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Snakes on the Balearic islands: an invasion tale with implications for native biodiversity conservation.

Silva-Rocha I, Salvi D, Sillero N, Mateo JA, Carretero MA - PLoS ONE (2015)

Bottom Line: The identification of the origin and colonization pathways of alien species, as well as the prediction of their expansion, is crucial to develop effective conservation strategies.For all of them, the ecological niche models showed a current low habitat suitability in the Balearic, which is however predicted to increase significantly in the next few decades under climate change scenarios.This trend has been reported also for recent invasions in NE Spain, thus showing that olive trees transplantation may be an effective vector for bioinvasion across the Mediterranean.

View Article: PubMed Central - PubMed

Affiliation: CIBIO Research Centre in Biodiversity and Genetic Resources, InBIO, Universidade do Porto, Vairão, Vila do Conde, Portugal.

ABSTRACT
Biological invasions are a major conservation threat for biodiversity worldwide. Islands are particularly vulnerable to invasive species, especially Mediterranean islands which have suffered human pressure since ancient times. In the Balearic archipelago, reptiles represent an outstanding case with more alien than native species. Moreover, in the last decade a new wave of alien snakes landed in the main islands of the archipelago, some of which were originally snake-free. The identification of the origin and colonization pathways of alien species, as well as the prediction of their expansion, is crucial to develop effective conservation strategies. In this study, we used molecular markers to assess the allochthonous status and the putative origin of the four introduced snake species (Hemorrhois hippocrepis, Malpolon monspessulanus, Macroprotodon mauritanicus and Rhinechis scalaris) as well as ecological niche models to infer their patterns of invasion and expansion based on current and future habitat suitability. For most species, DNA sequence data suggested the Iberian Peninsula as the potential origin of the allochthonous populations, although the shallow phylogeographic structure of these species prevented the identification of a restricted source-area. For all of them, the ecological niche models showed a current low habitat suitability in the Balearic, which is however predicted to increase significantly in the next few decades under climate change scenarios. Evidence from direct observations and spatial distribution of the first-occurrence records of alien snakes (but also lizards and worm lizards) suggest the nursery trade, and in particular olive tree importation from Iberian Peninsula, as the main pathway of introduction of alien reptiles in the Balearic islands. This trend has been reported also for recent invasions in NE Spain, thus showing that olive trees transplantation may be an effective vector for bioinvasion across the Mediterranean. The combination of molecular and ecological tools used in this study reveals a promising approach for the understanding of the complex invasion process, hence guiding conservation management actions.

No MeSH data available.


Habitat suitability models for the present and for the future (2020, 2050 and 2080) of all the study species.
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pone.0121026.g003: Habitat suitability models for the present and for the future (2020, 2050 and 2080) of all the study species.

Mentions: In general, the models projected to the Balearic Islands showed a limited suitability in the present for the four snakes at the given occurrence threshold (see below; Fig. 3). Nevertheless, it is worth noting that known occurrence points from each species fall within unsuitable areas. Moreover, in the projections for the future, Balearic Islands become more suitable for the all the species, with exception of the smooth false snake (Macroprotodon sp.) which only might occupy Formentera, south of Mallorca and Cabrera (Fig. 3). Both R. scalaris and Malpolon monspessulanus attained the highest suitability probabilities and might occupy almost all the extension of all the islands. The horseshoe whip snake (H. hippocrepis) might be widespread on the island with exception of the Serra Tramuntana mountain range. It is important to remark that the habitat suitability index was relatively high in the future models (with exception of Macroprotodon sp.), being the maximum values 0.57 in 2020 for H. hippocrepis, 0.34 in 2080 for Macroprotodon sp., 0.60 in 2080 for R. scalaris and 0.59 in all the three years for Malpolon monspessulanus.


Snakes on the Balearic islands: an invasion tale with implications for native biodiversity conservation.

Silva-Rocha I, Salvi D, Sillero N, Mateo JA, Carretero MA - PLoS ONE (2015)

Habitat suitability models for the present and for the future (2020, 2050 and 2080) of all the study species.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390158&req=5

pone.0121026.g003: Habitat suitability models for the present and for the future (2020, 2050 and 2080) of all the study species.
Mentions: In general, the models projected to the Balearic Islands showed a limited suitability in the present for the four snakes at the given occurrence threshold (see below; Fig. 3). Nevertheless, it is worth noting that known occurrence points from each species fall within unsuitable areas. Moreover, in the projections for the future, Balearic Islands become more suitable for the all the species, with exception of the smooth false snake (Macroprotodon sp.) which only might occupy Formentera, south of Mallorca and Cabrera (Fig. 3). Both R. scalaris and Malpolon monspessulanus attained the highest suitability probabilities and might occupy almost all the extension of all the islands. The horseshoe whip snake (H. hippocrepis) might be widespread on the island with exception of the Serra Tramuntana mountain range. It is important to remark that the habitat suitability index was relatively high in the future models (with exception of Macroprotodon sp.), being the maximum values 0.57 in 2020 for H. hippocrepis, 0.34 in 2080 for Macroprotodon sp., 0.60 in 2080 for R. scalaris and 0.59 in all the three years for Malpolon monspessulanus.

Bottom Line: The identification of the origin and colonization pathways of alien species, as well as the prediction of their expansion, is crucial to develop effective conservation strategies.For all of them, the ecological niche models showed a current low habitat suitability in the Balearic, which is however predicted to increase significantly in the next few decades under climate change scenarios.This trend has been reported also for recent invasions in NE Spain, thus showing that olive trees transplantation may be an effective vector for bioinvasion across the Mediterranean.

View Article: PubMed Central - PubMed

Affiliation: CIBIO Research Centre in Biodiversity and Genetic Resources, InBIO, Universidade do Porto, Vairão, Vila do Conde, Portugal.

ABSTRACT
Biological invasions are a major conservation threat for biodiversity worldwide. Islands are particularly vulnerable to invasive species, especially Mediterranean islands which have suffered human pressure since ancient times. In the Balearic archipelago, reptiles represent an outstanding case with more alien than native species. Moreover, in the last decade a new wave of alien snakes landed in the main islands of the archipelago, some of which were originally snake-free. The identification of the origin and colonization pathways of alien species, as well as the prediction of their expansion, is crucial to develop effective conservation strategies. In this study, we used molecular markers to assess the allochthonous status and the putative origin of the four introduced snake species (Hemorrhois hippocrepis, Malpolon monspessulanus, Macroprotodon mauritanicus and Rhinechis scalaris) as well as ecological niche models to infer their patterns of invasion and expansion based on current and future habitat suitability. For most species, DNA sequence data suggested the Iberian Peninsula as the potential origin of the allochthonous populations, although the shallow phylogeographic structure of these species prevented the identification of a restricted source-area. For all of them, the ecological niche models showed a current low habitat suitability in the Balearic, which is however predicted to increase significantly in the next few decades under climate change scenarios. Evidence from direct observations and spatial distribution of the first-occurrence records of alien snakes (but also lizards and worm lizards) suggest the nursery trade, and in particular olive tree importation from Iberian Peninsula, as the main pathway of introduction of alien reptiles in the Balearic islands. This trend has been reported also for recent invasions in NE Spain, thus showing that olive trees transplantation may be an effective vector for bioinvasion across the Mediterranean. The combination of molecular and ecological tools used in this study reveals a promising approach for the understanding of the complex invasion process, hence guiding conservation management actions.

No MeSH data available.