Assessed by COSSARO as Endangered
February 2011
Final

Part 1 COSSARO candidate species at risk evaluation form

February 2011
Nodding Pogonia (Triphora trianthophora)

Current designations:

GRANK – G3G4
NRANK Canada – N1
COSEWIC – Endangered (November 2010)
SARA – Endangered (Schedule 1)
General Status Canada – At Risk (2005)
ESA 2007 – Endangered
SRANK – S1
General Status °ÄÃÅÓÀÀû – At Risk (2005)

Distribution and status outside °ÄÃÅÓÀÀû:

Nodding Pogonia is widespread in eastern North America from southern New England south to Florida and Texas. It also occurs in Mexico, Guatemala, and Panama. It is a rare species throughout much of its range (NatureServe 2011). In Canada it occurs only in southwestern °ÄÃÅÓÀÀû.

Distribution and status in °ÄÃÅÓÀÀû:

Restricted in °ÄÃÅÓÀÀû to two nearby sites in southwestern °ÄÃÅÓÀÀû. The population at one of these sites has not been seen for more than 20 years.

Eligibility criteria

Native status

Yes First found in °ÄÃÅÓÀÀû in 1950 and observed as recently as 2008 (COSEWIC 2010). A non-weedy species at the northern limit of its range.

Taxonomic distinctness

Yes Taxonomically distinct and considered a valid species in all recent taxonomic treatments. °ÄÃÅÓÀÀû plants belong to subspecies trianthophora; subspecies Mexicana occurs in Mexico and Central America (COSEWIC 2010).

Designatable units

Known from two nearby °ÄÃÅÓÀÀû populations, one of which may be extirpated, in the same ecoregion (Great Lakes/St. Lawrence). Should be treated as a single DU in °ÄÃÅÓÀÀû.

Recent arrival

No

Non-resident

No

Primary criteria (rarity and declines)

  1. Global Rank
    Based on G3G4 rank (NatureServe 2011).
  2. Global Decline
    Not in any category. No evidence of global declines though rare in northern parts of its range.
  3. Northeastern North America Ranks
    Highly ranked (S1, S2, SH or SX) in 16 of 18 (89%) northeastern jurisdictions in which it occurs natively and is ranked. Triphora trianthophora is protected as a threatened (TH) or endangered (EN) species in Maine (TH), Vermont (TH), New Hampshire (TH), and Massachusetts (EN); it is thought to be extirpated in Connecticut (Ramstetter 2001). See Appendix 1.
  4. Northeastern North America Decline
    TH. 19 of 43 (44%) New England occurrences are considered extirpated (Ramstetter 2001).
  5. °ÄÃÅÓÀÀû Occurrences
    EN. Known from two °ÄÃÅÓÀÀû occurrences, one of which may be extirpated (COSEWIC 2010).
  6. °ÄÃÅÓÀÀû Decline
    Not in any category. One of the two °ÄÃÅÓÀÀû populations has not been seen since 1987, despite searches in 1998 and 2000, and may be extirpated. COSEWIC (2010) considers this an extant population because the species can remain underground and not visible aboveground and the site has not been visited recently due to lack of landowner permission. Population trends are difficult to assess in this species because the number of flowering stems may not be an accurate indication of the number of mature individuals since squirrels can cache tubers and therefore clumps of flowering stems may not necessarily come from the same plant (COSEWIC 2010).
  7. °ÄÃÅÓÀÀû’s Conservation Responsibility
    Not in any category. °ÄÃÅÓÀÀû makes up only a small fraction (<1%) of the species global range (COSEWIC 2010).

Secondary criteria (threats and vulnerability)

  1. Population Sustainability
    Not in any category. No definite evidence of reproductive or recruitment failure in °ÄÃÅÓÀÀû. The number of flowering stems at the extant °ÄÃÅÓÀÀû population fluctuates, with 1357 flowering stems counted in 2008 (COSEWIC 2010).
  2. Lack of Regulatory Protection for Exploited Wild Populations
    Not in any category. No known harvest in °ÄÃÅÓÀÀû.
  3. Direct Threats
    EN. °ÄÃÅÓÀÀû Nodding Pogonia populations are threatened by invasive plants, exotic earthworms, herbivory, change in land use, drought, stochastic events, and low genetic diversity. Invasive plants have reduced the quality of its habitat and additional limiting factors such as browsing by White-tailed Deer and reduction of the organic layer of the forest floor by exotic earthworms are detrimental impacts to the species (COSEWIC 2010).
  4. Specialized Life History or Habitat-use Characteristics
    EN. Nodding Pogonia grows in rich, moist beech-maple forests with a deep humus layer, a rare habitat type in °ÄÃÅÓÀÀû’s Carolinian Zone. While beech-maple forests are not provincially rare, those with a deep humus layer, preferred by Nodding Pogonia, are rare. Nodding Pogonia requires compatible fungal associates for nourishment throughout its life cycle (COSEWIC 2010). Triphora trianthophora is closely associated with Fagus grandifolia, and the orchid may be receiving nutrients and photosynthates from beech trees via mycorrhizal fungi connected both to the beech tree and the orchid (Ramstetter 2001).

COSSARO criteria met (primary/secondary)

Endangered – 2/2
Threatened – 2/0
Special concern – 0/0

°ÄÃÅÓÀÀû criteria met (primary 5, 6, and 7)

Endangered – [1]
Threatened – [0]
Special concern – [0]

Data deficient

No There are sufficient data to apply COSSARO and COSEWIC criteria.

