Dune tachinid fly (Germaria angustata): COSEWIC assessment and status report 2011
Special Concern – 2011
Table of Contents
- COSEWIC Assessment Summary
- COSEWIC Executive Summary
- Wildlife Species Description and Significance
- Distribution
- Habitat
- Biology
- Population Sizes and Trends
- Threats and Limiting Factors
- Protection, Status, and Ranks
- Acknowledgements and Authorities Contacted
- Information Sources
- Biographical Summary of Report Writer
- Collections Examined
List of Figures
- Figure 1. Dorsal (top) and lateral (bottom) views of a male Germaria angustata from Carcross, Yukon. Fly is approximately 9 mm long. Photos by Shannon Mahony and James O’Hara, Agriculture and Agri-Food Canada; used with permission
- Figure 2. Close-up of the head of the male Germaria in Figure 1, showing the elbowed arista of the antenna. Note the elongated second aristomere and (arrow) the flattened third aristomere. Photo by Shannon Mahony and James O’Hara, Agriculture and Agri-Food Canada; used with permission.
- Figure 3. Global distribution of Germaria angustata. Some locations in Mongolia and China are approximate.
- Figure 4. North American distribution of Germaria angustata (red dots). Other sites where specific but unsuccessful searches have been made are located by crossed dots.
- Figure 5. Known distribution of G. angustata in Canada.
- Figure 6. Aeolian deposits of the southern Yukon. Map courtesy of Stephen Wolfe, Geological Survey of Canada, Ottawa.
- Figure 7. Aeolian deposits of the southwestern Yukon (enlarged from lower inset in Figure 6). Vegetated, stabilized dunes in orange; active dunes in red; direction of transporting winds marked by arrows. Map courtesy of Stephen Wolfe, Geological Survey of Canada, Ottawa.
- Figure 8. Dunes at Bennett Lake beach, Carcross. SW from 60.1776°N 134.7295°W, 1 June 2009. Photo: S. Cannings
- Figure 9. Typical G. angustata habitat at the Bennett Lake beach dunes. Common plants include: Calamagrostis purpurascens, Elymus calderi, Bromus pumpellianus, Carex sabulosa, Polemonium pulcherrimum, Artemisia frigida, and Aster sibiricus. N from approx. 60.1776°N 134.7295°W, 22 July 2009. Photo: L. Schroeder; used with permission.
- Figure 10. Dunes 2 km N of Carcross, along Klondike Highway. Sparse cover in foreground is Carex sabulosa; Germaria angustata is not present in this grassless habitat. Note off-road vehicle disturbance. S from 60.1864°N 134.6936°W, 20 June 2008. Photo: S. Cannings.
- Figure 11. G. angustata habitat at the Carcross dunes: Baikal Sedge (Carex sabulosa), grasses (Bromus pumpellianus, etc.) and wildflowers (Lupinus kuschei, Aster sibiricus, Polemonium pulcherrimum). Note off-road vehicle disturbance. N from 60.1881°N 134.6934°W, 1 June 2010. Photo: S. Cannings
- Figure 12. Alsek dunes at confluence of Kaskawulsh and Dezadeash (Alsek) Rivers, Kluane National Park and Reserve. Vegetation includes Carex sabulosa, Equisetum arvense, Lupinus kuschei, and Artemisia tilesii, with occasional clumps of Juniperus communis. W from 60.6680°N 137.8003°W, 2008. 26 June 2008. Photo: S. Cannings.
- Figure 13. Mixed Carex sabulosa-grass-Lupinus kuschei-Penstemon gormani-Artemisia tilesii community, Alsek dunes. NE from 60.6698°N 137.8000°W, 26 June 2008. Photo: S. Cannings.
- Figure 14. Aerial view of the dune on the west side of the Takhini River, 6.8 km NNE of Kusawa Lake. Large dune is approximately 900 m long, but most of this dune is not appropriate habitat for G. angustata. NW from approximately 60.660°N 136.064°W, 13 October 2009. Photo: J. Meikle, Kwanlin Dun, First Nation; used with permission.
- Figure 15. Vegetated dune swale on the west side of the Takhini River, 6.8 km NNE of the outlet of Kusawa Lake. Appears as greyish streak on near side of dune in centre of Figure 14. Common plants include Carex sabulosa, Elymus calderi, and Lupinus kuschei. NNE from 60.6679°N 136.0763°W, 19 June 2009. Photo: S. Cannings.
- Figure 16. Aeolian sand and active dunes on top of lacustrine silt cliffs eroded by Yukon River, 5 km N of Whitehorse. SW from 60.7748°N 135.0826°W, 17 July 2008. Photo: S. Cannings.
- Figure 17. Blowout on top of bluffs above Yukon River, 5 km N of Whitehorse (in middle distance of Figure 15): common plants include Penstemon gormanii, Oxytropis campestris, and Elymus calderi. N from 60.7736°N 135.0863°W, 7 June 2009. Photo: S. Cannings.
- Figure 18. Aeolian sand and dunes on top of coarser sediments on Lookout Hill, at north end of Schwatka Lake reservoir, Whitehorse. Dominant grasses are Oryzopsis hymenoides, Elymus calderi, and Calamagrostis purpurascens. W from 60.6940°N 135.0322°W, 12 July 2008. Photo: S. Cannings.
- Figure 19. Stabilized dunes and small blowouts; aeolian sand on top of silt bluffs, west of downtown Whitehorse. Calamagrostis purpurascens in foreground; other vegetation dominated by Artemisia frigida, Carex supina, and Elymus trachycaulus. NNW from 60.7249°N 135.0712°W, 2 July 2009. Photo: S. Cannings.
- Figure 20. Dunes at confluence of Bullion Creek and Slims River, Kluane National Park and Reserve. Dominant plants are Elymus calderi and Artemisia frigida. SSW from 60.9608°N 135.6348°W, 3 July 2009. Photo: S. Cannings.
- Figure 21. Beach dunes at north end of Sekulmun Lake. Foreground vegetation includes Bromus pumpellianus, Hierochloe hirta ssp. arctica, Artemisia alaskana, Lupinus kuschei, Phlox hoodii, and A. uva-ursi. This was the site with the densest populations of G. angustata.WNW from 61.5619°N 137.5418°W, 13 July 2009. Photo: S. Cannings.
- Figure 22. Ridge-top aeolian sand and small blowouts in subalpine zone (1200 m el.) between Aishihik and Sekulmun Lakes. E from 61.4049°N 137.3540°W (on helicopter approach), 13 July 2009. Photo: S. Cannings.
- Figure 23. Increased ATV use at Carcross over the past 30 years may have caused a decline in the area of appropriate habitat for G. angustata. W from approximately 60.1852°N 134.6929°W, 20 June 2008. Photo: S. Cannings.
- Figure 24. Northern section of the Carcross dunes, east of the Klondike Highway, 2 km N of the village. NNE from about 60.1866°N 134.6951°W, 29 August 1984. Compare vegetation with present-day photo in Figure 25. Photo: C. Kennedy; used with permission.
