Euphrasia arguta R. Br. - critically endangered species listing

NSW Scientific Committee - final determination

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the herb Euphrasia arguta R. Br. as a CRITICALLY ENDANGERED SPECIES in Part 1 of Schedule 1A of the Act, and as a consequence, to omit reference to Euphrasia arguta R. Br. from Part 4 of Schedule 1 (species presumed extinct) of the Act. Listing of Critically Endangered species is provided for by Part 2 of the Act.

 

The Scientific Committee has found that:

 

1. Euphrasia arguta R. Br. (family Scrophulariaceae) is described by Barker (1992) as an "erect annual herb 20-35 cm high, branches densely hairy with recurved stiff non-glandular hairs. Upper stem leaves ovate to elliptic, often broadly so, 6-14 mm long, 3.5-13 mm wide, margins + deeply lobed, usually with 2-4 pairs of teeth. Racemes mostly 50-90-flowered. Calyx 5.5-7 mm long, usually scabrous. Corolla 10-14 mm long, white to lilac with yellow markings; tube 6.7-8.5 mm long, glabrous at base. Stamen filaments usually glabrous; anthers 0.9-1.7 mm long, connective hairy. Capsule 4-7.5 mm long, upper half bristly. Flowers October – January."

 

2. Euphrasia arguta R. Br. was rediscovered in the Nundle area of the NSW north western slopes and tablelands in 2008. Prior to this, it had not been collected for 100 years. Historically, Euphrasia arguta has only been recorded from relatively few places within an area extending from Sydney to Bathurst and north to Walcha (Barker 1982; Barker 1987; Barker 1992; records from National Herbarium of NSW, Sydney).

 

3. Ecological information from historical herbarium records is scarce. Three collections noted the following habitat, 'in the open forest country around Bathurst in sub humid places', 'on the grassy country near Bathurst', 'in meadows near rivers' (Barker 1982; 1987). The populations that are currently known are located in the Nundle State Forest and on nearby private land, in eucalypt forest with a mixed grass and shrub understorey (D Binns pers. comm. February 2009).

 

4. In the Nundle region there are currently four populations of Euphrasia arguta located in three areas approximately 23 km apart. The total number of mature individuals was not considered to be low following surveys in 2009 and 2011 (D. Binns unpublished data February 2009, January 2011). The largest population was estimated to contain 15 000 individuals in 2009, in an area that was cleared for a fire break in January 2007 and subsequently left to regenerate (D. Binns unpublished data February 2009). Euphrasia arguta plants were most dense in an open disturbed area, and along the roadside, indicating the species may be regenerating following the disturbance (D. Binns pers. comm. April 2009). However, much of this site was again cleared of vegetation and 1 cm of topsoil in December 2009, leading to an estimated initial loss of some 80% of plants. Regeneration of E. arguta was recorded when the site was surveyed in January 2011. However, in the area of habitat where the frequency of disturbance was high (two disturbance events within 2-3 years) there was a significant population decline relative to areas with only a single disturbance. Two further populations are located about 14 km to the south-east and are themselves separated by some 3 km. One contained only 6 plants at the time of observation, and the other 1120 plants (D. Binns pers. comm. February 2009). A fourth population has been located on private land and contains approximately 45 plants.

 

5. The number of Euphrasia arguta plants may vary over time depending on the season and the disturbance history at the site. E. arguta has an annual habit and has been observed to die off over the winter months. Active growth and flowering is between January and April (D. Binns pers. comm. April 2009). The populations of E. arguta have been observed for only a few seasons since the species was rediscovered and consequently trends in plant numbers over time are unknown.

 

6. The geographic distribution of Euphrasia arguta is estimated to be very highly restricted. The extent of occurrence, measured using a minimum convex polygon covering the known distribution, is estimated to be approximately 40 km2. This figure may be considered as a minimum as it is likely more populations may be located following searches of similar habitat in the Nundle area (D. Binns pers. comm. February 2009). The area of occupancy is estimated to be 20 km2, based on a 2 x 2 km grid, the scale of assessment recommended by IUCN (2010).

 

7. There are no known occurrences of Euphrasia arguta in a conservation reserve. The majority of E. arguta plants are located in Nundle State Forest. A small part of the largest population of E. arguta is located on private land that is adjacent to the State Forest. The land is currently used for rough grazing by sheep or cattle (D. Binns pers. comm. June 2009). The southern-most population is also on private land. Logging is currently occurring in Nundle State Forest and is planned for the land in the vicinity of the largest of the E. arguta populations (D. Binns pers. comm. June 2009). D. Binns (pers. comm. June 2009) notes that all sites where E. arguta is found, have been either logged in the last few decades, or appear to have regrown from past clearing. Road maintenance and clearing roadside vegetation for fire breaks is a threat to E. arguta. Clearing for a fire break resulted in good germination of the species in the largest population in 2007. When the same area was again cleared in December 2009, however, there was a reduced level of regeneration of E. arguta. This may suggest a decline in the species at this site as a result of repeated clearing. The frequency, seasonality and extent of road maintenance, along with any associated herbicide application may influence the response of the species to disturbance.

 

8. Euphrasia arguta R. Br. is eligible to be listed as a Critically Endangered species as, in the opinion of the Scientific Committee, it is facing an extremely high risk of extinction in New South Wales in the immediate future as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Regulation 2010:

 

Clause 7 Restricted geographic distribution and other conditions

The geographic distribution of the species is estimated or inferred to be:

(a)

very highly restricted,

and:

(d)

a projected or continuing decline is observed, estimated or inferred in either of the key indicators:

 

(a)

an index of abundance appropriate to the taxon, or

 

 

(b)

geographic distribution, habitat quality or diversity, or genetic diversity.

 

 

 

Dr Richard Major

Chairperson

Scientific Committee

 

Proposed Gazettal date: 25/11/11

Exhibition period: 25/11/11 – 03/02/12

 

References:

 

Barker WR (1982) Taxonomic studies in Euphrasia L. (Scrophulariaceae). A revised infrageneric classification, and a revision of the genus in Australia. Journal of the Adelaide Botanic Gardens 5, 1-304.

 

Barker WR (1987) Taxonomic studies in Euphrasia L. (Scrophulariaceae). V. New and rediscovered taxa, typifications, and other notes on the genus in Australia. Journal of the Adelaide Botanic Gardens 10, 201-221.

 

Barker WR (1992) Scrophulariaceae. In ‘Flora of New South Wales Volume 3’. (Ed. Harden GJ) pg. 588. (University of NSW Press, Sydney)

 

IUCN Standards and Petitions Subcommittee (2010) ‘Guidelines for Using the IUCN Red List Categories and Criteria Version 8.1.’ Prepared by the Standards and Petitions Subcommittee in March 2010. (http://intranet.iucn.org/webfiles/doc/SSC/RedList/RedListGuidelines.pdf)

Page last updated: 02 December 2011