Invasive Species Compendium

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Datasheet

Cymbopogon nardus
(citronella grass)

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Datasheet

Cymbopogon nardus (citronella grass)

Summary

  • Last modified
  • 19 November 2018
  • Datasheet Type(s)
  • Invasive Species
  • Preferred Scientific Name
  • Cymbopogon nardus
  • Preferred Common Name
  • citronella grass
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Monocotyledonae
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Identity

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Preferred Scientific Name

  • Cymbopogon nardus (L.) Rendle

Preferred Common Name

  • citronella grass

Other Scientific Names

  • Andropogon nardus L.
  • Cymbopogon afronardus Stapf. Stapf Otto
  • Cymbopogon validus (Stapf) Burtt Davy Stapf Otto

International Common Names

  • English: Ceylon citronella; citronella grass; geranium grass; nardus grass
  • Spanish: zacate limon
  • French: citronelle; citronelle de Ceylan; citronelle de Sri lamka
  • Chinese: ya xiang mao

Local Common Names

  • Brazil: ceilao lenabatu; citronela do
  • Congo Democratic Republic: false citronella
  • Denmark: citronella; lenabatugraes
  • Germany: Ceyloncitronell; Citronellgras; dichtblattriges Zitronellagras; Nardusgras
  • India: naid grass
  • Italy: cintronella di Ceylon
  • Japan: kou suigaya; seiron shitironera; shitoronera; shitoronera gurasu
  • Kenya: blue citronella grass
  • Mali: tiberimt; tiekala-ba
  • Netherlands: citroenmelisse
  • Nigeria: tsaure
  • Poland: palcztka szczetna
  • Portugal: citronela de Ceilan; citronela-de-java
  • Senegal: beignefala
  • Southern Africa: reuse terpentyngras
  • Sri Lanka: lenabatu citronella
  • Sweden: citronellagras
  • Taiwan: citronella grass
  • Thailand: ta khrai hom
  • Vietnam: cu sa

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Spermatophyta
  •             Subphylum: Angiospermae
  •                 Class: Monocotyledonae
  •                     Order: Cyperales
  •                         Family: Poaceae
  •                             Genus: Cymbopogon
  •                                 Species: Cymbopogon nardus

Description

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From Clayton et al. (2014):

Habit: Perennial; caespitose. Butt sheaths persistent and investing base of culm. Culms 75–300 cm long. Ligule an eciliate membrane; 3–9 mm long. Leaf-blades drooping; flat; 20–60 cm long; 3–15 mm wide; aromatic. Leaf-blade surface smooth, or scaberulous.

Inflorescence: Synflorescence compound; linear; 15–60 cm long; dense. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; enclosed. Spatheole elliptic; 1–2.5 cm long.

Racemes: 2; paired; deflexed; 1–2 cm long. Rhachis fragile at the nodes; semiterete; ciliate on margins. Rhachis hairs 0.5–3 mm long. Rhachis internodes linear. Rhachis internode tip transverse; cupuliform. Raceme-bases flattened; subequal.

Spikelets: in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; semiterete; ciliate. Spikelets without stalks, flat or concave on the back with winged keels (resembling the keel of a boat) (Napper, 1965Harrington and Pratchett, 1974).

Sterile spikelets: Basal sterile spikelets well-developed; 2 in lower raceme; 0 in upper raceme; with normal internodes; sessile and pedicelled. Basal sterile spikelet pedicels free; linear. Basal sterile spikelets equalling fertile. Companion sterile spikelets well-developed; male; lanceolate; 3.5–6 mm long; as long as fertile; deciduous with the fertile. Companion sterile spikelet glumes chartaceous; distinctly veined; 3–7 -veined (intercarinal); acute; muticous. Companion sterile spikelet lemmas 2; enclosed by glumes.

Fertile spikelets: Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; (3–)3.5–7 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus pilose; base obtuse; inserted.

Glumes: Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume linear; 1 length of spikelet; chartaceous; 2-keeled; keeled all along; keeled laterally; winged on keel; winged above. Lower glume intercarinal veins absent, or obscure; 0–4 in number. Lower glume surface convex, or flat, or concave. Lower glume apex emarginate. Upper glume lanceolate; 1-keeled. Upper glume apex acute.

Florets: Basal sterile florets barren; without significant palea. Lemma of lower sterile floret hyaline. Fertile lemma lanceolate; hyaline; without keel. Lemma apex lobed; 2 -fid; incised 0.5 of lemma length; muticous, or awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 5–15 mm long overall; with twisted column. Column of lemma awn glabrous. Palea absent or minute.