- Figure 25. Same view as Figure 24; 1 June 2010. Note apparently increased disturbance, smaller patches of vegetation, and virtual absence of vegetation on steeper, open slope. Photo: S. Cannings.
- Figure 26. Frequency of 30-minute sample sizes of G. angustata specimens taken at sites where at least one specimen was captured on that d
List of Tables
- Table 1. Known locations of G. angustata in Canada. All locations are in the Yukon. Areas are approximations of appropriate habitat.
- Table 2. Canadian specimens of G. angustata held in the Canadian National Collection, Agriculture and Agri-Food Canada, Ottawa.
- Table 3. Details on site inventories in 2008 and 2009 by Canadian Wildlife Service and Environment Yukon. Records highlighted in yellow indicate surveys that resulted in the capture of at least one G. angustata specimen. ‘Total’ indicates the number of G. angustata specimens taken. Specimens will be deposited at Canadian National Collection, Agriculture and Agri-Food Canada, Ottawa; Canadian Wildlife Service, Whitehorse; Royal British Columbia Museum, Victoria; and Museum für Naturkunde, Berlin.
COSEWIC status reports are working documents used in assigning the status of wildlife species suspected of being at risk. This report may be cited as follows:
COSEWIC. 2011. COSEWIC assessment and status report on the Dune Tachinid Fly Germaria angustatain Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. x + 43 pp.
Production note:
COSEWIC would like to acknowledge Syd Cannings for writing the status report on the Dune Tachinid Fly, Germaria angustata, in Canada, prepared under contract with Environment Canada. This report was overseen and edited by Paul Catling, Co-chair of the COSEWIC Arthropods Specialist Subcommittee.
For additional copies contact:
COSEWIC Secretariat
c/o Canadian Wildlife Service
Environment Canada
Ottawa, ON
K1A 0H3
Tel.: 819-953-3215
Fax: 819-994-3684
E–mail
Website
Cover illustration/photo:
Dune Tachinid Fly -- Photos by Shannon Mahony and James O’Hara, Agriculture and Agri-Food Canada; used with permission.
© Her Majesty the Queen in Right of Canada, 2011.
Catalogue No. CW69-14/623-2011E-PDF
ISBN 978-1-100-18673-3
Assessment Summary – May 2011
Common name
Dune Tachinid Fly
Scientific name
Germaria angustata
Status
Special Concern
Reason for designation
This rare fly is restricted to a very small area of unglaciated Beringia in southwestern Yukon. It is known from 11 largely isolated locations where it occurs in active to semi-stabilized dunes. It is a parasite of the larvae of a dune moth. The threats include a continuing decline in habitat caused by succession on dunes and the use of all-terrain vehicles in some areas which destroy required dune vegetation.
Occurrence
Yukon
Status history
Designated Special Concern in May 2011.
Dune Tachinid Fly
Germaria angustata
Wildlife species description and significance
The Dune Tachinid Fly, Germaria angustata (Zetterstedt), is a black, bristly, medium-sized fly in the family Tachinidae. The second segment of the antennal branch (arista) is elongated and the third aristomere is flattened side-to-side; these two features give the arista a distinctive, elbowed appearance which helps to identify this species.
This fly is significant in that it represents a group of invertebrate and plant species (a number of which are undescribed scientifically) that, at least in North America, are restricted to active dunes in the southern Yukon.
Distribution
In North America, the known distribution is restricted to 11 locations (14 individual sites) in the southwestern Yukon, from Whitehorse and Carcross west to Kluane National Park and Reserve. In Eurasia, it is rare at European coastal and interior dunes; and is known from a number of localities in Mongolia and adjacent China and Siberia.
Habitat
The Dune Tachind Fly is restricted to active or semi-stabilized dunes or smaller sand blowouts with scattered grasses, sedges, and other vegetation. This habitat preference is probably related to the habitat needs of its likely specific, but as yet unknown host caterpillar. In the Yukon, the known habitat always includes some grass or grasses. The dunes can be in coastal areas with a mesic climate (in Europe) or in interior boreal regions, with a more extreme (cold winter, hot summer) climate.
Biology
Tachinid flies are parasites of the larvae of other insects, often moth larvae. The host of the Dune Tachinid Flyis unknown. Female Dune Tachinid Flies fly low over the open sand, alighting on single stems of grass, walking to the base of each, and apparently depositing an egg there. The eggs undoubtedly hatch into a first instar larva that waits for a host caterpillar to come by. Because of the egg placement at the base of grass or sedge stems, the host of the Dune Tachinid Fly may be a cutworm larva (a moth in the family Noctuidae) that lives underground during the day and comes to the surface at night to feed on the base of the grass. A dune specialist cutworm that is found at Whitehorse and Carcross, and has a very similar global range to that of the Dune Tachinid Fly is the Coast Dart. In the Yukon, adult Dune Tachinid Flies have been collected from 6 June to 23 July; in coastal Europe the flight season is longer, from late May to mid-August.
Population sizes and trends
Appropriate habitat at a site is often limited, and this is a parasitic species dependent on a host moth, so population sizes are probably quite small for an insect. There is no information on population trends. Population size may vary a great deal from year to year, as in other tachinid flies, but there are no data. Although population size and density are difficult to estimate, thirty-minute searches in appropriate habitat result in catches of up to 13 specimens, usually 0 to 7.
Threats and limiting factors
There is no detailed information on limiting factors. The main, proximate limiting factor is probably the distribution and abundance of the Dune Tachinid Fly’s host moth. Since the end of the Pleistocene, dune stabilization and vegetation succession has eliminated most of the active dune habitat in the region. While some active dunes appear to be in equilibrium (i.e., new blowouts approximately equal areas stabilized), succession will probably eliminate more open dune area, especially at the large, but relatively young Alsek dunes in Kluane National Park and Reserve.
A potential, but significant threat is invasive species that have the ability to quickly stabilize dunes. Potential threat species include Altai Wild Rye and White Sweet-clover.
At the Carcross dunes, increasing recreational all-terrain vehicle use has caused a decline in habitat by eliminating vegetation and thereby eliminating food plants for host moths.
Protection, status, and ranks
There is no legal protection for this fly in Canada, except for that afforded its populations within Kluane National Park and Reserve and Kusawa Territorial Park.
It has not been ranked by the National General Status program; NatureServe ranks it G4G5 globally; the Yukon Conservation Data Centre ranks it S2 in the Yukon.
