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