EPPO Global Database

EPPO Reporting Service no. 06 - 2007 Num. article: 2007/123

Pathway analysis: alien plants introduced through the bird seed pathway


Studies were conducted in 1995 and again 2000 in England (UK) to determine which alien plant species may be introduced with commercial bird seed mixtures. Seed mixtures were sown and growing plants were identified, resulting in a list of species that may be introduced into the UK. Considering that these studies were done a few years ago and that the bird seed market is rapidly evolving, the list of plants presented below is not exhaustive but provides useful information on species which may be carried by this pathway.

This study reveals that despite the cleaning process of seeds (see “processing and cleaning” in EPPO RSE 2007/122), more than 450 plant species were found as contaminants of bird seeds. Among these 450 species, 120 are exotic for the whole EPPO region. For each of these 120 exotic species, their family, origin, and known invasive behaviour in the EPPO region are given (NOBANIS database and various other sources). The status of each species in the Global Compendium of Weeds (GCW) is given, to indicate their invasive behaviour elsewhere in the world.

Some of these species are particularly invasive and are listed in the EPPO List of Invasive Alien Plants: Ambrosia artemisiifolia (Asteraceae), Bidens frondosa (Asteraceae), Cenchrus incertus (Poaceae), Helianthus tuberosus (Asteraceae), Sicyos angulatus (Cucurbitaceae).
Many other species introduced as bird seeds contaminants are common weeds in the EPPO region: Abutilon theophrasti (Amaranthaceae), Amaranthus albus, A. blitoides, A. hybridus, A. retroflexus (Amaranthaceae), Bunias orientalis (Brassicaceae), Cuscuta campestris (Convolvulaceae), Eleusine indica (Poaceae), Paspalum dilatatum (Poaceae), Xanthium spinosum (Asteraceae), etc.

From this study, potentially emerging invasive alien species for the EPPO region plants could be identified:
- Dactyloctenium aegyptium (Poaceae): this species is considered a common weed of open ground and waste places in the tropics and subtropics and is known to occur in Crete, Italy and Sicily (Flora Europaea). A Weed Risk Assessment conducted in the Pacific Islands and concluded that this species represented a risk and should not be introduced (Pacific Island Ecosystems at Risk).
- Diplachne uninervia (Poaceae): according to a study on potential environmental weeds in Australia (Csurhes and Edwards, 1998) the plant thrives in areas along humid field edges, irrigation and drainage channels and is thought to have the potential to invade tidal and freshwater wetlands in temperate and sub-tropical zones. The plant is not known to occur in the EPPO region.
- Eragrostis megastachya (Poaceae): this plant is naturalized in tropical and warm temperate regions and is considered invasive in Ecuador, Hawaii, New Caledonia and New Zealand. It is not known to occur in the EPPO region and could only represent a risk in warmer places of the EPPO region.
- Microstegium vimineum (Poaceae): it is an annual grass native to Asia, invasive in the USA. Within the EPPO region, the plant is only reported in Turkey and its status there remains unknown (Global Invasive Species Database). It grows quickly, produces abundant seeds, and easily invades disturbed habitats. It occupies riparian habitats, lawns, woodland thickets, damp fields, and roadside ditches. The coldest winter temperature at which invasive populations occur is approximately -21° to -23° C. It spreads by rooting at nodes along the stem, and fruits and seeds are dispersed by water and animals. Fruits have been transported on cars and in hay and soil.
- Physalis peruviana (Solanaceae): the plant originates from South-America. It is considered invasive in Australia and New-Zealand (Pacific Island Ecosystems at Risk). It only reproduces by seeds. It is known as naturalized in Austria, Açores (PT), Czech Republic, Spain and Italy (Flora Europeae). It is also known to have escaped in the Islas Canarias (ES) (Martin Osoria, Victoria Eugenia ; Wolfredo Wildpret, pers. com.). More information on the behaviour of this species is needed.
- Senna obtusifolia (Fabaceae): annual or perennial herb probably originating from the neotropic. Common as a weed of open disturbed areas in Hawaii, in arid lowlands in the Galápagos Islands, and in drainage channels, overgrazed pastures, and along rivers and flood plains in Australia. The plant reproduces by seeds; seeds are dispersed in mud adhering to vehicles, machinery, animal hooves and fur or as a contaminant of hay, fodder and pasture seeds. A Weed Risk Assessment was conducted in the Pacific Islands and concluded that this species represented a risk and should not be introduced (Pacific Island Ecosystems at Risk).
Some other species may be of concern such as Achyranthes aspera (Amaranthaceae), Hordeum jubatum (Poaceae) and Navarretia squarrosa (Polemoniaceae).