Technical Summary
Germaria angustata
Dune Tachinid Fly Mouche tachinide des dunes
Range of occurrence in Canada: Yukon Territory
Demographic Information
Generation time (average age of parents in the population) | 1 yr |
Is there a continuing decline in number of mature individuals? Unknown; but based on habitat extent and condition, probably a local decline at Carcross; future, longer-term declines can be inferred for the Alsek dunes, which appear to be undergoing stabilization. |
Probable small, continuing decline |
Estimated percent of continuing decline in total number of mature individuals within 5 years. Unknown, but probably a small decline. |
Probable small decline |
Estimated percent reduction in total number of mature individuals over the last 10 years. Unknown; probably has declined somewhat because of habitat reduction at Carcross. |
Probable small decline |
Suspected percent reduction in total number of mature individuals over the next 10 years. Difficult to quantify, but a small decline can be inferred if present habitat trends continue. |
Unknown, but probably a small decline |
Estimated percent reduction in total number of mature individuals over any 10 year period, over a time period including both the past and the future. Difficult to quantify, but a small decline can be inferred if present habitat trends continue. |
Unknown, but probably a small decline |
Are the causes of the decline clearly reversible and understood and ceased? Causes of inferred declines from habitat loss at Carcross are reversible, but not ceased. |
No |
Are there extreme fluctuations in number of mature individuals? Unknown, but this may be the case, based on other tachinid populations. |
Unknown but probable |
Extent and Occupancy Information
Estimated extent of occurrence | 15,600 km² |
Index of area of occupancy (IAO) Figure given is for 2 km x 2 km grid; actual AO < 2 km² |
48 km² |
Is the total population severely fragmented? | No |
Number of “locations*” | 11 |
Is there an [observed, inferred, or projected] continuing decline in extent of occurrence? | No |
Is there an [observed, inferred, or projected] continuing decline in index of area of occupancy? Unknown; probably stable at the 2km2 grid scale, but may be declining at smaller grid scales. |
Unknown |
Is there an [observed, inferred, or projected] continuing decline in number of populations? Unknown, probably relatively stable |
Unknown |
Is there an [observed, inferred, or projected] continuing decline in number of locations? Unknown, probably stable |
Unknown |
Is there an observed, continuing decline in area and quality of habitat? Destruction of grasses at main Carcross dunes; in the long term, stabilization probably occurring at Alsek and parts of Carcross |
Yes, perhaps about 10% in last 20 years. |
Are there extreme fluctuations in number of populations? | No |
Are there extreme fluctuations in number of locations? | No |
Are there extreme fluctuations in extent of occurrence? | No |
Are there extreme fluctuations in index of area of occupancy? | No |
* See definition of location.
Number of Mature Individuals (in each population)
Population | N Mature Individuals |
---|---|
Total | Unknown |
Whitehorse, 5 km N | Unknown |
Whitehorse, bluffs to W | Unknown |
Whitehorse, Riverdale | Unknown |
Whitehorse, Schwatka L | Unknown |
Carcross | Unknown |
Takhini River | Unknown |
Dezadeash River, Champagne | Unknown |
Aishihik Lake, ridge to W | Unknown |
Sekulmun Lake | Unknown |
Alsek River | Unknown |
Slims River | Unknown |
Quantitative Analysis
Probability of extinction in the wild is at least [20% within 20 years or 5 generations, or 10% within 100 years]. | n/a |
Threats (actual or imminent, to populations or habitats)
At the large Carcross dunes, all-terrain vehicle use has degraded or eliminated some habitat. Natural succession in the Alsek River dunes is probably slowly reducing habitat there. These kinds of threats do not involve the majority of sites. Another potential but imminent threat is from invasive plants that can stabilize dune habitat |
Rescue Effect (immigration from outside Canada)
Status of outside population(s)? Not yet found in Alaska, but may occur there. However, any populations there would be very distant (approx. 1000 km), and short-term immigration rates would be negligible. |
|
Is immigration known or possible? | No |
Would immigrants be adapted to survive in Canada? | Yes |
Is there sufficient habitat for immigrants in Canada? Unknown, but probably not, because available habitat is occupied. | No |
Is rescue from outside populations likely? | No |
Current Status
Status and Reasons for Designation
Status: Special Concern |
Alpha-numeric code: Not applicable |
Reasons for designation: This rare fly is restricted to a very small area of unglaciated Beringia in southwestern Yukon. It is known from 11 largely isolated locations where it occurs in active to semi-stabilized dunes. It is a parasite of the larvae of a dune moth. The threats include a continuing decline in habitat caused by succession on dunes and the use of all-terrain vehicles in some areas which destroy required dune vegetation. |
Applicability of Criteria
COSEWIC History
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.
COSEWIC Mandate
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) determines the national status of wild species, subspecies, varieties, and nationally significant populations that are considered to be at risk in Canada. Designations are made on all native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fish, lepidopterans, molluscs, vascular plants, lichens, and mosses.
COSEWIC Membership
COSEWIC comprises representatives from each provincial and territorial government wildlife agency, four federal agencies (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biosystematic Partnership), three nonjurisdictional members and the co-chairs of the species specialist groups. The committee meets to consider status reports on candidate species.
Definitions (2010)
Wildlife Species
A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.
Extinct (X)
A wildlife species that no longer exists.
Extirpated (XT)
A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.
Endangered (E)
A wildlife species facing imminent extirpation or extinction.
Threatened (T)
A wildlife species likely to become endangered if limiting factors are not reversed.
Special Concern (SC)*
A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.
Not at Risk (NAR)**
A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.
Data Deficient (DD)***
A category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.
* Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.
** Formerly described as “Not In Any Category”, or “No Designation Required.”
*** Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” (insufficient scientific information on which to base a designation) prior to 1994.
The Canadian Wildlife Service, Environment Canada, provides full administrative and financial support to the COSEWIC Secretariat.
COSEWIC Status Report on the Dune Tachinid Fly Germaria angustata in Canada - 2011.
Kingdom: Animalia -- animals, animaux
Phylum: Arthropoda -- arthropods, arthropodes, Artrópode
Subphylum: Hexapoda -- hexapods
Class: Insecta -- hexapoda, insects, insectes, insectos
Order: Diptera -- true flies
Suborder Brachycera -- circular-seamed flies, mouches muscoïdes, muscoid flies, short-horned flies
Family: Tachinidae -- tachinid flies
Scientific name: Germaria angustata (Zetterstedt, 1844) -- Dune Tachinid Fly
Synonyms:
Gonia angustata Zetterstedt
Atractochaeta angustata (Zetterstedt)
Atractogonia angustata (Zetterstedt)
Germaria angustata (Zetterstedt) is a true fly (Order Diptera) in the family Tachinidae. The type locality is the Skåne district of Sweden. The genus Germaria Robineau-Devoisdy 1830 is a group of 13 species restricted to the Nearctic and Palearctic regions (Ziegler 2010; D.M. Wood, pers. comm. 2009; O’Hara 2008; O’Hara and Wood 2004; Herting and Dely-Draskovits 1993); G. angustata is the only member of the genus in the Nearctic region (O’Hara and Wood 2004; Wood 1994). There are no subspecies described. There is no official English name; the name “Dune Tachinid Fly” given here refers to the fact that this species is restricted to active aeolian sand.