Flower: 3 Anthers.

Distribution

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From Clayton et al. (2014):

Africa: west tropical, west-central tropical, northeast tropical, east tropical, southern tropical, south and western Indian ocean.

Asia-temperate: China and eastern Asia.

Asia-tropical: India, Indo-China and Malesia.

Pacific: southwestern and northwestern.

South America: Caribbean and northern South America

Distribution Table

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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.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

Asia

BangladeshPresenteMonocot, 2013
CambodiaPresenteMonocot, 2013
ChinaLocalisedeMonocot, 2013South central & south east
-HainanPresenteMonocot, 2013
IndiaWidespreadNativeUSDA-ARS, 2014
-Andaman and Nicobar IslandsPresenteMonocot, 2013
-Andhra PradeshWidespreadNativeUSDA-ARS, 2014
-AssamWidespreadNativeUSDA-ARS, 2014
-BiharWidespreadNativeUSDA-ARS, 2014
-KarnatakaWidespreadNativeUSDA-ARS, 2014
-ManipurWidespreadNativeUSDA-ARS, 2014
-Tamil NaduWidespreadNativeUSDA-ARS, 2014
-TripuraWidespreadNativeUSDA-ARS, 2014
-Uttar PradeshWidespreadNativeUSDA-ARS, 2014
-West BengalWidespreadNativeUSDA-ARS, 2014
IndonesiaPresent
-JavaPresenteMonocot, 2013
-MoluccasPresenteMonocot, 2013
-Nusa TenggaraWidespreadIntroducedUSDA-ARS, 2014
-SumatraPresenteMonocot, 2013
JapanPresentPresent based on regional distribution.
-Ryukyu ArchipelagoPresenteMonocot, 2013
LaosPresenteMonocot, 2013
MaldivesPresenteMonocot, 2013
MyanmarWidespreadNativeeMonocot, 2013
PhilippinesWidespreadIntroduced
Sri LankaWidespreadNativeeMonocot, 2013
TaiwanWidespreadIntroducedeMonocot, 2013
VietnamPresenteMonocot, 2013

Africa

AngolaPresenteMonocot, 2013
BeninPresenteMonocot, 2013
BotswanaPresenteMonocot, 2013
BurundiWidespreadNativeNdabaneze, 1989
Congo Democratic RepublicWidespreadNativeNdabaneze, 1989
EgyptWidespreadIntroducedeMonocot, 2013Nile region
KenyaPresentSsegawa, 2007Common in grasslands and open woodlands
LesothoPresenteMonocot, 2013
MadagascarPresenteMonocot, 2013
MozambiquePresenteMonocot, 2013
NigeriaWidespreadIntroducedeMonocot, 2013
RwandaWidespreadNativeNdabaneze, 1989
SeychellesPresenteMonocot, 2013
South AfricaWidespreadNative Invasive SANBI, 2005; Raimondo et al., 2009
SudanWidespreadNative Invasive USDA-ARS, 2014
SwazilandWidespreadNative Invasive SANBI, 2005; Raimondo et al., 2009
TanzaniaPresentSsegawa, 2007Common in grasslands and open woodlands
UgandaWidespreadIntroduced Invasive Boy and Witt, 2013Common in grasslands and open woodlands
ZimbabwePresenteMonocot, 2013

North America

MexicoLocalisedIntroducedeMonocot, 2013South east and south west
USAPresentPresent based on regional distribution.
-CaliforniaLocalisedIntroducedeMonocot, 2013Ornamental
-FloridaPresentIntroducedeMonocot, 2013Ornamental

Central America and Caribbean

BahamasLocalisedIntroducedeMonocot, 2013
CubaLocalisedIntroducedeMonocot, 2013
Dominican RepublicLocalisedIntroducedeMonocot, 2013
HaitiLocalisedIntroducedeMonocot, 2013
HondurasLocalisedIntroducedeMonocot, 2013
JamaicaLocalisedIntroducedeMonocot, 2013
Puerto RicoLocalisedIntroducedeMonocot, 2013
Trinidad and TobagoLocalisedIntroducedeMonocot, 2013

South America

BrazilLocalisedIntroducedeMonocot, 2013Northeast and west-central
ColombiaLocalisedIntroducedeMonocot, 2013

Oceania

FijiLocalisedIntroducedeMonocot, 2013
NiueLocalisedIntroducedeMonocot, 2013
Northern Mariana IslandsLocalisedIntroducedeMonocot, 2013
Papua New GuineaLocalisedIntroducedeMonocot, 2013

History of Introduction and Spread

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C. nardus is native to southeast Asia and grown commercially in Sri Lanka, India, Burma, Indonesia and Java. It is widely naturalized in tropical Asia and grown as an ornamental in South Florida and southern California (Floridata, 2014). Its native status in Africa is disputed (eMonocot, 2013; USDA-ARS, 2014).

