N. mucronata is an invasive species of arid and semi-arid rangelands within its native range, notably in parts of North Africa (Egypt and Morocco,) and the Middle East (Iraq, Iran and Syria). New records at the limit of its range may indi...
N. mucronata is an invasive species of arid and semi-arid rangelands within its native range, notably in parts of North Africa (Egypt and Morocco,) and the Middle East (Iraq, Iran and Syria). New records at the limit of its range may indicate further spread (e.g. in southern Russia). It is spiny and generally unpalatable. It increases in frequency and spreads following overgrazing, and its relative dominance is used as an indicator of poor rangeland management and land degradation. It is a little studied species not yet introduced to other areas, but of high potential risk if accidentally introduced, as has been seen with similar invasive rangeland plants.
Noaea is in the Chenopodiaceae family. It is one of 36 genera of the subfamily Salsoloideae, and all except three of these (tribe Suadeae) are in tribe Salsoleae (USDA-ARS, 2009). Missouri Botanical Garden (2009) incorrectly place Noaea Moq in the Amaranthaceae. Other common genera in the Chenopodiaceae family are Haloxylon, Salsola and Suaeda.
Noaea mucronata (Forssk.) Aschers. & Schweinf. is a well-defined species, and the only synonym appears to be Noaea spinosissima L. recorded by Flora Europaea (Royal Botanic Garden Edinburgh, 2009). Subspecies are very rarely mentioned in the literature, with the type Noaea mucronata subsp. mucronata, and a single record of subsp. tournefortii (Kaya et al., 2009). Its common name in English is the thorny saltwort, though it is also referred to as the bedouin sirr.
N. mucronata is a low, much-branched shrub, 20-50 (-75) cm high, with stems hardened at their base. Branches rigid, spine tipped though with no stipules. Leaves 0.5-1.0 (-1.5) cm long, glabrous, alternate and very narrow, cylindrical or terete, filiform and mucronate. Flowers are green, hermaphrodite, solitary and axillary, situated at the axils of the leaves. Perianth segments 5 (3 outer and 2 inner), around 4 mm long, all developing a transverse wing on the back in the white-reddish fruit with wings 3-6 mm, obovate or obovate- to circular with irregularly toothed margin. Stamens 5, stigmas 2. Seeds vertical.
The native range appears to include much of the Mediterranean basin, including the whole coastal region of North Africa, southeastern Europe, Turkey and West Asia, and is also present in Crete and the East Aegean islands (University of Reading, 2006). It is widespread in Iran, noted in Isfahan (Mirghaffari, 2005) and Yazd Province (Maybodi and Arzani, 2005; Maybodi et al., 2007), and as far east as Turkmenistan (Missouri Botanical Garden, 2009). At the southern extremes of its range, it is present in eastern Saudi Arabia and the mountains of Oman (Ghazanfar and Fisher, 1998), and thus may also be expected to be present in the United Arab Emirates. In addition, noting its presence across North Africa, it is also likely to be present in Tunisia though no records could be found.
It was first recorded in southern Russia in 2000 (Mavrodiev and Sukhorukov, 2000), the most northerly record. A record from Equatorial Guinea from 1912 (Missouri Botanical Garden, 2009) is considered here as an error, noting its preferences for dry Mediterranean climates. That Gintzburger et al. (2003) did not include it in a thorough analysis of rangelands plants from Uzbekistan, indicates that it is not present in that country.
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
Dominance of N. mucronata in areas within its native range has been reported as a relatively new phenomenon, e.g. in Syria (Sankary, 1982), Iraq (Zakirov, 1989) and Israel (Noy-Mier, 1990). It is uncertain whether recent records in southern Russia refer to first records of it as a native species, or from its spread or introduction to the region. However, acknowledging the expertise of Russian taxonomists and specialists in range management who would have recorded it if they found it, it appears that it is a recent arrival.
