Trying to take over the world: Potential distribution of Obama nungara (Platyhelminthes: Geoplanidae), the Neotropical land planarian that has reached Europe

Abstract

Obama nungara Carbayo, Álvarez-Presas, Jones, & Riutort, 2016 is a land planarian (Platyhelminthes: Geoplanidae) native to southern South America, which has recently dispersed towards several countries of the European continent, thus becoming a threat to the native soil fauna. Its dispersion would be favoured by its wide food habit and its tendency to live linked to humans, being the plant trade its most plausible vector of dispersion. Here, we explored the potential distribution of O. nungara on a global scale by using the MaxEnt software. We used 144 records (encompassing 10 countries) from sampling campaigns, citizen science, recent literature, and material deposited in scientific collections. Our results showed that southern South America has favourable climatic conditions for O. nungara. MaxEnt also allowed predicting expansions to countries of Europe where this planarian is already established and to others not yet colonized, as well as to Asia (southern coast of the Caspian Sea, Taiwan, and southeast of mainland China) and Oceania (south-east of Australia and New Zealand). The potential distribution of O. nungara was mainly outlined by climatic factors related to temperature (annual mean temperature, mean temperature of the coldest quarter, and annual temperature range). Thus, under a global warming scenario, a significant expansion of O. nungara relative to the current prediction is expected. This information may be useful to design strategies to prevent new introductions, since the dissemination of this planarian seems to be strongly man-linked.

Fine-tuning niche models matters in invasion ecology. A lesson from the land planarian Obama nungara.

“…Most of the methods follow those of Negrete et al (2020), but at each modelling step two alternative approaches were tested: one that uses default settings such as in Negrete et al (2020), and one that applies state-of-the-art recommendations to finetune the model. This includes manipulating the input data or selecting the best fitting parameter among a series of models.…”

“…The present study was inspired by a recent paper published by Negrete et al (2020), who used a maximum entropy approach to predict the potential distribution of Obama nungara, a land planarian native to South America, which has been recently found in Europe where it raised concerns about its possible impact on the native soil fauna (Justine et al, 2020). Despite the excellent occurrence dataset gathered by the authors and the relevance of conducting such a modelling study for this species, the whole approach seemed to be largely based on the raw input data and the default parameters of the MaxEnt software (Phillips et al, 2006).…”

The invasive land flatworm Obama nungara (Platyhelminthes: Geoplanidae) reaches a natural environment in the oceanic island of São Miguel (Açores)

“…Taking into account that the international plant commerce has been reported as one of the main causes of invasive land flatworm dispersion (e.g., Aldred 2016), the absence of allochthonous vegetal species in the spot where the O. nungara specimen was discovered is intriguing. Although invasive O. nungara populations in Europe seem to be persistent and capable of surviving different climatic conditions and temperatures (Sluys 2016;Soors et al 2019;Justine et al 2020;Negrete et al 2020), so far, the presence of this species in non-disturbed natural environments is still limited (The Local 2019; this study). The possible source of dispersion of this species into the natural area of São Miguel might be through the machinery which transported the building materials for the buildings found in the area, or the fact that several visitors frequent the area to enjoy the impressive views of the lake.…”

“…The specimen was photographed in situ and identified by its external morphology based on its large and broad leaf-like body with nearly parallel body margins, narrow and rounded anterior end, rounded posterior end, and dorsal pigmentation consisting of a light brown ground color covered with dark longitudinal and irregular stripes, and ventral surface grayish-white. Recent studies (Justine et al 2020;Negrete et al 2020) showed the reliability of photograph-based identification of O. nungara specimens. It is the sixth island where this species has been found (after Guernsey, Great Britain, Ireland, Corsica, and Madeira).…”

“…So far, most of the O. nungara records outside its native range are from urban areas, gardens and greenhouses (e.g., Lago-Barcia et al 2015, 2019Soors et al 2019, Justine et al 2020Negrete et al 2020). The single exception is the record from L'Albufera (Spain), where this invasive land flatworm has been recorded in a natural ecosystem with high ecological, conservation and social values (The Local 2019).…”