Risk of Introduction

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C. nardus establishes naturally from seed, which are spread by wind, animals, water, machinery and road vehicles (NARO, 2004).

Habitat

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C. nardus is native to warm temperate and tropical regions of southeast Asia. It is common in grassland and open woodland of Acacia and Combretum on hills in Uganda (Ssegawa, 2007).

Habitat List

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CategorySub-CategoryHabitatPresenceStatus
Terrestrial
 
Terrestrial – ManagedProtected agriculture (e.g. glasshouse production) Secondary/tolerated habitat Productive/non-natural
Managed forests, plantations and orchards Secondary/tolerated habitat Harmful (pest or invasive)
Industrial / intensive livestock production systems Secondary/tolerated habitat Productive/non-natural
Terrestrial ‑ Natural / Semi-naturalNatural grasslands Principal habitat Natural

Hosts/Species Affected

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Due to its competitiveness, C. nardus has the ability to affect diversity and population of other pasture species in grasslands, including Brachiaria decumbens, Themeda triandra and Hyparrhenia filipendula (Ssegawa, 2007).

Biology and Ecology

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Genetics

2n = 20 (Fedorov, 1974).

Reproductive Biology

C. nardus establishes naturally from seed, which are known to germinate prolifically after fire (Ssegawa, 2007). It can also be propagated by dividing a plant into clumps (Floridata, 2014). It lives for 4-5 years (CSIR, 2014).

Environmental Requirements

C. nardus grows well in the dry (summer) season at an altitude range of 2000-3000 m above sea level and a rainfall preference of 750 mm or more (FAO, 2014). It grows best in full sun. C. nardus is perennial in USDA zones 10-12. It needs a long, warm growing season, and may not survive cool, damp winters. In the USA, it usually is replanted anew each spring after the ground has warmed (Floridata, 2014).

Climate

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ClimateStatusDescriptionRemark
As - Tropical savanna climate with dry summer Preferred < 60mm precipitation driest month (in summer) and < (100 - [total annual precipitation{mm}/25])
Aw - Tropical wet and dry savanna climate Tolerated < 60mm precipitation driest month (in winter) and < (100 - [total annual precipitation{mm}/25])

Means of Movement and Dispersal

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Natural Dispersal

C. nardus establishes naturally from seed, particularly in highly grazed areas beneath bushes (Ssegawa, 2007). Seeds can be transported by wind or water.

Vector Transmission (Biotic)

Seeds can be spread by grazing animals.

Accidental Introduction

Seeds can be spread by vehicles and agricultural machinery.

Intentional Introduction

C. nardus is grown as an ornamental in south Florida and southern California, USA, and deliberately propagated in these regions (Floridata, 2014).

Plant Trade

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Plant parts liable to carry the pest in trade/transportPest stagesBorne internallyBorne externallyVisibility of pest or symptoms
Flowers/Inflorescences/Cones/Calyx Yes Pest or symptoms usually visible to the naked eye
Seedlings/Micropropagated plants Yes Yes Pest or symptoms usually visible to the naked eye
True seeds (inc. grain) Yes Yes Pest or symptoms usually visible to the naked eye

Impact Summary

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CategoryImpact
Cultural/amenity Positive
Economic/livelihood Positive
Environment (generally) Positive and negative

Economic Impact

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C. nardus invades grazing lands and affects plant species composition, lowering the quality and yield of forage (Ssegawa, 2007). It is unpalatable to cattle and cattle have been known to die of starvation when an abundance of C. nardus, in green condition, was available (Harrington, 1974).

Impact: Biodiversity

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C. nardus can take over rangelands, where it lowers the yield and quality of the forage (Ssegawa, 2007). It is unpalatable to cattle, although buffalo will eat C. nardus sparingly and elephants will accept it during the dry season (Field et al., 1973). It has been detected in national parks in Uganda, where it may constitute a threat to biodiversity (Ssegawa, 2007).