Germaria angustata is a shiny black, medium-sized fly, approximately 9 mm long (Figures 1, 2). Like other tachinids, it has long, stout bristles on its head, thorax, and abdomen; and a well-developed, convex subscutellum. Some parts of the body are covered in a waxy pruinosity, creating patterns of blue-grey on the otherwise shiny black surface. The eyes are burgundy in colour. The antennae of tachinid flies have a small branch, the arista, made up of three segments called aristomeres. Although the first aristomere of G. angustata is inconspicuous, the second aristomere is elongated and slightly curved (Figure 2). The third aristomere is flattened side-to-side, so that in lateral view it appears to be broader than it does in dorsal view (Figure 2). The robust arista thus has a distinctive, elbowed appearance that is visible with only small magnification, making field identification of the genus relatively easy.
The larva has not been collected or described.
Figure 1. Dorsal (top) and lateral (bottom) views of a male Germaria angustata from Carcross, Yukon. Fly is approximately 9 mm long. Photos by Shannon Mahony and James O’Hara, Agriculture and Agri-Food Canada; used with permission.
Figure 2. Close-up of the head of the male Germaria in Figure 1, showing the elbowed arista of the antenna. Note the elongated second aristomere and (arrow) the flattened third aristomere. Photo by Shannon Mahony and James O’Hara, Agriculture and Agri-Food Canada; used with permission.
Little information is available, but because of their need for active, aeolian sand habitat, and their parasitic dependence on a host moth, populations are isolated and often small. A few, such as those at Carcross, are probably significantly larger than most. There is no information on genetic variability, but Yukon specimens have been submitted to J. Ziegler at the Museum für Naturkunde in Berlin for a study on global genetic variability in this species.
Because all populations are restricted to the southwestern Yukon, and there is no evidence of genetic or morphological variability among populations, there is only one designatable unit.
Germaria angustata (and its frequent companion, the Baikal Sedge, Carex sabulosa Turcz. ex Kunth) represent a group of invertebrate and plant species (a number of which are scientifically undescribed and unnamed) that, in Canada at least, are restricted to active dunes in the southern Yukon. Other species in this group have not been considered for assessment by COSEWIC partly because they are not described and named, and partly because little is known of their distribution and biology.
They include (Polak 1989; D.M. Wood, pers. comm. 2009):
- Platycheirus new species (Diptera: Syrphidae)
- Coloradomyia new species (Diptera: Tachinidae; also known from Nogahabara Dunes in Alaska)
- Exorista new species (Diptera: Tachinidae)
- Panzeria new species (Diptera: Tachinidae).
Gnorimoschema ligulatum Povolny, a gelechiid moth, is described andknown only from the Carcross dunes, but this distribution restriction may be the result of undercollecting (Nazari and Landry 2009).
Other dune specialist species in the Yukon dunes have a broader, but still restricted distribution in North America. For example, the tachinid fly Allophorocera sajanica Mesnil is known from the dunes at Kusawa in the southern Yukon and the Lake Athabasca dunes in Saskatchewan. Its presumed host, the Kamchatka Crane Fly, Tipula kamchatkensis Alexander, is known from the Yukon dunes, the Athabasca dunes, and a few dunes in the Northwest Territories (Polak 1989). Gnorimoschema vastifica Braun, a gelechiid moth, is the most common species of its genus in the Yukon dunes, and is also found in dunes in Alberta, Saskatchewan, and Alaska (Nazari and Landry 2009).
In Eurasia, G. angustata is found in two distinct areas--Europe, and a part of central Asia, centred on Mongolia and including adjacent northern China and southern Siberia (Figure 3). The separation of the two Eurasian regions may reflect poor collecting effort. In Europe it is rare at coastal dunes along the North Sea and Baltic Sea coasts, and is even more sparsely distributed in the interior (Tschorsnig and Herting 1994; Belshaw 1993). In the United Kingdom, it has been collected only once in the past 70 years (Raper 2007). Joachim Ziegler (in litt.) has assembled data for all known Eurasian collection records: 33 coastal European sites (United Kingdom, Belgium, Netherlands, Germany, Denmark, Sweden, Poland, Lithuania, and Finland); 7 interior sites (Germany, Slovakia, Hungary, Ukraine, and Russia); and 17 central Asian sites (Mongolia, China, and Russia). Although there are published reports for sites in Transcaucasia and the Czech Republic, these are in error (J. Ziegler, pers. comm.).
In North America, it is known only from dunes in the southwestern Yukon (Wood 1994; Polak 1989; Canadian Wildlife Service fieldwork 2008-2009).
Figure 3. Global distribution of Germaria angustata. Some locations in Mongolia and China are approximate.
The species is known from 14 individual sites that make up eleven ‘locations’ as defined by COSEWIC (Table 1) in eight dune complexes in the southwestern Yukon: Carcross/Bennett Lake; Kusawa (upper Takhini River); Alsek River in Kluane National Park and Reserve; Slims River in Kluane National Park and Reserve; Sekulmun Lake; two, small, cliff-top blowouts near Champagne; similar blowouts around Whitehorse; and one isolated ridge-top blowout southeast of the Sekulmun Lake dunes (Figures 4, 5).
In calculating the number of locations, the three sites along the west bluffs of Whitehorse were considered one location. These sites, although separated by unsuitable habitat of up to 1 km, are part of the same bluff/sand complex. The next site north is 5 km away, so was considered a separate location, as it is unlikely to share a single threat (development, disturbance by vehicles, invasive plants, etc.). At the southeast corner of Whitehorse, the Schwatka Lake site was considered separate from the location on the north side of Riverdale; these locations are about 2 km apart across a suburban landscape, and about 2.4 km apart following the forested bluff edge. The Carcross dunes were sampled as two separate sites but are really part of one contiguous dune complex, so are considered one location united by threats such as invasive plants and disturbance by all-terrain vehicles. The two sites along the Dezadeash River near Champagne are along the same side of the river and only 700 m apart, so they were also considered the same location, because any local disturbance and development threats are likely to affect both sites.
It is possible that two of the locations around Whitehorse (those north of Riverdale and along the west side of the city) are sink populations, only maintained by immigration from the slightly larger populations at Schwatka Lake or perhaps from those 5 km north of the city. These are very small sites, fragmented by unsuitable forested or silty habitat, and no more than one fly has ever been captured in a visit.
Using a convex polygon around all Canadian sites, the extent of occurrence is approximately 15,600 km². Using a 2x2 km grid, the species is known to occupy 12 grid squares, for an index of area of occupancy of 48 km². The actual area of occurrence is at most approximately 200 ha, or 2 km². Much of this area is unvegetated sand in the large dunes, which is unsuitable habitat for this species.
Even though the Canadian distribution of G. angustata is probably incompletely known (see Search effort below), the dunes that it requires are small and sparsely distributed, and it is most likely confined to the southwestern Yukon.
There is no Aboriginal Traditional Knowledge (ATK) concerning distribution available for this species at this time.
Prior to 2008, active searches for this species in Canada were limited to the dunes at Carcross, Yukon; Lake Athabasca, Saskatchewan; and the Great Sand Hills, Saskatchewan (Figure 4).
Figure 4. North American distribution of Germaria angustata (red dots). Other sites where specific but unsuccessful searches have been made are located by crossed dots.
The Carcross dunes were visited seven times in the 1980s by D.M. (Monty) Wood and his colleagues, although most visits were relatively brief. Nevertheless, at least 231 specimens of G. angustata were collected in that decade.
