Butterfly conservation

Interest in butterflies used to be almost solely the domain of a relatively few amateur collectors and professional lepidopterists. But in recent years there has arisen a broader concern among the public for the conservation of butterflies and their habitats.

To date, no butterfly species found in Canada has become extinct, although a subspecies of the Large Marble (Euchloe ausonides), formerly found only on southern Vancouver Island, is now believed to be extinct. There is a growing number of butterflies of limited North American range that are considered endangered in Canada. All of these occupy ecological niches that are restricted or face huge pressures from human populations. These are mostly localized species of endangered habitats close to the U.S. border in Canada, such as virgin prairie, pine-oak barrens, and mountain valleys.

Most Canadian butterflies occupy wide ranges and are in no present danger. Over time, more species that occupy localized habitats can be expected to decline and could become threatened if habitat loss continues. In addition to threats to nationally or regionally vulnerable species, there are also local eliminations of butterfly populations. Every lepidopterist can tell of a favourite butterfly spot that has disappeared to the bulldozer. There is much less wetland now than there was a hundred years ago. Fortunately, many of our more significant wetlands are now in protected areas.

Some conservationists believe that laws to prevent the collection of butterflies are necessary to protect species. A growing number of countries have such laws and it is illegal to collect butterflies in national and provincial parks. In some cases, some protective legislation may be required, but the need to ban collecting of all species has never been demonstrated. By far the greatest danger is the steady elimination of the habitats that butterflies depend on to live and reproduce.

Why would anyone care if a butterfly species or even subspecies disappeared? Every life form has unique properties that make it an integral part of its ecosystem. When one species disappears, others, or maybe even all, could also be threatened. We are all a part of this web of life. Butterflies, because they are so noticeable, often act as a bell-wether for scientists to determine if a habitat is under threat.

Canada has, perhaps, more wilderness than any other country on this planet. But most of these large, wild areas are in the north where species diversity is relatively low. It is in the localized, threatened habitats of southern Canada where most endangered butterfly species are found, and it is these habitats in particular that need protection. Every local, provincial, or national park established will help ensure the preservation of some or many butterfly species. Every backyard planted with larval foodplants and nectar sources will help to ensure there are still butterflies to be enjoyed.

Several attempts have been made to classify butterflies found in some parts of the country as to their threatened status. Guppy et al. (1994) in British Columbia and Holmes et al. (1991) in Ontario used criteria established by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and by the Nature Conservancy (United States) for suggesting a status for species and subspecies of concern in those two provinces.

Only two provinces in Canada have attempted to protect threatened butterfly species by legislation. The West Virginia White (Pieris virginiensis) was the first butterfly placed on the Ontario Endangered Species list. However, after new, more widespread, populations were discovered it was withdrawn in 1990. Two other species from southwestern Ontario, the Frosted Elfin (Incisalia irus) and the Karner Blue (Lycaeides melissa samuelis) have recently been placed on the list, but they are probably already extirpated in the province. New Brunswick has recently placed the Maritime Ringlet (Coenonympha nipisiquit) on its "Endangered Species" list because of its very limited range and specialized habitat. The Monarch (Danaus plexippus) was placed on the list of "Vulnerable Species" in 1997 by COSEWIC because of continued habitat destruction at the overwintering sites in Mexico.

The following are the truly endangered habitats and butterfly populations in Canada. Every effort should be made to ensure their preservation.

Found only in the northeastern United States and a few isolated locations in southwestern Ontario, these sandy barrens have contained some unique butterfly species. The most notable examples are the Pinery Provincial Park and the St. Williams Forest Reserve. The Karner Blue (Lycaeides melissa samuelis) (considered endangered throughout its North American range) at both locations and the Frosted Elfin (Callophrys irus) at St. Williams have had long-standing, but unstable colonies. The larvae of both butterflies feed on wild lupines, which require periodic fires to keep the habitat open. Neither butterfly has been seen in Canada since 1991.