Social Impact

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Farmers who cannot afford to continuously remove C. nardus from their land are forced to move from place to place (Ssegawa, 2007).

Risk and Impact Factors

Top of page Invasiveness
  • Invasive in its native range
  • Proved invasive outside its native range
  • Abundant in its native range
  • Highly adaptable to different environments
  • Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
  • Pioneering in disturbed areas
  • Tolerant of shade
  • Benefits from human association (i.e. it is a human commensal)
  • Long lived
  • Fast growing
  • Has high reproductive potential
  • Gregarious
  • Reproduces asexually
  • Has high genetic variability
Impact outcomes
  • Altered trophic level
  • Changed gene pool/ selective loss of genotypes
  • Ecosystem change/ habitat alteration
  • Increases vulnerability to invasions
  • Loss of medicinal resources
  • Modification of successional patterns
  • Monoculture formation
  • Negatively impacts agriculture
  • Negatively impacts cultural/traditional practices
  • Negatively impacts animal health
  • Negatively impacts livelihoods
  • Negatively impacts tourism
  • Reduced native biodiversity
  • Threat to/ loss of endangered species
  • Threat to/ loss of native species
  • Negatively impacts animal/plant collections
Impact mechanisms
  • Competition - monopolizing resources
  • Competition - shading
  • Competition - smothering
  • Herbivory/grazing/browsing
  • Interaction with other invasive species
  • Rapid growth
  • Rooting
Likelihood of entry/control
  • Highly likely to be transported internationally deliberately
  • Difficult to identify/detect in the field
  • Difficult/costly to control

Uses

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Taken from Floridata (2014):

C. nardus is the source of citronella oil, used in perfumery and as an insect repellent. Inexpensive soaps sold in Asian markets are scented with citronella oil. Citronella oil can be mixed with other vegetable oils and used in massage or rubbed on the skin for an insect repellent. Citronella candles and incense, however, are less effective.

Practitioners claim citronella oil is a stimulant when inhaled or rubbed on the skin, and an antiseptic that can be used to sterilize food preparation surfaces. It is also used in Chinese medicine and traditional medicine for the treatment of rheumatism, digestive problems, fever and intestinal problems, and in aromatherapy to treat colds, flu and headaches (Akhila, 2009).

Social Benefit

C. nardus emits a pleasant fragrance and is planted along walkways or near houses. It is also reported that citronella oil repels cats (Floridata, 2014).

Prevention and Control

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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.

Control

Whichever control method is chosen, controlling the weed before it seeds will reduce future problems. Control is generally best applied to the least infested areas before dense infestations are tackled. Consistent follow-up work is required for sustainable management (Ssegawa, 2007).

Cultural Control and Sanitary Measures

The manipulation of grazing regimes can be used as a management method. Light grazing encourages growth, but heavy grazing pressure of one bullock per hectare prevented recolonisation of C. nardus; however, it is generally avoided by grazers. Periodic heavy stocking was able to convert a slope pasture of 47% C. nardus to a mixed pasture dominated by Brachiaria decumbens. The application of 158 kg N/ha increased the content of B. decumbens still further (Ssegawa, 2007).

Physical/Mechanical Control

Uprooting the tufts with a hoe is effective over small areas but was deemed impractical on large scale areas due to high labour costs. At 2005 prices, this mode of control was costed at 1 Ankole cow per acre of land cleared (approx. US $175). Burning the grass is also suggested, but C. nardus regrows immediately when the rains come (NARO, 2004).

Chemical Control

Spot spraying with glyphosphate can reduce C. nardus without negatively impacting indigenous species (Ssegawa, 2007).

IPM

In addition to a late burn in the long dry season, a soil tillage treatment combined with the sowing of Eragrostis curvula at 2.64 kg/ha during the wet season revegetated severely damaged Themeda/Cymbopogon veld and increased dry-matter production (Ssegawa, 2007).

Gaps in Knowledge/Research Needs

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The native status of C. nardus in parts of Africa is still disputed, (eMonocot, 2013; USDA-ARS, 2014).

References

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Akhila A, 2009. Essential oil-bearing grasses: the genus Cymbopogon [ed. by Akhila, A.]. London, UK: CRC Press Inc., 262 pp.

