Recent Invaders in Small Mediterranean Islands: Wild Boars Impact Snakes in Port-Cros National Park.

Diversity 2021, 13, 498.


Mediterranean islands host unique ecosystems that are particularly vulnerable to invasive species. However, knowledge regarding the precise impact of invasive species on local biodiversity remains limited for many of these systems. Here we report on the negative impacts of invasive wild boars (Sus scrofa) on native snakes on islands in the Mediterranean basin. Capture-mark-recapture was initiated in 2012 on two snake species (Montpellier snake, Malpolon monspessulanus and Ladder snake, Zamenis scalaris) across two islands of Port-Cros National Park. Several wild boars, an invasive species, reached the islands in 2007. They remained confined to small areas of the islands for several years. In Port-Cros, the numbers of wild boars suddenly increased in 2015, and rapidly colonized the whole island damaging vast land surfaces. In Porquerolles, wild boars did not proliferate. This offered an opportunity to examine the impact of wild boar outbreak with a Before-After Control-Impact design (BACI). Snake counts and mark-recapture modeling showed that demographic traits were stable before 2016 for both snake species on both islands. As well as abundance, recruitment, and population growth rate of Montpellier snakes significantly declined where wild boars proliferated but remained constant on the island where they did not. Wild boars probably impacted snake numbers through habitat destruction and direct killing. The rapid decline of snakes (apex predators) and intensive uprooting that strongly damage ground dwelling species (plants, animals) suggest that wild boars represent a serious threat to island biodiversity. As elsewhere around the world, these invasive ungulates proliferate in the Mediterranean basin, they are proficient swimmers and exhibit a remarkably high invasive potential. We recommend vigilance and fast eradication to prevent population outburst; even a few a localized non-proliferating individuals contain the latent potential for devastating outbreaks.


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Control of the ladder snake (Rhinechis scalaris) on Formentera using experimental live-traps.

In: C.R. Veitch, M.N. Clout, A.R. Martin, J.C. Russell and C.J. West (eds.) (2019). Island invasives: scaling
up to meet the challenge, pp. 332–336. Occasional Paper SSC no. 62. Gland, Switzerland: IUCN.


The ladder snake (Rhinechis scalaris ) is a recent alien invasive species found on Formentera (83 km2), in the Balearic Archipelago (4,492 km2). It has been introduced in the last decade as cargo stowaway hidden within ornamental olive trees from the Iberian Peninsula, causing negative impacts on native fauna. This paper describes the methodology used to reduce the ladder snake population as a first attempt since it was detected in 2006. For this purpose, an experimental live-trap was designed by the wildlife management team of the Consorci per a la Recuperació de la Fauna de les Illes Balears (COFIB) during the 2016 campaign. As a result, 314 R. scalaris were trapped in an area of 472 ha, achieving an efficiency of up to 0.167 captures per trap and night, and 0.040 captures per unit effort on average. This outcome encourages the use of the live-trap as a cost-effective method for reducing the snake population in Formentera. Nonetheless, this method should be considered a starting point toward R. scalaris control.


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Dienstag, 08 März 2022 16:00

CALMONTE, T. & FERRI, V. (1987).

Un serpente nuovo per la Fauna italiana: il Colubro scalare, Elaphe scalaris (Schinz, 1822).

Atti Soc.ital.Sci.nat., Museo civ. Stor. Nat. Milano, 128 (3-4): 314-316.


First time found in Italy the Ladder Snake, Elaphe scalaris (Schinz, 1822) (Reptilia, Colubridae). A specimen of Ladder Snake, Elaphe scalaris, was recently found near Ventimiglia, Imperia. This is the first record for this species in Italy.


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Sonntag, 20 Februar 2022 11:34

JOGER, U., & BÖHME, W. (2006)

Handbuch der Reptilien und Amphibien Europas - Schlangen (Serpentes) III: Viperidae.

420 Seiten. AULA-Verlag. 978-3-89104-617-3 (ISBN)


Der dritte Teil des Schlangenbandes hat die Vipern zum Thema, die einzige Familie in Europa, deren Gift dem Menschen gefährlich werden kann. Der Aufbau der Artkapitel entspricht dem in Band 3/ I und 3/ II A. Insgesamt werden 13 Arten besprochen:
Agkistrodon halys (Halysgrubenotter) – Macrovipera lebetina (Levanteotter) – Macrovipera schweizeri (Kykladenviper) – Vipera ammodytes (Sandotter) – Vipera aspis (Aspisviper, Juraviper) – Vipera berus (Kreuzotter) – Vipera dinnicki (Westkaukasische Otter) – Vipera kaznakovi (Kaukasus-Otter) – Vipera latastii (Stülpnasenotter) – Vipera nikolskii (Nikolskij`s Viper) – Vipera seoanei (Nordiberische Kreuzotter) – Vipera ursinii (Wiesenotter) – Vipera xanthina (Bergotter).