In 1988, Michal Polak and Monty Wood searched specifically for this species at a number of locations, but found it only at Carcross (Polak 1989). They surveyed the dunes along the south shore of Lake Athabasca, Saskatchewan, within a 2 km radius of a base camp at Yakow Lake (approximately 59° 12’ N, 108° 02’ W). Collections were made from June 23 to July 5, during warm and mostly sunny weather. They also surveyed the Great Sand Hills of Saskatchewan in mid-June that year, for several days. Finally, they searched the Kobuk and Nogahabara dune complexes in western Alaska; about a week was spent at each site in July (Figure 4; D.M. Wood, pers. comm. 2009).
In 2008, Syd Cannings and Lea Randall visited the Carcross dunes three times in late June and early July; the dunes west of the Takhini River near Kusawa Lake once in late June; and the Alsek dunes at the confluence of the Dezadeash (Alsek) and Kaskawulsh Rivers for two days in late June. Cliff-top sand sites in Whitehorse (Schwatka Lake, Riverdale, Mountain View Golf Course) were visited on one or two brief visits each (Randall and Cannings 2008).
For the 2009 inventory (led by S. Cannings, Canadian Wildlife Service), potential sites were identified first using a map of aeolian sand deposits in southern Yukon provided by Steve Wolfe of the Geological Survey of Canada (Figures 6, 7). To check for active dunes, i.e., those potentially inhabited by Germaria, the sites were assessed further using satellite imagery from GoogleTM Earth, and aerial photos from the library of the Yukon government’s Energy, Mines and Resources department. Some small sites in Whitehorse were identified by sight alone. Identified sites were prioritized for visit by apparent suitability and by ease of access.
In all of Yukon it is estimated that there are approximately 30 potential sites. Of these sites, 26 were visited in 2009 at least once for a minimum of 30 minutes during good weather. Dune Tachinid Flies were absent from half of these sites. Site visits are detailed in Table 3 and sites are mapped in Figure 5. Search effort in 2008 and 2009 totaled approximately 64 person-hours.
Four Yukon sites that hold potential for Germaria were not visited, primarily because of difficulty of access. These are mapped in Figure 5 as open circles. Two dunes are in the immediate vicinity of the Takhini River dune (Kusawa Territorial Park) but, because they lie on the east shore of the river, are only accessible by canoe or helicopter. These may be considered part of the same location,as defined by COSEWIC. Similarly the dunes along the Alsek River, 25 km south of those at the junction of the Kaskawulsh and Dezadeash Rivers, were inaccessible without the use of a helicopter or raft. Finally, small cliff-top dunes along the Yukon River, 10 km N of Big Salmon Village, appear similar in photographs to those at Whitehorse.
Although there are many aeolian sand deposits west of Pelly Crossing (Figure 6), no open, active dunes could be seen in aerial photographs, and no sites were ground-checked during Germaria flight season. One large dune complex immediately south of the confluence of the Pelly and Yukon Rivers (at directional arrow east of Pelly Crossing in Figure 6) was visited in early October, 2009, but no active sand areas were found.
Figure 6. Aeolian deposits of the southern Yukon. Map courtesy of Stephen Wolfe, Geological Survey of Canada, Ottawa.
Figure 7. Aeolian deposits of the southwestern Yukon (enlarged from lower inset in Figure 6). Vegetated, stabilized dunes in orange; active dunes in red; direction of transporting winds marked by arrows. Map courtesy of Stephen Wolfe, Geological Survey of Canada, Ottawa.
There are a few active dunes in the NWT (S. Wolfe, pers. comm.), but these are outside Beringia and similar sites in Saskatchewan have been surveyed without success (Polak 1989). A brief focused survey (Greg Pohl, Colin Jones, Syd Cannings for 3 hours in 2010) and numerous general insect surveys in the region of Fort Smith (which has a number of sandy sites in and around the settlement) have recorded probable host moths, but no Germaria specimens. There have been general insect surveys, but no focused surveys for Germaria in the dunes in the Jasper, Alberta area, where probable host moths have been found. Finally, there have been a number of general insect surveys of the coastal dunes of British Columbia (e.g., at Naikoon Provincial Park on Graham Island, and Pacific Rim National Park on Vancouver Island), but there may have been no specific searches for tachinid flies there.
In summary, it is possible that G. angustata occurs at a few more sites in the Yukon, but these would probably result in a total of fewer than 20 locations. There are also other possible sites in northwestern Canada outside the Yukon, but these are considered unlikely to have G. angustata populations. Similarly, dunes elsewhere in Canada including the prairie region and Great Lakes have been subjected to extensive study by entomologists without any indication of G. angustata occurring there (D.M. Wood, pers. comm.). Finally the surveys noted above that contribute to these conclusions were completed in appropriate mild, sunny weather as indicated or involved relatively long periods when such weather likely occurred, so that weather is not considered a constraint of the analysis.
Germaria angustata is restricted to sites where its (as yet unknown) host moth lives, and to habitats that meet the requirements of the larva of this moth. Throughout its range, it is restricted to active dunes, although the dunes can be found anywhere from coastal Europe to the subalpine zone in the Yukon.
In the southwestern Yukon, G. angustata is found in active dunes and blowouts with sparse vegetation, where sand is being deposited but the dune is somewhat stabilized. All sites where it was found in 2009 are >60% open sand. However, much of the area of large dunes such as those along the highway north of Carcross, or those along the Takhini River, are essentially 100% open sand, and these areas support few if any G. angustata. Photographs of most of the sites are presented in Figures 8-22; these photographs were all taken in 2008 and 2009.
Figure 8. Dunes at Bennett Lake beach, Carcross. SW from 60.1776°N 134.7295°W, 1 June 2009. Photo: S. Cannings.
Figure 9. Typical G. angustata habitat at the Bennett Lake beach dunes. Common plants include: Calamagrostis purpurascens, Elymus calderi, Bromus pumpellianus, Carex sabulosa, Polemonium pulcherrimum, Artemisia frigida, and Aster sibiricus. N from approx. 60.1776°N 134.7295°W, 22 July 2009. Photo: L. Schroeder; used with permission.
Figure 10. Dunes 2 km N of Carcross, along Klondike Highway. Sparse cover in foreground is Carex sabulosa; Germaria angustata isnot present in this grassless habitat. Note off-road vehicle disturbance. S from 60.1864°N 134.6936°W, 20 June 2008. Photo: S. Cannings.
Figure 11. G. angustata habitat at the Carcross dunes: Baikal Sedge (Carex sabulosa), grasses (Bromus pumpellianus, etc.) and wildflowers (Lupinus kuschei, Aster sibiricus, Polemonium pulcherrimum). Note off-road vehicle disturbance. N from 60.1881°N 134.6934°W, 1 June 2010. Photo: S. Cannings.