There is a strong risk of N. mucronata becoming an invasive species in rangelands in non-tropical dry areas where it is not yet present, and dry Mediterranean-type climates in general. At risk may be areas in Central Asia, Australia, North and South America, southern Africa and South and East Asia. From the same family, the related Salsola vermiculata is already an invasive plant in drylands of California, USA, introduced as a palatable range species. In addition, Alhagi maurorum is also native to sympatric areas and has also proved to be highly invasive where introduced. Other similar perennial shrubs/sub-shrubs that are also considered as ‘invasive’ by some range managers within its native range (M Louhachi, ICARDA, Syria, personal communication, 2010), and thus also pose a risk if introduced, include: Anabasis syriaca, Capparis spinosa, Haloxylon articulataum, Pergamum harmala, Poterium spinosum and Prosopis farcta. Herb and grass species also noted as having ‘invasive’ tendencies in its native range include: Aegilops triuncialis, Asphodelus microcarpus, Carex stenophylla, Centaurea coronopifolia, Gundelia tournefortii, Euphorbia macroclada, Halogeton glomeratus, Hypericum triquetrifolium and Zygophyllum fabago.
N. mucronata is a typical shrub in many arid and semi-arid steppes in the south and east of the Mediterranean basin. It is commonly found in the Mesopotamian and Maghribian sub-provinces of the Irano-Turanian chorotype (Gintzburger et al., 2003). In Israel, it is found in Mediterranean woodlands and shrublands, semi-steppe shrublands, shrub-steppes, deserts and extreme deserts, and even in the montane vegetation of Mount Hermon (Flora of Israel, 2009), which may be typical of habitats elsewhere in its range.
The chromosome number has not been recorded, and a detailed genetic study of the species across its native range appears warranted.
All flowers are hermaphrodite only. Details of its reproductive function appear not to have been studied, though they are similar to closely related members of the Chenopodiaceae, being seed propagated.
Physiology and Phenology
N. mucronata is a perennial, broadleaved shrub. It has been classified as a chamaephyte, and a non-succulent xerophyte.
However, one crucial difference between N. mucronata and other shrubs is its extended growing period (Rae et al., 2001), thus giving it a comparative advantage, unless there is heavy grazing specifically at either end of the green season when only N. mucronata may be growing.
N. mucronata is a common plant of some arid and semi-arid Mediterranean rangelands, as is associated with many others typical of such plant communities. In degraded land, it is often found with Pergamum hamala, being another unpalatable plant that also increases in frequency in areas that have been overgrazed. Along the coast in Egypt, the Echiochilon fruticosum - Noaea mucronata association is common (Mossallam et al., 2009). It is also recorded in the Anabasis and Hammada vegetation communities in Wadi Rum, Jordan, and in the Teucrio multicauli - Crataegetum aroniae community in southeastern Turkey (Kaya et al., 2009). N. mucronata was identified as dominant in three plant associations in Syria (ICARDA, 2005), the Crataegus aronia - Noaea mucronata, Noaea mucronata - Carex stenophylla, and Noaea mucronata - Capparis spinosa associations.
N. mucronata is found mostly in Mediterranean climates, with cold wet winters and long hot dry summers. It can survive long periods of drought and high temperatures, as well as occasional winter frosts. It grows from sea level to altitudes in excess of 1000 m. At the eastern end of its native range in Iran, it appears to tolerate a climate that is not typically Mediterranean.
It can tolerate poor desert soils or a variety of types from sands to clays, and stony and/or thin soils. It is tolerant of alkaline soils, and of ten species tested by Morsy et al. (2008), it was the best performer at pH 8.5. It is also resistant to salinity and can dominate in saline soils.
Studies have shown that chronic and intensive grazing of semi-arid rangelands can have significant negative impacts on plant community structure and decrease total plant cover. This degradation often leads to an increase in the frequency of undesirable (toxic or unpalatable) species, weed invasion, sharp declines in plant biomass production and a loss of species diversity (Louhaichi et al., 2009). Thus, invasion of weeds such as N. mucronata is a symptom of overgrazing, but such plants could also play a role in the dynamic ecology that may have direct or indirect impacts on other species.
In semi-arid rangeland in Syria that has been exposed to long term grazing, Louhaichi et al. (2009) found that selective grazing of more palatable species during year-long grazing, shifted plant community composition toward less desirable forage species (such as N. mucronata and Euphorbia macroclada). A reduction in floristic structure and composition subsequently reduced livestock carrying capacity to levels that were straining the economic and social fabric of the region.