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A Taxonomic Revision of Boas (Serpentes: Boidae).

Zootaxa 3846 (2): 249-260.


Large molecular datasets including many species and loci have greatly improved our knowledge of snake phylogeny, particularly within the group including boas (Table 1). Recent taxonomic revisions using molecular phylogenies have clarified some of the previously contentious nomenclature of the group (Wilcox et al. 2002; Lawson et al. 2004; Burbrink 2005; Noonan & Chippindale 2006), resulting in a robust taxonomy that is mostly concordant with the phylogeny as currently known, which includes ~85% of described, extant species (Pyron et al. 2013; Reynolds et al. 2014). However, a few unresolved issues remain, related primarily to the rules of the International Code of Zoological Nomenclature (the Code hereafter) and the application of Linnaean ranks (International Commission on Zoological Nomenclature et al. 1999).


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Donnerstag, 01 Oktober 2020 15:01


Vorläufige Liste der Schlangen des Tai-Nationalparks / Elfenbeinküste und angrenzender Gebiete.

SALAMANDRA 36(1): 25-38


Wir stellen die Schlangenfauna des Tai-Nationalparks (TNP) mit Angabe weiterer biologischer Daten vor. Insgesamt sind nun 39 Schlangenarten aus dem TNP bekannt. Im Primär-Regenwald wurden 22 und in offeneren Habitaten beziehungsweise am Waldrand 17 Schlangenarten gefunden. 15 Arten waren arborikol, 19 lebten am Boden und fünf unterirdisch. Wir gehen davon aus, daß die bisherigen Nachweise etwa zwei Drittel der für diesen letzten großen Regenwald Westafrikas zu erwartenden Arten ausmachen.


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Dienstag, 29 September 2020 16:24

ROELKE, C. E. & SMITH, E. N. (2010)

Herpetofauna, Parc National des Volcans, North Province, Republic of Rwanda.

Check List 6 (4): 525-531. Jan. 2010. DOI: 10.15560/6.4.525


Herein is presented a list of the reptiles and anurans from the Parc National des Volcans (PNV)(01°43’ S, 29°52’ W), an area in the west and north provinces of the Republic of Rwanda in the Albertine Rift region of Africa.  Fieldwork was conducted between two and six days per week from June through August 2007 and 2008. We also conducted literature searches of all historical expeditions within the park for species records. Seventeen species of reptiles and anurans are recorded from the PNV. Nine of the species were anurans, distributed in five families: Arthroleptidae (3), Bufonidae (1), Hyperoliidae (3), Phrynobatrachidae (1), and Pipidae (1). Eight species of reptiles were recorded from five families: Chamaeleonidae (1), Lacertidae (2), Scincidae (2), Colubridae (2), and Viperidae (1). Eight of the seventeen species found in the PNV are endemic to the Albertine Rift.


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Limitations of Climatic Data for Inferring Species Boundaries: Insights from Speckled Rattlesnakes.

PLoS ONE 10(6): e0131435. doi:10.1371/journal.pone.013143


Phenotypes, DNA, and measures of ecological differences are widely used in species delimitation. Although rarely defined in such studies, ecological divergence is almost always approximated using multivariate climatic data associated with sets of specimens (i.e., the “climatic niche”); the justification for this approach is that species-specific climatic envelopes act as surrogates for physiological tolerances. Using identical statistical procedures, we evaluated the usefulness and validity of the climate-as-proxy assumption by comparing performance of genetic (nDNA SNPs and mitochondrial DNA), phenotypic, and climatic data for objective species delimitation in the speckled rattlesnake (Crotalus mitchellii) complex. Ordination and clustering patterns were largely congruent among intrinsic (heritable) traits (nDNA, mtDNA, phenotype), and discordance is explained by biological processes(e.g., ontogeny, hybridization). In contrast, climatic data did not produce biologically meaningful clusters that were congruent with any intrinsic dataset, but rather corresponded to regional differences in atmospheric circulation and climate, indicating an absence of inherent taxonomic signal in these data. Surrogating climate for physiological tolerances adds artificial weight to evidence of species boundaries, as these data are irrelevant for that purpose. Based on the evidence from congruent clustering of intrinsic datasets, we recommend that three subspecies of C.mitchellii be recognized as species: C.angelensis,C.mitchellii, and C.Pyrrhus.


