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Invasions! Palau, A. Ecologia
bàsica del musclo zebrat. Vulnerabilitat de les masses d’aigua
enfront l’espècie Basic ecology of zebra mussel and water masses vulnerability During summer 2001, zebra mussels (Dreissena polymorpha) were found in the low Ebro River (Catalunya, Northeast Spain), marking the first known instance of their successful colonization in the Iberian Peninsula. This species was most likely introduced during the transport of exotic fish species to the Ebro. By 2002, these mussels had achieved densities measuring 200.000 individual/m2. Since their introduction, and aided by human activity, they have spread rapidly, across the entire Ebro Basin as well as to additional watersheds. Their inherent biological characteristics make them ideally suitable to become an invading species. These traits include a great breeding capacity, few specialized requirements, a high resistance to adverse conditions and few natural predators. The negative ecological, social, and economic effects of the zebra mussel have been well documented. On an ecological level, zebra mussels affect the cycle of organic matter and nutrients, altering the composition of plankton and benthos. In addition, this species has been a vector of at least one new parasite threatening Iberian fish. In 2007, an index measuring the vulnerability of water masses was developed: the IVMZ (Index of Vulnerability to the Mussel Zebra) has been applied to approximately 90 lakes and reservoirs, with good results. The zebra mussel has proven to be an agent of radical change both in the composition and structure of aquatic ecosystems, the consequences of which still remain largely unknown. |
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