The EPPO Secretariat would greatly appreciate to receive any information about the occurrence and invasive behaviour in the EPPO countries of the species listed below and any additional information related to the bird seed pathway.

Species
Family
Origin
GCW
Known invasiveness in EPPO countries
Abutilon theophrasti
Malvaceae
W Asia
NW, EW
AT, DE, ES, NL, SE
Achyranthes aspera
Amaranthaceae
SW Asia
QW, NW, EW
;
Amaranthus albus
Amaranthaceae
Americas
NW, EW
ES, IT, SE
Amaranthus blitoides
Amaranthaceae
N-Am.
Nat W, QW
ES, GR, IT, S
Amaranthus bouchonii
Amaranthaceae
Neotrop.
/
NL
Amaranthus capensis subsp. uncinatus
Amaranthaceae
Southern Af.
Nat W
;
Amaranthus caudatus
Amaranthaceae
Neotrop.
EW
IT
Amaranthus cruentus
Amaranthaceae
C. Am.
/
;
Amaranthus graecizans
Amaranthaceae
Paleotrp
NW
ES
Amaranthus hybridus
Amaranthaceae
Neotrop.
/
ES, HU, IT, S
Amaranthus muricatus
Amaranthaceae
S-Am.
/
ES, IT
Amaranthus paniculatus
Amaranthaceae
trop Am.
/
;
Amaranthus quitensis
Amaranthaceae
S-Am.
/
;
Amaranthus retroflexus
Amaranthaceae
N-Am.
NW, EW
ES, HU, IT, LT, SE
Amaranthus scleropoides
Amaranthaceae
N-Am.
abs.
;
Amaranthus standleyanus
Amaranthaceae
S-Am.
/
;
Amaranthus thunbergii
Amaranthaceae
Africa
QW, Nat W
;
Amaranthus viridis
Amaranthaceae
Neotrop.
EW
ES, IT
Ambrosia artemisiifolia
Asteraceae
N-Am.
NW, Nat W, EW
List of IAP, GIS Database
Amsinckia calycina
Boraginaceae
Americas
EW
;
Amsinckia intermedia
Boraginaceae
Americas
/
;
Amsinckia micrantha
Boraginaceae
N-Am.
abs
;
Anoda cristata
Malvaceae
Americas
/
;
Argemone mexicana
Papaveraceae
S-Am.
QW, NW, EW
;
Arthraxon hispidus
Poaceae
Asia, Australia
/
;
Atriplex nitens
Chenopodiaceae
SW Asia
abs
CZ, LT
Beckeropsis petiolaris
Poaceae
Africa
/
;
Beckmannia syzigachne
Poaceae
China, Japan
/
;
Bidens biternata
Asteraceae
E-Asia
/
;
Bidens frondosa
Asteraceae
N-Am.
Nat W
List of IAP
Bidens pilosa
Asteraceae
trop Am.
EW
;
Bidens tripartita
Asteraceae
Americas
/
;
Brachiaria platyphylla
Poaceae
N-Am.
/
;
Brassica carinata
Brassicaceae
Africa
/
;
Bromus willdenowii
Poaceae
S-Am.
/
;
Calceolaria chelidonioides
Scrophulariaceae
C;S Am.
abs
;
Celosia argentea
Amaranthaceae
Pantrop.
W
;
Cenchrus incertus
Poaceae
trop Am.
QW, NW
List of IAP
Cephalaria syriaca
Dipsacaceae
Africa, temp Asia
QW
;
Chamomilla suaveolens
Asteraceae
N Am.
/
;
Chenopodium ambrosioides
Chenopodiaceae
trop Am.
EW
;
Chenopodium capitatum
Chenopodiaceae
N-Am.
/
;
Chenopodium giganteum
Chenopodiaceae
perhaps Asia
/
;
Chenopodium probstii
Chenopodiaceae
N. Am.
/
;
Cosmos bipinnatus
Asteraceae
C-Am, W-India
EW
;
Cuscuta campestris
Convolvulaceae
N-Am.
QW, NW, EW
CY, CZ, HU, LT, NL, SE, SL
Cynodon dactylon
Poaceae
trop. Af.
SW, NW, EW
;
Dactyloctenium aegyptium
Poaceae
trop Af., Asia
EW
;
Datura stramonium
Solanaceae
trop. Am.?
QW, NW, EW
;
Digitaria ciliaris
Poaceae
trop Am. Asia, Af.
Nat W
;
Digitaria ternata
Poaceae
Asia, Africa
Nat W, EW
;
Diplachne uninervia
Poaceae
SW N-Am.
QW, EW
;
Dracocephalum parviflorum
Lamiaceae
N-Am.
NW
;
Echinochloa colonum
Poaceae
India
EW
;
Eleusine africana
Poaceae
Af.
QW
;
Eleusine coracana
Poaceae
Af. Temp. Asia