Recommended Status: Endangered.

Summary

Nodding Pogonia (Triphora trianthophora) is Endangered in °ÄÃÅÓÀÀû. This globally rare (G3G4) orchid of rich woods is widespread in eastern North American and known in Canada from only two small populations. Both populations are in °ÄÃÅÓÀÀû’s Carolinian Zone, and the continued survival of one population is not known. This plant is an underground saprophyte depending upon an association with a fungus and only shows above ground when flowering. The species faces a variety of threats including habitat deterioration caused by invasive plants and exotic earthworms as well as herbivory by deer, change in land use, stochastic events, and low genetic diversity.

Information Sources

COSEWIC. 2010. Update COSEWIC Status Report on Nodding Pogonia Triphora trianthophora in Canada. Committee on the Status of Endangered Wildlife in Canada, Ottawa. Two-month Interim Report (Nov. 2010). 21 pp.

COSEWIC. 2011. Wildlife Species Search – Nodding Pogonia. Committee on the Status of Endangered Wildlife in Canada website. http://www.cosewic.gc.ca/eng/sct1/index_e.cfm [link inactive] (accessed 31 Jan. 2011).

NatureServe. 2011. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available . (Accessed: 31 Jan. 2011).

°ÄÃÅÓÀÀû Ministry of Natural Resources (OMNR). 2010. Species At Risk in °ÄÃÅÓÀÀû (SARO) list (updated September 29, 2010). /page/species-risk (accessed 31 January 2011)

°ÄÃÅÓÀÀû Ministry of Natural Resources (OMNR). 2011. Natural Heritage Information Centre (NHIC), °ÄÃÅÓÀÀû Biodiversity Explorer website. /page/natural-heritage-information-centre (accessed 31 January 2011)

Ramstetter, J. M. 2001. Triphora trianthophora (Swartz) Rydb. (Three-birds Orchid) Conservation and Research Plan. New England Wild Flower Society, Framingham, Massachusetts, USA. 26 pp.

Species at Risk Act Public Registry, 2011. [http://www.sararegistry.gc.ca/default_e.cfm [link inactive]]. (Accessed 31 Jan. 2011).

Appendix 1 Northeastern North America Rank, status and decline

Region Rank
CT S1 (NatureServe 2011)
DE S1 (NatureServe 2011)
IL S3? (NatureServe 2011)
IN SNR (not ranked; NatureServe 2011)
IA S3 (NatureServe 2011)
KY SNR (not ranked; NatureServe 2011)
LB Not present (NatureServe 2011)
MA S1 (NatureServe 2011)
MB Not present (NatureServe 2011)
MD S1 (NatureServe 2011)
ME S1 (NatureServe 2011)
MI S1 (NatureServe 2011)
MN Not present (NatureServe 2011)
NB Not present (NatureServe 2011)
NF Not present (NatureServe 2011)
NH S2 (NatureServe 2011)
NJ S1 (NatureServe 2011)
NS Not present (NatureServe 2011)
NY S2 (NatureServe 2011)
OH S2 (NatureServe 2011)
ON S1 (NatureServe 2011)
PA SH (NatureServe 2011)
PE Not present (NatureServe 2011)
QC Not present (NatureServe 2011)
RI Not present (NatureServe 2011)
VA S1 (NatureServe 2011)
VT S1 (NatureServe 2011)
WI S2 (NatureServe 2011)
WV S2 (NatureServe 2011)

Occurs as a native species in 20 of 29 northeastern jurisdictions SRANK or equivalent information available for 18 of 20 jurisdictions = (90%) S1, S2, SH, or SX in 16 of 18 = (89%)

Part 2 °ÄÃÅÓÀÀû Evaluation Using COSEWIC Criteria

Regional (°ÄÃÅÓÀÀû) COSEWIC Criteria Assessment

Criterion A – Declining Population

Insufficient information. One of two °ÄÃÅÓÀÀû populations may be extirpated.

Criterion B – Small Distribution and Decline or Fluctuation

EN B1ab(iii)+2ab(iii). Meets Endangered B1ab(iii)+2ab(iii) based on very small Extent of Occurrence and Index of Area of Occupancy and presence at only two locations with a continuing decline in the quality of habitat due to invasive earthworms and plants.

Criterion C – Small Population Size and Decline

Insufficient information. There are fewer than 2500 flowering stems in any year (1357 counted is 2008), however the number of mature individuals is not known. More than 95% of the individuals are probably in one location (if one assumes the other location is extirpated or very small) and there may be extreme fluctuation in the number of mature individuals. However the relationship of number of flowering stems to number of mature individuals is not known and plants are known to remain underground making population estimates difficult.

Criterion D – Very Small or Restricted

N/A. There are < 5 populations (1 or 2). The AO is 16 km2 based on 2×2 km squares. Stochastic events such as invasion by earthworms, windstorm or severe fire could endanger the species. However threats may not be sufficient to cause a rapid decline in a short period of time.

Criterion E – Quantitative Analysis

N/A. No quantitative analysis available.

Rescue Effect

N/A. Unlikely to be rescued from adjacent jurisdictions since the species is restricted to a rare habitat, is rare in adjacent jurisdictions, and separated from U.S. populations by large water bodies.