Pelargonium sp. - 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 Pelargonium sp. (G. W. Carr 10345) 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.
The Scientific Committee has found that:
1. Pelargonium sp. (G. W. Carr 10345) (family Geraniaceae) is a tufted perennial herb with a basal vegetative rosette and flowering stems to 15 cm tall, with fleshy and often extensively branched rhizomes giving rise to ramets in clonal colonies up to several metres wide; ramets persist for several years. The stems, peduncles and pedicels are sub-velvety with short glandular and non-glandular hairs in roughly equal proportions, and occasional (or no) emergent longer non-glandular hairs. The leaves are all or mostly basal; cauline leaves, if present, are opposite. The basal leaves are borne on petioles 2-6 cm long; the leaf lamina is ovate, 1-2.5 cm long, 1-2 cm wide, entire or shallowly lobed (commonly 5-7 lobes), with the margin crenate; the leaf surfaces are minutely pubescent along the veins and near the margin with both glandular hairs and short coarse non-glandular hairs. Umbels are 1-3(-7)-flowered, borne on peduncles 1-4 (-8.5) cm long and pedicels 1-2 cm long; the sepals are narrowly elliptic, 4.5-5.5 mm long, acute, sub-velvety with short glandular hairs and sometimes scattered longer hairs; the sepal spur is 1-1.5 mm long; the petals are obovate, 8-11 mm long, pale pink with darker crimson or purple longitudinal branching striations; the fertile stamens number 10, 4-7 fertile. Fruits (schizocarps) are 10-15 mm long, the five mericarps are pilose. Flowering is from October to February or March, with peak flowering in November and December. Seeds ripen and are shed about five weeks after flowering (G. Carr in litt.).
2. Pelargonium sp. (G. W. Carr 10345) has been known in recent years as Pelargonium sp. 1 (Smith & Walsh 1999; Ross & Walsh 2003; DSE 2005; Walsh & Stajsic 2007), and prior to 1999 as P. aff. rodneyanum (e.g. Ross 1996). In Victoria it is known by the common name 'Omeo Storks-bill'. Its affinities are uncertain, with Smith & Walsh (1999) placing it closest to P. australe, and G. Carr (pers. comm. July 2009) regarding it as closer to P. rodneyanum; these species differ from P. sp. (G. W. Carr 10345) in the following features (fide Smith & Walsh 1999). P. australe is widespread across most of Australia and has the indumentum of the stems, peduncles and pedicels composed mainly of long non-glandular hairs with only a few sessile or shortly-stalked glands present; the sepal spur 1-4(-8) mm long; the plants with a strong taproot and only rarely (and shortly) rhizomatous, not forming large clonal colonies, and the leaves a more even mix of basal and cauline. P. rodneyanum has petals 12-20 mm long, deep rosy magenta; the roots tuberous, not rhizomatous; leaves 2-5.5 cm long; the sepal spur 3-9 mm long, and the fruits 16-25 mm long. P. rodneyanum occurs in Victoria and South Australia, and has been regarded as occurring also in New South Wales in a restricted region on the middle reaches of the Shoalhaven River catchment between Nerriga and Bungonia (e.g. Harden 1992), but that NSW population may be a distinct and undescribed taxon (G. Carr pers. comm. July 2009).
3. Pelargonium sp. (G. W. Carr 10345) is a terrestrial plant with a narrow habitat usually just above the high-water level of irregularly inundated or ephemeral lakes, in the transition zone between surrounding grasslands or pasture and the paludal and aquatic communities. It sometimes colonises exposed lake beds during dry periods. The extent of habitat at any one site, and the persistence of the species, is likely be closely related to the combined effects of inundation frequency and the topography of lake bed and shoreline, in maintaining a more or less extensive disturbed interzone between grass-dominated communities and sedge-dominated aquatic vegetation, as well as to past and current grazing regimes and other forms of disturbance. The possibility of occurrence in non-lake situations is suggested by one report (G. Carr in litt.) of a small remnant population in Victoria at some kilometres distance from a larger lakeside occurrence. The persistence of rhizomes and soil seedbank through prolonged inundation or drought is unknown.
4. In New South Wales Pelargonium sp. (G. W. Carr 10345) is currently known to occur at four localities in the Southern Tablelands, at altitudes ranging from 680-1030 m a.s.l.: Lake Bathurst near Goulburn, on grazing leasehold; two populations (one probably extinct) on private grazing properties south-west of Cooma; and at Maffra Lake near Dalgety in a fenced Travelling Stock Reserve assessed as having high conservation values (Benson & Jacobs 1994). It is known to occur in the local government areas of Goulburn-Mulwaree, Cooma-Monaro, and Snowy River, but may occur in other LGAs with potentially suitable habitat; these may include Bombala, Eurobodalla, Palerang, Tumbarumba, Tumut, Upper Lachlan, and Yass Valley. Pelargonium sp. (G. W. Carr 10345) also occurs in north-east Victoria (Benambra area) at Lake Omeo.