/
;
Eleusine indica
Poaceae
Af.
QW
EE, ES, GR, HU, IT, SE
Eleusine tristachya
Poaceae
S-Am.
QW
SE
Eragrostis megastachya
Poaceae
Af.
Nat W, EW
;
Eragrostis neomexicana
Poaceae
SW Am.
/
;
Eragrostis tef
Poaceae
Africa
/
;
Eragrostis virescens
Poaceae
S-Am.
/
;
Euphorbia hirta
Euphorbiaceae
trop ; subtrop
/
;
Euphorbia serpens
Euphorbiaceae
N-Am.
/
;
Galinsoga ciliata
Asteraceae
S-Am.
/
;
Glycine max
Fabaceae
Asia
/
;
Glycine soja
Fabaceae
Asia
/
;
Helianthus tuberosus
Asteraceae
Americas
NW, Nat W, EW
List of IAP
Hordeum jubatum
Poaceae
N-Am.
QW, NW, Nat W
;
Ipomoea eriocarpa
Convolvulaceae
Madagascar
NW
;
Ipomoea hederacea
Convolvulaceae
Americas
/
GR, LT
Ipomoea hederacea var. integriuscula
Convolvulaceae
Americas
/
;
Ipomoea purpurea
Convolvulaceae
trop Am.
QW, NW, EW
ES, IT, LT, SE
Iva xanthifolia
Asteraceae
N-Am.
NW, Nat W
;
Lepidium bonariense
Brassicaceae
S-Am.
EW
IT
Lepidium densiflorum
Brassicaceae
N-Am.
NW, Nat W, EW
;
Lepidium divaricatum
Brassicaceae
Af.?
/
;
Matricaria inodora
Asteraceae
Australia
EW
;
Microstegium vimineum
Poaceae
Asia
EW
GIS Database
Navarretia squarrosa
Polemoniaceae
W N-Am.
EW
;
Nicandra physalodes
Solanaceae
S-Am.
/
;
Panicum capillare
Poaceae
N-Am.
/
;
Panicum dichotomiflorum
Poaceae
N-Am.
NW, Nat W, EW
DE, LT, N
Panicum effusum
Poaceae
Australia
/
;
Panicum laevifolium
Poaceae
C;S Af.
/
;
Panicum subalbidum
Poaceae
Southern Af.
Nat W
;
Paspalum dilatatum
Poaceae
S-Am.
EW
FR, IT, SE
Pennisetum glabrum
Poaceae
Af.
abs
;
Pennisetum nubicum
Poaceae
Af.
abs
;
Persicaria glabra
Polygonaceae
Trop and subtrop Asia and Af.
/
;
Persicaria pensylvanica
Polygonaceae
N-Am.
/
;
Phaseolus angularis
Fabaceae
E Asia
/
;
Phaseolus aureus
Fabaceae
Madagascar
/
;
Physalis peruviana
Solanaceae
trop Am.
Nat W, EW
;
Physalis philadelphica
Solanaceae
C ; S Am.
/
;
Polygonum nepalense
Polygonaceae
China, Japan, Korea, Himalaya
QW
;
Potentilla norvegica
Rosaceae
N-Am.
NW, EW
;
Psoralea corylifolia
Fabaceae
India
QW
;
Rumex brownii
Polygonaceae
Australia
NW, EW
;
Rumex triangulivalvis
Polygonaceae
N-Am.
/
;
Salvia reflexa
Lamiaceae
N-Am.
NW, Nat W
;
Senna obtusifolia
Caesalpiniaceae
trop Am.
QW, NW
;
Sesamum capense
Pedaliaceae
S-Af.
abs
;
Sesbania exalta
Fabaceae
N-Am.
/
;
Setaria faberi
Poaceae
China, Japan
QW, NW
LT
Setaria geniculata
Poaceae
C ; S Am.
/
;
Setaria macrostachya
Poaceae
Americas
abs
;
Setaria sphacelata
Poaceae
southern Af.
Nat W
;
Sicyos angulatus
Cucurbitaceae
N Am.
NW, Nat W
List of IAP
Sida spinosa
Malvaceae
trop Am.
/
;
Solanum cornutum
Solanaceae
N Am.
/
;
Solanum physalifolium
Solanaceae
S Am.
EW
;
Solanum pseudocapsicum
Solanaceae
S Am.
EW
;
Solanum sarrachoides
Solanaceae
S Am.
QW
;
Solanum sisymbriifolium
Solanaceae
S Am.
NW
;
Spinacia oleracea
Chenopodiaceae
Iran
/
;
Tetragonia tetragonioides
Tetragoniaceae
New Zealand
Nat W
;
Trachyspermum ammi
Apiaceae
India
/
;
Trigonella caerulea
Fabaceae
N Am.
/
;
Triticum durum
Poaceae
China
abs
;
Urochloa panicoides
Poaceae
southern Af.
NW, Nat W
;
Verbesina encelioides
Asteraceae
N Am.
/
;
Wedelia glauca
Asteraceae
S-Am.
QW
;
Xanthium spinosum
Asteraceae
trop Am.
QW, NW, EW
;

