Surveys for Bremner’s Fritillary Speyeria zerene bremnerii

Surveys for Bremner’s Fritillary (Speyeria zerene bremnerii) on

Salt Spring, Mayne and Galiano Islands, British Columbia, 2009

Report Citation: Parkinson, L., S.A.Blanchette and J. Heron. 2009. Surveys for Bremner’s Fritillary (Speyeria zerene bremnerii) on Salt Spring, Mayne and Galiano Islands, British Columbia, 2009. B.C. Ministry of Environment, Ecosystems Branch, Wildlife Science Section, Vancouver, B.C. Cover Illustration: Bremner’s Fritillary (Speyeria zerene bremnerii), July 28 2009, Mt. Tuam on Salt Spring Island. Photo by Sophie-Anne Blanchette. Content and photographs may be used without permission, with appropriate credit to the photographer and this report. Contact Information for Report: Jennifer Heron, Invertebrate Specialist, B.C. Ministry of Environment, Ecosystems Branch, Wildlife Science Section, 316 – 2202 Main Mall, Vancouver, B.C., Canada, V6T 1Z1. Phone: 604-222-6759. Email: [email protected]

Surveys for Bremner’s Fritillary (Speyeria zerene bremnerii) on Salt Spring, Mayne and Galiano Islands, B.C., July 2009 iii

1. Acknowledgements Fieldwork was conducted Laura Parkinson and Sophie-Anne Blanchette, B.C. Conservation Corps Invertebrate Species at Risk Crew (butterfly surveys; larval surveys) and Jennifer Heron (larval surveys). Jennifer Heron provided maps, guidance and supervision for this project. Fieldwork on Denman Island was conducted by Laura Parkinson, Sophie-Anne Blanchette, Jennifer Heron, and Suzie Lavallee. Local conservancy groups are an invaluable resource and contributed greatly to the success of this project. Thank you to Robin Annschild from Salt Spring Island Conservancy for providing maps and advice on Bremner’s Fritillary habitat. Thank you to Micheal Dunn from the Mayne Island Conservancy for advising on potential habitat for Bremner’s Fritillary and helping us with surveys. Thank you to the Galiano Island Conservancy: Kenn Millard, Tyla Crowe and Pauline BrestvanKenten for providing support in the field and advising on potential habitat for Bremner’s Fritillary. Funding for this project is from the B.C. Conservation Corps Program (Ben Finkelstein, Manager and Bianka Sawicz, Program Coordinator) and the B.C. Ministry of Environment Wildlife Science Section (Alec Dale, Manager) and Conservation Framework Funding (James Quayle, Manager). The program was administered by the British Columbia Conservation Foundation (BCCF). Joanne Neilson (BCCF) provided tremendous help and support. This project was links with and was partially funded by the federal Habitat Stewardship Program. Thank you to Brenda Costanzo (B.C. Ministry of Environment) for providing background information on plants and vegetation characteristics for butterflies on the Gulf Islands. A big thank-you to Crispin Guppy for sharing his theory on a separate subspecies of Zerene Fritillary on Northern Vancouver Island and information on previous records for Bremner’s Fritillary. B.C. Conservation Data Centre also provided previous records and location information for Bremner’s Fritillary and other butterfly species at risk. Thanks to everyone who identified specimens collected opportunistically. Rex Kenner from the University of British Columbia Beaty Biodiversity Museum identified aquatic beetles. James Miskelly identified grasshoppers (Orthoptera). Rob Cannings from the Royal British Columbia Museum identified some terrestrial insects collected by hand. Kristiina Ovaska identified terrestrial gastropods and Kristiina Ovaska and Lennart Sopuck identified aquatic molluscs. Survey information from this project was sent to the B.C. Conservation Data Centre and provincial Wildlife Species Inventory warehouse. Specimens collected are deposited with the Beaty Biodiversity Museum Spencer Entomological Collection at the University of British Columbia, Vancouver (Karen Needham, Curator) and at the Royal British Columbia Museum, Victoria (Claudia Copley, Collections Manager).

Surveys for Bremner’s Fritillary (Speyeria zerene bremnerii) on Salt Spring, Mayne and Galiano Islands, B.C., July 2009 iv

Photographs in this report were taken by Laura Parkinson, Sophie-Anne Blanchette and Jennifer Heron.

2. Executive Summary Bremner’s Fritillary (Speyeria zerene bremnerii) is a large, charismatic orange and black butterfly, a subspecies of the zerene fritillary (Speyeria zerene). In British Columbia (B.C.), there are records of Bremner’s Fritillary from southern Vancouver Island and Salt Spring Island and from a few old records from the lower mainland. Bremner’s Fritillary is red-listed by the B.C. Conservation Data Centre (2009), a global rank of G5T3T4 (Natureserve, 2009) and is currently awaiting assessment by COSEWIC (2009). This survey was initiated to gain more information on the biology and range extent of Bremner’s Fritillary on the Gulf Islands. Nine days of surveys targeting Bremner’s Fritillary habitat were completed during July and August, 2009. The geographic area surveyed focused on Salt Spring, Mayne and Galiano Islands. Habitats targeted for surveys included sites where Bremner’s Fritillary had previously been recorded (Mt. Tuam, Salt Spring Island), as well as Garry Oak and exposed ridge habitats on Galiano and Mayne Islands. All butterfly observations were recorded. During surveys for Bremner’s Fritillary, incidental observations and collections of non-target invertebrates were also completed. Results from these surveys are also within this report. Eleven butterfly species were observed during this survey. Two species of conservation concern were recorded, the target species, Bremner’s Fritillary, and the Common Wood Nymph (Cercyonis pegala incana). At least seventeen Bremner’s Fritillary adults were observed at Mt. Tuam on Salt Spring Island, but at no other locations. Individuals were observed flying in groups near the suspected potential host plant, montane violet (Viola praemorsa spp. Praemorsa) and thistles (Cirsium spp.), a potential food source. Habitats where Bremner’s Fritillary was observed include a Garry oak meadow at the peak of Mt. Tuam on Salt Spring Island, and a regenerating clearcut adjacent to the road leading up to the peak of Mt. Tuam. Future inventory should focus on Garry Oak and other natural meadows where violet species occur on the Gulf Islands and Southern Vancouver Island.

Table of Contents

1. Acknowledgements ...................................................................................................................................... iii

2. Executive Summary ........................................................................................................................................ v

3. Introduction ...................................................................................................................................................... 9

4. Background Information ............................................................................................................................. 11

5. Survey Area .................................................................................................................................................... 13 Salt Spring Island.................................................................................................................................................... 14 Mayne Island .......................................................................................................................................................... 17 Galiano Island ........................................................................................................................................................ 17

6. Methods ........................................................................................................................................................... 19 Field Surveys .......................................................................................................................................................... 19 Pitfall Traps ............................................................................................................................................................ 20 Hand-searching for other terrestrial invertebrates ................................................................................................ 21 Denman Island ........................................................................................................................................................ 21

7. Results ............................................................................................................................................................. 22

8. Bremner’s Fritillary Observations ............................................................................................................. 23 Mt. Tuam, Salt Spring Island .................................................................................................................................. 23

9. Common Wood Nymph (Cercyonis pegala incana) Observations.................................................... 25

10. Other Butterfly Observations ................................................................................................................ 25 Hydaspe Fritillary (Speyeria zerene hydaspe) ........................................................................................................ 25 Woodland skipper (Ochlodes sylvanoides) ............................................................................................................. 27 Mylitta crescent (Phycoides mylitta) ....................................................................................................................... 27 Lorquin’s Admiral (Limentus lorquini) ................................................................................................................... 27 Grey hairstreak (Strymon melinus) ......................................................................................................................... 27 Pine white (Neophasia menapia) ............................................................................................................................ 28 Cabbage white (Pieris rapae) ................................................................................................................................. 28 Painted lady (Vanessa cardui) ................................................................................................................................ 28

