species (IAS) are considered one of the main causes of biodiversity loss
globally, costing billions of euros to the global economies. International conventions,
national legislations, and projects aim to tackle the introduction, the spread
and the adverse effects of IAS on biodiversity.
But there are also
cases where IAS are listed as threatened facing extinction in their native home
range: for example the Eurasian Beaver (Castor fiber), the Monterrey Cypress (Cupressus
macrocarpa) and the antilopes. Such species were intentionally
introduced by humans for commercial purposes or as ornamental animals and soon
escaped or were released. This is also the case of the Wattle-necked
Soft-shelled Turtle (Palea steindachneri) in Hawaii. The
species originates from China, where it is considered valuable as a food
source. For this reason Chinese immigrants brought individuals when migrating
to Hawaii back in 1850s. Currently the species has established an invasive
population in some of the islands, threatening the local biodiversity. Interesting
is the case of the African Sacred Ibis (Threskiornis aethiopicus). The species is associated with
Thoth, an ancient Egyptian god, and is appreciated by the local communities.
However, the African Sacred Ibis is extinct from Egypt, while currently is
invading Europe, creating many problems to its biodiversity (spreading
diseases, competing for nests, feeding with threatened species of insects etc.)
and is listed as IAS of Union concern, under EU Regulation 1143/2014 (link) .
Such paradoxes puzzle
scientists, conservationists and policy makers. Sometimes the decision to eradicate
an IAS species that is threatened by extinction within its home range, can be
replaced by reintroduction projects. In native areas.
Similar situations are expected to increasingly challenge decision makers in
the future due to the anthropogenic impact on biodiversity.
Photo credit: @Mathieu
The conservation paradox of endangered and
— Three amigos exempted from endangered species list
or threatened species? A paradox in conservation biology