Committee on the Status of Species at Risk in Ontario (COSSARO)
Assessed November 2009 by COSSARO as Endangered
November 2009

Part 1: COSSARO Candidate Species at Risk Evaluation Form – Nov. 2009

Virginia Mallow (Sida hermaphrodita)

Current designations:

GRANK – G3
NRANK Canada – N1
COSEWIC – Not evaluated
SARA – Not listed
General Status Canada – May be at risk
ESA 2007 – Not listed
SRANK – S1
General Status Ontario – May be at risk

Distribution and status outside Ontario:

Endemic to eastern North America, with its distribution centered on the Appalachian Mountains. Considered native in 10 U.S. states, south to Tennessee, and in Ontario, Canada (NatureServe 2009). Rare throughout its range.

Eligibility criteria

Native status

✔ Yes? Virginia Mallow has previously been considered both native and not native to Ontario. It was first documented in Ontario in 1951 by Bert Miller and considered by Scoggan (1978) to be "scarcely established" (however the population has persisted since at least 1951). Morton and Venn in their 1990 Ontario vascular plant checklist regarded it non-native, though it has been characterized as a rare native plant by Newmaster et al. (1998) and Oldham and Brinker (2009). In the core of its range it occurs mainly "in sunny, moist, disturbed situations along roadsides and railroad rights- of-way" which are located on riverine terraces or floodplains (Spooner et al. 1985). The species is "rare and local throughout its range but locally very abundant, primarily in non-natural habitat"; in the Ohio drainage "it flourishes in artificially disturbed areas such as roadsides and railroad embankments" (NatureServe 2009). Both Ontario sites are in disturbed habitat and one is along a watercourse. Spooner et al. (1985) consider the species native to the Great Lakes drainage, though they do not map Virginia Mallow from the U.S. in areas adjacent to the Niagara Peninsula where the two Ontario populations are located. Allison Cusick, an Ohio botanist who has visited many of the U.S. populations has also visited one of the Ontario sites and considers the habitat consistent with that at presumed native populations in the U.S. (A.W. Cusick pers. comm. to M.J. Oldham, 1994). Although the species is sometimes cultivated and has been cultivated in at least one Ontario nursery (COSEWIC 2009), it is not commonly cultivated in Ontario.

Taxonomic distinctness

✔ Yes. Virginia Mallow is universally regarded as being a valid species in recent taxonomic and floristic literature and may merit its own monotypic genus (Fryxell 1997). A recent genetic study (Fuertes et al. 2003) suggests that it is only distantly related to most other Sida species.

Designatable units

Both Ontario populations occur in a single ecozone and are only about 35 km apart (COSEWIC 2009), therefore a single Designatable Unit is appropriate.

Priority-setting criteria

Recent arrival

✔ No. Known in Ontario since 1951 (COSEWIC 2009).

Non-resident

✔ No.

Primary criteria (rarity and declines)

1. Global rank

✔ Threatened. G3.

2. Global decline

✔ Insufficient information. Declines have been reported in parts of the species' range, e.g. "Estimated that within last 100 years, 66% of Potomac River population has been extirpated. Sites near Charleston, West Virginia, being lost to development." (NatureServe 2009), but these have not been quantified throughout the range. The species has not been seen in Tennessee since 1883-1885 (Spooner et al. 1985) and is extirpated from the District of Columbia (NatureServe 2009).

3. Northeastern North America ranks

✔ Endangered. Highly ranked (S1, S2, SH or SX) in 8 of 9 northeastern jurisdictions in which it occurs natively (89%). See Appendix 1.

4. Northeastern North America decline

✔ Insufficient information. Declines have been reported in the northeast (see Global Decline above, and Appendix 1), but are generally unquantified.

5. Ontario occurrences

✔ Endangered. Known from two Ontario occurrences.

6. Ontario decline

✔ Not in any category. No documented decline in Ontario.

7. Ontario’s conservation responsibility

✔ Not in any category. Ontario makes up only a small fraction of the species global range (Fig. 2 in COSEWIC 2009).

Secondary criteria (threats and vulnerability)

1. Population sustainability

✔ Not in any category. No evidence of reproductive or recruitment failure in Ontario. No Population Viability Analyses have been conducted for the species in Ontario.

2. Lack of regulatory protection for exploited wild populations

✔ Not in any category. No known harvest in Ontario.

3. Human threats

✔ Threatened. One of the two Ontario populations is threatened by quarry expansion and gas pipeline maintenance. A portion of the other population may be threatened by mowing and the presence of Common Reed (Phragmites australis), a known invasive species.

4. Specialized life history or habitat-use characteristics

✔ Not in any category. Not a habitat specialist or restricted to provincially rare habitats.