Figure 12. Alsek dunes at confluence of Kaskawulsh and Dezadeash (Alsek) Rivers, Kluane National Park and Reserve. Vegetation includes Carex sabulosa, Equisetum arvense, Lupinus kuschei, and Artemisia tilesii, with occasional clumps of Juniperus communis. W from 60.6680°N 137.8003°W, 2008. 26 June 2008. Photo: S. Cannings.
Figure 13. Mixed Carex sabulosa-grass-Lupinus kuschei-Penstemon gormani-Artemisia tilesii community, Alsek dunes. NE from 60.6698°N 137.8000°W, 26 June 2008. Photo: S. Cannings.
Figure 14. Aerial view of the dune on the west side of the Takhini River, 6.8 km NNE of Kusawa Lake. Large dune is approximately 900 m long, but most of this dune is not appropriate habitat for G. angustata. NW from approximately 60.660°N 136.064°W, 13 October 2009. Photo: J. Meikle, Kwanlin Dun, First Nation; used with permission.
Figure 15. Vegetated dune swale on the west side of the Takhini River, 6.8 km NNE of the outlet of Kusawa Lake. Appears as greyish streak on near side of dune in centre of Figure 14. Common plants include Carex sabulosa, Elymus calderi, and Lupinus kuschei. NNE from 60.6679°N 136.0763°W, 19 June 2009. Photo: S. Cannings.
Figure 16. Aeolian sand and active dunes on top of lacustrine silt cliffs eroded by Yukon River, 5 km N of Whitehorse. SW from 60.7748°N 135.0826°W, 17 July 2008. Photo: S. Cannings.
Figure 17. Blowout on top of bluffs above Yukon River, 5 km N of Whitehorse (in middle distance of Figure 15): common plants include Penstemon gormanii, Oxytropis campestris, and Elymus calderi. N from 60.7736°N 135.0863°W, 7 June 2009. Photo: S. Cannings.
Figure 18. Aeolian sand and dunes on top of coarser sediments on Lookout Hill, at north end of Schwatka Lake reservoir, Whitehorse. Dominant grasses are Oryzopsis hymenoides, Elymus calderi, and Calamagrostis purpurascens. W from 60.6940°N 135.0322°W, 12 July 2008. Photo: S. Cannings.
Figure 19. Stabilized dunes and small blowouts; aeolian sand on top of silt bluffs, west of downtown Whitehorse. Calamagrostis purpurascens in foreground; other vegetation dominated by Artemisia frigida, Carex supina, and Elymus trachycaulus. NNW from 60.7249°N 135.0712°W, 2 July 2009. Photo: S. Cannings.
Figure 20. Dunes at confluence of Bullion Creek and Slims River, Kluane National Park and Reserve. Dominant plants are Elymus calderi and Artemisia frigida. SSW from 60.9608°N 135.6348°W, 3 July 2009. Photo: S. Cannings.
Figure 21. Beach dunes at north end of Sekulmun Lake. Foreground vegetation includes Bromus pumpellianus, Hierochloe hirta ssp. arctica, Artemisia alaskana, Lupinus kuschei, Phlox hoodii, and A. uva-ursi. This was the site with the densest populations of G. angustata.WNW from 61.5619°N 137.5418°W, 13 July 2009. Photo: S. Cannings.
Figure 22. Ridge-top aeolian sand and small blowouts in subalpine zone (1200 m el.) between Aishihik and Sekulmun Lakes. E from 61.4049°N 137.3540°W (on helicopter approach), 13 July 2009. Photo: S. Cannings.
Figure 23. Increased ATV use at Carcross over the past 30 years may have caused a decline in the area of appropriate habitat for G. angustata. W from approximately 60.1852°N 134.6929°W, 20 June 2008. Photo: S. Cannings.
Although the sites vary in size and in plant community composition, a consistent feature is the presence of scattered grasses. Polak (1989) noted that G. angustata has been observed to lay eggs on the grass Bromus pumpellianus, and inferred that the larva of its host moth probably eats grasses. No single grass species occurs at all sites, but Festuca saximontana, Bromus pumpellianus, Calamagrostis purpurascens var. purpurascens, and Elymus calderi are frequent, and E. trachycaulus is sometimes present (Table 3). Baikal Sedge, Carex sabulosa (listed as Threatened under the Species at Risk Act) is a dominant feature of many of the sites, but Germaria is found at a number of sites where C. sabulosa is absent, and is absent at a number of sites where C. sabulosa is present. In fact, G. angustata was never found where C. sabulosa was the only plant species present. Other frequent plant species include Artemisia campestris, A. frigida, Aster sibiricus, Equisetum arvense, Lupinus kuschei, Oxytropis campestris, Penstemon gormanii, Pinus contorta, Populus balsamifera, P. tremuloides, Polemonium pulcherrimum, Solidago simplex, and Stellaria longipes (COSEWIC 2005; inventory associated with present report, Table 2).
Dunes are maintained by a constant source of open sand and consistent winds. At Carcross and Sekulmun Lakes the source is abundant beach sand, and the lakes are oriented so that the prevailing southerly winds hit the beach with force (Figures 8 and 19). At the various river sites, the river runs through deposits that are either wholly sand or are capped by thick sand deposits. These deposits are kept open through constant erosion from below, and are blown into dunes where the river runs at right angles to the prevailing wind (e.g., Figure 15).
The elevation of these sites ranges from 660 m at Bennett Lake to 1450 m on the ridge between Sekulmun and Aishihik Lakes.
There are several aeolian sand sites with active blowouts in southwestern Yukon that are not now directly associated with a lake or a river (e.g., Robinson, Taye Lake, and Dezadeash Lake areas), but G. angustata has not been found in these blowouts which are among those mapped in Figure 5 as “searched but without finding G. angustata”.
In the long term, the dune habitat of Germaria angustata in Canada has been substantially reduced since glaciation through natural succession (Figures 5, 6). The few, small active dunes that remain are those that can be maintained by a consistent source of materials and consistent winds (see Habitat section above).
Air photos taken during the mid-1940s and, more recently, between 1977 and 1999, indicate that all but one of the larger dune systems remain unchanged. Only the Bennett Lake dunes at Carcross show significant changes between 1948 and 1999. There appears to be a reduction of about 15 to 20% in dune area at this site (COSEWIC 2005).
The Alsek dunes located at the junction of the Kaskawulsh and Dezadeash Rivers in Kluane National Park are younger than most of the other dunes in the region, because they are located on the site of Recent Lake Alsek. This proglacial lake, formed by the damming of the Alsek River by the Lowell Glacier, existed as late as 1852, and would have been about 10 to 50 m deep at the present dune site (Kindle 1952; Johnson and Raup 1964). Portions of these young dunes now appear to be undergoing stabilization as vegetation invades (although there is no time sequence data), and it seems likely that the active dunes will be smaller in the future.
