Taxon Attribute Profiles

Juncus articulatus L.

Common Name

Jointed Rush

Introduction

Juncus articulatus is a common rush to half-a-metre tall. Introduced into Australia its ability to grow in a wide variety of wet environments has allowed it to become well-established in the Murray-Darling Basin where it is a common weed of waterways and can obstruct drainage channels.

Taxonomy and Ecology

Classification

Family: Juncaceae
Genus: Juncus – c. 300 species worldwide with 31 species endemic to Australia and a further 21 species naturalised (Wilson et al., 1993).

Click to enlarge map

Life form

Juncus articulatus is a rhizomatous perennial with terete culms, often rooting at the nodes. It forms tufts or swards which are often tinged with red. It ranges in height from 15 cm to about 50 cm (Albrecht, 1994; Cunningham et al., 1981; Wilson et al., 1993). See Albrecht (1994) and Wilson et al. (1993) for further descriptive information.

Distribution

A native of Europe, Asia, North Africa and Northern America it is introduced in South Africa, Australia and New Zealand (Grime et al., 1988). Juncus articulatus is naturalised and widespread across Australia. It is currently known from all States except for the Northern Territory (Albrecht, 1994; Wilson et al., 1993).

Habitat

Juncus articulatus grows along the margins of drains, irrigation channels, creeks, rivers and wetlands. It grows in wet mud or sand in shallow, still or slow-moving water. It can also be found in moist pastures and soakage areas (Cunningham et al., 1981; Albrecht, 1994).

Juncus articulatus growing along a drainage channel near Hanwood (© Sainty and Jacobs, 1981)	Juncus articulatus at unidentified WA location (© J. Chambers)	Juncus articulatus at unidentified WA location (© J. Chambers)

Juncus articulatus growing in Kosciuszko National Park (C. Totterdell © ANBG)

"Status" in community

Because of its creeping rootstock and vigorous growth Juncus articulatus may be locally common in its habitat (Cunningham et al., 1981). At the Mother of Ducks Lagoon in northern New South Wales Juncus articulatus is one of the two dominant perennials, covering large areas of the site (Smith and Brock, 1998). It is a strong competitor with native species (Sainty and Jacobs, 1994).

Associated species

Juncus articulatus has been recorded in association with grasses (such as Glyceria australis, Themeda triandra and Poa labillardierei), sedges and rushes (such as Typha, Eleocharis and Schoenoplectus) and other weedy species (such as Rumex) on the fringes of wet areas (Smith and Brock, 1998; Australian National Herbarium, Canberra, 2005).

Qualitative and quantitative data – abundance, cover, biomass

Benson (in review) has recorded Juncus articulatus as a characteristic weed species in the ‘Common Reed - Bushy Groundsel reedland/forbland of inland river systems’ and ‘Cumbungi rushland of shallow semi-permanent water bodies of the inland river systems’ in New South Wales. It is one of the main species posing a major threat to the latter community in some areas. In Victoria it is listed as a highly invasive weed of the Sedgy Riverine Forest/Riverine Swamp Forest Complex in the Murray Fans Bioregion (Department of Sustainability and Environment, 2004).

Species – interactions with other biodiversity

No specific information has been located at this time regarding interactions of Juncus articulatus either positively or negatively with fauna. Due to its weedy tendencies it can clearly be detrimental to native plant communities (see Qualitative and quantitative data; Conservation status).

Physiological traits and adaptations

In the growth pattern of the perennial Juncus articulatus height is sacrificed in early growth in favour of tiller* number, a trait normally associated with annual species that rely on seed production for population maintenance. This avoids any limitation on seed production and allows for increased chances of establishment over space and time (see Reproduction). However, as a result, when water level fluctuations occur rapidly during the early growth phases, the shorter plants are more likely to drown than taller plants (Smith and Brock, 1998). As a result manipulation of water levels is a potential management tool as restoring or introducing variation in water levels in the habitat of Juncus articulatus is likely to result in a reduction in its dominance over time (Smith and Brock, 1998).

*tiller - the shoot or stalk of a grass or other herbaceous plant; usually arising basally and laterally and growing erect.

