Natura Pitiusa

Alien predators may impose a great threat to naïve preys. Podarcis pityusensis lizards live in Ibiza, a snake-free island until 2003. We studied lizards’ discrimination of scents of two invader snakes: one that predates on lizards, Hemorrhois hippocrepis, and another that does not, Rhinechis scalaris. We compared two populations of P. pityusensis: one from the main island of Ibiza, which coexists with both snakes, and another from the close snake-free islet of Sal Rossa. Lizards from Ibiza recognized the scent of H. hippocrepis and responded with clear antipredator behaviours. However, they reacted to the scent of R. scalaris similarly than to the odorless and the pungent controls. Lizards from Sal Rossa did not recognize any snake species. Thus, lizards can rapidly acquire the ability to react to a totally novel type of predator. There are two possible explanations: (1) rapid evolution of antipredator behavior, and (2) the ability of lizards to learn how to avoid new predators. There ...

Invasive species currently account for a major threat to global biodiversity, and island ecosystems are among the most vulnerable, because of the frequency and success of spe- cies introductions on islands. Within Mediterranean islands, reptiles not only are frequently introduced species but are also among the most threatened because of these introductions. The Balearic archipelago is a good example of this, since only two of its current 16 species of reptiles are native. Thirteen years ago, the snake Hemorrhois hippocrepis was introduced by cargo in Ibiza island, and it is in expansion. Individuals obtain- ed from an early eradication campaign showed a fast expres- sion of phenotypic plasticity and acquired larger sizes than those of the source population, probably due to a high prey availability and predator scarcity. The species is thriving at the expense of a small variety of native and non-native prey, but the predation pressure on the endemic Podarcis pityusensis, the only nativ...

Se ha realizado un estudio comparativo entre las faunas parásitas de diversas especies reptilianas en relación al tipo de alimentación ...... Roca, V (1999) Rev. Esp. de herpetologia 13

La lagartija de las Pitiusas, Podarcis pityusensis (Boscá, 1883), es una especie introducida en el peñón de Gaztelugatxe (Bizkaia), que en menos de 20 años ha desplazado  por completo a la especie autóctona, la lagartija roquera, P. muralis (Laurenti, 1768).  Desde el año 2008 se están llevando a cabo campañas de control poblacional de la  especie introducida. En la de 2008 se capturó un macho adulto que presentaba una cifosis múltiple en su columna vertebral, diagnosticada mediante radiografía de alta  resolución. El caso presentado sería el primero conocido para una lagartija europea del  género Podarcis. GARIN-BARRIO, I,  SANZ-AZKUE, I,   GOSÁ, A. y  BANDRÉS, A.  (2011)  Munibe (Ciencias Naturales-Natur Zientziak), num 59 

INTRODUCCIÓ Ja hem fet un repàs de les espècies típiques de les Pitiüses (vegeu EIVISSA núm 12). En aquest número ens dedicarem exclusivament a la sargantana de les Pitiüses o Podarcis  (= Lacerta pityusensis). A. M. Cirer  (1983) Eivissa nº 13

In this study we tested the hypothesis that the dispersal success (estimated here as fruit removal rate) of a native shrub species living in the Balearic Archipelago, Cneorum tricoccon L. (Cneoraceae), has decreased significantly in those islands where endemic lizards of the genus Podarcis have disappeared. These lizards acted as the main seed dispersers of the plant and became extinct after the introduction of carnivores. At least one of these carnivores, the pine marten (Martes martes L.), is also an important frugivore, consuming the fruits and dispersing the seeds of C. tricoccon and thus allowing the comparison of fruit removal rates between the two groups of vertebrates (lizards and mammals). We further tested the possibility that lizards (in particular, P. pityusensis Bosca` ) could be exerting selection on seed size. Núria Riera, Anna Traveset and Oscar García (2002)  Journal of Biogeography , 29

Although it is well established that many insects, birds and mammals serve as important pollinators and seed dispersers of flowering plants, the role of lizards in these processes has traditionally been considered as rare and less important. However, recent work shows both that their role as mutualistic agents has been underestimated and also reveals a striking pattern – that pollination and seed dispersal by lizards is most common on islands. We argue that this island phenomenon occurs because island lizards reach very high densities (density compensation) and experience a lower predation risk than do those on the mainland and, consequently, can expand their diet to include nectar, pollen and fruit. Although further empirical evidence is needed to confirm this explanation, such relationships could be ideal systems with which to study fundamental ecological problems, such as niche shifts, ecological release and competition. Jens M. Olesen a...