G.W. Douglas (in COSEWIC 2005) made the observation that, between 1974 and 2003, the large central area of the dunes along the Klondike Highway near Carcross has “remained mostly unvegetated.” In other words, he saw no noticeable decrease in vegetation at that site in recent decades. He reasoned that vegetation was not able to establish there because of the exceptionally strong winds that come off Bennett Lake and directly hit the southwest-facing slope below Caribou Mountain. This may be true for the primary, steeper slope, but local residents recall that, in general, the dunes next to the highway were more vegetated with grass and flowers in the 1970s than they are now (R.L. Mennell, pers. comm. 2009). Figure 24 and 25 compare the Carcross dunes as they were 26 years ago in 1984 with a 2010 view. Today, there are only small patches of sparse grass and forbs in this part of the complex; even areas that are relatively flat are mostly completely devoid of vegetation (Figure 11). It is possible that up to 10 ha of formerly suitable habitat has been degraded; approximately 12% of the Carcross complex. The cause of this decline is undoubtedly the increase in recreational motorcycle and All-terrain Vehicle (ATV) traffic in that area in the past 30 years (Figures 10, 11, and 23). Motorized traffic has also destroyed vegetation in small, linear portions of the Carcross beach dunes.
Figure 24. Northern section of the Carcross dunes, east of the Klondike Highway, 2 km N of the village. NNE from about 60.1866°N 134.6951°W, 29 August 1984. Compare vegetation with present-day photo in Figure 25. Photo: C. Kennedy; used with permission.
Figure 25 Same view as Figure 24; 1 June 2010. Note apparently increased disturbance, smaller patches of vegetation, and virtual absence of vegetation on steeper, open slope. Photo: S. Cannings.
Figure 26. Frequency of 30-minute sample sizes of G. angustata specimens taken at sites where at least one specimen was captured on that day.
In summary there is solid evidence of recent habitat decline only at Carcross. However, natural succession at the Alsek dunes appears to be causing a decline in active sand movement there as well. It should be noted that these are the sites of the two largest populations of G. angustata known in Canada. Although there are threats in other locations (e.g., invasion of exotic plants), a future decline at those sites cannot be inferred at this time based on available evidence.
Little is known of the biology of this species; however, based on direct observations of its behaviour, phenology, and knowledge of other tachinids, some reasonable speculations of its life history can be made. Tachinid flies are parasitoids of the larvae of other insects, often moth caterpillars. The host of G. angustata is unknown.
Adult G. angustata have been collected in the southern Yukon from 9 June to 23 July. In 2009, during a relatively intensive sampling season, the last flies were seen on July 22; however, that summer was hotter and drier than usual in June and July, so the flight season may go later in more moderate years. In coastal Europe the flight season is definitely longer, from late May to mid-August (Belshaw 1993; Herting 1960; Tschorsnig and Herting1994).
At Carcross, females of G. angustata fly low over the open sand, alight on single stems of grass (e.g., Bromus pumpellianus), walk to the base of each, and apparently lay an egg there (Polak 1989; D.M. Wood, pers. comm. 2008). At Whitehorse in 2009, flies were seen landing on stalks of Elymus calderi and running quickly up and down the stalk (S. Cannings, pers. obs.). The eggs probably hatch quickly into a first instar larva that waits for a host caterpillar to come by. Because of the egg placement at the base of grass stems, D.M. Wood (pers. comm. 2008) hypothesizes that the host of G. angustata is a cutworm larva (a moth in the family Noctuidae) that burrows in the sand during the day and comes to the surface at night to feed on the base of the grass.
A dune-inhabiting cutworm species that is found at Whitehorse and Carcross, and has a very similar global range to that of G. angustata is the Coast Dart, Euxoa cursoria (Hufnagel). E. cursoria larvae are generalist herbivores, feeding on a variety of grasses and forbs growing in sand (Don Lafontaine, pers. comm. 2008; De Prins 2005). Adult E. cursoria fly from late July to the end of the summer; the next generation overwinters as eggs or small larvae and begin feeding the following spring. Pupation takes place deep beneath the sand surface (Don Lafontaine, pers. comm. 2008; De Prins 2005).
The known hosts of two species of Eurasian Germaria are moths in the family Sesiidae (Richter 1992); however, this does not mean that G. angustata is likely to have a similar host (D.M. Wood, pers. comm. 2009). There are two species of sesiids known from the Yukon, but neither is specific to dunes (Lafontaine and Wood 1997, D. Lafontaine, pers. comm. 2009) and sesiids are not known to use grasses as hosts (G. Anweiler, pers. comm. 2010).
There is no direct information on physiology.
The flies are active in cloudy or sunny weather. The lower temperature limit for activity is not precisely known, but flies are definitely active on cloudy days when the temperature is about 14°C. Activity probably increases with increasing temperature, but it is not possible to measure this using present data. The upper temperature limit is also unknown, but this would probably not normally be encountered by flies in Yukon dunes.
The flies are also active in the open dunes during very windy days, but a number have been seen congregating in the lee of small poplar trees on these days (Lee Mennell, pers. comm. 2009).
Adaptability may be considered limited, because G. angustata is restricted to areas of active dunes and sand blowouts; this narrow habitat niche is probably related to that of a specific moth host. On the other hand, this fly is able to live in a wide variety of dunes from moderate seaside climates in Europe to the subalpine zone in the continental climate of boreal North America.
No information is available. These flies, although relatively small, are strong fliers, presumably capable of flights of a number of kilometres. They could also be blown greater distances by strong winds. However, there is no data on how often they leave the small dune areas in search of new habitat.
No information is available.
During the 2009 survey, most sites were sampled for at least 30 minutes between 10:00 am and 5:00 pm PDT in favourable weather (favourable weather is defined as any day warmer than 14° C and not raining, because cloud cover and wind did not appear to significantly inhibit fly activity). Surveyors walked in a meandering path through presumed good habitat for 30 minutes, catching every tachinid fly encountered. In larger sites, care was taken to continually sample ‘new’ habitat; in smaller sites, some retracing of steps or crossing of paths was necessary. Flies were caught with standard 15-inch aerial insect nets. Air temperature, cloud cover and, in some cases, wind velocity was recorded.
In 2008, Malaise traps were tested in sampling Germaria but, primarily because of constant wind, they proved unsuccessful. Traps not only blew down in the loose sand, but the wind vortices in the trap rendered them ineffective (Randall and Cannings 2008).
Population size is difficult to estimate, but 30-minute searches in appropriate habitat resulted in samples of up to 13 specimens, usually 0 to 7 (Figure 26). Intensive inventories at Carcross in the 1980s resulted in up to 67 specimens being captured in 1-2 days, based on specimens at the Canadian National Collection. At the larger sites (e.g., Carcross, Sekulmun, and Alsek), one could speculate that more than 100, and perhaps several hundred flies are active in early July. Still, because appropriate habitat is limited, and because these are parasitic flies, the populations are undoubtedly quite small relative to most insect populations. Populations at some of the very small dunes around the city of Whitehorse may be maintained only by immigration from the two larger sites there.
No quantitative information is available, because earlier sampling programs were not done systematically, and did not record search effort. At Carcross, there is no qualitative evidence that the species is more or less abundant now than when it was sampled in 1987. D.M. Wood (pers. comm. 2009) believes that, like other tachinid flies, the populations can fluctuate dramatically from year to year. This was not evident, however, in sampling in 2008 and 2009.
