Effects of invasive species snails in continental aquatic bodies of Pernambucano semiarid

Abstract

Aim: The aim of this study was to survey the species of molluscs and to evaluate the effect of exotic species on the native mollusks of three reservoirs in the Pajeú Basin Cachoeira II, Jazigo and Serrinha. Methods: Sampling was carried out with trawl net (5 mm mesh opening) and hand net (2 mm mesh opening). Results and conclusions: Were quantified 60,244 specimens, distributed among the species Melanoides tuberculata (49,398), Pomacea lineata (573), Biomphalaria straminea (376) and Physa marmorata (01). The invasive exotic species M. tuberculata was dominant in all reservoirs with a relative abundance greater than 85% and the other species were classified as occasional and rare, with emphasis in Physa marmorata that is present in the red list of species vulnerable to extinction. Regarding the frequency of occurrence, all species were classified as euconstant (occurrence greater than 65%), except P. lineata and P. marmorata, which were classified as ancillary (occurrence less than 40%). Among the species, M. tuberculata were the highest average density (1,636 ind.m -2 ) in Serrinha reservoir, showed a strong adaptation to the environmental conditions, due to its high dominance in all the reservoirs, being probably the main cause for the low diversity and density indices of native molluscs. Since P. marmorata presented low density and frequency, becoming an important point to be investigated as possible species impaired by the dominance of M. tuberculata.

Freshwater mollusks from three reservoirs of Piauí, northeastern Brazil

“…The high number of individuals observed is a consequence of the set of biological traits mentioned, which allows M. tuberculata to become a successful competitor in new environments, capable of even suppressing the growth of native species population. The role of this invasive species in the reduction of native species have been described in different environments (Freitas et al 1987, Pointier 1999, Fernandez 2001, Almeida et al 2018). There are reports of the decline in B. glabrata and B. straminea densities from the Southeastern region (Giovanelli et al 2003, Almeida et al 2018, as well as it was responsible for the low diversity and density indices of native species in Northeastern reservoirs (Almeida et al 2018).…”

“…The role of this invasive species in the reduction of native species have been described in different environments (Freitas et al 1987, Pointier 1999, Fernandez 2001, Almeida et al 2018). There are reports of the decline in B. glabrata and B. straminea densities from the Southeastern region (Giovanelli et al 2003, Almeida et al 2018, as well as it was responsible for the low diversity and density indices of native species in Northeastern reservoirs (Almeida et al 2018). Although the effect of M. tuberculata on mollusk community of the São Julião reservoirs has not been evaluated, the expressive differences observed among abundances of this species, B. straminea and Pomacea lineata, suggest attention to a putative interspecific competition.…”

“…There is no systematized information about native mollusk fauna nor exotic regarding Brazilian reservoirs, and the few existing reports about this group are restricted to large dams, mainly those related to hydroelectric plants (Thiengo et al 2005, Fernandez et al 2018, Rocha et al 2011, Fernandez et al 2014. Likewise, studies focused on mollusk fauna of small and medium-sized reservoirs in the Brazilian Northeast built for water storage are still scarce (e.g., Santos & Eskinazi-Sant'anna 2010, Almeida et al 2018, Medeiros et al 2018. Considering the importance of the malacofauna previously described and the fact that small reservoirs accumulate diverse uses by the populations, the knowledge of its composition is extremely important.…”

Fossil freshwater gastropods from northern Mexico – A case of a “silent” local extirpation, with the description of a new species

“…It cannot be ruled out that invasive species such as Melanoides tuberculata are at least partly responsible for the loss of gastropod diversity in the Laguna District. This species has long been suspected of displacing native populations (Thompson, 2004;Almeida et al, 2018). Although extirpation and invasion coincide temporally and spatially in the area of study, a causal relationship such as interspecific competition or increased parasitism is unclear.…”

New records of the invasive mollusk Melanoides tuberculata (Müller, 1774) (Gastropoda, Thiaridae) in the Brazilian Northeast

“…This set of biological features allow for M. tuberculata to out-compete with other species in newly invaded places mainly due to its capacity to suppress populations of native species. Its presence in reservoirs in semiarid Brazil is said to be responsible for the low diversity of native mollusks in these areas (Almeida et al 2018). Fernandez et al (2001 reported on the decline of a population of Pomacea lineata (Spix, 1827) due to the presence of M. tuberculata.…”