Species in bold are listed in the EPPO List of invasive alien plants.
* Abbreviations for the Global Compendium of Weeds column:
NW: noxious weed; Nat W: native weed; QW: quarantine weed; abs: not quoted in the GCW; /: no clear sign of invasiveness

Sources

Csurhes S, Edwards R (1998) Potential Environmental Weeds in Australia - Candidate Species for Preventative Control National Weeds Program. Queensland Department of Natural Resources. http://www.environment.gov.au/biodiversity/invasive/publications/weeds-potential/results-diplachne.html
Flora Europaea – Royal Botanic Garden Edinburg. http://rbg-web2.rbge.org.uk/FE/fe.html
Global Invasive Species Database – Microstegium vimineum. http://www.issg.org/database/species/ecology.asp?si=686;fr=1;sts=
Hanson CG, Mason JL (1985) Bird seed aliens in Britain. Watsonia 15, 237-252. http://www.watsonia.org.uk/html/watsonia_15.html
Hanson CG (2000) Update on birdseed aliens(1985-1998) Watsonia 23, 213-220.
North European and Baltic Network on Invasive Alien Species (NOBANIS). http://www.nobanis.org/
Pacific Island Ecosystems at Risk - Dactyloctenium aegyptium. http://www.hear.org/pier/species/dactyloctenium_aegyptium.htm
Pacific Island Ecosystems at Risk - Eragrostis megastachya. http://www.hear.org/pier/species/eragrostis_cilianensis.htm
Pacific Island Ecosystems at Risk - Physalis peruviana. http://www.hear.org/pier/species/physalis_peruviana.htm
Pacific Island Ecosystems at Risk – Senna obtusifolia. http://www.hear.org/pier/species/senna_obtusifolia.htm