Rytidosperma vickeryae - endangered species listing
The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the grass Rytidosperma vickeryae M. Gray & H.P. Linder as an ENDANGERED SPECIES in Part 1 of Schedule 1 of the Act. Listing of endangered species is provided for by Part 2 of the Act.
NSW Scientific Committee - final determination
The Scientific Committee has found that:
1. Rytidosperma vickeryae M. Gray & H.P. Linder (family Poaceae) is a small perennial grass to 0.3 m high, with tufts of leaves at intervals along a rhizome; the leaves have the ligule reduced to a ciliate rim of hairs c. 0.3 mm long, with longer hairs at the sides; the leaf blade becomes folded, c. 2 mm wide, mostly smooth; the panicle is exserted, 3-4 cm long, open, loose, with fine branches, the spikelets clustered at the ends; spikelets are 2-4-flowered, long-pedicellate, 5-7 mm long, the florets consistently longer than the glumes; the glumes are subequal, 3.8-4.2 mm long, with membranous margins; the lemma body is 3.5-4.5 mm long, obscurely 6-7-nerved, smooth on the back except for a few scattered hairs near the base and two small tufts at the level of the sinus, a tuft of hairs on the callus, and one tuft (the upper) near each margin; the lateral lobes are acute, very short, scarcely separating from the central awn; central awn brown, slightly twisted in the lower part or straight; the palea reaching almost to the top of the lobes. A full technical illustration is in Linder (1999: 143); some diagnostic features are illustrated in Jacobs & Hastings (1993) and in Wheeler et al. (2002).
2. Rytidosperma vickeryae M. Gray & H.P. Linder is described under the name Danthonia sp. A in Jacobs & Hastings (1993), where it is said to be most closely related to D. nivicola (=Rytidosperma nivicolum), which has the leaves tightly inrolled at the base, the florets shorter than the glumes except for the exserted awns, and the central awn well separated from the lateral lobes. More recent work by Linder (1999) has reassigned both these species to Rytidosperma (along with three others also occurring in the Kosciuszko area), but suggests that the closest relatives of R. vickeryae are likely to be two New Zealand species, R. thomsonii (Buchan.) Connor & Edgar and R. exiguum (Kirk) H.P. Linder, with R. vickeryae having speciated following a distance dispersal event from New Zealand to south-eastern Australia.
3. Rytidosperma vickeryae is endemic to Kosciuszko National Park, at altitudes of 1500-1900 m. Its geographical distribution is highly restricted with most populations having been recorded in tributaries of the upper Snowy River, from Perisher Valley and the Spencers Creek - Betts Creek - Guthrie Creek system east of Charlottes Pass. An outlying population has been recorded at Happy Jacks Plains (north-west of Lake Eucumbene) about 35-45 km away from these main occurrences. The total extent of occurrence is approximately 80 to 150 km2, and the area of occupancy about 16 km2, based on occupancy of four 2 × 2 km grid cells, the scale of assessment recommended by IUCN (2008).
4. Rytidosperma vickeryae occurs in subalpine treeless vegetation, and is mainly recorded from stream-sides, the edges of tarns, and in and around bogs; within bogs, it is often found growing in mounds of Sphagnum cristatum. Vascular plant species often co-occurring with R. vickeryae include Rytidosperma nivicolum, Oreomyrrhis ciliata, Oschatzia cuneifolia, Carex gaudichaudiana, Carpha nivicola, Juncus falcatus, Empodisma minus, and Nertera granadensis.
5. Very few populations of R. vickeryae have been recorded despite considerable intensity of general surveys in the area of occurrence, and some recent targeted surveys (e.g. McDougall & Walsh 2007). The species appears to be naturally rare and of restricted range and habitat, and is inconspicuous. Total population size is unknown, but K. McDougall ( in litt. November 2006) estimates total number of ramets “in the hundreds or perhaps a thousand plants”. The degree of potential genetic diversity is difficult to estimate - the species is known to be able to produce new clonal ramets from rhizomes; the frequency of reproduction from seed is not known.
6. The largest population of R. vickeryae occurs within the developed resort area in Perisher Valley, and in the vicinity of several further proposed developments. The species in this area is directly and indirectly threatened by resort development and potentially affected by routine resort maintenance activities. Part of the likely habitat for the species has been removed in the past for the construction of car parks. The remainder of the habitat in Perisher Creek is fragmented. The species has also been recorded in Spencers Creek and so may occur in or near the Charlottes Pass resort.
7. Rytidosperma vickeryae is suspected to have undergone a reduction in population size as a result of resort development, based on the known loss of apparently suitable habitat and the degradation of some wetland communities in Perisher Valley (K. McDougall in litt. November 2006). Most populations of this species occur in a very small area of about 6 km2, within which they are threatened directly and indirectly by resort development. The total population of R. vickeryae is estimated to be low (
8. The alpine habitat and restricted environmental niche of R. vickeryae are likely to render the species particularly susceptible to the effects of climate change, and to changes in hydrology associated with either climate change (e.g. through reduced snow meltwater) or development. ‘Alteration to the natural flow regimes of rivers and streams and their floodplains and wetlands’, ‘Anthropogenic Climate Change’, and ‘Clearing of Native Vegetation’ are listed as Key Threatening Processes under the Threatened Species Conservation Act 1995.
9. Rytidosperma vickeryae M. Gray & H.P. Linder is not eligible to be listed as a Critically Endangered species.
10. Rytidosperma vickeryae M. Gray & H.P. Linder is eligible to be listed as an Endangered species as, in the opinion of the Scientific Committee, it is facing a very high risk of extinction in New South Wales in the near future as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Regulation 2002:
Clause 15
The geographic distribution of the species is estimated or inferred to be:
(b) highly restricted,
and:
(d) a projected or continuing decline is observed, estimated or inferred in:
(i) an index of abundance appropriate to the taxon
(ii) geographic distribution, habitat quality or diversity, or genetic diversity
(e) the following conditions apply:
(i) the population or habitat is observed or infered to be severely fragmented
(ii) all or nearly all mature individuals are observed or inferred to occur within a small number of populations or locations
Clause 16
The estimated total number of mature individuals of the species is:
(b) low,
and:
(d) a projected or continuing decline is observed, estimated or inferred in:
(i) an index of abundance appropriate to the taxon,
(ii) geographic distribution, habitat quality or diversity, or genetic diversity
(e) the following conditions apply:
(i) the population or habitat is observed or inferred to be severely fragmented
(ii) all or nearly all mature individuals are observed or inferred to occur within a small number of populations or locations
Dr Richard Major
Chairperson
Scientific Committee
Proposed Gazettal date: 31/07/09
Exhibition period: 31/07/09 - 25/09/09
References:
IUCN (2008) ‘Guidelines for using the IUCN Red List Categories and Criteria. Version 7.0.’ (Standards and Petitions Working Group of the IUCN Species Survival Commission Biodiversity Assessments Sub-committee: Switzerland)
Jacobs SWL, Hastings SM (1993) Danthonia. In: Harden GJ (ed.), Flora of New South Wales vol. 4. New South Wales University Press, Kensington, NSW.
Linder HP (1999) Rytidosperma vickeryae – a new danthonioid grass from Kosciuszko (New South Wales, Australia): morphology, phylogeny and biogeography. Australian Systematic Botany 12: 743-755.
McDougall KL, Walsh NG (2007) Treeless vegetation of the Australian Alps. Cunninghamia 10: 1-57
Wheeler DJB, Jacobs SWL, Whalley RDB (2002) Grasses of New South Wales, 3rd edition. The University of New England, Armidale, NSW.