BIODIVERSITY OF CROATIA

INVASIVE ALIEN SPECIES
Like other European countries, Croatia has many problems with
invasive alien species (IAS). As late as 1910, 11 individuals of
the small Indian mongoose (Herpestes javanicus auropunctatus)
were introduced on the island of Mljet for the biological control
of poisonous snakes. Over a 20 year period, the introduced animals
eliminated all the snakes on the island and began attacking
other small wild animals, including migratory birds and domestic
animals. Although about 100 mongooses are eliminated every
year, and some attempts for total eradication were made in the
past, these animals still inhabit the island and have a negative
impact both on wild and domestic fauna.
Known threats to Croatian biodiversity by IAS today are numerous.
The tropical green algae Caulerpa taxifolia and Caulerpa
racemosa are spreading rapidly accros the Adriatic Sea coastal
benthic habitats.
Allochthonous freshwater fish in Croatia
Rainbow trout
Prussian carp
Pumpkinseed
Goldfish
Silver carp
Big head carp
Grass carp
False harlequin
Brown bullhead
Charr
Brook trout
Largemouth bass
Black bullhead
Peled
Schelly
Mosquito fish
Oncorhynchus mykiss
Carrasius gibelio
Lepomis gibbosus
Carassius auratus
Hypophthalmichthys molitrix
Hypophthalmichthys nobilis
Ctenopharyngodon idella
Pseudorasbora parva
Ameiurus nebulosus
Salvelinus alpinus
Salvelinus fontinalis
Micropterus salmoides
Ameiurus melas
Coregonus peled
Coregonus lavaretus
Gambusia affinis
Removing of invasive tropical green algae (Caulerpa taxifolia) by
divers can only slow down its invasion (photo: A. @uljevi})
16 allochthonous fish species have been introduced into Croatian
rivers and lakes during the past century - the Adriatic Basin, rich in
endemic fish species, is extremely threatened in this regard.
Goldfish (Carassius auratus) (photo: SINP, M. Pov`)
The plant species false indigo (Amorpha fruticosa) is spreading
through riverine and forest edge habitats in the Pannonian
lowlands, creating significant problems for the regeneration of
forest areas after the cutting. The common ragweed (Ambrosia
artemisifolia) has spread through ruderal habitats throughout
Croatia - it is known as the greatest allergen in Europe. The
clam Dreissenia polymorpha, known as a pest in water regulation
and hydroelectric power stations, poses a great threat to
autochthonous freshwater mussel populations (Unionidae) and
other benthic organisms. The Mediterranean form of black rat
(Rattus rattus) and the Italian lizard (Podarcis /sicula/ campestris)
have had a strongly negative impact on native island fauna.
The invasive allochthonous spinycheek crayfish (Orconectes
limosus), the crayfish plague carrier, has been found in Kopa~ki
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