Boy G; Witt A, 2013. Invasive alien plants and their management in Africa., Malta: Gutenberg Press Limited. http://www.cabi.org/Uploads/CABI/publishing/promotional-materials/african-invasives-book.pdf

Clayton WD; Govaerts R; Harman KT; Williamson H; Vorontsova M, 2014. GrassBase - The Online World Grass Flora. http://www.kew.org/data/grasses-db.html

CSIR, 2014. Technologies for the Rural Sector. Council of Scientific and Industrial Research. http://www.csir.res.in/

eMonocot, 2013. eMonocot: An online resource for monocot plants. http://e-monocot.org/

FAO, 2014. Grassland species profiles. http://www.fao.org/ag/AGP/AGPC/doc/Gbase/Default.htm

Fedorov A, 1974. Chromosome numbers in flowering plants. Koenigstein, Germany: Koeltz Scientific Books.

Field CR; Harrington GN; Pratchett D, 1973. A comparison of the grazing preferences of buffalo and Ankole bullocks on three different pastures. East African Wildlife Journal, 11:19-29.

Floridata, 2014. FLORIDATAbase website. Tallahassee, Florida, USA: Floridata.com. http://www.floridata.com/

Harrington GN, 1974. Fire effects on a Ugandan savanna grassland. Tropical Grasslands, 8(2):87-101.

Harrington GN; Pratchett D, 1974. Stocking rate trials in Ankole, Uganda. 1. Weight gain of Ankole steers at intermediate and heavy stocking rates under different managements. Journal of Agricultural Science, UK, 82(3):497-506.

Harrington GN; Thornton DD, 1969. A comparison of controlled grazing and manual hoeing as a means of reducing the incidence of Cymbopogon afronardus Stapf in Ankole pastures, Uganda. East African Agricultural and Forestry Journal, 35(2):154-9.

JSTOR Global Plants, 2014. JSTOR Global Plants Database. Ann Arbor, MI and New York, NY, USA: JSTOR. http://plants.jstor.org/

McMurtrie SA; Sinton AMR; Winterbourn MJ, 2014. Lucid Key Server. Key Version: 1.0. http://keys.lucidcentral.org/key-server/keys.jsp

Missouri Botanical Garden, 2014. Tropicos database. St. Louis, Missouri, USA: Missouri Botanical Garden. http://www.tropicos.org/

Napper DM, 1965. Bull. 18 Min. Agric. For. Wildlife, Tanzania. 146 pp.

NARO, 2004. Implementation of Invasive Plant Prevention and Control Programmes in Uganda. Report Submitted to CAB International Under the PDF-B Phase of the UNEP/GEF-Funded Project: Removing Barriers to Invasive Plant Management in Africa. Entebbe, Uganda: National Agricultural Research Organization, 10-15.

Ndabaneze P, 1989. Catalogue of the grasses of Burundi. (Catalogue des graminées du Burundi.) Lejeunia, No. 132. 208pp.

Raimondo D; Staden Lvon; Foden W; Victor JE; Helme NA; Turner RC; Kamundi DA; Manyama PA, 2009. Red list of South African plants 2009 [ed. by Raimondo, D.\Staden, L. von\Foden, W.\Victor, J. E.\Helme, N. A.\Turner, R. C.\Kamundi, D. A.\Manyama, P. A.]. Pretoria, South Africa: South African National Biodiversity Institute, ix + 668 pp.

SANBI, 2005. Red List of South African Plants version 2014. http://redlist.sanbi.org/index.php

Ssegawa P, 2007. Effects of Herbicide on the Invasive grass, Cymbopogon nardus (Franch.) Stapf (Tussocky Guinea grass) and Responses of Native Plants in Kikatsi subcounty, Kiruhuura district, western Uganda. Final Report on Activity 3.4 of Component 3 of the UNEP/GEF-IAS funded Project (NARO): Removing Barriers to Invasive Plant Management in Africa. http://www.naro.go.ug/Invasive%20plants/Reports/1-Effects%20of%20Herbicide%20on%20the%20Invasive%20grass_Cymbopogon%20nardus.pdf

USDA-ARS, 2014. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch.aspx

Links to Websites

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WebsiteURLComment
GISD/IASPMR: Invasive Alien Species Pathway Management Resource and DAISIE European Invasive Alien Species Gatewayhttps://doi.org/10.5061/dryad.m93f6Data source for updated system data added to species habitat list.

Contributors

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17/07/14 Original text by:

Esther Arengo, National Agricultural Research Laboratories, Uganda

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