11. Other Invertebrate Observations .......................................................................................................... 29 Pitfall Traps ............................................................................................................................................................ 29 Hand Collected Terrestrial Invertebrates ............................................................................................................... 29

12. Discussion ................................................................................................................................................. 32

13. Recommendations for future surveys ................................................................................................ 34

14. References ................................................................................................................................................. 35

15. Appendix 1 ................................................................................................................................................. 37

16. Appendix 2 ................................................................................................................................................. 41

17. Appendix 3 ................................................................................................................................................. 41 List of Tables Table 1: Summary of Butterfly Observations (June 16-23, 2009) ...................................... 23 Table 2: Bremner’s Fritillary Observations at Mt. Tuam, Salt Spring Island, July 28 – 29,

2009...................................................................................................................................... 24 Table 3: Invertebrates identifed from pitfall traps installed on Mt. Maxwell, collected on

June 20, 2009 ..................................................................................................................... 29 Table 4: Terrestrial gastropods collected opportunistically from Salt Spring, Mayne and

Galiano Islands, 2009. Identifications confirmed by Kristiina Ovaska. ...................... 30 Table 5: Terrestrial insects collected opportunistically from Salt Spring and Galiano

Islands, as identified by Rob Cannings .......................................................................... 30 List of Figures and Photographs Figure 1: Montane violet (Viola praemorsa spp. praemorsa), a potential Bremner’s

Fritillary larval host plant on Mt. Tuam on May 12 2009. Photo by Laura Parkinson................................................................................................................................................ 12

Figure 2: Transects of habitat surveyd for Bremner’s Fritillary on Salt Spring, Mayne and Galiano Islands (dotted lines). .......................................................................................... 13

Figure 3: Early Blue Violet (Viola adunca) on Mt. Tuam, Salt Spring Island, May 12, 2009. Photo by Jennifer Heron. ....................................................................................... 15

Figure 4: Early Blue Violet (Viola adunca) on Mt. Tuam, Salt Spring Island, May 12, 2009. Photo by Jennifer Heron. ....................................................................................... 15

Figure 5: The slopes of Mt. Tuam on Salt Spring Island with domestic sheep in the background, July 29, 2009. Photo by Sophie-Anne Blanchette. ................................ 15

Figure 6: Regenerating clearcut adjacent to the road leading up to Mt. Tuam on Salt Spring Island, July 28, 2009. Photo by Sophie Anne Blanchette. .............................. 15

Figure 7: Small patches of vegetation on Mt. Tuam containing montane violets is protected from sheep grazing in exclosures, May 13, 2009. Photo by Jennifer Heron.................................................................................................................................... 16

Figure 8: Mt. Maxwell Ecological Reserve on Salt Spring Island, May 13, 2009. Photo by Sophie-Anne Blanchette. .................................................................................................. 16

Figure 9: Large area on Mt. Maxwell Ecological Reserve on Salt Spring Island gated to exclude feral sheep and/or goats, May 13, 2009. Photo by Jennifer Heron. ............ 16

Figure 10: Slope with Garry oaks in Henderson Park on Mayne Island, August 1, 2009. Photo by Laura Parkinson. ............................................................................................... 17

Figure 11: Bodega Ridge on Galiano Island, August 3 2009. Photos by Laura Parkinson. ............................................................................................................................ 18

Figure 12: Garry Oak habitat on slopes near the peak of Mt. Sutil on Galiano Island, August 4 2009. Photos by Laura Parkinson .................................................................. 18

Figure 14: Potential Bremner’s Fritillary larvae found at the base of Viola adunca. on Mt. Tuam on May 12, 2009. Photo by Laura Parkinson. Specimens were collected and will be sent to an expert for verification. ......................................................................... 22

Figure 15: Photos of Bremner’s Fritillary ventral and dorsal views taken on Mt. Tuam on Salt Spring Island on July 28 2009. Photos by Sophie-Anne Blanchette. ................ 24

Figure 16: Hydaspe Fritillary (ventral view) taken on the road up to Mt. Tuam on Salt Spring Island on July 28 2009. Photo by Sophie-Anne Blanchette ............................ 26

Figure 17: Comparison of dorsal view of Hydaspe (bottom) and Bremner’s (top) Fritillary taken on the road up to Mt. Tuam on Salt Spring Island on July 28 2009. Photo by Sophie-Anne Blanchette. .................................................................................................. 26

Figure 18: View from the parking area on the peak of Mt. Tuam May 12 2009. Photo by Laura Parkinson. ................................................................................................................ 26

Introduction

3. Introduction Bremner’s Fritillary (Speyeria zerene bremnerii) is a large, charismatic orange and black butterfly. It is one of several subspecies of the zerene fritillary, which is the most variable fritillary species found in British Columbia. Zerene Fritillary is globally distributed from the Alaska Panhandle across southern B.C. east to southwestern Saskatchewan and as far south as central Utah, Nevada, California and New Mexico (Guppy and Shepard, 2001). Bremner’s Fritillary has a global distribution through the Willammette Valley in Oregon, the San Juan Islands and Puget Trough in Washington, and Salt Spring Island and Vancouver Island in British Columbia (B.C.). Bremner’s Fritillary is red listed in B.C. (B.C. Conservation Data Centre, 2009) due to the small number of occurrences and limited distribution in the province. Its global conservation status rank is G5T3T4 (globally secure but locally vunerable to extirpation) (Natureserve, 2009). At the national level Bremner’s Fritillary has not been assesed by COSEWIC, although the subspecies is considered a priority for status assessment (COSEWIC 2009). In B.C. Bremner’s Fritillary records are known from east coast of Vancouver Island and Salt Spring Island. The B.C. Conservation Data Center has records of occurrences of Bremner’s fritillary north of Port Alice, and on Mt. Arrowsmith south of Cameron Lake on Vancouver Island. Other than one current population known on Mt. Tuam on Salt Spring Island, there are no other records of Bremner’s Fritillary occurrences on the Gulf Islands (B.C. Conservation Data Center, 2009). There are also Bremner’s Fritillary records from near Campbell River on Vancouver Island and a few older records from the Lower Mainland. Zerene Fritillaries observed north of Campbell River may have both genetic and morphological differences (they are smaller and darker in colour) in comparison to individuals observed from Salt Spring Island and Cameron Lake (C. Guppy, pers. comm., 2009). Zerene Fritillaries from Northern Vancouver Island may be a separate subspecies of Zerene Fritillary from those at Cameron Lake and on Salt Spring Island. A description of this new subspecies of Zerene Fritillary is pending (C. Guppy, pers. comm., 2009). Thus, the distribution of Bremner’s Fritillary in B.C. may be even more limited than previously believed. No other currently described subspecies of the zerene fritillary are found within the range of Bremner’s Fritillary (Guppy and Shepard, 2001). The only similar species that occurs within the range of Bremner’s Fritillary is Hydaspe Fritillary (Speyeria hydaspe). Few recent surveys for Bremner’s Fritillary on the Gulf Islands have been conducted. Salt Spring Island Conservancy completed limited surveys on Mt. Tuam in previous years and observed individuals flying on July 4th and in greater numbers on July 17th, 2009 (R. Annschild, 2009). The Mayne Island Conservancy and Galiano Island Conservancy are not aware of any previous surveys conducted for Bremner’s Fritillary nor have these conservancies led surveys targeting this species habitat.

