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Changes to Plant S-Ranks; Festuca halli S3
November 27, 2017

The Botanical Assessment Working Group (BAWG) recently completed subnational rank reassessments of five vascular plant taxa. Five taxa were added to the provincial tracking list, one of which was a new addition to the provincial species list. Please see the table below for a summary of the changes.

Species with a low S Rank are at a higher risk of extirpation.

The rank reassessment of Festuca hallii (Plains Rough Fescue) may be of particular interest. This taxon, which is currently a medium assessment priority for the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was previously ranked as S5 in Saskatchewan. In the past, the majority of subnational ranks in Saskatchewan have been based on abundance and distribution information, and the previous rank reflected this. More recently (since approximately 2010) the SKCDC has regularly factored threats into any rank reassessment calculations. Trends are also part of the assessment methodology (Master et al. 2012), but this is the first time that trend data has been available for a plant reassessment. Using abundance, distribution, threats and trends information via the rank calculator (NatureServe 2015), the subnational rank of Festuca hallii has been calculated as S3.

Festuca hallii is a widespread species in Saskatchewan, ranging from the Cypress Hills to the Manitoba border, and north to Meadow Lake and Candle Lake. It is often abundant where it is found; however, data suggests that over any 20 year period in the last 100 years the species has experienced a decline of >30% (Henderson unpubl.). The threat level for this species has been calculated as high, to which the following threats contributed: agriculture (annual crops and livestock ranching), invasive and problematic species (invasive species and problematic native species), and pollution (air borne-pollutants). The methodology for threats calculations and the threat calculator in general can be found in Master et al. (2012).

Cuscuta gronovii var. gronovii © Sarah Vinge-Mazer

BAWG has also reassessed the Cuscuta gronovii varieties. All Cuscuta species, with the exception of C. umbrosa, are now tracked in Saskatchewan. Saskatchewan material was formerly often placed within C. gronovii but has since been revised and mostly placed to C. umbrosa (Harms unpublished). As a result, both varieties of C. gronovii are much more rare in the province than previously thought. Harms notes that Cuscuta species in general are poorly documented in Saskatchewan (2017). The SKCDC welcomes submissions of any observations of this group. BAWG will be posting a key to the Saskatchewan Cuscuta species to the SKCDC website soon, as well as a key to the Cryptantha species (see Resources >> Publications >> Taxonomic Resources).

Please note that every effort has been made to ensure that the summary list of ranks provided here is accurate; however, the lists provided on our lists page are the final authority for this type of information. For the convenience of our users, we have added the rank reassessment and rank change dates into the excel files of our species lists. This will allow users to sort the data and view the most recently assessed taxa.

For more information on the ranking process, please see our ranking page. If you have a plant taxon that you believe should be a priority for a rank reassessment, please contact the SK CDC botanist.

Scientific Name Common Name New (or current) S-rank Old S-rank Notes
Carex sterilis Dioecious Sedge S1S2 S4 Added to the tracking list
Cerastium brachypodum Short-stalked Mouse-ear Chickweed S3 S4? Added to the tracking list
Cuscuta gronovii var. gronovii Gronovious Dodder S1 S5? Added to the tracking list
Cuscuta gronovii var. latiflora Large-flowered Dodder S1 SNR Added to the provincial taxon list, added to the tracking list
Festuca hallii Plains Rough Fescue S3 S5 Added to the tracking list

The Botanical Assessment Working Group would like to thank Darcy Henderson for providing detailed information for the Festuca hallii reassessment.


Harms, V.L. 2017. Annotated Catalogue of Saskatchewan Vascular Plants (Draft). Unpublished.

Harms, V.L. Unknown date. Unpublished data. W.P. Fraser Herbarium, University of Saskatchewan.

Henderson, D. 2017. Unpublished data. Environment and Climate Change Canada.

Master, L.L., D. Faber-Langendoen, R. Bittman, G. A. Hammerson, B. Heidel, L. Ramsay, K. Snow, A. Teucher, and A. Tomaino. 2012. NatureServe Conservation Status Assessments: Factors for Evaluating Species and Ecosystem Risk. NatureServe, Arlington, VA. [Accessed online]

NatureServe. 2015. NatureServe Conservation Status Assessments: Rank Calculator Version 3.185. NatureServe, Arlington, VA. [Accessed online]


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