In rangeland of the Near East, Bahhady (1986) also noted that “Early grazing and overgrazing are common and are considerably accelerating the decline of the steppe. Undesirable plants such as Noaea mucronata, Alhagi maurorum, Peganum harmala, Anabasis spp. have replaced the palatable species e.g. Salsola vermiculata, Artemisia herba-alba, Atriplex leucoclada, Stipa spp. as well as many other perennial and annual grasses and legumes.”
In Morocco, the important protein-rich range species S. vermiculata, whose presence indicates good grazing land, became reduced in extent during the 1970s and 1980s due to over-exploitation and conversion of rangelands to agriculture, and N. mucronata is most abundant thorny shrub, with its extent increasing in over-grazed areas (Fagouri et al., 1996).
The plant is widely used as a fuel for cooking and heating (Al-Oudat et al., 2005). Its value for such purposes is largely due to there being very little other woody biomass available in such rangeland areas, all the other trees and shrubs having already been removed. Also, in such over-exploited regions, N. mucronata increases in frequency, is desirable, and is thus a ‘free’ resource.
N. mucronata is mostly recorded as having low palatability, but it is recorded as a forage plant. However, it is likely to be browsed more at the end of the dry season where little other forage is available. It is browsed by goats in Iran (Maybodi and Arzani, 2005), and in Syria sheep and goats were noted to occasionally eat the soft shoots in spring (Al-Oudat et al., 2005). Elsewhere, camels are also known to browse N. mucronata. In Central Asia, the dry matter of new shoots in summer were found to contain: 13.5% protein, 2.3% fat, 23.0% fibre, 2.1% ash, and 40.0% nitrogen-free extract (NFE) (Al-Oudat et al., 2005).
N. mucronata is an effective accumulator plant for phytoremediation of heavy-metals-polluted soils, and was the best accumulator for Pb, Zn, Cu, Cd of five species tested in Iran (Chehregani et al., 2009).
Pharmacological effects of N. mucronata have also been studied in Egypt (El-Eraky, 2001), and N. mucronata is included in a list of medicinal plants of Saudi Arabia (Moussa, 1987).
Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.
The effects of two-decade exclusion on vegetation steppic rangelands in Iran, found that the cover and density of N. mucronata was significantly greater in grazed areas (Maybodi et al., 2007), supporting the hypothesis that it is a good indicator of overgrazing.Sankary (1982) and Deiri (1990) assumed that this shift in floral composition towards dominance by N. mucronata in Syrian rangelands was the result of overgrazing and poor management, and that a reduction in grazing pressure would lead to the return of a climax community dominated by the palatable shrub Salsola vermiculata.
Improved grazing management is a viable tool for the sustainable management of rangeland ecosystems, reducing rangeland degradation, slowing the rate of desertification in more vulnerable arid and semi-arid regions, and consequently improving livestock production. From analysing the relative palatability of rangeland species, Louhaichi et al. (2009) proposed a management strategy to reduce the impacts of overgrazing on the composition of plant communities, including the increased density of N. mucronata.
However, this simple cause and effect hypothesis, of overgrazing leading to increases in N. mucronata density, was questioned by Rae et al. (2001) in Syria, who proposed that rather than being due to overgrazing, the increase in N. mucronata is a result of changes in the composition of livestock types grazing the steppe (camels, goats, sheep), coupled with the adoption and widespread use of hand feeding during winter. However, the evidence they cited that questioned the validity of the widely accepted range succession models in arid environments, comprised of two small trials reported in unpublished FAO reports from 1966 and 1967, and the results of a single study in Israel (Noy-Mier, 1990). Nonetheless, the authors of Rae et al. (2001) also draw from much personal experience in range management, and the discussions provide interesting counter-arguments to commonly held views.
N. mucronata is one of many invasive plants of arid and semi-arid rangelands that remain little studied, until they become invasive outside of their native range (e.g. Salsola vermiculata, Alhagi maurorum). Also, such dry areas have historically been under-represented in studies on invasive species in general, and merit further investigation. A thorough survey needs to be undertaken that identify and assess the impacts of native invasive plants in dry rangeland areas, and undertaking detailed studies on those of greatest impact and highest risk of further introduction to new areas.