Ecologia del calàpet, Bufotes balearicus (Boettger, 1880): Demografía i avaluació de l'ús de la fotoidentificació com a mètode de marcatge individual no invasiu

[cat] En el present estudi, s’ha obtingut informació per primera vegada sobre l’ecologia del calàpet Bufotes balearicus (Boettger, 1880) dins l’Illa de Mallorca, concretament al Parc Natural de Mondragó. Es van fer un total de 31 sortides de camp repartides en tres anys (2018-2020) a 5 punts de cria de la espècie. Es realitzaren 463 captures, de 193 individus diferents. Es van marcar els individus capturats amb microxip per un estudi de capturamarcatge recaptura. De tots ells, es prengueren dades de sexe, longitud i massa corporal. La caracterització de la població de mascles va donar com a resultat una mitja de longitud corporal de musell a l’urostil de 67.01 mm i una mitja de massa corporal de 30.98 g. Els mascles madurs de B. balearicus semblen no desplaçar-se entre els diferents punts de cria observats comportant-se com a poblacions tancades. Per altra sembla ser que els mascles no segueixen cap estratègia en el temps d’arribada als punts de cria. Finalment amb el software APHIS es va testar el mètode de fotoidentificació permetent el reconeixement de tots els exemplars recapturats amb un 96.89% de les recaptures en primera posició.[eng] In the present study, information was obtained for the first time about the ecology of the Balearic green toad Bufotes balearicus (Boettger, 1880) at the island of Mallorca, specifically in the natural park of Mondragó. A total of 31 sampling occasions were made over three years (2018-2020) to 5 breeding points of the species. 463 captures were made, of 193 different individuals. Captured individuals were tagged with transponders to carry out a CMR study. From all of them, data on sex, body length, and body mass were taken. The characterization of the male population resulted in an average snoutvent length of 67.01 mm and an average body mass of 30.98 g. According to movements recorded, mature males of B. balearicus do not appear to move between the different breeding points, thus behaving as closed population. On the other hand, it seems that the males do not follow any strategy at the time of arrival at the breeding points. Finally, with the APHIS software, the photoidentification was tested allowing to match all the recaptured specimens with 96.89% of the recaptures in the first position

Colonització de l'os rentador (Procyon lotor) a l'illa de Mallorca

[cat] En el present estudi, s’ha donat informació per primera vegada sobre la demografia i l’impacte Procyon lotor com espècie invasora dins l’Illa de Mallorca. Dit estudi consistia en l’analitzi d’aparells digestius d’individus capturats principalment per trampes, i poder observar quin és l’impacte real com depredador que està tenint dins l’illa. També s’han analitzat dades demogràfiques i de distribució de l’espècie les quals han donat informació de l’estat de l’espècie com de la seva colonització del territori. Les dades obtingudes demostren que P. lotor està adaptat i en fase d’expansió sent així un problema present i de futur per la fauna degut a la fragilitat d’ecosistemes insulars. Per part de les dades en la dieta de P. lotor no s’han observat diferencies en la dieta, tot i que es demostra com és una espècie omnívora oportunista que s’ha adaptat als recursos que li proporciona Mallorca. Concloent de forma definitiva que és necessari posar en marxa un control sobre l’espècie i evitar la seva expansió per l’illa.[eng] In the present study, for the first time, information has been provided on the demography and impact of Procyon lotor as an invasive species within the Island of Mallorca. This study consisted on analyzing the digestive tract of captured individuals, and to assess the real impact as an invasive predator on the island. Demographic and distribution data of the species have also been analyzed. It provided information about the status of the species as well as the colonization process of the territory. Data showed that P. lotor is adapted and under an expansion behaviour. Thus, it could become a future problem for the conservation biodiverisity in insular ecosystems. Related to diet data, the composition was mainly the same as previous studies around its natural and introduced distribution area. Although, it is shown how an opportunistic omnivorous species has adapted to the resources provided by Mallorca. Due to the potencial impact on native biodiversitsy it is necessary to implement control actions and prevent its expansion to the rest of the island

Tail breakage and predatory pressure upon two invasive snakes (Serpentes: Colubridae) at two islands in the Western Mediterranean

Tail breakage is an important anti-predator mechanism in snake populations, which can be used as a proxy for predation intensity as natural observations of predator-prey interactions are scarce. Frequency of tail breakage was calculated for two Iberian colubrids recently introduced in the Balearic Islands (Western Mediterranean, Spain): Hemorrhois hippocrepis (Linnaeus, 1758) in Eivissa and Zamenis scalaris (Schinz, 1812) in Formentera. The effect of sex, life-stage, dorsal coloration pattern, body length and body condition on frequency of tail breakage and on remaining subcaudal scale pairs (SBC) were analyzed and compared between the native range and the invaded islands. An increase of the frequency of tail breakage with body size was found, supporting a size-related effect, which also occurs in the native range. Frequency of tail breakage of H. hippocrepis was lower in Eivissa when compared with the original area, while in Formentera Z. scalaris showed a higher frequency, which could be related to the different predator community on each island compared with the mainland. The study of the main ecological aspects of these recent introduced species may allow to assess their potential impact on insular ecosystems and their native biodiversity as well as to promote future control actions in these areas previously free of snakes.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author