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Butterflies of the Southern Gulf Islands
July 26, 2023 @ 6:45 pm - 8:45 pm
At the Ag Hall and also on Zoom – participants can join Zoom from 6:45pm onwards, the presentation will begin at 7:00pm.
Everyone loves butterflies – for some they are the highlight of the summer.
Join us for a presentation by Linda Gilkeson about the 30 species of butterflies that are common to our region! Peruse a display of butterfly specimens borrowed from the Royal BC Museum.
Linda’s presentation will cover basic butterfly biology and then will go into detail on how to identify the species we are most likely to see on the Gulf Islands, including how to tell confusingly similar species apart.
Among her many teaching tools Linda has developed a presentation for participants in the Salt Spring butterfly count. The slides cover basic biology, how to identify common species and tell confusing species apart, and methods for participating in the monthly counts. Information in the slides are relevant for gardeners in coastal British Columbia and Washington and was current as of 2019.
About Linda Gilkeson. She earned a Ph.D. in Entomology from McGill University in 1986, then moved to British Columbia to work for Applied Bio-Nomics Ltd., a company that produces biological controls. From 1991 to 2002 she worked for the provincial government, promoting programs to reduce and eliminate pesticide use. She was head of the provincial State of Environment Reporting Unit for the next six years, then the Executive Director of the Salt Spring Island Conservancy until the end of 2011. Linda now devotes her time to writing, teaching and consulting.
Did you know that South-eastern Vancouver Island and the Gulf Islands have by far the highest butterfly diversity in coastal BC? Many species and varieties found in this area occur nowhere else in Canada, and several are endangered throughout their ranges. Unfortunately, local butterflies have declined greatly. The Victoria area has lost roughly twenty species, about half of its original number, since record keeping began in the late 1800’s. Most of this loss is due to historic conversion of native meadows and woodlands, first to farmland and then to residential and commercial uses.
More subtle threats come from habitat change. Many butterfly populations have disappeared even from parks and protected areas. There are several reasons for this. Many local meadows and woodlands were historically maintained by fire. In the absence of fire, these open ecosystems become closed forests and shrub thickets. Almost all of the butterflies that have disappeared from the region have herbaceous host plants, while most species whose larvae feed on shrubs and trees have persisted. Other threats include invasive plants like Scotch Broom, which transform meadows into shrub lands; trampling, which can harm larvae or reduce host plant populations; and overabundant deer, which can reduce host plant populations or ingest the larvae incidentally while eating leaves. (Yet another reason to address the Invasive Fallow Deer issue on Mayne Island).