Several threats to biodiversity in Tunisia. Climate change is a real concern pattern. The recent work on climate change in Tunisia predict the resurgence of extreme climatic events : drought and floods. The latest models stipulate an increase in temperature of 1.8 to 2.7 ° C by 2050. Climate change and its effects are already being felt, especially for marine species, where some thermophilic species begin to colonize the northern coasts of Tunisia that could disrupt ecosystems.
Anthropogenic threats are nevertheless the most immediate danger and weigh heavily on Biological Diversity. This includes urbanization, loss of range of cultivated varieties, crop intensification and non-consumptive uses of pesticides, degradation of steppe areas and forests, overfishing of some species, hunting etc.
Pressure on agricultural systems:
Les variétés locales sont en danger d’extinction vu la tendance à l’intensification de l’agriculture et l’utilisation des variétés introduites. Par ailleurs, l’emploi excessif des pesticides de tous types aura incontestablement un effet délétère sur la biodiversité de la faune sauvage particulièrement les invertébrés. Les pesticides causent l’intoxication des espèces non cibles, l’extinction des espèces vulnérables, des problèmes de stérilité et de mutations.
Pressures on forests and rangelands:
The Pastoral areas are particularly at risk of degradation mainly due to overgrazing. Indeed, although the proportion of courses in the diet has been declining, the increase in staff coupled with a decrease in land for the path leading to an increase in animal load per hectare. Tunisia has the highest density in Africa with 40.3 sheep / km2.
The forests also suffer overgrazing and overexploitation of resources. Furthermore, and particularly since the revolution of 14 January 2014, certain illegal constructions have emerged in forest areas.
The Climate change, drought events, desertification, erosions are phenomena constituting a threat to ecosystems in Tunisia. All models agree in indicating a temperature increase of about 1 to 2.8 ° C and a decrease in rainfall of up to 104mm / year by 2050. These climate change will threaten many ecosystems and therefore several species of flora of Tunisia.
Pressures on the fauna
The hunt contributed significantly to the decline of the workforce of some taxa and the complete disappearance of certain species of Tunisia, especially for large mammals or ostrich. Despite the current stringent regulations, illegal hunting continues to be a serious threat to the maintenance of certain species such as gazelle, some birds or small carnivores such as zorille Libya (Ictonyxlibyca; Poecilictislibyca). Other species such as some snails, chameleons, turtles, snakes and scorpions suffer anarchic levies seriously threatening their populations.
Pressures on the coastal and marine ecosystems
The marine ecosystems in their plant and animal components, are the subject of several threats. The special habitats such foreshore of the Sfax region are threatened by backfilling operations or by extensions of saline. The pollution, including that phosphogypsum are also responsible for the deterioration of some parts of the coast. The fishing and the use of equipment such as otter trawls are nevertheless responsible for the most extensive destruction of both flora and herbaria that the fishery resource. The trawling and overfishing are responsible for the threats that weigh on other important marine ecosystems of Tunisia as the coralligenous. This is illustrated among others by falling red coral stocks from 25 tonnes in 1980 to less than 1 ton or by being the significant decrease in populations of some fish such as groupers.
The Tunisian coast is another special ecosystem undergoing several threat. Some of these threats are linked to climate change, especially rising sea levels. It has been shown that the beaches are the most vulnerable to these phenomena. Other threats, human-induced, also affect the coastline, the anarchic and illegal constructions.
The Climate change, especially the rise in temperature, resulted in the appearance in the seas of northern Tunisia, and the proliferation of certain hemophilic species were found only at the Gulf of Gabes (southern Tunisia).
Exotic and invasive species
Invasive species or invasive species is an alien species which becomes a disturbance agent harmful to native biodiversity of natural ecosystems including natural or semi she settled. The phenomena of biological invasion are now considered by the UN as one of the major causes of biodiversity regression.
Some species considered invasive alien encountered in Tunisia
|Scientific Name||Common name||Origin||Environment of appearance||terrestrial/marine|
|Arctotheca calendula (L.) Levyns / Artoctis calendula (L.) / Cryptostemma MUEC calendula (L.) Drucesouce||Artothèque||Endemic to South Africa||North west of Tunisia: Tabarka, Nefza Sedjenane ...|
(accidentally introduced in the 1970s)
|Solanum cleagnifolium Cav.||Silverleaf nightshade||Mexico||Sidi Bouzid, Kairouan, Sousse, Zaghouan Nabeul, the capital Tunis, Bizerte, Beja, Seliana (accidentally introduced around the 1980s)||Terrestrial|
|Solanum rostratum Dunal||Buffalobur||Etas Unis||Sidi Bouzid town, irrigated perimeters in Sidi Bouzid (accidentally introduced in Sidi bouzid 2000)||Terrestrial|
|Oxalis articultakunth||Oxalis hingedly / Oxalide hingedly||Europa/Asia||Silvo-pastor tabarka Institute and the National park of El Feidja (accidentally introduced in Tabarka and El Feidja in 2000)||Terrestrial|
|Metapenaeus monoceros||White shrimp||Gulf of Gabes||marine|
|Pinctaclaradiata||Pintadue radiée||Indo-Pacific||Gulf of Gabes (migration accidental sepsienne since 1891)||marine|
|Libinia dubia||Crabe||America||Gulf of Gabes||marine|