Invasive species

 
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Invasive alien species have distressing impacts on native biota, causing decline or even extinctions of native populations. All major invasions are due to deliberate or unintentional actions of humans, birds, animals and, to a certain extent, due to traffic across the borders. Though majority of introductions have only minor impacts to the ecosystem, some of them led to numerous problems. The vegetation of Saudi Arabia, particularly of the plant diversity hotspots in the southwestern region including some of the Red Sea Islands is inundated by the influx of several alien plants. Forty eight exotic species have been recorded from Saudi Arabia, some of which have entered and naturalized in the Kingdom several decades ago. Among these, 40 are from American continents, 4 from Tropical countries, and one each from East Asia, South Asia, Iran and Australia. All major invasive species in Saudi Arabia are native to American Continents.  Among these, the species that potentially damaging the biodiversity or altering the ecosystems in general are: Argemone ochrolecuca, Nicotiana glauca, Opuntia dellenii, O. ficus-indica, Prosopis juliflora and Trianthema portulacastrum.

Farasan Islands: Prosopis juliflora invaded in a plant community dominated by

Acacia ehrenbergiana

Opuntia dellenii (Cactaceae) invaded along the eastern slopes of Raida Escarpments

Argemone ochroleuca, Papaveraceae

 Prosopis juliflora is the most troublesome invasive species in majority of places in Tihama. Among the major invaders, four species (Argemone ochroleuca, Nicotiana glauca, Opuntia dellenii, O. ficus-indica,) have been seen in areas above 1000 meters while Prosopis juliflora and Trianthema portulacastrum have been observed in areas below 800 m and in areas between 100-1500 m respectively. Opuntia spp. showed a preference for warm and dry climates and are common on the east facing slopes of southwestern highlands; while N. glauca responded well to low temperature and high precipitation rates. P. juliflora, Argemone spp. and Nicotiana glauca illustrated a strong association with high levels of human influence, proximity to urban and disturbed areas.

New growth of Nicotiana glauca in a disturbed area along the sides of road in Raida Escarpments, Abha

Vegetation of the northwestern Hijaz Mountain is less affected by invasions. Only P. juliflora and Cuscuta campestris are the major exotic species seen among the communities of lowlands and slopes of the mountains. The influence of exotic species in the central and eastern regions are also less significant. P. juliflora, Cuscuta campestris, Cenchrus echinatus, Euphorbia spp., Verbesina encelioides, Leucaena leucocephala, Prosopis koelziana, etc. are the main invaders spotted among native plant populations. Unlike the southern islands in the Red Sea (Farasan Al-Kabir), islands of Arabian Gulf are devoid of exotic species, except for a few Prosopis juliflora plants close to the farms of one of the inhabited islands, Jana Island, off Jubail coast.

Exotic species in Saudi Arabia

Species

Family

Chorotype

Distribution in

Saudi Arabia

Habit

Altitude (Meter)

Score

0-500

500-1000

1000-2000

2000-3000

Alternanthera pungens

Amaranthaceae

American

Southwestern Mountains

Herb

+

+

+

 

1

Amaranthus albus

Amaranthaceae

American

Central, Eastern and Western regions

Herb

+

+

 

 

1

Amaranthus hybridus

Amaranthaceae

American

Throughout Saudi Arabia

Herb

+

+

+

 

1

Amaranthus spinosus

Amaranthaceae

American

Southwestern mountains

Herb

+

+

+

+

1

Annona squamosa

Annonaceae

American

Southwestern mountains (Jabal Fayfa)

Tree

 

 

+

 

1

Argemone mexicana

Papaveraceae

South American

Southwestern mountains

Herb

 

 

+

+

3

Argemone ochroleuca

Papaveraceae

S. American

Southwestern mountains

Herb

 

 

+

+

5

Atriplex suberecta

Chenopodiaceae

Australian

Central and eastern regions

Herb

 

 

 

 

1

Bidens aurea

Asteraceae

American

Southwestern mountains

Herb

 

 

 

 

1

Cenchrus echinatus

Leguminosae

American

Central, eastern western and northern regions

P. grass

+

+

 

 

3

Cenchrus setigerus

Poaceae

South Asia

Southwestern mountains

P. grass

+

+

 

 

1

Cuscuta campestris

Cuscutaceae

N. American

Central , eastern and  northern regions

Herb

+

+

 

 