Introduction

The B.C. Conservation Corps Invertebrate Species at Risk Crew conducted surveys for Bremner’s Fritillary on Mayne Island, Salt Spring Island and Galiano Island on July 28th – August 5th, 2009 (Figure 12). The objectives of this survey are to:

1) Survey potentially suitable habitats for Bremner’s Fritillary on the borders of the species known range in the Gulf Islands

2) Gain information on the habitat preferences and life history of Bremner’s Fritillary 3) Survey opportunistically for other insects at risk in endangered ecosystems such

as Garry Oak and sand dune habitats on the Gulf Islands using pitfall traps and by hand searching

Background Information

4. Background Information Bremner’s Fritillary is a large, conspicuous butterfly with a wing span of 5 - 6 cm. The species’ dorsal wing colouration is orange with black spots and markings. The ventral hindwing is a reddish brown colour with silver spots. The majority of the ventral forewing is pale orange and black, except the upper outer tip which is a reddish brown (Figure 13). Bremner’s Fritillary flies from early July to late August with one generation per year (Guppy and Shepard, 2001). The host plant for Bremner’s Fritillary is unknown, although the suspected host plants include montane violet (Viola praemorsa spp. praemorsa) (Figure 1) and other Viola spp. (Guppy and Shepard, 2001). Eggs are laid at the base of a violet plant during the flight season. Larvae hatch in August, overwinter in the leaf litter or at the base of the plant and begin feeding on its leaves the following spring (Guppy and Shepard, 2001). Montane violet is a rare plant known in Canada from few locations on southeastern Vancouver Island and the Gulf Islands. Canadian populations of the Montane Violet are known to occur only in Garry oak meadows, a rare and endangered ecosystem (Garry Oak Ecosystems Recovery Team, 2003). Montane Violet is listed as endangered by COSEWIC (COSEWIC, 2007) and red listed in B.C. (B.C. Conservation Data Centre, 2009). Occurrences are known from a few sites in the Victoria, Saanich, and Duncan areas and Mt. Tuam and Mt. Maxwell on Salt Spring Island (B.C. Conservation Data Center, 2009). Bremner’s Fritillary habitat includes Garry oak and associated ecosystems, open wet meadows, clearings and forest openings. The species is known to occur on hilltops and exposed windy peaks at elevations under 600m (B.C. Conservation Data Centre, 2009). A suspected decline in overall butterfly diversity has been anecdotally observed on the Gulf Islands in recent decades. A major cause of this decline is the loss of habitat, particulary open areas and meadows required by Bremner’s Fritillary and other butterflies, either to development or to alteration by fire suppression and invasive plants, which results in the loss of native food plants (Baron and Backhouse, 1999). Scotch broom (Cytisus scoparius) has become widespread on the Gulf Islands and Vancouver Island and has invaded the Garry Oak ecosystems on these islands.

Background Information

Figure 1: Montane violet (Viola praemorsa spp. praemorsa), a potential Bremner’s Fritillary larval host plant on Mt. Tuam on May 12 2009. Photo by Laura Parkinson.

Survey Area

5. Survey Area Surveys for Bremner’s Fritillary were conducted on Salt Spring, Mayne and Galiano Islands between July 28 and August 5, 2009 (Figure 2).

Figure 2: Transects of habitat surveyd for Bremner’s Fritillary on Salt Spring, Mayne and Galiano Islands (dotted lines).

Survey Area

Salt Spring Island Potential habitat for Bremner’s Fritillary on Salt Spring Island was surveyed for adults from July 28-30, 2009. Two sites were surveyed: Mt. Tuam and Mt. Maxwell. Mt. Tuam is a provincial Ecological Reserve, combined with federally owned property and private lands. Several patches of montane violet (Figure 1) and the more common early blue violet (Viola adunca) (Figure 2 – 3) are known to occur around the peak and surrounding slopes of Mt. Tuam. The peak and slopes of Mt. Tuam consist of open Garry oak meadows on rocky slopes interspersed with plateaus. There are some feral sheep that graze these meadows (Figure 4), and there is currently a study occurring on the effects of sheep grazing on vegetation that compares plant diversity in exclosures with that of unprotected areas (R. Annschild, pers. comm., 2009). As a result some (but not all) patches of montane violets are protected from sheep grazing within exclosures (Figure 6). Grazing by sheep may be responsible for the lack of scotch broom observed on the slopes and peak of Mt. Tuam (R. Annschild, pers. comm., 2009). The forest service road leading up to Mt. Tuam was also surveyed for Bremner’s Fritillary; it consists of regenerating clearcut containing patches of thistle (Figure 5). This is approximately 2 km of road leading up to the peak, which is gated and branches off from the main road. Mt. Maxwell is located on the west coast of Salt Spring Island overlooking the Georgia Straight. The peak and some surrounding area including old-growth Douglas fir stands are designated as Mt. Maxwell Provincial Park. Surveys were conducted in the adjacent provincial Mt. Maxwell Ecological Reserve. This area was designated as a reserve in part to protect the Garry oak ecosystems found on Mt. Maxwell’s slopes. These dry, rocky, steep west facing slopes are interspersed with plateaus and represent relatively extensive Garry oak meadows (Figure 7). Although there are some invasive plants in the reserve, there are also some rare native plants, including the montane violet, and the meadows appear relatively intact. In the past, Mt. Maxwell was grazed by feral goats (R. Annschild, pers. comm., 2009). A large area of the reserve is now fenced in to keep out feral goats and sheep (Figure 8).

Survey Area

Figure 3: Early Blue Violet (Viola adunca) on Mt. Tuam, Salt Spring Island, May 12, 2009. Photo by Jennifer Heron.

Figure 4: Early Blue Violet (Viola adunca) on Mt. Tuam, Salt Spring Island, May 12, 2009. Photo by Jennifer Heron.

Figure 5: The slopes of Mt. Tuam on Salt Spring Island with domestic sheep in the background, July 29, 2009. Photo by Sophie-Anne Blanchette.

Figure 6: Regenerating clearcut adjacent to the road leading up to Mt. Tuam on Salt Spring Island, July 28, 2009. Photo by Sophie Anne Blanchette.

Survey Area

Figure 7: Small patches of vegetation on Mt. Tuam containing montane violets is protected from sheep grazing in exclosures, May 13, 2009. Photo by Jennifer Heron.

Figure 8: Mt. Maxwell Ecological Reserve on Salt Spring Island, May 13, 2009. Photo by Sophie-Anne Blanchette.

Figure 9: Large area on Mt. Maxwell Ecological Reserve on Salt Spring Island gated to exclude feral sheep and/or goats, May 13, 2009. Photo by Jennifer Heron.

Survey Area

Mayne Island Potential habitat for Bremner’s Fritillary on Mayne Island was surveyed from July 31-August 2, 2009. Sites surveyed for Bremner’s Fritillary were restricted to two parks; Mounte Parke and Henderson Park. Mounte Park consists of a mostly forested ridge with some natural openings along the ridge and slopes. Henderson Park consists of some Garry oak habitat along a slope and an adjacent regenerating clearcut (Figure 9). Scotch broom appears to be thriving at both sites.

Figure 10: Slope with Garry oaks in Henderson Park on Mayne Island, August 1, 2009. Photo by Laura Parkinson.

Galiano Island Potential habitat for Bremner’s Fritillary on Galiano Island was searched August 3 – 5, 2009. On Galiano Island, surveys for Bremner’s Fritillary were conducted on Bodega Ridge and Mt. Sutil. Bodega Ridge is a relatively open ridge with Garry oak habitat occurring on steep west facing slopes above a coastal Douglas fir (Pseudotsuga menziesii var. menziesii) forested area (Figure 10). Surveys on Mt. Sutil were conducted in a large expanse of Garry oak meadow on the peak and along the south facing slopes above a forested area (Figure 11). Mt. Sutil is considered to be a relatively intact and undisturbed Garry oak ecosystem and includes many of the native plants known to occur in Garry oak ecostysems. Although there is substantial Scotch broom (Cytisus scoparius) encroachment at both sites, the conservancy is executing some manual removal of Scotch broom as part of ongoing site management (K. Millard, pers. comm., 2009).

Survey Area

Other surveys on Galiano Island occurred in the heritage forest, focusing on an area regenerating from fire, open areas along Bodega Beach road and near Laughlin Lake. Although none of these areas were optimal habitat for Bremner’s Fritillary they were chosen for survey because they were relatively open sites with some flowers for foraging (due to hot and dry conditions there were very few flowers in Garry oak sites), and for the purpose of general butterfly surveys. Bodega Beach drive is a relatively open road near the coast, which was the only site on Galiano Island where blooming flowers were observed in abundance, although these represented mostly weedy species with relatively low overall diversity.

