitably located, or suitable for the area, to sustain the larvae to maturity. In some cases the butterfly could be re-introduced, but unfortunately there is very little experimental work been done to determine what numbers of the butterfly, as eggs, larvae, pupae or adults that would be required for this purpose, and each butterfly would have a different requirement.

There has been increasing help from (particularly) the Federal Government by way of grants to undertake native revegetation and fencing projects to rehabilitate or protect broadacres. However, private landholders need to understand that serious thought needs to be applied to your undertakings as to what are your ultimate intentions. Whether you are doing it for better land management and the potential increase to property value, or because of your environmental concern. If the latter then consideration should be given to placing your work efforts under the protection of a heritage or conservation agreement.

Planning Butterfly Habitat Restorations

The following information is an excerpt from Mason 1997, concerning butterfly habitat restoration work in Europe and North America. Read Full Article

Ecologists and entomologists in Britain and the United States have participated in numerous projects aimed at restoring, expanding, and mitigating losses of habitat for native butterflies. Some of these butterflies have been listed as threatened or endangered; others have been lost or are in decline in certain portions of their former ranges. The experiences and observations of these scientists illustrate potential needs and concerns when planning to restore or improve existing butterfly habitat. This paper relates several cases in which complex biotic and abiotic interactions played important roles in the success or failure of butterfly habitat restoration and the reestablishment of butterfly populations.

Although each butterfly species has its own unique combination of habitat requirements and life history, some fundamental principles concerning butterfly biology (New 1991) are significant in planning habitat restorations. Most caterpillars are herbivores, and many are specialists which feed on only one kind or a few related kinds of plants. Therefore, the presence of appropriate larval host plants is the primary requirement of habitat restoration. In addition, many butterfly species require that the larval food plant be in a particular growth stage, of a certain height, exposed to the proper amount of sunlight, or in close proximity to another resource.

Adults typically utilize a wider range of plants or other resources as food, and flight gives them expanded mobility. However, adult dispersal ability varies from species to species. For some, physical features such as a few meters of open space, a stream, a hedge, or a change in gradient create intrinsic barriers to dispersal; other species routinely migrate long distances. Species with greater levels of mobility form "loose" or "open" populations with indistinct boundaries. Such a species may have a wide, relatively continuous geographic dispersion and may be considered rare if found in low density within its range.

In contrast, as many as 85 percent of butterflies in temperate regions may form "tight" or "closed" populations, discrete colonies with distinct geographic boundaries (New 1991). Closed populations may be restricted to particular geological formations, soil types which support characteristic vegetation, or an early successional stage of vegetation. These colonies are often part of "metapopulations" groups of local populations which occupy distinct habitat patches and interact through small-scale movement between colonies. Within a cluster of these habitat patches, a metapopulation can survive for many years, as long as the habitat remains suitable. Extinction of one colony will be offset by recolonization from another. However, when closed populations become isolated due to habitat degradation or fragmentation, they become more vulnerable to locally variable conditions and environmental changes. Also, the adaptive ability of an isolated population may be decreased as the gene pool is no longer refreshed by immigration. Low dispersal ability may then lead to species extinction.

Butterflies, like many other insects, are uniquely adapted to precise, fine-scaled environmental conditions. Meeting these subtle environmental requirements, often indiscernible to the human observer, is essential to restoring habitat for butterflies in human-dominated landscapes.

The essential features of butterfly habitat are not always apparent. Many species are restricted in their resource and habitat needs, and even very closely related species may differ substantially in their biology and behavior. As the example of the Large Blue butterfly shows, intensive investigation of insect habitats and life histories can yield complex and surprising results. Few butterflies have been studied so thoroughly.

The term "plagioclimax" can be applied to a vegetation community in which natural succession is halted by continuous management such as cutting, grazing, or fire (Thomas 1995a). Most plagioclimax vegetation consists of a mosaic of microhabitats and microclimates which is essential to butterflies and other insects which are adapted to the early successional environment. Management for butterfly species which inhabit the ephemeral plagioclimax will require ongoing intervention and a continuity of habitat types in close enough proximity to allow colonization. Some butterflies may require different host plants, habitats, or microhabitats in different years or different seasons. The best breeding habitat in a wet year may be different from the best breeding habitat in a dry year, so long-term conservation of these species requires larger areas which incorporate both habitat types (Thomas 1995a).

In Britain, butterfly reserves protect portions of metapopulations and provide habitat refuges from temporarily unsuitable environmental conditions. Habitat patches can then be re-colonized from these refuges, and the creation of habitat "stepping stones" can prevent colonies from becoming isolated. The probability of recolonization of a restored area, within a given time period, is a function of the distance of the restored area from existing populations and the size of each potential source population (Thomas 1995a). It is possible to model this probability, but the accuracy of such a model depends upon knowing vital population parameters, and they are often unknown.

There are numerous instances in which butterflies have become extinct in reserves, some designed primarily for their conservation, because little or no suitable breeding habitat was created or maintained. These examples should serve as an ongoing reminder that even our best-intentioned efforts may be counterproductive if undertaken without thorough scientific study. Specialist butterfly communities can serve as sensitive indicators of vegetation structure and change, and restorations which successfully create habitat for these butterflies will result in unique sites which contribute to the preservation of regional diversity.

Literature Cited

New, T. R. 1991. Butterfly conservation. Oxford University Press, South Melbourne.

Thomas, C. D. 1995a. Ecology and conservation of butterfly metapopulations in the fragmented British landscape. Pages 46-63 in A. S. Pullin, editor. Ecology and conservation of butterflies. Chapman and Hall, London.