24th Congress for Conservation Biology, Canada 2010
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Status of Endangered Small White Lady's-slipper (Cypripedium candidum) orchid in Canada and its conservation planning
![Status of Endangered Small White Lady's-slipper ( Cypripedium candidum ) orchid in Canada and its conservation planning Aamalesh DHAR Mixedwood Ecology and Management Program, University of Northern British Columbia, 3333 University Way, Prince George, BC, Canada V2N 4Z9 ( Corresponding author : dhar@unbc.ca) Ecological Condition Small white lady’s-slippers orchid naturally inhabit mesic to wet-mesic areas with calcareous soils (Bowles 1983). They are found in areas such as tall grass and mixed-grass prairies, roadside ditches, railroad allowances, abandoned homesteads and in open areas around fens/marshes and prairie sloughs. They thrive under full sunlight conditions (Falb and Leopold 1993). Reproduction (i.e., seed pod formation) of small white lady’s slippers depends on the pollination actions of bees from the families Andrenidae (e.g. Andrena ziziae) and Halictinae (e.g., Halictus confusus ); Catling and Knerer 1980; Brownell 1981, Bowles 1983; Bender 1985). These bees require areas of bare, dry, light soil or exposed banks for nesting sites (Ostlie 1990). Like all orchids, germination and growth of small white lady’s-slipper is dependent on mycorrhizal fungi (Bernard 1904). Genetic variation Most populations of small white lady’s-slippers in Canada tend to be in small, isolated pockets. According to Case (1994) genetic variability was low in populations of only 12 to 3000 individuals. This implies that most Canadian populations may be at risk from low genetic diversity and inbreeding. Hybridization The genetic integrity of small white lady’s-slipper is also at risk across Manitoba and Ontario because the species is known to readily hybridize with the more small yellow lady’s-slipper ( Cypripedium calceolus ) as it has a very high genetic identity (79%) with the Small Yellow Lady's Slipper (Case 1994). There are two subspecies ( C. c. parviflorum and C. c. subescens ) of yellow lady’s slippers and when cross bred with small white lady’s slippers produce C. x. andrewsii and C. x. favillianum respectively. Hybrid plants have been identified from all populations in Manitoba and Ontario (Environment Canada 2006) ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Present distribution of Small White Lady’s-slipper in Canada (Environment Canada 2006) Potential causes of small white lady’s-slipper declination Introduction The small white lady’s-slipper ( Cypripedium candidum Muhlenberg ex Willdenow) is an attractive perennial orchid. It is distributed at southern Ontario and southern Manitoba in Canada as well as eastern and western parts of the U.S.A (Environment Canada 2006; Worley et al. 2009). At present it has recognized as a globally endangered prone of extinction orchid species and in Canada it is categorized as an N2 (endangered) species but in Ontario and Manitoba, this species has Rank of S1 (critically endangered). Less than 7% of the historical distribution of small white lady’s-slipper was found in Canada which occupies approximately 173 ha of land and the area of occupancy and number of extant locations has declined over time (Environment Canada 2006). The main reason for declination of this species are widespread destruction and fragmentation of grassland environments, encroachment by invasive weeds and woody plants, hybridization with other lady’s-slipper species, low genetic variation (Case 1994), inbreeding, isolated populations, orchid collection etc. At present there are only 8 populations in southern Ontario and 15 populations in southern Manitoba have been identified. Among them one population in Manitoba and one in Ontario contain three-quarters of all of Canada’s small white lady’s slippers whereas rest 13 populations have less than 100 individuals and some of these consist of only a few plants