Fish Point Nature Reserve, Pelee Island, Ont. J. Kamstra

Like the pine-oak barrens, this habitat is found in the eastern United States, and is limited in Canada to extreme southern Ontario, where it is somewhat more widespread - from Point Pelee in the southwest to remnants north of Kingston in eastern Ontario. It is characterized by tree species such as the Tulip-tree (Liriodendron tulipifera) and the Black Oak (Quercus velutina). Agriculture has eliminated almost all of these woodlands. Butterfly species in Canada limited to Carolinian woodlands include the Giant Swallowtail (Papilio cresphontes) and the Spicebush Swallowtail (P. troilus). Hackberry-feeding butterflies, such as the American Snout (Libytheana carinenta) and the Hackberry Emperor (Asterocampa celtis) are also mainly limited to this habitat in Canada. Significant stands of Carolinian woodlands in Canada are found in Point Pelee National Park and Rondeau Provincial Park.

Near Medicine Hat, Alta. J.D. Lafontaine

This is an endangered habitat throughout central North America where settlers ploughed up the prairie for growing crops. Only an estimated few per cent of the original habitat is still left. In western Canada, it occurs in a few scattered locations in southern Manitoba, for example near Lundar. Some prairie butterflies, including the Dakota Skipper (Hesperia dacotae), Poweshiek Skipperling (Oarisma poweshiek), and the Regal Fritillary (Speyeria idalia ), are limited to this habitat and are considered threatened species throughout their range. There are also a few outlying prairie remnants in extreme southwestern Ontario, particularly on Walpole Island and the Ojibway Prairie near Windsor.

This specialized habitat exists in Canada only in the lower Fraser Valley, on southern Vancouver Island, and on adjacent Gulf Islands in the Georgia Strait. There are nine butterfly subspecies localized to this habitat that are now considered extinct, endangered, or vulnerable in Canada because of urbanization, industrialization, or agriculture. Although Garry Oaks still exist widely as ornamental trees, the open meadows and grassy knolls associated with the trees and important to the butterflies are disappearing. One of these restricted subspecies, an unnamed subspecies of the Large Marble (Euchloe ausonides) is now considered globally extinct, while a subspecies of Edith's Checkerspot (Euphydryas editha taylori) and the vulnerable nominate subspecies of Moss's Elfin (Callophrys mossii mossii) are considered endangered in Canada. For an in-depth analysis of the conservation status of the butterflies of this and other threatened habitats in British Columbia see Guppy et al., 1994

The dry, desert-like valley bottoms of the southern interior of British Columbia are home to a variety of unique and now endangered butterflies in Canada. Many species reach their northern limit here, and the lands are now being rapidly developed, especially the Okanagan and Similkameen Valleys. Some butterflies in particular danger are the Mormon Metalmark (Apodemia mormo), Behr's Hairstreak (Satyrium behrii), and Sooty Hairstreak (S. fuliginosum).

In addition to habitat loss, the widespread use of insecticides also has a major negative effect on butterfly populations. DDT, before it was banned, had a large, but difficult to quantify, impact on butterfly numbers. Aerial spraying to control the Gypsy Moth kills off many caterpillars of harmless species. During the 1970s the use of BT (Bacillus thuringiensis, a biological agent) to control the Gypsy Moth in eastern Ontario, where isolated populations of butterfly species such as the West Virginia White (Pieris virginiensis) and the Eastern Tiger Swallowtail (Papilio glaucus) live, seriously depleted butterfly populations.

However, butterflies do have many friends. Naturalists across the country have organized to preserve habitats and even enhance degraded habitats to bring back butterflies. An example is the establishment of a butterfly meadow at the Fletcher Wildlife Garden in Ottawa, where once only grass grew. Now female Black Swallowtails (Papilio polyxenes) and Monarchs (Danaus plexippus) lay their eggs on the garden plants.

An organization called the Xerces Society has been established to help preserve the world's invertebrates, including butterflies. It got its name from the Xerces Blue butterfly (Glaucopsyche xerces) that went extinct in the San Francisco area in the middle of this century. The Society now has many Canadian members.

>Reproduced with permission from The Butterflies of Canada by Ross A. Layberry, Peter W. Hall, and J. Donald Lafontaine. University of Toronto Press; 1998. Specimen photos courtesy of John T. Fowler. The Toronto Entomologists' Association thanks Agriculture and Agri-Food Canada for providing the content and computer code for this web page.