5. No targeted broad-scale survey for Pelargonium sp. (G. W. Carr 10345) has yet been conducted across the southern tablelands of NSW. There is likely to be further suitable habitat between Lake Bathurst and the Victorian border (well over 200 natural lakes), but the vegetation and/or drainage of most are now heavily modified. No Pelargonium species were recorded during extensive studies of the Monaro grasslands (Benson 1994) and the plant communities of the Monaro lakes (Benson & Jacobs 1994). One site now known to harbour P. sp. (G. W. Carr 10345) (Maffra Lake Travelling Stock Reserve) was surveyed for the former study, and three of the four NSW sites of occurrence were sampled for the latter work (albeit concentrating on aquatic and paludal species, and conducted in the wet year of 1993 in which most Monaro lakes were full and parts of the Pelargonium populations would have been submerged). More limited targeted searches for P. sp. (G. W. Carr 10345) in recent years have confirmed it as extant at three of the four recorded NSW sites, but have failed to locate any other occurrences (J. Miles, R. Rehwinkel, G. Carr, I. Crawford, pers. comm. July 2009). The species was reported once in 1962 from the fourth site, on private land near Cooma, but has not been found there in a recent search (R. Rehwinkel pers. comm. July 2009).
6. Within New South Wales, the known sites fall into a narrow 180 km strip. The Extent of Occurrence is 540 km2, and the Area of Occupancy is 16 km2 based on 2 x 2 km grid cells, the scale recommended for assessing area of occupancy by IUCN (2008). The known NSW populations are separated by distances ranging from about 13-140 km, and the species distribution is best regarded as highly fragmented. The closest distance to the sole known Victorian population is about 120 km.
7. In New South Wales, species directly associated with Pelargonium sp. (G. W. Carr 10345) vary considerably between sites, but are typically a disturbed (often intermittently grazed) grass/sedge/herb assemblage. At Lake Bathurst (I. Crawford pers. comm. July 2009) it occurs with Dodonaea procumbens, Schoenus nitens and Carex bichenoviana, in sandy soils. At Maffra Lake, it occurs in basaltic soils and among boulders with Carex bichenoviana, Austrostipa bigeniculata, A. scabra subsp. falcata (Speargrass), Chloris truncata (Windmill Grass), Cullen tenax (Emu-foot), Ranunculus diminutus, and an introduced Alyssum species. The Maffra Lake site is, on the basis of the remnant terrestrial species reported, probably correlated (J. Miles in litt. November 2009) with an original adjacent native grassland community of 'Community 4: Poa sieberiana - Acaena ovina grassland on basalt' (fide Benson 1994). The Maffra Lake population, and a probably extinct population near Cooma are correlated with an adjacent inundation community (fide Benson & Jacobs 1994) of 'Community 4: Deep freshwater sedge-herb marsh: Carex bichenoviana - Ranunculus diminutus - Lepilaena bilocularis', and the Quartz Hill site with 'Community 2: Shallow freshwater sedge-herb marsh: Myriophyllum simulans - Potamogeton tricarinatus - Glossostigma elatinoides - Amphibromus nervosus'. The habitat of Pelargonium sp. (G. W. Carr 10345) is mostly or wholly included in the two Endangered Ecological Communities 'Natural Temperate Grassland of the Southern Tablelands of NSW and the Australian Capital Territory' and 'Upland Wetlands of the New England Tablelands (New England Tableland Bioregion) and the Monaro Plateau (South Eastern Highlands Bioregion)' as listed under the Commonwealth' Environment Protection and Biodiversity Conservation Act 1999 (respectively, Endangered Species Scientific Subcommittee 200l; Threatened Species Scientific Committee 2005). In terms of New South Wales legislation, some parts of the habitat may fall into the Endangered Ecological Community 'Montane peatlands and swamps of the New England Tableland, NSW North Coast, Sydney Basin, South East Corner, South Eastern Highlands and Australian Alps Bioregions' as listed under the Threatened Species Conservation Act 1995 (NSW Scientific Committee 2005).
8. Pelargonium sp. (G. W. Carr 10345) is known to form clonal colonies by rhizomatous propagation at all sites (Smith & Walsh 1999; G. Carr, J. Miles, I. Crawford pers. comm. July 2009). However, variation in some floral features, (G. Carr pers. comm. July 2009; R. Makinson pers. obs. July 2009, November 2009) implies some capacity also for sexual reproduction by seed. The extent of genetic variation is unknown, but the very limited herbarium material available suggests that the Lake Bathurst population may have some morphological differences from other sites, including tendencies to more flowers per umbel and perhaps a higher proportion of cauline leaves. The distribution of the species, in specific but scattered habitats over a range about 300 km north to south, also strongly implies a capacity for seed reproduction, and the likelihood of seed dispersal over considerable distances (probably by shore birds).
