Tag Archives: invasive species

Non-native South American species

An extensive analysis just appeared from Darrigan et al. (advance online) about the occurrence of non-native molluscs throughout South America. Their abstract is “Non-native species have been introduced at escalating rates during the last decades, mainly due to the dispersion generated by the increasing trade and transport worldwide. Mollusks, the second largest metazoan phylum in terms of species richness, are no exception to this pattern, but, to date, a comprehensive synthesis of non-native mollusk species (NNMS) in South America was not available. For this purpose, an e-discussion group was formed with malacologists and taxonomists from South America, where we exchanged and analyzed bibliography, databases and information about NNMS, providing expert opinion to this assessment. The first list of non-native mollusk species for South America, considering terrestrial, freshwater and marine environments, includes 86 NNMS distributed in 152 ecoregions (terrestrial, freshwater and marine) of the 189 recognized for the South American continent. Information on their native region, vectors, first record for South America and distribution, are also provided. In the analysis of the distribution of the NNMS and the entry points of each species (e.g., ports, cargo and passenger airports, cities) and status of conservation of the ecoregions, four hot spots were recognized: Subtropical-Atlantic, Northern Andes, Central Andes and Southern Andes. This work, thus, sets the baseline on NNMS for South America, a key piece of information regarding the development of policies targeting the management of biological invasions and their socio-ecological impacts“.

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An interesting study that was totally done by South American malacologists. The paper contains a number of graphs and figures that illustrates the rapid increase over the past decades of non-native species in this understudied continent. It will be a good basis for further studies.

Darrigan, G. et al., 2020. Non-native mollusks throughout South America: emergent patterns in an understudied continent. – Biological Invasions (advance online): 19 pp. https://doi.org/10.1007/s10530-019-02178-4.

Ovachlamys in Brazil

Just published: a report that confirms the occurrence of a new invasive snail in this country. “The occurrence of the invasive non-native Asiatic jumping land snail Helicarionidae Ovachlamys fulgens (Gude, 1900) is finally confirmed by us in the southern Brazil region, specifically on the Santa Catarina State territory, from previous records available since the year 2013 “masked” under the identity of another species. This report increases to 27 the number of exotic continental molluscs confirmed in the State of Santa Catarina/ SC.“.

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Not surprisingly the occurrences are mainly situated near the region where the port activities occur. I wouldn’t be surprised if these snail travel with sea containers, as the distribution of Bulimulus sp. suggests (ongoing research, unpublished data).

Aguda-Padron, I., 2019. Confirmed occurrence of the invasive asiatic jumping land microsnail Helicarionidae Ovachlamys fulgens (Gude, 1900) in the Southern Brazil region. – Bioma (El Salvador) 5 (49): 11–15.

Achatina in Ecuador

Earlier this year a paper by Cuasapaz-Sarabia & Salas presented results about the occurrence of Achatina fulica in a private nature reserve. “Achatina fulica is an invasive terrestrial gastropod known as one of the 100 most harmful invasive species in the world. Achatina fulica is known in Ecuador since 2008, but the impact over their native ecosystems has not evaluated. The main objective was to determine the home range (HR) of this species in two zones with different levels of intervention in the Cerro Blanco reserve. The field work consisted in the capture, marking, recapture, taking of morphometric measurements and georeferencing of the individuals; for the analysis of data, HR was calculated using the convex polygon method, and environmental variables were correlated through a principal component analysis (PCA). The average HR in the altered zone was 3.58 m2 (± 0.93, n = 30), and on the ecotourist trail was 3.27 m2 (± 0.48, n = 40); the humidity was the environmental parameter that directly influences the life area and the population density in both zones study. The management of this invasive species does not appear as a key management issue for this private reserve, so it is recommended a control actions for its eradication“.