along roadside ditches. References (selected) Case, M. 1994. Extensive variation in the levels of genetic diversity and degree of relatedness among five species of Cypripedium ( Orchidaceae ). American Journal of Botany 81: 175-184. Dhar A. Ruprecht H., Vacik H. 2008. Population Viability Risk Management (PVRM) for in-situ management of endangered tree species – a case study on a Taxus baccata L. population. Forest Ecology and Management, 255 (7) 2835-2845 Environment Canada 2006. Recovery Strategy for the Small White Lady’s-slipper ( Cypripedium candidum ) in Canada (proposed). Envir. Canada, Ottawa Punter, C.E. 1999. Update supplement for Manitoba populations of Small White Lady’s-slipper. (COSEWIC Status Report on the Small White Lady’s Slipper Cypripedium candidum ). Committee on the Status of Endangered Wildlife in Canada. 11 pp. Floral biology The small white lady’s-slipper is a diminutive perennial orchid that commonly grows to a height less than 40 cm. One, or rarely two, fragrant flowers in a single stem and mature plants commonly form small dense clumps of 4-20 stems. Flowers appear from May to early June as a white, slipper-like pouch, 2-5 cm long. Flowers may be veined or spotted with fine purple markings on the outside and heavier purple colouring on the inside. Sepals and lateral petals are elongate, twisted, and tend to be pale green with fine purple striations. Two to four firm, strap-shaped leaves crowd the stem. Fruit capsules form in June and July, and are about 2-4 cm long. Fruit begins to open in September and October. Each fruit capsule contains thousands of minute, dust-like seeds. Estimated historical distribution of Small White Lady’s-slipper in North America (Bowles 1983) Manitoba Ontario Young stage of Lady's-slipper Clump of Lady's-slipper orchid Flower Seed pod stage Mature flower Some basic information about small white lady’s slipper populations in Manitoba and Ontario (Environment Canada 2006) Manitoba Ontario Location Recent Pop. Estimate (year) Maximum Recorded Pop. (year) Land Type Site Recent Pop. Estimate (year) Maximum Recorded Pop. (year) Land Type Franklin A (Southeast) 20-30 stems (2000) 47 fl stems (1999) MB road Hastings Co. 638 stems (2003) 638 stems (2003) Provincial Park Tall Grass P. P.(Southeast) 40,000-50,000 stems (2005) 40,000-50,000 stems (2005) Conserv. Orgs. Norfolk Co. 1 fl stem (1993) 100 clumps (1920s) Provincial Park Kleefeld (Southeast) 340 stems (2004) 683 stems (1987) MB road Walpole Is. First Nation # 1 11,600 clumps (2003) unknown First Nations St. Laurent (Interlake) 5000-10,000 stems (2005) 5000-10,000 stems (2005) MB road, private Walpole Is. First Nation # 2 1350 clumps (2003) unknown First Nations St. Laurent new (Interlake) 1938 stems (2005) 1938 stems (2005) private Walpole Is. First Nation # 3 1130 clumps (2003) unknown First Nations L. Francis (Interlake) 241 fl stems (2005) 241 fl stems (2005) private Walpole Is. First Nation # 4 192 clumps (2003) unknown First Nations Woodlands ROW (Interlake) 338 stems (2005) ~600 stems (1997) MB road Walpole Is. First Nation # 5 1 clump (2003) unknown First Nations Woodlands Rail (Interlake) 268 stems (2005) 268 stems (2005) corporation Walpole Is. First Nation # 7 38 clumps (2003) unknown First Nations Brandon Hills(Brandon) > 2000 stems (2002) 6660 stems (2001) MB road, private __ __ __ __ Brandon C (Brandon) 139 stems (2004) 984 stems (1998) MB crown __ __ __ __ Brandon G (Brandon) 60 stems (2002) 1222 stems (1999) MB road __ __ __ __ Causes of Declination Encroachment Trampling by all-terrain vehicles (ATV) traffic Collectors Lack of knowledge about management Altered hydrology Hybridization Loss of genetic variation/inbreeding Invasion by non-native plants Overgrazing](https://image.slidesharecdn.com/p2-192amaleshdhar-100714000224-phpapp02/85/24th-congress-for-conservation-biology-canada-2010-1-320.jpg)
Status of Endangered Small White Lady's-slipper (Cypripedium candidum) orchid in Canada and its conservation planning