Figure 11: Bodega Ridge on Galiano Island, August 3 2009. Photos by Laura Parkinson.

Figure 12: Garry Oak habitat on slopes near the peak of Mt. Sutil on Galiano Island, August 4 2009. Photos by Laura Parkinson

Methods

6. Methods Potential habitat surveyed for Bremner’s Fritillary included Garry oak meadows and natural and disturbed forest openings, ideally containing violets. Meadows or open areas located on hilltops, ridges or slopes were targeted as Bremner’s Fritillary typically migrate upslope (Acorn and Sheldon, 2006; Guppy and Shepard, 2001). Disturbed areas, such as regenerating clear cuts with lots of flowers for forage were also surveyed. Permission to access private land was facilitated by representatives from the local conservancy groups.

Field Surveys Using the habitat search image described above, survey sites were suggested and access was facilitated by local conservancy groups. On May 12th, before the flight season of Bremner’s Fritillary, hand searches for larvae were conducted on Mt. Tuam. This entailed searching at the base of early blue violets (Figure 2, Figure 3) just below the soil surface for larvae. Montane violets were not searched for larvae to avoid causing damage or disturbance to these rare plants; they are also legally protected on crown land by the federal Species at Risk Act. Surveys for Bremner’s Fritillary adults were conducted July 28-31 on Salt Spring Island, August 1-3 on Mayne Island and August 3-5 on Galiano Island. Surveys occurred from 9:00 to 17:00 during the species’ flight period (early July - late August). Although surveys prioritized Bremner’s Fritillary habitat, all butterflies were recorded as incidental observations (see Appendix 1). Surveys were conducted by the B.C. Conservation Corps Invertebrate Species at Risk crew: two people completing wandering transects through potential habitat. Wandering transects follow no set transects, pre-determined grid, or fixed route and allow the surveyor to change course depending on habitat suitability. Wandering transects are an efficient method of determining butterfly presence when little information is available. Wandering transects were recorded as tracks using a Garmin handheld GPS (geographic positioning system) unit. When butterflies were observed (including incidental observations), the following information was recorded: 1) butterfly species and number of individuals observed; 2) point location using GPS handheld device (accuracy within 10m); 3) general weather comments; 4) general location description. Butterflies were identified by sight when possible. A net was used to capture individuals and confirm identification using field guides when it was not possible to identify the species in flight, as well as to photograph specimens. Attempts were made to capture all fritillaries observed, as it is difficult to distinguish Bremner’s Fritillary from Hydaspe

Methods

Fritillary, which is similar in appearance. Bremner’s Fritillary is distinguished from Hydaspe Fritillary by the noticeably paler post-medial line on the ventral hindwing, redder and warmer brown colouration on ventral hindwing compared to the darker brown colouration of the Hydaspe fritillary (Figure 14, Figure 15), slightly larger overall size and less black colouration overall on the dorsal wings (Figure 16). Two Bremner’s Fritillary and three Hydaspe Fritillary specimens were taken and specimens deposited at the Beaty Biodiversity Museum Spencer Entomological Collection at the University of British Columbia. Due to limited field time sites were only visited once (with the exception of Mounte Parke and Henderson Park on Mayne Island which were visited three times each) with a minimum search time of fifteen minutes at the site. Most sites were searched for longer.

Individuals were identified using Butterflies of British Columbia (Acorn and Sheldon, 2006.

Pitfall Traps Fifteen pitfall traps were installed in Mt. Maxwell on Salt Spring Island on May 13th and collected and deactivated on June 20th. Six pitfall traps were also installed on Mayne Island in Henderson Park and Mount Parke on August 1st and collected and deactivated August 2nd (see Appendix 2 for pitfall trap locations). The purpose of the pit fall traps was to opportunistically investigate the species composition of ground dwelling insects found in these Garry oak ecosystems. Installation entailed digging a shallow hole so that a plastic cup placed inside would be level with the soil. The cup was then filled approximately half full with non-toxic propylene glycol to preserve insects that fall into the cup. A cardboard covering with a brief explanation of the trap and contact information was placed over the cup (slightly elevated on sticks or rocks) to prevent rainfall and other debris from accumulating in the trap. Contents of the traps were collected when traps were deactivated. All animals in the traps were preserved in 95% ethanol. All parts of the trap were removed from sites and holes were filled in to minimize disturbance to the sites. The contents of the pitfall traps were coarsely sorted in the lab and separated by Subphylum, Order or Family into the following groups: Vertebrata (vertebrates) Isopoda (pill bugs) Gastropoda (slugs and snails) Araneae (spiders) Chilopoda and Diplopoda (Centipedes and Millipedes) Hymenoptera (bees and wasps – not including ants) Formicidae (ants) Hemiptera (true bugs)

Methods

Coleoptera (beetles – not including Silphidae) Silphidae (carrion beetles) Orthoptera (grasshoppers and crickets) Diptera (flies) Other Insects (termites, earwigs, other miscellanaeous insects) All traps from Mt. Maxwell were pooled together and all traps from Mayne Island were pooled together. Groups of invertebrates were sent to their respective experts for identification.

Hand-searching for other terrestrial invertebrates During butterfly surveys other terrestrial insects and gastropods were collected opportunistically by hand or using the butterfly net and stored in vials in 95% ethanol. Although several different families were collected, the bias was towards collecting beetles (Coleoptera), particularly Tiger Beetles (sub-family Cicindelinae) and Lady Beetles (Coccinellidae), and grasshoppers (Orthoptera). Some sandy habitats on Mayne and Galiano Islands (as advised by conservancy representatives) were hand searched specifically targeting beetles.

Denman Island Incidental aquatic and terrestrial insects and gastropods collected from Denman Island during surveys for Taylor’s Checkerspot (Euphydryas editha taylori) are also included in this report. Terrestrial invertebrates were collected opportunistically during butterfly surveys conducted between May 19 and June 6 2009. Butterfly surveys were conducted within large regenerating clearcuts that occupy approximately ¼ of the area on northern Denman Island. They contain small patches of forest and scattered trees. Aquatic Surveys Aquatic sampling was conducted opportunistically at Graham Lake on Denman Island on June 2, 2009, and also in a marshy area adjacent to a small lake on June 4, 2009. Samples were collected using aquatic sampling round-rimmed dip nets, which were used to scrape the top soft layer of sediment at a depth of up to approximately 1.25 m along the shore of small lakes, roadside marshes and swampy areas. The sediment in the net was then sifted through and any aquatic molluscs or insects observed were collected. Specimens were preserved in vials in 95% ethanol. Specimens were sent to experts for identification. Sampling was conducted along accessible shoreline.

Results

7. Results Combined search results for surveys on Salt Spring, Mayne and Galiano Islands totalled 237 butterflies representing at least eleven different species (some butterflies were identified only to genera) (Table 1, Appendix). Two red listed species were found on Salt Spring Island: 17 individuals of the target species Bremner’s Fritillary on Mt. Tuam and one Common wood Nymph, incana subspecies (Cercyonis pegala incana) on Mt. Maxwell. One introduced species, Cabbage White, was also observed on Mt. Tuam and at Laughlin Lake on Galiano Island. A total of sixty hours (3594 minutes) was spent surveying potential habitat for Bremner’s Fritillary in the 15 different sites on Salt Spring, Mayne and Galiano Islands. A total distance covering 59.2 km of transects was surveyed over nine days. Time spent surveying was maximized for sites with suitable habitat and minimized for sites with marginal habitat (minimum fifteen minutes at each site; see potential habitat description above). Surveys for Bremner’s Fritillary larvae were conducted on Mt. Tuam on May 12. Approximately 300 early blue violet (Figure 2, Figure 3) plants were searched for larvae for approximately 7.5 hours (three people searching for 2.5 hours). Larvae were only found and collected at the base of two plants (Figure 13). Identification of the larvae by an expert is pending.

