Animal Invaders in São Paulo State Reservoirs

Abstract

Freshwaters are among the most vulnerable ecosystems regarding biological invasions. Reservoirs built after the last half century in São Paulo State have been continuously subjected to the introduction and establishment of alien species, both exotic and allochtonous. Here we present a short historical and the present status of some recent, still going on, biological invasion processes, for both, invertebrate and vertebrates, with emphasis on Tietê River basin. Among reservoir communities, the zooplankton has the lowest number of established exotic species, with 4 species: the cladocerans Ceriodaphnia dubia and Daphnia lumnholtzi, the cyclopoid copepod Mesocyclops ogunnus and the rotifer Kellikotia bostoniensis. Among the macroinvertebrate communities there is a fast ongoing invasion by three exotic species of mollusks, the Asian clam, Corbicula fluminea, the African-Asian gastropod, Melanoides tuberculata, and the golden mussel, Limnoperna fortunei, this latter a cause of greatest concern. However by far the community most affected by introduction of alien species is the ichthyofauna. In reservoirs of Tietê, Paranapanema and Rio Grande rivers, the main tributaries of the Upper Parana basin, the relative proportion of alien species vary approximately between 10 and 25% of the total number of species. Most introductions were derived from anthropic activities, either from direct local introduction, the so called peixamento or by accidental escape from nearby fish farming installations. Some species have profound effects on the structure of the fish community, as recently happened in Lobo (Broa) reservoir after the introduction of the Cichla kelberi. The African Sarotherodon niloticus and Tilapia rendalli and the allochtonous Plagioscion squamosissimus became the dominant species in many São Paulo state reservoirs. The complex interaction between biological invasions, water pollution and eutrophication, is the possible cause for many native species extinction going on in São Paulo State rivers and cascade of reservoirs. At short time and local scale, management actions are urgently required to eradicate or minimize the impact of exotic species in the reservoirs, especially in the small ones, and at longer time and larger scales, education and law enforcement are essential tools for both prevention of new introductions and management to the already existing problems.

A malacological survey in the Manso Power Plant, State of Mato Grosso, Brazil: new records of freshwater snails, including transmitters of schistosomiasis and exotic species

“…Reservoirs have been continually subject to the introduction and establishment of alien species, as reported by Rocha et al 24 in State of São Paulo. The authors showed that rapid invasion processes were ongoing on the Tietê River basin for three species of mollusks: C. fluminea, Limnoperna fortunei (Dunker, 1857) and M. tuberculata.…”

More than two decades after the introduction of Limnoperna fortunei (Dunker 1857) in La Plata Basin

“…The first registers of golden mussel in the reservoir cascades of this region of La Plata were reported in the beginning of 2000's. Between 2001 and 2004 its presence was detected in the reservoirs of Ilha Solteira, Jupiá, Porto Primavera and Itaipu, upper Paraná River (Zanella and Marenda, 2002;Mansur et al, 2004;Von Ruckert et al, 2004 andAvelar et al, 2004); during 2006 in the reservoirs of Canoas I, Canoas II and Capivara, Paranapanema River (Garcia et al, 2009;Rocha et al, 2011);during 2007/2008 in Tibagi and Iguaçu Rivers (Pestana et al, 2010); during 2004 in the Tietê River (already mentioned) (Pareschi et al, 2008). In the most northern large rivers of the basin, Paranaíba and Grande Rivers, we did not register the species presence.…”

Ocorrência de um molusco invasor (Melanoides tuberculata, Müller, 1774), em diferentes sistemas aquáticos da bacia hidrográfica do Rio Sorocaba, SP, Brasil

“…Deve ser salientado, que rápidos processos de invasão também estão em andamento por outras espécies de moluscos, como o bivalve asiático Corbicula fluminea e o mexilhão dourado Limnoperna fortunei (Rocha et al, 2011).…”

“…Além disso, foi uma das espécies dominantes encontrada no reservatório de Salto Grande em Americana, SP (Pamplim et al, 2005) e nas represas do médio e baixo rio Tietê (Suriani et al, 2007;Rocha et al, 2011). Com a grande ocorrência deste organismo no Brasil e especialmente no estado de São Paulo, é de grande importância fornecer informações da ocorrência e da sua distribuição espacial, sendo informações úteis para o controle da sua dispersão.…”