Rescue effect is probably nil. This species has yet to be discovered in Alaska, and even if it were found at the Kobuk or Nogahabara dunes in northwestern Alaska (Figure 4), it would not likely to be able to traverse the intervening 1000 or so kilometres and find a small dune in southwestern Yukon.
Mapping of the aeolian sand deposits in the territory (Figures 6, 7) suggests that dunes were common in the Yukon and other northern landscapes during the last ice age (Stephen Wolfe, pers. com. 2008). However, most of these dunes have since been covered by boreal forest through natural succession. Succession is still occurring, but in active dune areas, blowouts can create new dune habitat at the same time other areas are lost to vegetation. Natural succession may be an increasing limiting factor at the Alsek dunes in Kluane National Park. There, the dunes are only about 150 years old, being formed following the flooding and subsequent catastrophic draining of Glacial Lake Alsek in the mid-19th century.
Invasive species are perhaps the greatest threat to Canada’s G. angustata populations. Invasive dune stabilizers such as Leymus angustus (Altai Wild Rye) are beginning to encroach upon the Carcross Dunes area (B. Bennett, pers. comm. 2009). This species was first noted along a roadside in the Carcross village area in 1998, and is now more widespread in Carcross and along the South Klondike Highway from Lewes Lake, Yukon, south to the White Pass summit (BC-AK). At this time, it remains primarily confined to roadsides and has yet to invade the dunes (B. Bennett, pers. comm. 2009). Melilotus alba (White Sweet-clover) was first discovered in the Carcross dunes at the South Klondike Highway site in 2009, and is also beginning to invade the Dezadeash River corridor, possibly threatening the riverside sites in the Champagne area. This species could move downstream along the Dezadeash to the dunes along the Alsek River (B. Bennett, pers. comm. 2009). Based on knowledge of these invasive species in other jurisdictions, the effects of their establishment at the dunes could be severe in a very short time period (Conn et al. 2008).
Recreational use of ATVs and motorcycles is not a threat for populations in Kluane National Park, and for those in the dunes located on the east side of the Takhini River, as these sites are fairly inaccessible and are not visited often by humans. However, recreational use may pose a problem for other populations (west side of Takhini River, Carcross, Whitehorse, and Champagne), as they are more easily accessed.
Use of motorized recreational vehicles in the dunes can compact the sand, and remove and physically kill vegetation. This is of particular concern in the Carcross dunes, where off-road vehicle use is prevalent. There is anecdotal evidence that the grass and sedge vegetation on the main Carcross dune along the Klondike highway has declined since the great increase in off-road vehicle use in the last 30 or so years (Figures 10, 11, 23-25; see Habitat trends above). However, in some areas light ATV traffic may promote habitat for the moths and their Dune Tachinid predators.
Since 2007, a local tour company has been offering summer ATV excursions through the dunes along the Klondike Highway. Most of these are packaged tours for Holland America cruise passengers. It appears the tours generally follow the same route each time, limiting their impact to a small area. However, the impact these tours are having has not been studied. In addition to this commercial venture, individual citizens also use the dunes along the Klondike Highway on a regular basis for ATV and motorcycle recreation in summer (Figure 22). This use has apparently increased greatly over the last 25 years, but as yet, no monitoring program has been initiated to quantify this use and to understand its effects (Baikal Sedge Draft Recovery Strategy 2009
Snowmobiles are also used extensively in the Carcross dunes. It is estimated that up to 30 snow machines can be using the dunes during a winter weekend (Barrett, pers. comm., in Baikal Sedge Draft Recovery Strategy 2009). While the snow machines are using the dunes primarily when they are covered with snow, they may have a compacting effect. Snow may be quite shallow in certain areas at times, and snow machines may damage vegetation in these cases. Erosion of sand along the crest of dunes has been observed in Carcross (Baikal Sedge Draft Recovery Strategy 2009). Again, the impacts of these activities are unclear, and increased monitoring would be required to develop a clearer picture of the effects of snow machines.
There is no existing protection for this species.
Tachinid flies have not been ranked in the National General Status program. NatureServe ranks Germaria angustata G4G5 (apparently or demonstrably secure) globally; The Yukon Conservation Data Centre (Environment Yukon) ranks it S2 (Imperiled) in the Yukon.
Two populations of G. angustata occur in Kluane National Park and Reserve: one at the confluence of the Dezadeash and Kaskawulsh rivers, and the other along the Slims River at the Bullion Creek confluence. The dune systems along the Takhini River are protected within Kusawa Territorial Park. The remaining locations are not specifically protected; their ownership is detailed in Table 1.
The report writer would like to thank Monty Wood, for introducing Germaria angustata to him in Carcross in 1987, and for introducing it to COSEWIC 20 years later. He also worked many hours identifying flies collected during the 2008 and 2009 inventories. Joachim Ziegler, of the Museum für Naturkunde in Berlin, freely shared his data on Eurasian Germaria.
Lea Randall, Lee Mennell, and Lori Schroeder provided wonderful field and lab assistance in 2008 and 2009. Other field assistants included Kaz Kuba, Fiona Schmiegelow and John Spence. Bruce Bennett and Jennifer Line offered botanical advice. Surficial geologists Jeff Bond and Stephen Wolfe greatly aided in the search for aeolian sand, and Stephen kindly offered his Yukon map. Jim O’Hara gave the report writer access to the Canadian National Collection, and arranged for Shannon Mahony to take the fly photographs in that institution. Don Lafontaine, Jean-François Landry, and Vazrick Nazari passed along their expert knowledge of dune moths.
John Meikle provided advice on dune locations, provided photographs, and searched out some remote sites.
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Syd Cannings is a Species at Risk Biologist in the Canadian Wildlife Service in Whitehorse. He received his MSc in Zoology at the University of British Columbia in 1978, studying, among other things, the physiological ecology of water boatmen. Following graduation, he became the curator of the Spencer Entomological Museum, the major insect collection at UBC. In that position, he began a series of insect surveys to the Yukon, from 1979 to 1990, in order to help compile data on the distribution of the insects in the territory for the book Insects of the Yukon. Beginning in 1991, he spent 11 years as the Program Zoologist for the BC Conservation Data Centre in Victoria and became interested in assessing the status of species at risk. From 2000 to 2003 he was a Research Zoologist for NatureServe, ranking, compiling data and establishing data standards for birds and mammals throughout North America. Over the years, Syd has collaborated with his brothers on a number of books, including: Birds of the Okanagan Valley; British Columbia: A Natural History; The BC Roadside Naturalist; Geology of British Columbia; and The World of Fresh Water.
The Canadian National Collection (Agriculture and Agri-Food Canada, Ottawa) was examined for specimens; these are detailed in Table 2. The collections of the Beaty Biodiversity Museum (Spencer Entomological Collection), University of British Columbia; and the Royal Ontario Museum were searched, but no specimens were found. The collection data for those specimens collected in 2008 and 2009, and held temporarily at the Canadian Wildlife Service collection in Whitehorse, Yukon, are presented in Table 3.
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