Es presenten les dades de distribució 5x5 km a I'illa d'Eivissa de les 5 especies d'herpets presents amb seguretat, que s'acompanyen amb un mapa. A més es fa un  recorregut per la bibliografia en referencia a les  tortugues de terra a les Pitiüses i es menciona la troballa d'un exemplar de Testudo graeca a prop de Corona. La feina de camp es va dur a terme entre l'any 1992 i 1995, si bé s'ha incorporat alguna dada posterior i es va centrar a zones adients per al calàpet. Paraules  clau:  atles,  herpets,  Eivissa,  biogeografia. Palerm, J.C. (1997)  Boll. Soc. Hist. Nat. Balears ,  40

Els amf ibis i rèptils s'han considerat posseïdors  d'estranys i malèfics poders  a tot arreu del món. És per això que la seua  protecció ès poc  defensada pel saber  popular. Sol fer  riure  que  s'haguin de  protegir les  serps  verinoses o els lletjos calàpets. Pero aquestos animals fan un gran servei a l'home i a  tota la  Naturalesa per la manera d'alimentar-se, a més del gran interès que poden despertar als científics. Les espècies que habiten les illes Pitiüses són insectivores en la part fonamental de la seva dieta. (...) La situació en què es troben  actualment  aquestos animals és de clara regressió. Cada vegada tenim menys individus d'aquestes espècies  animals, a pesar de  no semblar-ho al primer  colp de vista.Un breu repàs a la nostra herpetofauna ens  mostrarà que la majoria d'espècies estan en perill d'una ...

PLEGUEZUELOS J. M., R. MÁRQUEZ y M. LIZANA, (eds.) 2002. Atlas y Libro Rojo de los Anfibios y Reptiles de España. Dirección General de Conservación de la Naturaleza-Asociación Herpetologica Española (2ª impresión), Madrid, 587 pp.

Resumen: Se analizo el ciclo reproductor de una poblacion de lagartija de las Pitiusas (Podarcis pityusensis), introducida en un area urbana de la ciudad de Barcelona. La madurez sexual se alcanzo generalmente en el segundo año de vida apareciendo subadultos en primavera. El periodo reproductor abarco desde abril hasta agosto, siendo una de las fenologias mas tardias entre los lacertidos ibericos. Se observaron fuertes diferencias intersexuales en el ciclo de las reservas grasas. La estrategia teproductora resulto ser mas K-seleccionada que en otros representantes del genero Podarcis, con un tamano de puesta bajo y el tamafio de los huevos alto. Finalmente, se evaluan las caracteristicas reproductoras de esta poblacion en funcion de sus condicionamientos ambientales y su historia evolutiva. Palabras clave: reproduccion, Lacertidae, Podarcis pityusensis, poblacion introducida. CARRETERO, M.A.,  LLORENTE, G.,  SANTOS, X. & MONTORI, A. (1995) Rev. Esp.. Herp .

Salvador, A. (2009). Lagartija de las Pitiusas  – Podarcis pityusensis. En: Enciclopedia Virtual de los Vertebrados Españoles. Salvador, A., Marco, A. (Eds.) .

Abstract. The behavioral thermoregulation of P. pityusensis was studied for a period of one week during August, 1980. The cloacal temperatures and the ground and air temperatures were recorded by means of thermistors. P. pityusensis behaves like a heliotermic species with a temperature range between 28.5 and 41.5 ° C. Very significant correlations were found to exist between the Tc (Body temperatures) and the Ta (Air temperatures) or between the Tc and the Ts (Ground temperatures) in all ofthe specimens analyzed. There are also significant statistical differences between te mean Tc in individuals during thermoregulation and  the Tc of individuals active on the ground or inactive underneath stones. The daily pattern of activity is bimodal; the variations in body temperatures, being as a whole relatively independent of the fluctuations in the ambient temperature, adjust themselves to this pattern. P. pityusensis, roughly speaking, manifest severa...

Abstract. Here, we update the current list of amphibian and reptile fauna present in the Balearic Islands, probably the most outstanding case in the Mediterranean and of the most in the world where massive species introduction is in conflict with the survivorship of highly restricted endemic taxa. Resulting of a long term evolution in insularity, endemic herpetofauna was already decimated during the Pleistocene but, after the human colonisation of the archipelago, the introduction of alien species, passive or deliberate, has been provoking new extinctions and range retractions in the native herpetofauna. Such process is not interrupted but has even intensified during the last years. The current species list is composed by five amphibians (one native) and 21 reptiles (2 native). A critical review of the evidence on extinctions and introductions is provided together with the conservation implications. Compared to the last review (Mayol, 1985)...

RESUM. Presentam l'amilisi biogeografica de la biota herpetologica de les Balears i Pitiüses. Baleaphryne muletensis, Laeerta (Podareis) lilfordi i Laeerta (Podareis) pityusensis són considerats paleondemismes que, presumiblement, haurien colonitzat les nostres illes durant el Messinia. Totes les altres especies de l'actual biota herpetologica haurien immigrat a les Balears i Pitiüses gracies a l'acció de l'home. ALCOVER, J.A. I  MAYOL, J. (1981).  Boll. Soc. Hist. Nat. Balears , 25 

Les illes Pitiüses han merescut el sobrenom d'Illes de la sal» per la importància que en lemps passats assumiren les seues salines. L'explotació de sal a les illes es remunta possiblement a la seua ocupació pels cartaginesos, sent des de Uavò una activitat ininterrompuda de la qual depenia la conservació i benefici total de les illes... Guerau d'Arellano i Tur, Cristòfol i Ramon Torres, Salvador (1979). Ses Salines d’Eivissa i Formentera. Eivissa nº9