Figure 13: Potential Bremner’s Fritillary larvae found at the base of Viola adunca. on Mt.

Results

Tuam on May 12, 2009. Photo by Laura Parkinson. Specimens were collected and will be sent to an expert for verification.

Table 1: Summary of Butterfly Observations (June 16-23, 2009)

Common

Name

Scientific Name

Conservation Status Rank* Number

Observed British

Columbia Provincial Global

Bremner’s Fritillary

Speyeria zerene bremnerii Red listed S2 G5T3T4 17

Hydaspe Fritillary

Speyeria zerene hydaspe Yellow listed S4S5 G4G5 7

Unknown Fritillary**

Speyeria zerene spp. 41

Lorquin's Admiral Limenitus lorquini Yellow listed S5 G5 5 Mylitta Cresent Phycoides mylitta Yellow listed S5 G5 17

Pine White Neophasia menapia Yellow listed S5 G5 2

Common Woodnymph

Cercyonis pegala incana Red listed S2 G5T3T4 1

Cabbage White Pieris rapae Exotic NA G5 2 Painted Lady Vanessa cardui Yellow listed S5 G5 1 Grey Hairstreak Strymon melinus Yellow listed S5 G5 4 Woodland Skipper

Ochlodes sylvanoides Yellow listed S5 G5 138

Unknown skipper 1 Unknown Anglewing Polygonia sp. 1 Unknown Lady Vanessa sp. 1

* See BC Conservation Data Center and NatureServe for explanation of rankings systems ** Unknown fritillary observations are either Bremner’s Fritillary or Hydaspe Fritillary.

8. Bremner’s Fritillary Observations

Mt. Tuam, Salt Spring Island Mt. Tuam was surveyed for Bremner’s Fritillary on July 28th and 29th 2009 in hot and hazy weather with temperatures of >30 C. Transects occurred in open meadows at the peak of Mt. Tuam and in Garry oak meadows on south facing slopes, adjacent to forested areas. Survey efforts were focused near known patches of montane violet and other violet species. Transects were also completed along the forest service road leading up to the peak of Mt. Tuam, which is adjacent to regenerating clearcut.

Results

Bremner’s Fritillaries were observed congregating near thistle patches (species unknown), both along the road leading up to Mt. Tuam and within the Garry oak meadow on the slopes of Mt. Tuam at between 464 and 575 m elevation (Figure 14, Table 2). At at least three separate thistle patches, five or more fritillaries (either Bremner’s or Hydaspe) were observed, with at least one positively identified as a Bremner’s Fritillary. Several individuals were observed perching on thistle flowers.The only other observation of a group of fritillaries of this size was near a patch of montane violet, a suspected host plant of this species. Other Bremner’s Fritillary observations consisted of one or two individuals flying along the road or in open Garry oak areas at the peak and on the slopes of Mt. Tuam. One Bremner’s Fritillary seen on the road leading up to Mt. Tuam was observed dipping its abdomen in a puddle several times.

Figure 14: Photos of Bremner’s Fritillary ventral and dorsal views taken on Mt. Tuam on Salt Spring Island on July 28 2009. Photos by Sophie-Anne Blanchette.

Table 2: Bremner’s Fritillary Observations at Mt. Tuam, Salt Spring Island, July 28 – 29, 2009.

Number Observed Date

UTM Zone 10U; UTM Datum 83

Elevation (m) UTM Easting UTM Northing

1 28-Jul-09 463644 5398235 475 2 28-Jul-09 463784 5398037 495 1 28-Jul-09 463793 5397973 487 5 28-Jul-09 463854 5397868 503 1 28-Jul-09 463361 5398914 464 1 29-Jul-09 464507 5397068 580 3 29-Jul-09 464632 5396852 521 1 29-Jul-09 464339 5397100 575 1 29-Jul-09 463950 5397705 522 1 29-Jul-09 463959 5397611 557

Results

9. Common Wood Nymph (Cercyonis pegala incana) Observations Common Wood Nymph incana subspecies is found on the Gulf Islands, southeastern Vancouver Island and a few locations in the lower mainland including Sechelt, Powell River and Lilloet, typically in Garry oak ecosystems. This subspecies likely uses grasses and/or sedges as a host plant, (Guppy and Shepard, 2001) although the specific host plant is unknown. The incana subspecies is red-listed species in B.C., due to its limited range, and loss and degradation of habitat (B.C. Conservation Data Center, 2009). Mt. Maxwell was surveyed on July 30 2009 in hot sunny weather. One Common Wood Nymph was captured while flying through the Garry oak meadow at 12:20 pm and 352 m elevation (UTM zone 10, NAD 83, easting 460491, northing 5406617). No other behaviour was observed. Transects took place along steep west facing slopes of Garry oak meadows in the Mt. Maxwell ecological reserve. The meadow was very dry during the survey with few flowers in bloom to provide forage. The only other butterflies observed at this site were six woodland skippers (Ochlodes sylvanoides).

10. Other Butterfly Observations Butterflies below are all yellow listed in B.C., with the exception of Cabbage White, which is exotic. General site descriptions are given above in the survey area section.

Hydaspe Fritillary (Speyeria zerene hydaspe) Hydaspe Fritillary is found throughout B.C. from the Rocky Mountains west to Vancouver Island. The butterfly most abundant in July (flies from June to August) and prefers moist clearings in forested areas where lots of flowers are available for nectaring. The rhodope subspecies is the only one present in Canada (Species Bank, 2003). Seven Hydaspe Fritillary (Figure 15) were observed on Mt. Tuam. One specimen was observed on the road leading up to the peak on July 28 2009. It was observed flying with Bremner’s Fritillary (Figure 16) in a regenerating clearcut adjacent to the road (Figure 5). The clearcut contained abundant thistle and some other wildflowers. Three Hydaspe Fritillary were observed on July 29, one flying in the Garry Oak meadow on the peak of Mt. Tuam, in a rocky area near the parking area on the peak (Figure 17). The other two Hydaspe Fritillary were observed on the road leading up to the peak of Mt. Tuam congregating near a thistle patch with Bremner’s Fritillary and unidentified fritillary. Two Hydaspe Fritillary were observed in a small natural roadside meadow on the road to the peak of Mt. Tuam – a wet area with tall grass but few flowers adjacent to young forest on July 29, 2009. Seven Hyaspe Fritillary observed is certainly an underestimate; 41 unknown fritillary – either Bremner’s or Hydaspe Fritillary - were observed in flight only and could not be captured for positive identification.

Results

Figure 15: Hydaspe Fritillary (ventral view) taken on the road up to Mt. Tuam on Salt Spring Island on July 28 2009. Photo by Sophie-Anne Blanchette

Figure 16: Comparison of dorsal view of Hydaspe (bottom) and Bremner’s (top) Fritillary taken on the road up to Mt. Tuam on Salt Spring Island on July 28 2009. Photo by Sophie-Anne Blanchette.

Figure 17: View from the parking area on the peak of Mt. Tuam May 12 2009. Photo by Laura Parkinson.

Results

Woodland skipper (Ochlodes sylvanoides) Woodland skipper is one of the most abundant grass skipper species in B.C. from eastern Vancouver Island across the southern quarter of the province and north into the Skeena drainage below 1000 m elevation (Guppy and Shepard, 2001). Woodland Skipper flies from July to September in open, grassy areas. Larvae are known to utilize various grasses as host plants (Guppy and Shepard, 2001). Woodland Skipper was by far the most common butterfly observed on the Gulf Islands with 138 individuals observed at all sites surveyed on all three Gulf Islands with the exception of Bodega Ridge on Galiano Island. Individuals were observed in flight at most sites, perching on thistle flowers on Mt. Tuam, resting on dry grass on Mt. Maxwell, Mt. Parke and Henderson Parke, and nectaring on roadside flowers at Laughlin Lake and Bodega Beach Drive.