COSSARO criteria met (primary/secondary)

Endangered – 2/0
Threatened – 1/1
Special concern – 0/0

Summary

Virginia Mallow (Sida hermaphrodita) is a globally rare tall perennial herb endemic to eastern North America. It occurs in disturbed floodplains and is known from two Ontario sites. Although the species has declined in some parts of its range, there are no documented declines in the Ontario population. One of the two Ontario sites is in a highly disturbed site that is further threatened by quarry expansion and gas pipeline maintenance and the other population is potentially threatened by mowing and an invasive exotic species (Phragmites australis). The second of these populations is in a conservation area. There is no evidence of population declines, with the first population having remained stable at about 210 stems and the second increasing from 83 stems in a 2001 estimate to about 2,300 stems in 2008. Virginia Mallow is occasionally cultivated and has escaped from cultivation elsewhere in its range. It is not known with absolute certainty that the Ontario populations are native, but there are no known cultivated plants in the vicinity of either population and one of the populations has persisted for more than 50 years. Habitat at one of the Ontario sites is consistent with habitat at presumed native sites in the core of the species range.

Information sources

COSEWIC. 2009. COSEWIC status report on Virginia Mallow Sida hermaphrodita. Committee on the Status of Endangered Wildlife in Canada, Ottawa. Two-month Interim Report (Sept. 2009). 20 pp.

Fryxell, P. A. 1997. The American genera of Malvaceae-II. Brittonia 49(2): 204-269.

Fuertes, J., P. A. Fryxell, and R. K. Jansen. 2003. Phylogenetic relationships and classification of the Sida generic alliance (Malvaceae) based on nrDNA ITS evidence. Systematic Botany 28(2): 352-364.

Morton, J. K., and J. M. Venn. 1990. A Checklist of the Flora of Ontario: Vascular Plants. University of Waterloo Biology Series No. 34, University of Waterloo, Ontario. 218 pp.

NatureServe. 2009. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer. (Accessed: October 13, 2009).

Newmaster, S. G., A. Lehela, M. J. Oldham, P. W. C. Uhlig, and S. McMurray. 1998. Ontario Plant List. Forest Information Paper No. 123, Ontario Forest Research Institute, Sault Ste. Marie, Ontario. 550 pp. + appendices.

Oldham, M. J. and S. R. Brinker. 2009. Rare Vascular Plants of Ontario, Fourth Edition. Natural Heritage Information Centre, Ontario Ministry of Natural Resources, Peterborough, Ontario. 190 pp.

Scoggan, H. J. 1978. The Flora of Canada. National Museum of Natural Sciences, National Museums of Canada. Volume 3.

Spooner, D. M., A. W. Cusick, G. F. Hall, and J. M. Baskin. 1985. Observations on the distribution and ecology of Sida hermaphrodita (L.) Rusby (Malvaceae). Sida 11(2): 215-225.

Thomas, L. K., Jr. 1979. Distribution and Ecology of Sida hermaphrodita (L.) Rusby: A rare plant species. Bartonia, No. 46: 51-59.

Appendix 1: Northeastern North America rank, status and decline

CT Not present (NatureServe 2009)
DE Not present (NatureServe 2009)
IL Not present (NatureServe 2009)
IN S1 (NatureServe 2009)
IA Not present (NatureServe 2009)
KY S2S3 (NatureServe 2009)
LB Not present (NatureServe 2009)
MA SNA (introduced; NatureServe 2009)
MB Not present (NatureServe 2009)
MD S1 (NatureServe 2009). Decline in the Potomac and Susquehanna drainages (Thomas 1979).
ME Not present (NatureServe 2009)
MI S1 (NatureServe 2009)
MN Not present (NatureServe 2009)
NB Not present (NatureServe 2009)
NF Not present (NatureServe 2009)
NH Not present (NatureServe 2009)
NJ SNA (introduced; NatureServe 2009)
NS Not present (NatureServe 2009)
NY SNA (introduced; NatureServe 2009)
OH S3 (NatureServe 2009)
ON S1 (NatureServe 2009)
PA S2 (NatureServe 2009). Decline in the Potomac and Susquehanna drainages (Thomas 1979).
PE Not present (NatureServe 2009)
QC Not present (NatureServe 2009)
RI Not present (NatureServe 2009)
VA S1 (NatureServe 2009). Decline in the Potomac and Susquehanna drainages (Thomas 1979).
VT Not present (NatureServe 2009)
WI Not present (NatureServe 2009)
WV S2 (NatureServe 2009)

Occurs as a native species in 9 of 29 northeastern jurisdictions SRANK or equivalent information available for 9 of 9 jurisdictions = (100%) S1, S2, SH, or SX in 8 of 9 = (89%)

Part 2: Ontario evaluation using COSEWIC criteria

Regional (Ontario) COSEWIC criteria assessment

Criterion A – Declining population

No. No documented decline.

Criterion B – Small distribution and decline or fluctuation

No. Meets Endangered B1a and B2a based on EO and IAO below critical values and presence at two locations. There is no documented decline or fluctuation, although one could possibly infer or project a future decline based on the threat of quarrying, mowing, or invasive species.

Criterion C – Small population size and decline

No. No continuing decline in number of mature individuals.

Criterion D – Very small or restricted

Yes. (Threatened D2). Meets Threatened D2 based on the occurrence of only two locations with an IAO of <20 km2 and threats from aggressive invasive grass and potential quarry expansion.

Criterion E – Quantitative analysis

No. No quantitative analysis available.

Rescue effect

No. Unlikely to be rescued from adjacent jurisdictions since the species is globally rare and there are no known U.S. populations in the area of the Ontario populations (eastern Lake Erie). Ontario populations are hundreds of kilometers from the closest non-Ontario population.