Slender Darling Pea - profile

Scientific name: Swainsona murrayana
Conservation status in NSW: Vulnerable
National conservation status: Vulnerable

Description

A sparsely-downy forb with greyish, thin or tapered, stiffly leathery pods. The pea-like flowers are pink or purple with red stripes on densely and darkly hairy slender stalks. It is distinguished by the strongly twisted hypanthium and keel with retracted tip.

Location and habitat

Distribution
Found throughout NSW , it has been recorded in the Jerilderie and Deniliquin areas of the southern riverine plain, the Hay plain as far north as Willandra National Park, near Broken Hill and in various localities between Dubbo and Moree.

Habitat and ecology

The species has been collected from clay-based soils, ranging from grey, red and brown cracking clays to red-brown earths and loams.
Grows in a variety of vegetation types including bladder saltbush, black box and grassland communities on level plains, floodplains and depressions and is often found with Maireana species. Plants have been found in remnant native grasslands or grassy woodlands that have been intermittently grazed or cultivated.
Plants produce winter-spring growth, flower in spring to early summer and then die back after flowering. They re-shoot readily and often carpet the landscape after good cool-season rains.
The species may require some disturbance and has been known to occur in paddocks that have been moderately grazed or occasionally cultivated.
Swainsona species contain a poisoning principle, swainsonine, which affects the nervous system and is toxic to stock.

Regional information
This species is found in the following catchment management authority regions. Click on a region name to see more details about the distribution, vegetation types and habitat preference of the species in that region.

Threats

Heavy grazing by domestic stock, since the species is heavily grazed at most growth stages and is regarded as a useful forage plant (although this may be harmful to stock due to its poisoning effect). Heavy grazing in the flowering and fruiting season in particular, may influence the soil seed bank and hence future abundance of the species on travelling stock reserves and adjoining paddocks.
Loss of grassland habitat to cultivation, either for pasture improvement or crops, particularly rice crops.
Invasion of grassland habitat by exotic species due to ploughing or heavy grazing of paddocks, which provides an environment suitable for the invasion of exotic species.
Increased salinisation, which affects the suitability of habitat.
Frequent fires may directly affect plants or alter the habitat in which it grows.
Rabbits and other herbivorous pest species may contribute to the total grazing pressure on this species.
Urban developments and the expansion of townships into surrounding grasslands has the potential to result in the loss of, or impact on, plants and their habitat.

Recovery strategies

Priority actions are the specific, practical things that must be done to recover a threatened species, population or ecological community. The Department of Environment and Conservation has identified 6 priority actions to help recover the Slender Darling Pea in New South Wales.

What needs to be done to recover this species?

Control of herbivorous pest species such as rabbits and goats.
Where developments are proposed in areas of suitable habitat, surveys for the species must be conducted during the flowering season.
There should be no loss of Swainsona murrayana plants due to developments.
Where grazing has been occurring in suitable habitat, ensure that it is light, intermittent grazing as opposed to heavy grazing.
Further research is required into the ecology and impacts of disturbances on the species.

References

Benson, J.S., Ashby, E.M. and Porteners, M.F. (1996) The native grasslands of the southern Riverina, New South Wales. Report to the Australian Nature Conservation Agency. Royal Botanic Gardens, Sydney.
Harden, G.J. (ed.) (2002) Flora of New South Wales Volume 2 Revised Edition. UNSW, Sydney.
NSW National Parks and Wildlife Service (2003) Threatened Plants in Western New South Wales. Information Review. Profiles H-Z. NPWS Dubbo.