Mylitta crescent (Phycoides mylitta) Mylitta Crescent is a common butterfly found in southern British Columbia, Washington, Oregon and California. The species is commonly observed in meadows, parks and along roads. Caterpillars utilize thistles (Cirsium and Caardus spp.) as food plant (Opler, et. al., 2009). Seventeen Mylitta Crescent butterflies were observed: one on the road leading to the peak of Mt. Tuam on Salt Spring Island on July 28, seven in Henderson Park on Mayne Island on July 31, one at Laughlin Lake on Galiano Island on August 3, five in the Heritage forest and three on Bodega Beach Drive on Galiano Island on August 5 2009.

Lorquin’s Admiral (Limentus lorquini) Lorquin’s Admiral is wide spread across the southern part of B.C. including Vancouver Island up to Emerald Lake. It is found in or adjacent to forested areas, parks and orchards. Its larval food plant includes many deciduous trees like Willow, Poplar and Cottonwood, and Cherry (Prunus spp.) (Guppy and Shepard, 2001). Five Lorquin’s Admiral were observed: two on Mt. Tuam on Salt Spring Island on July 28, one in Henderson Park on Mayne Island on July 31, one at Laughlin Lake on Galiano Island on August 3, and one on Bodega Beach Drive on August 5 2009.

Grey hairstreak (Strymon melinus) Grey Hairstreak is found on Vancouver Island and across southern B.C. It flies in two broods, one from late April to early July and the second from mid-July to late August. Grey Hairstreak is usually found in the understory of Douglas Fir (Psuedotsuga menziesii) or Pine (Pinus spp.) or in riparian areas that provide habitat for plants in the legume family (Fabaceae), the larval food plants of Grey Hairstreak (Guppy and Shepard, 2001).

Results

Four Grey Hairstreaks were observed on Galiano Island. One was observed at Laughlin Lake on August 3 2009, one on Bodega Beach drive and two in the Heritage Forest on Galiano Island on a hot and sunny August 5 2009.

Pine white (Neophasia menapia) Pine White butterflies are found in southern B.C. and Vancouver Island and as far north as the Chilcotin in the Fraser Valley and the Bella Coola Valley on the coast (Species Bank, 2003). The adults prefer coniferous forest where they lay their eggs on Pine (Pinus) and Fir (Abies) species (Guppy and Shepard 2001). Two Pine White butterflies were observed: one on Mt. Tuam on Salt Spring Island on July 29 and one at Henderson Park on Mayne Island on July 31 2009.

Cabbage white (Pieris rapae) Cabbage White is an introduced species that has now invaded North America south of the Arctic. They are present in highly disturbed areas as well as in more natural settings. Cabbage White utilizes host plants from the Mustard family (Brassicaceae) (B.C. Conservation Data Centre, 2009). Two Cabbage White butterflies were observed: one on Mt. Tuam on Salt Spring Island on July 28 2009 and one at Laughlin Lake on Galiano Island on August 3 2009.

Painted lady (Vanessa cardui) Painted Lady is one of the most cosmopolitan butterflies in the world, found in both tropical, temperate and arctic areas across the northern and southern hemispheres. They are found scattered all over B.C., although they are most common in southern B.C., including Vancouver Island. Painted Lady migrates to B.C. from deserts in the southern United States and northern Mexico, and are not seen every year. A diversity of larval food plants are used, usually Bull Thistle (Cirsium vulgare) or Canada Thistle (Cirsium arvense) in B.C. (Guppy and Shepard, 2001). One Painted Lady was observed in flight on Bodega Beach drive on Galiano Island August 5 2009.

Results

11. Other Invertebrate Observations

Pitfall Traps Six families of beetles, one family of grasshoppers, and one family of slug were captured in the pitfall traps installed at Mt. Maxwell. Due to time constraints, not all specimens were identified, and some were not identified to greater precision than the level of family or genus. Three juvenile slugs were either reticulate (andersoni) or yellow bordered (foliolatum) taildroppers. Table 3: Invertebrates identifed from pitfall traps installed on Mt. Maxwell, collected on June 20, 2009

Common Name Order Family Genus Species

Ground Beetles

Coleptera Carabidae

Weevils Coleptera Curculionidae Click Beetles Coleptera Elateridae Carrion Beetles

Coleptera Silphidae Nicrophorus

Rove Beetles Coleptera Staphylinidae Darkling Beetles

Coleptera Tenebrionidae Eleodes

Camel Cricket Orthoptera Rhaphidophoridae Pristoceuthophilus Celatus Taildropper Stylommatophora Arionidae Prophysaon andersonii/foliolatum Few invertebrates were captured in the pitfall traps installed on Mayne Island, as these traps were only active for approximately one day. The only specimens identified from these traps are four Camel Crickets.

Hand Collected Terrestrial Invertebrates Terrestrial Gastropods Eleven terrestrial gastropods were collected opportunistically on Salt Spring, Mayne and Galiano Islands, representing at least five different species (Table 3). Some individuals were live, but empty shells were also identified. All individuals found were yellow listed, except the Pacific Sideband (Monadenia fidelis), which is blue listed (S3S4) (B.C. Conservation Data Centre, 2009). Five Pacific Sidebands were found on Mt. Tuam, Mt. Maxwell and Ruckle Park on Salt Spring Island and Mt. Sutil on Galiano Island. They were found in patches of forest within Garry Oak meadows, and also in more open areas within the meadows. Three Glossy Pillar snails were found in the soil at the base of early blue violets on Mt. Tuam while searching for Bremner’s Fritillary larvae on May 12.

Results

Table 4: Terrestrial gastropods collected opportunistically from Salt Spring, Mayne and Galiano Islands, 2009. Identifications confirmed by Kristiina Ovaska.

Species Name

Common Name Date Location Number Age

UTM Zone 10; NAD 83 Easting Northing

Cochlicopa lubrica

Glossy Pillar 12-May-09

Mt Tuam (Salt Spring Island) 3 2 adult 464410 5397095

Monadenia fidelis

Pacific Sideband 12-May-09

Mt.Tuam (Salt Spring Island) 1 juvenile 464410 5397095

Ancotrema species

Lancetooth species 13-May-09

Mt. Maxwell (Salt Spring Island) 1 Juvenile 461026 5406571

Monadenia fidelis


Mt. Maxwell (Salt Spring Island) 1 n/a 460752 5406427

Monadenia fidelis


Mt. Maxwell (Salt Spring Island) 1 n/a 460810 5406451

Monadenia fidelis


Ruckle Park (Salt Spring Island) 1 n/a 472672 5402781

Zonitoides arboreus

Quick Gloss 31-Jul-09

Henderson Park (Mayne Island) 1 adult 480493 5408359

Ancotrema species

Lancetooth species 31-Jul-09

Henderson Park (Mayne Island) 1 juvenile 480467 5408358

Monadenia fidelis

Pacific Sideband 04-Aug-09

Mt. Sutil (Galiano Island) 1 n/a 471927 5413418

Terrestrial Insects Nine terrestrial insects were collected opportunistically by hand on Salt Spring, Mayne and Galiano Islands, representing three orders and at least eight different species (Table 4). All specimens have not been identified, and some were not identified to greater precision than the level of family or genus. Grasshoppers collected by hand are awaiting identification. Specimens are deposited at the Royal B.C. Museum (Victoria, B.C.) or University of British Columbia Beaty Biodiversity Museum Spencer Entomological Collection (Vancouver, B.C.). None of the species below have been assessed and assigned a conservation status by the B.C. Conservation Data Center, with the exception of the Greater Night-Stalking Tiger Beetle and the Western Tiger Beetle, which are yellow listed in B.C. The Seven-spotted Ladybird Beetle and the Asian Spotted Ladybird Beetle are both exotic species introduced from Europe and Japan respectively. They were both introduced intentionally as a form of biological control for aphids, and have become very common in some areas, particularly urban areas (Haggard and Haggard, 2006).