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Evolution of rattlesnakes (Viperidae; Crotalus) in the warm deserts of western North America shaped by Neogene vicariance and Quaternary climate change.

Molecular Ecology (2006) 15, 3353 – 3374. doi: 10.1111/j.1365-294X.2006.03007.x


During Pleistocene, the Laurentide ice sheet rearranged and diversified biotic distributionsin  eastern  North  America,  yet  had  minimal  physical  impact  in  western  North  Americawhere  lineage  diversification  is  instead  hypothesized  to  result  from  climatic  changes.  If Pleistocene climatic fluctuations impacted desert species, the latter would reflect patterns of restricted gene flow concomitant with indications of demographic bottlenecks. Accordingly, molecular evidence for refugia should be present within these distributions and for subsequent range expansions as conditions improved. We sought answers to these questions by evaluating mitochondrial DNA (mtDNA) sequences from four species of rattle-snakes [Crotalus mitchellii (speckled rattlesnake), Crotalus cerastes (sidewinder), Crotalus tigris (tiger rattlesnake), Crotalus ruber (red  diamond  rattlesnake)] with distributions restricted to desert regions of southwestern North  America. We inferred relationships using  parsimony  and  maximum likelihood, tested  intraspecific  clades  for  population expansions, applied an isolation-with-migration model to determine bi-directional migration rates (m) among  regions, and inferred divergence times for species and clades by applying a semiparametric penalized likelihood approach to our molecular data. Evidence for significant range expansion was present in two of eight  regions in  two  species (Crotalus mitchellii pyrrhus, C. tigris region north). Two species (C. cerastes, C. mitchellii) showed a distribution concomitant with northward displacement of Baja California from mainland México, followed by vicariant separation into subclades. Effects of Pleistoceneclimate  fluctuations were found in the distributions of all four species. Three regional diversification patterns were  identified: (i) shallow genetic diversity that resulted  from Pleistocene climatic events (C. tigris, C. ruber); (ii)  deep Pleistocene divisions indicating allopatric segregation of subclades within refugia (C. mitchellii, C. cerastes); and (iii) line-age diversifications that extended to Pliocene or Late Miocene (C. mitchellii, C. cerastes). Clade-diversifying and clade-constraining effects impacted the four species of rattlesnakes unequally.  We found relatively high levels of molecular  diversification in the two most broadly distributed species (C. mitchellii, C. cerastes), and lower levels of genetic diversification in the two species (C. tigris, C. ruber) whose ranges are relatively more restricted. Furthermore, in several cases, the distributions of subspecies were not congruent with our molecular information. We suggest  regional conservation perspectives for southwestern deserts cannot rely upon subspecies as biodiversity surrogates, but must instead employ a molecular and deep historical perspective as a primary mechanism to frame biodiversity reserves within this region.


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A preliminary analysis of phylogenetic relationships and biogeography of the dangerously venomous Carpet Vipers, Echis (Squamata, Serpentes, Viperidae) based on mitochondrial DNA sequences.

Amphibia-Reptilia 30(2):273-282. DOI: 10.1163/156853809788201090.


Phylogenetic analysis of 1117 bp of mitochondrial DNA sequences (731 bp of cytochrome b and 386 bp of 16S rRNA) indicate that Echis consists of four main clades: E. ocellatus, and the E. coloratus, E. pyramidum, and E. carinatus groups. In the E. coloratus group, E. coloratus itself shows substantial genetic divergence from E. omanensis, corroborating their separate species status. In the E. pyramidum clade, E. pyramidum from Egypt and E. leucogaster from West Africa are genetically very similar, even though samples are separated by 4000 km. South Arabian populations of the E. pyramidum group are much better differentiated from these and two species may be present, animals from Dhofar, southern Oman probably being referable to E. khosatzkii. In the E. carinatus group, specimens of E. carinatus sochureki and E. multisquamatus are very similar in their DNA. The phylogeny indicates that the split between the main groups of Echis was followed by separation of African and Arabian members of the E. pyramidum group, and of E. coloratus and E. omanensis. The last disjunction probably took place at the lowlands that run southwest of the North Oman mountains, which are likely to have been intermittently covered by marine incursions; they also separate the E. pyramidum and E. carinatus groups and several sister taxa of other reptiles. The E. carinatus group may have spread quite recently from North Oman into its very extensive southwest Asian range, and there appears to have been similar expansion of E. pyramidum (including E. leucogaster) in North Africa. Both these events are likely to be associated with the marked climatic changes of the Pleistocene or late Pliocene. Similar dramatic expansions have also recently occurred in three snake species in Iberia.


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