Reproduction and Establishment

Reproduction

Juncus articulatus reproduces both sexually and vegetatively. Germination from the seed bank was found to be important after drought periods and disturbance by water birds and cattle in the Mother of Ducks Lagoon in northern New South Wales (Smith and Brock, 1998). In Western Australia, it reproduces readily from seed and rhizomes compared with other reproductively more specialized species (Chambers and McComb, 1992 in Smith and Brock, 1996).

Juncus articulatus inflorescence and capsule (David Mackay © Royal Botanic Gardens and Domain Trust)	Close-up of Juncus articulatus inflorescence in flower (© E. Dronnet, 2003)

Dispersability; establishment and growth

Juncus articulatus produces large numbers of minute seeds which show a high rate of germination. Seeds germinate during spring (but can germinate throughout the year) or are incorporated into a persistent seed bank. The seed bank persists for at least 12 years (Chambers et al., 1995; Grime et al., 1988; Roberts and Marston, 2000).The mucilaginous seeds are widely dispersed and are probably transported in mud (Grime et al., 1988). Light is required for germination (Chambers et al., 1995).

Juncus articulatus is a pioneer species on dunes and in wet fen meadows in Europe due to its persistent and large seed bank. It can reach a high-percentage of cover in one to two years of regeneration. Unlike other Juncus species, which disappear within a few years, it retains this high frequency for at least five years subsequent to regeneration (Patzelt, et al., 2001; Grootjans et al., 2001).

Juncus articulatus may form dense mats that restrict water flow (Sainty and Jacobs, 1994).

Juvenile period

No specific information has been located at this time concerning the juvenile growth period of Juncus articulatus. Given its weedy status and indications that it is a colonizing species, it suggests that establishment and survival of seedlings is good (see comments in Reproduction and Dispersability; establishment and growth).

Hydrology and salinity

Hydrology

Juncus articulatus grows in water depths to 0.45 m (Chambers et al., 1995). It is common in creek or drain habitats characterized by long periods of constant depths and relatively short periods of flooding or drought (Smith and Brock, 1998). Below ground productivity decreases markedly as water depth increases due to the relatively small growth habit preventing the maintenance of sufficient leaf area above the water level. Peak total biomass is seen in waterlogged soil (Froend et al., 1993). In the Mother of Ducks Lagoon Juncus articulatus prefers fluctuating and higher water levels compared to the native grass Glyceria australis, at least in the short term. Long term affects are unknown (Smith and Brock, 1996).

Rhizome transplantation of Juncus articulatus will not be successful in areas with seasonality of flooding as transplants will die when flooded if the seasonal variation is greater than 0.3 m (Chambers et al., 1995).

Salinity tolerance

Little specific information has been located at this time. Juncusarticulatus is not known to demonstrate salinity tolerance, generally growing in fresh water (Chambers et al., 1995).

Flooding regimes

As previously noted Juncus articulatus is common in creek or drain habitats characterized by long periods of constant depths and relatively short periods of flooding or drought (Smith and Brock, 1998).

Change in water regimes

As discussed in Hydrology Juncus articulatus prefers relatively constant water depths and is likely to be disadvantaged by rapid fluctuations in water levels (Smith and Brock, 1998).

Response to disturbance (non-hydrological)

Grazing

Juncus articulatus is reported to be moderately resistant to both grazing and trampling (Grime et al., 1988). In Australia it is not known to be eaten by stock (Cunningham et al., 1981).

In the Mother of Ducks Lagoon Juncus articulatus tends to be more concentrated in lower, wetter areas which are more disturbed by birds and cattle (Smith and Brock, 1996). It appears to have a comparative advantage in areas that are grazed or disturbed frequently (Smith and Brock, 1998).

Weeds

Juncus articulatus is a common and potentially serious weed in its own right (see Conservation status). It is not known to be affected by other weeds.

Conservation status

In the United Kingdom, Juncus articulatus is probably decreasing as a result of wetland habitat destruction and the impacts of eutrophication (Grime et al., 1988). In Australia it is a common weed of inland waterways and commonly obstructs water flow in drainage channels (Albrecht, 1994; Sainty and Jacobs, 1981; Cunningham et al., 1981). Humphries et al. (1991) considered it to be a potentially serious environmental weed of aquatic systems.

