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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.


Results from genetic analysis and geographic origin of the introduced populations.Numbers on branches indicate ML bootstrap values (BP) over 1000 replicates (BP<50 are not reported). (2A): ML tree based on of the combined 12S+cytb dataset depicting the relationships between haplotypes of the native range of Hemorrhois hippocrepis from Carranza et al. [23] and those from the introduced populations from Mallorca and Ibiza Islands. MSA: Morocco+Iberia+Algeria; T: Tunisia. (2B) ML tree based on of the cytb dataset depicting the relationships between haplotypes of native range of Malpolon monspessulanus from Carranza et al. [23] and those from the introduced populations from Mallorca Island. Mmm: Malpolon m. monspessulanus; Mmi: Malpolon m. insignatus; Mmf: Malpolon m. fuscus. (2C) ML tree based on of the cytb dataset depicting the relationships between haplotypes of native range of Macroprotodon sp. from Carranza et al. [24] and those from the introduced populations from Mallorca and Menorca Islands. Mbi: Macroprotodon brevis ibericus; Mct: Macroprotodon cucullatus textilis; Mbb: Macroprotodon brevis brevis; Ma: Macroprotodon abubakeri; L—Libyan clade; Mm: Macroprotodon mauritanicus. (2D) Statistical parsimony network depicting the genealogical relationships between cytb haplotypes from the native range and from Balearic individuals (Ibiza: 12002; Mallorca: 9250; Menorca: 7076 and 7138) of R. scalaris.
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pone.0121026.g002: Results from genetic analysis and geographic origin of the introduced populations.Numbers on branches indicate ML bootstrap values (BP) over 1000 replicates (BP<50 are not reported). (2A): ML tree based on of the combined 12S+cytb dataset depicting the relationships between haplotypes of the native range of Hemorrhois hippocrepis from Carranza et al. [23] and those from the introduced populations from Mallorca and Ibiza Islands. MSA: Morocco+Iberia+Algeria; T: Tunisia. (2B) ML tree based on of the cytb dataset depicting the relationships between haplotypes of native range of Malpolon monspessulanus from Carranza et al. [23] and those from the introduced populations from Mallorca Island. Mmm: Malpolon m. monspessulanus; Mmi: Malpolon m. insignatus; Mmf: Malpolon m. fuscus. (2C) ML tree based on of the cytb dataset depicting the relationships between haplotypes of native range of Macroprotodon sp. from Carranza et al. [24] and those from the introduced populations from Mallorca and Menorca Islands. Mbi: Macroprotodon brevis ibericus; Mct: Macroprotodon cucullatus textilis; Mbb: Macroprotodon brevis brevis; Ma: Macroprotodon abubakeri; L—Libyan clade; Mm: Macroprotodon mauritanicus. (2D) Statistical parsimony network depicting the genealogical relationships between cytb haplotypes from the native range and from Balearic individuals (Ibiza: 12002; Mallorca: 9250; Menorca: 7076 and 7138) of R. scalaris.

Mentions: The genetic analysis of H. hippocrepis revealed two different haplotypes, both in cytb and 12S+cytb datasets, among the Balearic samples, corresponding to those already found in the native range by Carranza et al. [25] (Fig. 2A). Snakes from Mallorca and Ibiza are related to those most commonly found in Spain and Morocco. Therefore, the genetic data do not allow to distinguish the exact source.


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)

Results from genetic analysis and geographic origin of the introduced populations.Numbers on branches indicate ML bootstrap values (BP) over 1000 replicates (BP<50 are not reported). (2A): ML tree based on of the combined 12S+cytb dataset depicting the relationships between haplotypes of the native range of Hemorrhois hippocrepis from Carranza et al. [23] and those from the introduced populations from Mallorca and Ibiza Islands. MSA: Morocco+Iberia+Algeria; T: Tunisia. (2B) ML tree based on of the cytb dataset depicting the relationships between haplotypes of native range of Malpolon monspessulanus from Carranza et al. [23] and those from the introduced populations from Mallorca Island. Mmm: Malpolon m. monspessulanus; Mmi: Malpolon m. insignatus; Mmf: Malpolon m. fuscus. (2C) ML tree based on of the cytb dataset depicting the relationships between haplotypes of native range of Macroprotodon sp. from Carranza et al. [24] and those from the introduced populations from Mallorca and Menorca Islands. Mbi: Macroprotodon brevis ibericus; Mct: Macroprotodon cucullatus textilis; Mbb: Macroprotodon brevis brevis; Ma: Macroprotodon abubakeri; L—Libyan clade; Mm: Macroprotodon mauritanicus. (2D) Statistical parsimony network depicting the genealogical relationships between cytb haplotypes from the native range and from Balearic individuals (Ibiza: 12002; Mallorca: 9250; Menorca: 7076 and 7138) of R. scalaris.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0121026.g002: Results from genetic analysis and geographic origin of the introduced populations.Numbers on branches indicate ML bootstrap values (BP) over 1000 replicates (BP<50 are not reported). (2A): ML tree based on of the combined 12S+cytb dataset depicting the relationships between haplotypes of the native range of Hemorrhois hippocrepis from Carranza et al. [23] and those from the introduced populations from Mallorca and Ibiza Islands. MSA: Morocco+Iberia+Algeria; T: Tunisia. (2B) ML tree based on of the cytb dataset depicting the relationships between haplotypes of native range of Malpolon monspessulanus from Carranza et al. [23] and those from the introduced populations from Mallorca Island. Mmm: Malpolon m. monspessulanus; Mmi: Malpolon m. insignatus; Mmf: Malpolon m. fuscus. (2C) ML tree based on of the cytb dataset depicting the relationships between haplotypes of native range of Macroprotodon sp. from Carranza et al. [24] and those from the introduced populations from Mallorca and Menorca Islands. Mbi: Macroprotodon brevis ibericus; Mct: Macroprotodon cucullatus textilis; Mbb: Macroprotodon brevis brevis; Ma: Macroprotodon abubakeri; L—Libyan clade; Mm: Macroprotodon mauritanicus. (2D) Statistical parsimony network depicting the genealogical relationships between cytb haplotypes from the native range and from Balearic individuals (Ibiza: 12002; Mallorca: 9250; Menorca: 7076 and 7138) of R. scalaris.
Mentions: The genetic analysis of H. hippocrepis revealed two different haplotypes, both in cytb and 12S+cytb datasets, among the Balearic samples, corresponding to those already found in the native range by Carranza et al. [25] (Fig. 2A). Snakes from Mallorca and Ibiza are related to those most commonly found in Spain and Morocco. Therefore, the genetic data do not allow to distinguish the exact source.

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.