Invasive Species

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Invasive species continue to be a major threat to all types of ecosystems and species in Egypt. There are no signs of reduction of this pressure on biodiversity, and there are indications that it is increasing. A famous example is the detrimental effect of the introduction of the Water Hyacinth (Eichhornia crassipes) in the Nile River and the networks of irrigation and drainage canals throughout the country. Another example is the introduction of the Water Fern (Azolla filiculoides) to be used as a biological fertilizer in rice fields which has inadvertently escaped into water courses where it seems to be wiping out a number of other native hydrophytes (e.g. Lemna spp. and Spirodela spp.). Similarly, the exotic freshwater crayfish (Procambarus clarkii) introduced in aquaculture basins found its way into major water channels where it became a serious pest to commercial fish and to biodiversity in general. The recent non-intentional introduction of the Red Palm Weevil and avian flu are other good examples of invasive species. The estimated damage caused by invasive species may be as high as one billion Egyptian pounds.
Several attempts have been made to record different taxonomic groups of alien and invasive species in Egypt. However, most of these did not apply or acknowledge the appropriate international criteria used to evaluate invasive species status.
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In one comprehensive recent study by Shaltout (2008), the list of alien species in Egypt included 137 plant species: causals (50 species), naturalizers (50 species), weeds (31 species), invaders (5 species) and transformer (1 species) (Annex 2) distributed in 7 habitat groups: cultivation fields (group Ι); ruderal places (group Π); sand formation (group Ш); aquatic bodies (group IV); gardens and fence lines (group V); Nile land and silty soil (group VΙ); and wadi beds, stony hillsides, pasture, and newly reclaimed land (group VII). Forty-three of the alien species in the Egyptian flora (17 naturalized and 12 casual species = 32.1% of the total aliens) have at least one aspect of the environmental services. In addition, 111 species (81% of the total aliens) have at least one aspect of the potential or actual economic goods. The alien species in the Egyptian flora belong to 20 origins divided into 14 origins in the old world and 6 origins in the new world. The plants from South America (25 species = 18.2%) are the most represented, followed by Tropical Africa (21 species = 15.3%), North America and South Asia (18 species = 13.1% for each), Tropical America (17 species = 12.4%), Europe (16 species = 11.7%), Medetranian region (15 species = 10.9% for each), West Asia and South Africa (10 species = 7.3% for each one), Tropical Asia (7 species = 5.1% for each), Central America and Asturallia (6 species = 4.4%), South Europe and East Asia (5 species = 3.6%). The study covered introduction of the alien species in the last 250-300 years (1750 to 2008) and concluded that 5 species (3.6% of total species) were introduced between 1800-1850, 49 species (35.8%) in the period 1850-1900, 19 species (13.9%) in1900-1950, 42 species (30.7%) in 1950-2000 and with 2 species (Dichondra micrantha and Galinsoga parviflora) after 2000., and only one species (Dalbergia sissio). The probable dates of the introduction of the remaining 18 species were not recorded. Time lags of the invasive and transformer species in the Egyptian flora ranged between 5 years to 181 years. The time lag is defined as the period between the time when a species is introduced and the time when its population growth explodes.
Currently available information about invasive species in Egypt is still insufficient and exerted efforts are still limited in spite of the fact that invasive species represent real threat to Egyptian ecosystems, the economy and human health.
In 2010, the number of invasive species increased to 211 species. The recorded species included aquatic plants (44), terrestrial plants (40), crustaceans (16), insects (26), spiders (1), fish (29), mammals (3), birds (5), reptiles (1), amphibians (1), viruses (17), fungi (8), bacteria (6), nematodes (5), mollusks (5), echinoderms (1), coelenterates (1) and polychaetes (2).
Among the invasive species recorded in Egypt, 21 species were included in the world list of the worst 100 invasive species (Black List) developed by The World Program of Invasive Species (2010). This indicator reflects the extent and spread of invasive species and the measures necessary to be taken to limit their spread.
It is important to note the upward trend in the numbers of invasive species arriving in Egypt and the uncertainty of their number. More expert studies are needed to ascertain the accuracy of recorded invasive species over the years and additional studies are required to record the changes in the extent (land area or coastline) of widely established invasive species in freshwater, marine and terrestrial environments. Such information is important for setting eradication priorities, decision making and formulating and implementing credible invasive species programs and action plans.
As Egypt becomes warmer under the influence of global climate changes, it seems likely that its ecosystems will become increasingly prone to invasions by more alien species. Extreme climate events, such as floods, exacerbate the problem, allowing invasive alien species to move into new areas.