Invasive Alien Species

Invasive alien (non-indigenous) species are defined as non-native species of flora and fauna whose introduction can pose a threat to local biodiversity (Bax, 2001). Invasive alien species are the second most destructive human influence on biodiversity after direct habitat destruction by humans (Schmitz and Simberloff, 1997; Walker and Steffen 1997). This not only affects local environments (Simberloff, 1996; Parker et al., 1999) but also threatens agriculture (Ricciardi et al. 2000). Nearly half a million species have been reported as invasive worldwide (Pimental et al., 2001 see also global invasive species database). The term "invasive" is used for the most aggressive of these species as they grow and reproduce rapidly, causing major disturbances to nature in areas in which they are present. Positive interactions among non-native species have the potential to disrupt ecosystems by amplifying invasions and can occur via indirect mechanisms (Adams et al., 2004). The invasiveness threat has increased because both ease of transportation and human habitat destruction open many opportunities for invasive alien species to establish themselves around the world. In fact, these invasive species are now considered the second most important threat to biodiversity after direct habitat destruction by humans (Kettunen et al., 2009; UNEP-WCMC 2012).

There is still some debate on the issue of whether increased local biodiversity protects from invasive alien  species or not, and how best to deal with this phenomenon (Levine, 2000), including how climate change could be a key factor of increasing invasiveness around the world (Ziska and Dukes, 2014). Climate change could be a key factor for increasing invasiveness around the world (Dangles et al., 2008; Hellman et al., 2008). Moreover, the influence of invasive alien species is not limited to the macro-scale; they also affect the diversity and success of diseases by disrupting previously stable communities and can drive local species to extinction through genetic hybridization.  Invasive alien species in historic Palestine varied between groups, and they keep increasing and currently include 2 mammals, 18 birds, 2 reptiles, 27 fish, 50 vascular plants, 19 freshwater snails, 33 land snails, and over 200 insects (Roll et al., 2007a, 2007b, 2008, 2009; Dufour-Dror, 2012).

Within the State of Palestine,there are 50 invasive plant species of which the most aggressively  invasive ones are Acacia saligna, Ailanthus altissima, Conyza bonariensis, Oxalis pes-caprae, Ambrosia confertiflora, Ricinus communis, Nicotiana glauca, Prosopis juliflora and Solanum elaeagnifolium. Nine invasive bird species are reported in SP and four of them are detected in the West Bank: Indian Silverbill Lonchura malabarica, Common Myna Acridotheres tristis, Monk Parakeet Myiopsitta monachus and Rose-ringed Parakeet Pisttacula krameri. Most species have been deliberately brought in captivity and subsequently released or escaped. For example, the Common Myna were introduced in 1997 after a group of birds escaped from the Park Hayarkon area in Tel Aviv (Handal and Qumsiyeh 2021).

Amongst mammals, the house mouse, black rat, and coypu are noted. Fish have been introduced unintentionally and intentionally for various reasons to many regions (Roll et al., 2007b). In Historic Palestine, 27 introduced species are found in the Jordan Basin, Sea of Galilee, and the coastal plain rivers. Of these 27, 10 are invasive alien species: Oncorhynchus mykiss, Salmo trutta, Hypophthalmichthys molitrix, Gambusia affinis, Poecilia velifera, Xiphophorus hellerii, Liza ramada, Mugil cephalus, Oreochromis aureus and Tilapia zillii, which have established themselves in the Jordan River Basin within fishponds and some of them have penetrated to the river itself (Roll et al., 2007b). According to Lowe et al., (2000) two of these 10 species are considered aggressively invasive: Brown trout, Salmo trutta and the Rainbow trout, Oncorhynchus mykiss.

There are around 33 introduced species of freshwater and land snails within SP, of which 19 are considered invasive. The majority of snails have been introduced via import of seedlings and aquaria fishes (Roll et al., 2009). Some invasive land snails such as Cornu aspersum, Eobania  vermiculata and  Rumina decollate have been observed in the West Bank. Moreover, these two freshwater snails are among the most invasive: Pseudoplotia scabra and Planorbella duryi (Handal et al., in preparation).   Furthermore, Prietocella barbara was detected in a shipment of Red Cabbage to the Gaza Strip (Vaisman & Mienis, 2016a, 2016b). Another invasive alien species found in the Gaza Strip is Novisuccinea ovalis, recorded during the occupation by Israel (1967-2005) (Vaisman & Mienis, 2016a, 2016b).

Among the invasive alien species within the West Bank and Gaza Strip is the prevalence of the Red Palm Weevil, Rhynchophorus ferrugineus, which has led to a devastating loss in crops (Kehat, 1999; Abd Rabou & Radwan, 2017). Other studies have revealed the existence of 26 invasive alien insects associated with Eucalyptus trees which were introduced from various countries (Mendel & Protasov, 2019). One of the most invasive species, with high impact upon public health, is the Asian Tiger Mosquito, Aedes albopictus (Adawi, 2012). Another study recorded the presence in SP the Western Conifer Seed Bug Leptoglossus occidentalis (Handal & Qumsiyeh, 2019). Paratrechina longicornis, Rhynchophorus ferrugineus and Deroplax silphoides have also been shown to be within SP (Handal, 2017; Handal and Qumsiyeh, 2019).

The invasive alien species in SP are expanding both in number of species and in the scale of their proliferation. The sole restrictions on the import of invasive alien species into the country are those of the Ministry of Agriculture, but Israel remains the authority in charge of borders (EQA, 2015). There are ongoing studies on the issue of invasive flora and fauna in SP. However, very few control measures have been developed and implemented based on the National Strategy to deal with Invasive Alien Species that developed by Environmental Quality Authority in 2022 and is working to implement this strategy in partnership with relevant Governmental Institutions and Non Governmental Organizations.

Link to National Strategy to deal with Invasive Alien Species

See References in the Publications