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It is remarkable that – although the occurrence of this species in Ecuador is known for more than 10 years – eradication programs seem to be lagging behind. And even (private) nature reserves are not alarmed about it. Thus the risk of spread of this important pest species is still prevalent. A serious issue…

Cuasapaz-Sarabia, J. & Salas, J.A., 2019. Área de vida de la especie invasora Achatina fulica (Gastropoda: Achatinidae) en un área de conservación de bosque seco ecuatoriano. Revista peruana de biología 26(1): 41 – 48.

Naesiotus in Spain

The globalisation of snails has taken a next step: Ramos Sánchez et al. just published a first record of a Bulimulidae species in Europe.

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Their abstract reads: “In the this article, the presence of a Bulimulidae species, classified as Naesiotus quitensis (Pfeiffer, 1848), is reported from an urban park in Madrid (Spain). This is the first citation of a species of this highly diversified Neotropical gastropod family in Europe. The species seems established in the park, but the ways of its introduction are unknown”.

Although it is a very slow process, the introduction of alien species in other ecological realms is clearly the consequence of human interventions, one way or the other. Hence there is little doubt that this introduction was a human act. We can only hope that the Spanish authorities will at least take monitoring actions.

Ramos Sánchez, J.M. et al., 2018. First citation for an exotic Bulimulidae species in Europe. Folia conchyliologica, 47: 11-14.

Ruminia decollata in Cordoba

Reyna & Gordillo just published a brief research note in which they report the finding of specimens of Ruminia decollata (Linnaeus, 1758) in Córdoba Province, Argentina.

According to these authors this snail is a potential host of roundworms that are common in dogs and cats, and thus may also affect susceptible humans. Moreover, this alien species may affect crops and horticultural products.

Reyna, P. & Gordillo, S., 2018. First report of the non-native snail Rumina decollata (Linnaeus, 1758) (Subulinidae: Gastropoda) in Córdoba (Argentina): implications for biodiversity and human health. – American Malacological Bulletin, 36 (1): 150-152.

Newly introduced snail

Agudo-Padrón is a frequent author of news about the southern Brazilian malacofauna. This time he published about a new introduction of a species from Asia, which he identified as Macrochlamys cf. indica (Benson, 1832).

This record was published in a new online journal from the University of El Salvador, named ‘Minerva’; a name which is already applied by at least 2 other journals and thus may be considered as a junior homonym 🙂

Agudo-Padrón, I & Souza da Luz, J., 2018 (‘2017’). Primer record confirmado de ocurrencia de un Caracol terrestre indo-asiático en Brasil y las Américas. – Revista Minerva, El Salvador, 1: 19-27.

A ritual link to snail invaders

Vazquez et al. (2017) recently published interesting research related to invasions. Their abstract reads as follows “The giant African snail, Lissachatina fulica, is considered one of the most invasive species worldwide, acting as a crop pest and diseases vector. It was first detected in Cuba in 2014 and is dispersing throughout Havana. We mapped 34 sites in the vicinity of Havana to assess its spread and analysed ecological (forestation and humidity) and anthropogenic (pollution and religious sites) factors in relation to the presence/absence of the snails using multivariate correspondence analysis. There were 14 sites at which the snail was present and where religious rituals of the Yoruba creed, an African rooted religion, were observed. No other variables showed significant relationships. This indicates that the rituals may be a major factor in the dispersal of the snail in Havana and more widely in Cuba. In light of this an outreach program with key Yoruba leaders may help in slowing the dispersal of the snail within Cuba, once the threats posed by this species are known”.

Reading through their paper I noticed that there may be also a ritual origin of the introduction of this snail in Florida, while there are indications that something similar maybe at stake in Brazil. Perhaps time for an ethnobiological approach complementary to the usual eradication schemes? Eradication without taking the driving force away behind the spread of this snail may simply not be sufficient.

Vazquez, A.,  Sanchez, J., Martinez, E. & Alba, A., 2017. Facilitated invasion of an overseas invader: human mediated settlement and expansion of the giant African snail, Lissachatina fulica, in Cuba. – Biological Invasions, 19 (1):1-4.