Table 5: Terrestrial insects collected opportunistically from Salt Spring and Galiano Islands, as identified by Rob Cannings Common

Name Order Family Genus Species Location Date

Ground beetle

Coleoptera Carabidae Mt. Tuam (Salt Spring Island)

12-May-09

Results

Table 5: Terrestrial insects collected opportunistically from Salt Spring and Galiano Islands, as identified by Rob Cannings Common

Name Order Family Genus Species Location Date

Greater Night-Stalking Tiger Beetle

Coleoptera Carabidae Omus dejeanii Mt. Tuam (Salt Spring Island)

12-May-09

Seven-spotted Ladybird Beetle

Coleoptera Coccinellidae Coccinella septempunctata Mt. Tuam (Salt Spring Island)

12-May-09

Stink bug Hemiptera Pentatomidae Chlorochroa Mt. Maxwell (Salt Spring Island)

13-May-09

Western Tiger Beetle

Coleoptera Carabidae Cicindela oregona Bodega Ridge (Galiano Island)

03-Aug-09

Click Beetle Coleoptera Elateridae Bodega Ridge (Galiano Island)

03-Aug-09

Robber Fly Diptera Asilidae Stenopogon inquinatus Bodega Ridge (Galiano Island)

03-Aug-09

Western Tiger Beetle

Coleoptera Carabidae Cicindela oregona Matthew’s Point (Galiano Island)

04-Aug-09

Snail-killer Carabid

Coleoptera Carabidae Scaphinotus angusticollis Matthew’s Point (Galiano Island)

04-Aug-09

Denman Island Twenty-seven terrestrial insects collected opportunistically on Denman Island were identified, representing eight different families of beetles and one family of true bugs. Two specimens of one terrestrial snail collected was also identified (see Appendix 2). Seventy minutes were spent conducting aquatic surveys at two sites, from which ten specimens, including aquatic beetles and molluscs were identified (see Appendix 2).

Discussion

12. Discussion The population of Bremner’s Fritillary on Mt. Tuam appears to be breeding within the open habitats, as individuals have been observed in previous years by the Salt Spring Island Conservancy (R. Annschild, pers. comm., 2009). During surveys, butterflies were observed congregating around potential violet host plants, possibly to engage in breeding behaviours. The observation of larvae found on May 12, 2009 at the base of the early blue violet may be Bremner’s Fritillary larvae. However, on July 29 Bremner’s Fritillary was not observed congregating near the patch of the early blue violet where the larvae were collected on May 12. The larvae are currently awaiting identification by an expert. On May 12 2009 montane violet and early blue violet were observed flowering on Mt. Tuam, often noted growing in close proximity to one another. On July 28 - 29th 2009 the violets were no longer flowering so it was more difficult to distinguish the two species. Therefore the montane violet patch where the Bremner’s Fritillary were observed congregating may have included early blue violet, which represents another potential host plant for Bremner’s Fritillary. As only two days were spent surveying on Mt. Tuam it is difficult to draw any conclusions from these observations. Surveys on July 28th and 29th took place towards the end of the peak flight period of Bremner’s Fritillary, so observations may have differed at other points during the flight period (which may have been influenced by extreme weather conditions as described below). Although the nectar source for adult Bremner’s Fritillary is not officially known (Speyeria zerene bremnerii, 2003), the butterfly has been observed perching and congregating on thistles in previous surveys on Mt. Tuam by the Salt Spring Island Conservancy. During surveys on July 28-30th 2009 Bremner’s Fritillary was also observed perching on and congregating near thistle by the BCCC crew, although actual feeding behaviour was not observed. Due to their similar appearance, it is difficult to distinguish between Bremner’s and Hydaspe Fritillary when observed in flight (Figure 16). Both these fritillary species are fast, strong fliers, making them challenging to catch. Due to difficulties distinguishing these species while in flight, 41 fritillary observations were recorded as unknown. Thus, the the total number of Bremner’s Fritillary observed (17 observations) is likely a substantial underestimate (Table 1). Due to a period of high temperatures on the Gulf Islands prior to and during surveys, conditions on the islands were extremely hot and dry. As a result, there were very few flowers in a majority of the sites surveyed on Mayne and Galiano Islands. Other than thistles, there were also very few flowers at Mt. Tuam on Salt Spring Island. Few butterflies of any species (except for Woodland Skippers) were observed at sites other than Mt. Tuam, probably at least in part to lack of flowers at these sites for foraging.

Discussion

The lack of Bremner’s Fritillary observations on Mayne and Galiano Islands may have been due to a number of factors, in addition to the marginal weather conditions described above. Although potential habitat is found and was surveyed on both islands, neither the Mayne Conservancy nor Galiano Conservancy were aware of any occurrences of Bremner’s Fritillary or the montane violet on these islands, and the B.C. Conservation Data Center has no records for either species on Mayne or Galiano Islands. In addition, the Garry Oak habitats surveyed on both islands had substantial encroachment by scotch broom, and as a result, the area of open meadow was much more protracted than on Mt. Tuam which represented a larger expanse of meadow. Lack of scotch broom encroachment on Mt. Tuam is probably due to sheep grazing, although the effect of sheep grazing on Viola spp. that are the suspected host plants of Bremner’s Fritillary are potentially adverse.

Recommendations for future surveys

13. Recommendations for future surveys On Salt Spring Island, there is substantial habitat that remains to be surveyed, including Mt. Erskine. Surveys should be completed on Mt. Maxwell, as montane violet (and other violet species) is known to occur in this habitat (and was observed by the B.C. Conservation Corps Invertebrate Species at Risk Crew on May 13 2009.) On Galiano Island, Mt. Sutil is a relatively large tract of Garry Oak habitat representing good potential habitat for Bremner’s Fritillary. However, weather during surveys conducted was not ideal for butterfly activity (overcast and misty with cool temperatures). In addition, recent high temperatures had created dry conditions all over the Island, resulting in no to few flowers to provide forage for butterflies in most areas surveyed, including Mt. Sutil. Therefore it would be worthwhile to resurvey Mt. Sutil and also Bodega Ridge, a Garry oak ridge habitat, in future years. Mayne Island also contains further habitat that remains to be surveyed. Surveys could also be conducted on potential habitat on other southern Gulf Islands and southeastern Vancouver Island.

References

14. References Acorn, J. and I. Sheldon. 2006. Butterflies of British Columbia. Lone Pine Publishing: Edmonton. 360pp. Baron, N. and F. Backhouse. 1999. Rare Butterflies of Southeastern Vancouver Island and the Gulf Islands. British Columbia Ministry of Environment, Lands and Parks. 6 pp. B.C. Conservation Data Centre. 2009. Species Summary: Cercyonis pegala incana. B.C. Minist. of Environment. Available: http://a100.gov.bc.ca/pub/eswp/ B.C. Conservation Data Centre. 2009. Species Summary: Pieris rapae. B.C. Minist. of Environment. Available: http://a100.gov.bc.ca/pub/eswp/ COSEWIC. 2007. COSEWIC assessment and update status report on the yellow montane violet, praemorsa subspecies, Viola praemorsa ssp. praemorsa, in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vii + 24 pp. (www.sararegistry.gc.ca/status/status_e.cfm). Garry Oak Ecosystems Recovery Team. 2003. Species at Risk in Garry Oak and Associated Ecosystems in British Columbia. Garry Oak Ecosystems Recovery Team, Victoria, British Columbia. Guppy, C. 2009. Butterfly Specialist. Personal Communication. Guppy, C. and J. Shepard. 2001. Butterflies of British Columbia. UBC Press: Vancouver. p 211. Haggard, P. and J. Haggard. 2006. Insects of the Pacific Northwest. Timber Press Field Guide: Oregon. 295 pp. NatureServe. 2009. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer. Opler, Paul A., Kelly Lotts, and Thomas Naberhaus, coordinators. 2009. Butterflies and Moths of North America. Bozeman, MT: Big Sky Institute. http://www.butterfliesandmoths.org/ (accessed August 18, 2009). Pojar, J. and A. McKinnon. 1994. Plants of Coastal British Columbia including Washington, Oregon and Alaska. B.C. Ministry of Forests and Lone Pine Publishing, Vancouver, B.C. 526pp. Species Bank, Canadian Biodiversity Information Facility. 2003. Government of

http://a100.gov.bc.ca/pub/eswp/�

http://a100.gov.bc.ca/pub/eswp/�

http://www.sararegistry.gc.ca/status/status_e.cfm�

References

Canada. http://www.cbif.gc.ca/spp_pages/butterflies/speciesindex_e.php. (Accessed August 31, 2009).