9. Numbers of individual plants (ramets) are not known with certainty, and the vegetative mode of propagation makes it hard to estimate the number of genets. The Lake Bathurst site is reported as 'thousands' of ramets (I. Crawford pers. comm. July 2009 for observations in 1996), although subsequent drought may have reduced this to some hundreds (R. Makinson pers. obs. November 2009); an extant population near Cooma occurs over about 5 ha of a lake bed (R. Rehwinkel pers. comm. July 2009); the total number of ramets in NSW (other than at Lake Bathurst) is estimated by J. Miles (in litt. March 2009) as well in excess of 2,500. Large natural fluctuations in numbers are likely as portions of populations that have colonised lake beds during dry periods may be eliminated by prolonged inundation in wet periods.
10. Past decline may be reasonably inferred from the fact that the grasslands and lakes of the Monaro (and north to Lake Bathurst) are virtually all grazed; that much of the grasslands of the region, including lake edges, have been converted to exotic pasture; that weed infestations are common throughout the grassy systems of the area; and that none of the lakes are in the conservation reserve system.
11. Future decline may reasonably be inferred as likely from persistence of the threats noted in paragraph 10. Additionally the severity of recent drought has rendered lakes formerly regarded as frequently inundated, dry for long periods of time, potentially allowing significant changes to vegetation and soil seedbanks around lake margins and across lake beds. The exact relationship between persistence of Pelargonium sp. (G. W. Carr 10345) and inundation regime, and the role of inundation in maintaining or renewing physical and floristic features of the Pelargonium habitat, are not known. Competition from and displacement by weedy species is a potential cause of future decline. The Lake Bathurst population is potentially threatened (J. Miles in litt., I. Crawford pers. comm. July 2009, R. Makinson pers. obs November 2009) by the exotic grass Nassella trichotoma (Serrated Tussock), which is widespread across the Monaro region. The exotic grass Eragrostis curvula (African Lovegrass) is becoming a major problem across the northern Monaro, although not yet at any Pelargonium sites. 'Invasion of native plant communities by exotic perennial grasses' and 'Alteration to the natural flow regimes of rivers and streams and their floodplains and wetlands', are listed as Key Threatening Processes under the Threatened Species Conservation Act 1995. Pasture management activities that include heavy stocking rates, use of lake margins as watering points, conversion of remnant vegetation to exotic pasture, or spraying for control of noxious weeds such as Serrated Tussock and Hypericum perforatum (St Johns Wort), are all potential threats. 'Clearing of native vegetation' is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995. All known sites, and most potential sites on the Monaro, are subject to grazing, and the grassland/wetland interzone may be particularly vulnerable to stock pressures (grazing, pugging, and trampling). A boulder field within the habitat at Maffra Lake probably aids persistence of plants and rhizomes. Browsing by rabbits is noted as a likely threat at Lake Bathurst (I. Crawford pers. comm. July 2009). 'Competition and grazing by the feral European Rabbit, Oryctolagus cuniculus (L.)' is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995. The small spatial extent of populations also places them at risk of stochastic events. An additional factor likely to contribute to future decline is climate change, specifically the trend towards warmer and seasonally dryer climate expected for those parts of highland New South Wales in which the species occurs (Hennessy et al. 2004), including a possible decrease in winter-spring rainfall. 'Anthropogenic Climate Change' is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995. 'Loss of terrestrial climatic habitat caused by anthropogenic emissions of greenhouse gases' is listed as a Key Threatening Process under the Commonwealth's Environment Protection and Biodiversity Conservation Act 1999.
12. Pelargonium sp. (G. W. Carr 10345) is not eligible to be listed as a Critically Endangered species.
13. Pelargonium sp. (G. W. Carr 10345) 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:
The species has undergone, is observed, estimated, inferred or reasonably suspected to have undergone or is likely to undergo within a time frame appropriate to the life cycle and habitat characteristics of the taxon:
(b) a large reduction in population size,
(e) geographic distribution, habitat quality or diversity, or genetic diversity.
The geographic distribution of the species is estimated or inferred to be:
(b) highly restricted,
(d) a projected or continuing decline is observed, estimated or inferred in either:
(i) an index of abundance appropriate to the taxon, or
(ii) geographic distribution, habitat quality or diversity, or genetic diversity, or
(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,
(iii) extreme fluctuations are observed or inferred to occur in either:
(A) an index of abundance appropriate to the taxon, or
(B) geographic distribution, habitat quality or habitat diversity.
Dr Richard Major
Proposed Gazettal date: 13/08/10
Exhibition period: 13/08/10 - 08/10/10
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Page last updated: 28 February 2011