The Prodigal Butterfly: As Butterflies Go Extinct Species by Species in the Georgia Basin, the Story of the Island Marble Gives Some Hope

Article excerpt

FOUR PRINCIPLES of ecology that I had believed since becoming a naturalist stumbled and fell to their knees when a butterfly called the island marble flew back into existence on a West Coast island not far from my own. The principles were as follows: first, extinction is forever; second, invasive species are categorically bad; third, warfare has aided few recoveries of species at risk; and four, islands are more vulnerable than mainlands.

The island marble, known scientifically by the Latin name Euchloe ausonides insulanus, is a rather blousy, blotchy white-and-green butterfly. It recently fluttered back onto the international stage and overturned my assumptions completely. Part of the Euchloe tribe, the island marble is a coastal grassland species with a penchant for mustard plants that grow in small, moist divets of sod, overturned at the appropriate time of year. It had no proper Latin name before 1998 and only a hint of identity from a handful of specimens because it had disappeared supposedly forever from the islands of the Salish Sea in 1908.

My first encounter with the ghost of that butterfly was over a decade ago. At that time, I was documenting the loss of the ecosystem that I had grown up in--the Garry oak meadows. The range of this coastal grassland in Canada includes only the rain shadow areas of the Georgia Basin or Salish Sea, as it has now come to be called. These places, like the butterfly, have had only a hint of identity over the last 100 years.

At the turn of the century, ecologists were only partly through ascribing Latin names to the thousands of meadow inhabitants; colonial artists were only just starting to paint the disappearing, ephemeral beauty of the Eden-like wild-flowers; gardeners were only just looking up to see the last patches of native diversity as they double-dug them under to plant specimens from Europe. Before contact, the meadows had a strong identity as "place of camas" in the different Salish dialects. Like Camosun (for Victoria), those names carried a cachet because two stunning blue, multiheaded lilies--Camassia quamash and Camassia leichtlinii--provided a staple food crop that the First Nations depended on so fundamentally they went to war over them.

I read about the island marble in an article by lepidopterist Crispin Guppy that described the decline of ten butterfly species from habitat destruction in these places of camas. The mysterious marble was the first species documented to have gone extinct in this ecosystem. It became the poster child of local conservation campaigns that coined the name "Garry oak meadow" to describe one of the most endangered ecosystems in Canada.

The island marble was my panda bear of the Gulf of Georgia. I wore a T-shirt that had the pattern of the marble's delicate markings silkscreened in white and green onto a black background. I believed the butterfly gone and used the case study when trying to educate school children or politicians on what extinction means in one's own backyard.

For much of the 1990s, the optimistic turnaround decade after the Rio Convention on Biodiversity, other butterflies still clinging to small patches of island habitats occupied the attention of the conservation community. I was involved in writing an ecosystem management plan to save Taylor's checkerspot in a provincial park on Hornby Island, their last stronghold. The adult checkerspots fed on the nectar of spring-gold and the native larkspur, companions to the camas, while the larvae moved between plantain species. The striking black, white and red checkerspots live up to their namesake.

Isolated subpopulations of checkerspots had been scattered through the region in Garry oak meadows. Now it was down to one last tribe. We scoured ethnographies of the Island Pentlatch people, who themselves were declared an extinct linguistic group halfway through the century, for descriptions of the camas-gathering sites. …