15. Appendix 1 Incidental Butterfly Observations

Date Common Name Species Name

Number of Butterflies Observed

UTM Zone 10; Datum 83

Easting Northing

28/07/2009 Lorquin's Admiral Limenitus lorquini 1 463784 5398037

28/07/2009 Bremner’s Fritillary

Speyeria zerene bremnerii 1 463644 5398235



















28/07/2009 Cabbage White Pieris rapae 1 463466 5398674 03/08/2009 Cabbage White Pieris rapae 1 463277 5421911

30/07/2009 Common Woodnymph Cercyonis pegala 1 460491 5406617

03/08/2009 Grey Hairstreak Strymon melinus 1 463251 5421713 05/08/2009 Grey Hairstreak Strymon melinus 1 471364 5417415 05/08/2009 Grey Hairstreak Strymon melinus 1 471209 5417334 05/08/2009 Grey Hairstreak Strymon melinus 1 460558 5424895

28/07/2009 Hydaspe Fritillary Speyeria Hydaspe 1 463939 5397819




03/08/2009 Lorquin`s Admiral Limenitus lorquini 1 463247 5421825



Incidental Butterfly Observations




Easting Northing


31/07/2009 Mylitta Crescent Phycoides mylitta 1 480527 5408124 31/07/2009 Mylitta Crescent Phycoides mylitta 3 480488 5408066 31/07/2009 Mylitta Crescent Phycoides mylitta 1 480472 5408245 03/08/2009 Mylitta Crescent Phycoides mylitta 1 463277 5421911 05/08/2009 Mylitta Crescent Phycoides mylitta 1 471404 5417311 05/08/2009 Mylitta Crescent Phycoides mylitta 1 471163 5417345 05/08/2009 Mylitta Crescent Phycoides mylitta 1 460385 5425149 28/07/2009 Mylitta Cresent Phycoides mylitta 1 463644 5398235 31/07/2009 Mylitta Cresent Phycoides mylitta 1 480540 5408015 31/07/2009 Mylitta Cresent Phycoides mylitta 1 480518 5408030 05/08/2009 Mylitta Cresent Phycoides mylitta 2 471362 5417347 05/08/2009 Mylitta Cresent Phycoides mylitta 1 471306 5417293 05/08/2009 Mylitta Cresent Phycoides mylitta 1 461100 5424356 05/08/2009 Mylitta Cresent Phycoides mylitta 1 461191 5424160 05/08/2009 Painted Lady Vanessa cardui 1 461856 5423682 31/07/2009 Pine White Neophasia menapia 1 480468 5408325 29/07/2009 Pine White Neophasia menapia 1 463950 5397705

28/07/2009 Unknown Fritillary Speyeria spp. 1 463430 5398741














29/07/2009 Unknown Speyeria spp. 1 463959 5397611





Easting Northing Fritillary



01/08/2009 unknown Lady Vanessa spp. 1 480597 5407944

05/08/2009 unknown skipper 1 460438 5425038

28/07/2009 Woodland Skipper

Ochlodes sylvanoides 1 463430 5398741













































Easting Northing











































16. Appendix 2 Locations of Pitfall Traps Installed on Salt Spring and Mayne Islands

UTM Zone 10; NAD 83 Location Pitfall Trap ID Easting Northing Period Active

Mt. Maxwell MM 1 460860 5406497 May 13-June 20, 2009 Mt. Maxwell MM2, MM3 460869 5406465 May 13-June 20, 2009 Mt. Maxwell MM4, MM5 460775 5406468 May 13-June 20, 2009 Mt. Maxwell MM6 460716 5406444 May 13-June 20, 2009 Mt. Maxwell MM7 460612 5406546 May 13-June 20, 2009 Mt. Maxwell MM8 460544 5406577 May 13-June 20, 2009 Mt. Maxwell MM9 460421 5406611 May 13-June 20, 2009 Mt. Maxwell MM10 460324 5406661 May 13-June 20, 2009 Mt. Maxwell MM11, MM12 460281 5406581 May 13-June 20, 2009 Mt. Maxwell MM13 460385 5406466 May 13-June 20, 2009 Mt. Maxwell MM14 460444 5406527 May 13-June 20, 2009 Mt. Maxwell MM15 460516 5406558 May 13-June 20, 2009 Henderson Park MI1 480659 5408043 Aug 1 – Aug 2, 2009 Henderson Park MI2 480727 5407930 Aug 1 – Aug 2, 2009 Henderson Park MI3 480767 5407922 Aug 1 – Aug 2, 2009 Henderson Park MI4 480755 5407890 Aug 1 – Aug 2, 2009 Mt. Parke MI5 479247 5409538 Aug 1 – Aug 2, 2009 Mt. Parke MI6 479027 5409479 Aug 1 – Aug 2, 2009

17. Appendix 3 Insects and Gastropods Opportunistically Collected from Denman Island

Common Name Order Family Genus Species Location Date

Seven-spotted ladybug Coleoptera Coccinellidae Coccinella septempunctata NDL 20-May-09 Click beetles Coleoptera Elateridae Ctenicera suckleyi NDL 20-May-09 Lancetooth Stylommatophora Haplotrematidae Ancotrema NDL 20-May-09 Stink bugs Hemiptera Pentatomidae Chlorocroa NDL 23-May-09 Darkling beetles Coleoptera Tenebrionidae Iphthiminus serratus NDL 25-May-09 Sculptured pine-borer Coleoptera Buprestidae Chalcophora virginiensis NDL 1-Jun-09 Seven-spotted ladybug Coleoptera Coccinellidae Coccinella septempunctata NDL 1-Jun-09 Rams-horn Basommatophora Planorbidae Helisoma Graham Lake 2-Jun-09 Fingerling Clam Veneroida Sphaeriidae Graham Lake 2-Jun-09

Western Floater Unionoida Unionidae

Anodonta kennerlyi Graham Lake 2-Jun-09

Yellow Velvet Long-horned beetle Coleoptera Cerambycidae Cosmalia chrysocoma NDL 4-Jun-09 Predaceous Diving Beetle Coleoptera Dytiscidae Hydroporus NDL 4-Jun-09 Water Scavenger Beetle Coleoptera Hydrophilidae Anacaena lutescens NDL 4-Jun-09 Whirligig Beetle Coleoptera Gyrinidae Gyrinus picipes NDL 4-Jun-09 Crawling Water Beetle Coleoptera Halipidae Haliplus leechi NDL 4-Jun-09 Multi-coloured Asian Lady Beetle Coleoptera Coccinellidae Harmonia axyridis SE NDL 26-May-09 Seven-spotted ladybug Coleoptera Coccinellidae Coccinella septempunctata SE NDL 26-May-09 Western Blood-red Lady Beetle Coleoptera Coccinellidae Cycloneda polita SE NDL 26-May-09 Fireflies Coleoptera Lampyridae Ellychnia SE NDL 26-May-09 Ground Beetles Coleoptera Carabidae Carabus granulatus SE NDL 3-Jun-09 Western Tiger Beetle Coleoptera Carabidae Cicindela oregona SE NDL 3-Jun-09 False Blister Beetles Coleoptera Oedemeridae Ditylus quadricollis SE NDL 3-Jun-09 Pine Ladybird Beetle Coleoptera Coccinellidae Mulsantina Picta

Fillongley campground 5-Jun-09

Documents

Surveys for Bremner’s Fritillary Speyeria zerene bremnerii