Uses (including ethnobotanical)

Summary

Juncus articulatus is a common weed of Australian waterways, recorded in all states apart from the Northern Territory. Through its production of large numbers of seeds with high rates of germination and persistence in the seed bank it appears to be particularly adapted to colonizing disturbed wet areas. While it grows in a variety of habitats from waterlogged soils to water depths of 0.45 m it prefers long periods of constant water depth with short periods of flooding and drought but does not appear to tolerate salinity. A potentially serious weed of waterways, it can obstruct water flow and out-compete native species. However, its preference for constant conditions may make it vulnerable to control through manipulating water levels.

References

Australian National Herbarium, Canberra. (2005). Australian National Herbarium Specimen Information Register. Available at: http://www.anbg.gov.au/cgi-bin/anhsir [Accessed: January 2005].

Albrecht, D.E. (1994) Juncus. In Walsh, N.G. and Entwisle, T.J. (eds) Flora of Victoria Vol. 2: Ferns and Allied Plants, Conifers and Monocotyledons. Inkata Press, Melbourne, p. 224.

Benson, J.S. (in review a) Classification and assessment of the native vegetation of New South Wales, Australia: Part 2. The plant communities of the NSW Western Plains. Submitted to Cunninghamia:

Chambers, J.M., Fletcher, N.L. and McComb, A.J. (1995) A guide to emergent wetland plants of south western Australia. Murdoch University, Marine and Freshwater Research Laboratory, Perth, p. 61-65.

Cunningham, G.M., Mulham, W.E., Milthorpe, P.E. and Leigh, J.H. (1981) Plants of Western New South Wales. Soil Conservation Service of New South Wales. p. 177.

Department of Sustainability and Environment (2004) Ecological Vegetation Classes (EVC) Benchmarks by Bioregion. Available at http://www.dse.vic.gov.au/dse/nrence.nsf [Accessed August 2005].

Froend, R.H., Farrell, R.C.C., Wilkins, C.F., Wilson, C.C. and McComb, A.J. (1993) Wetlands of the Swan Coastal Plain Vol. 4: The effect of altered water regimes on wetland plants. WA EPA and Water Authority of Western Australia.

Grime, J.P., Hodgson, J.G. and Hunt, R. (1988) Comparative plant ecology: a functional approach to common British species. Unwin Hyman Ltd, London, p342-343.

Grootjans, A.P., Everts, H., Bruin, K. and Fresco, L. (2001) Restoration of wet dune slacks on the Dutch Wadden Sea Islands: Recolonization after large scale sod cutting, Restoration Ecology 9(2): 137-146.

Humphries, S.E., Groves, R.H. and Mitchell, D.S. (1991) Plant invasions of Australian ecosystems. Report to: Australian National Parks and Wildlife Service Endangered Species Program, Project No. 58, Australian National Parks and Wildlife Service, Canberra.

Hurd, E.G., S. Goodrich, & N.L. Shaw. 1997. Field guide to Intermountain rushes. Gen. Tech. Rep. INT-306. USDA, FS, RMRS, Ogden, UT . Available at: http://plants.usda.gov/cgi_bin/topics.cgi?earl=plant_profile.cgi&symbol=JUAR4 [Accessed August 2005].

Patzelt, A., Wild, U. and Pfadenhauer, J. (2001) Restoration of wet fen meadows by topsoil removal: vegetation development and germination biology of fen species, Restoration Ecology 9(2): 127-136.

Roberts, J. and Marston, F. (2000) Water regime of wetland and floodplain plants in the Murray-Darling Basin. A sourcebook of ecological knowledge. CSIRO Land and Water, Canberra.

Sainty, G.R. and Jacobs, S.W.L. (1981) Waterplants of New South Wales. Water Resources Commission New South Wales, Sydney

Sainty, G.R. and Jacobs, S.W.L. (1994) Waterplants in Australia: a field guide (3 rd ed.), Sainty and Associates, Darlinghurst.

Smith, R.G.B. and Brock, M.A. (1996) Coexistence of Juncus articulatus L. and Glyceria australis C.E.Hubb. in a temporary shallow wetland in Australia, Hydrobiologia 340: 147-151.

Smith, R.G.B. and Brock, M.A. (1998) Germination potential, growth patterns and reproductive effort of Juncus articulatus and Glyceria australis in temporary shallow wetlands in Australia, Wetlands Ecology and Management 5: 203-214.

Wilson , K.L. Johnson, L.A.S. and Bankoff, P. (1993) Juncus. In G.J. Harden (ed) Flora of New South Wales. Vol. 4. University of NSW Press, Sydney, p. 286.