1

Datura ferox

Solanaceae

N. American

Southwestern region

Herb

 

 

+

 

1

Datura innoxia

Solanaceae

N. American

Through out Saudi Arabia

Herb

+

 

 

 

3

Datura metel

Solanaceae

N. American

Southwestern region

Herb

 

 

+

 

1

Datura stramonium

Solanaceae

N. American

Southwestern region

Herb

+

 

 

 

1

Eclipta prostrata

Asteraceae

N. American

Central

Shrub

+

+

 

 

1

Encelia farinosa

Asteraceae

N. American

Southwestern region     

Shrub

 

 

+

 

1

Euphorbia cyathophora

Euphorbiaceae

American

Eastern Province

P. Herb

 

+

 

 

1

Euphorbia heterophylla

Euphorbiaceae

American

Eastern province

P. herb

 

 

 

 

1

Euphorbia hirta

Euphorbiaceae

American

Throughout Saudi Arabia

Herb

+

+

+

+

1

Euphorbia prostrata

Euphorbiaceae

American

Central region

Herb

 

+

 

 

1

Euphorbia supina

Euphorbiaceae

American

Central region

Herb

 

+

 

 

1

Euphorbia tirucalli

Euphorbiaceae

East Africa

Southwestern region    

Shrub/Tree

 

+

+

 

1

Galinsoga parviflora

Asteraeae

N. American

Southwestern region    

Shrub

 

+

 

 

1

Heliotropium curassavicum

Boraginaceae

American

Eastern, central and southwestern regions

Herb

+

 

 

 

1

Ipomoea carnea ssp. fistulosa

Convolvulaceae

American

Tihama, SW region

Shrub

+

 

 

 

1

Jatropha curcas

Euphorbiaceae

American

Southwestern region

Shrub

+

+

 

 

1

Lantana camara

Verbenaceae

American

Southwestern mountains

Shrub

 

+

+

+

1

Leucaena leucocephala

Leguminosae

S.  American

Central, eastern and southern reigons 

Tree

+

+

 

 

1

Malvastrum coromandelianum

Malvaceae

Tropical

Central region             

P. Herb

 

+

 

 

1

Nicotiana glauca

Solanaceae

S. American

Asir and Jazan Mountains

Shrub

 

 

+

+

5

Operculina turpethum

Convolvulaceae

East Asian

Southwestern region   

P. Herb

+

 

 

 

1

Opuntia dellenii

Cactaceae

Pan  American

Southwestern region

Shrub

 

+

+

+

5

Opuntia ficus-indica

Cactaceae

Pan American

Southwestern region

Shrub

 

+

+

+

5

Opuntia stricta

Cactaceae

Pan American

Southwestern region  

Shrub

 

+

 

 

1

Parthenium hysterophorus

Asteraceae

S. American

Southwestern region       

Herb

+

 

 

 

1

Paspalum dilatatum

Poaceae

Pan American

Southwestern region

Annual

+

 

 

 

1

Physalis acuminata

Solanaceae

S. American

Tihama, SW region

Herb

+

 

 

 

1

Potamogeton perfoliatus

Potamogetonaceae

Tropical

Central region                  

P. Herb

+

 

 

 

1

Prosopis juliflora

Leguminosae

S. American

All regions in Saudi Arabia

Tree

+

+

+

 

5

Prosopis koelziana

Leguminosae

W. Asia (Iran)

Central region

Tree

+

 

 

 

1

Sesuvium portulacastrum

Aizoaceae

Tropical

Eastern and central region    

P. Herb

+

 

 

 

1

Tagetes minuta

Asteraceae

N. American

Southwestern region

P. Herb

 

 

+

+

3

Trianthema portulacastrum

Aizoaceae

N. American

Southwestern region

Herb

+

+

 

 

5

Tridax procumbens

Asteraceae

N. American

Southwestern region

Herb

 

 

+

+

1

Verbesina encelioides

Asteraceae

N. American

Southwestern region

Herb

+

+

+

 

3

Xanthium spinosum

Asteraceae

N. American

Southwestern region

P. Herb

 

+

+

 

1

Courtesy:  Jacob Thomas et al. 2016. Impact of alien invasive species on habitats and species richness in Saudi Arabia. Journal of Arid Environments 127: 53-65.

Page designed and written by Dr. Jacob Thomas, Herbarium (KSU), Dept. of Botany & Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia.