CONICET | Buscador de Institutos y Recursos Humanos

After more than 10 years without reevaluating the conservation status of the herpetofauna of Argentina, a new categorization of amphibians and reptiles was published last year. This work was organized and carried out by the Argentine Association of Herpetology (AHA), which is a non profit organization. More than 100 specialists participated in it. They contributed with new systematic, biogeographic and ecological information to reappraise 583 taxa of amphibians and reptiles. As a result of this new analysis, 187 taxa were considered threatened in this argentinean red list. Among these 187 taxa, there are 17 endangered, 39 threatened and 131 vulnerable. These categories were homologated with those of the IUCN (International Union for Conservation of Nature), although the methodology to obtain them was different. For listing a taxon in one of threatened IUCN categories (Critically Endangered, Endangered or Vulnerable) at least one quantitative criterion out of several ones should be fulfilled. These criteria are based on numerical data about population decline (in past, present or future), population size and/or geographic range contraction of the taxa. In our country, but I think it is a general situation in Latin america, extensive or long term population monitoring is not commonly carried out, hence the data to test whether the IUCN criteria are fulfilled or not, are scarce or inexistent. Furthermore, the natural landscapes are being modified at an increasing rate, making this type of data collection little effective for conservation purposes in the short time. For that reason, alternative methods were developed in Argentina, based on qualitative data about features relevant for the survival of the taxa. These methods did not provide an estimation of the risk of extinction of a species, but instead, they provided a measure of its degree of vulnerability. The method we applied to assess the conservation status of the herpetofauna of Argentina presents six criteria that range from 0 to 5. The criteria of the method are the following: Distribution: Here we do not consider the distribution of the taxa in other countries, only at national level. This criterion ranges between wide distributed to micro-endemism. Ecological specificity: this criterion ranges from generalist to specialist for habitat, microhabitat and diet. Anthropogenic effect: This criterion ranges from non negative to highly negative impact of human activities. Among the human activities, habitat modification is considered to have a worse impact on natural populations than hunting. Reproductive potential: for snakes this criterion ranges from annual oviparous species with litters of more than 20 eggs to viviparous or oviparous species with less than 5 off springs per year in average. Body size: from small to big species Abundance: this criterion ranges from abundant and commonly recorded in the last decade to non recorded despite being properly searched. So, all the taxa were evaluated for each criterion. The sum of the values of all criteria is the index taken to assess the categorization status of the taxon. The proposed theoretical limit for considering a species threatened is the 75% percentile, being considered Vulnerable species with index between 18 and 19, Threatened between 20 and 23 and Endangered between 24 and 30. What happens with the boas in Argentina? I will explain how our studies provided information to categorize their conservation status. Regarding the first criterion, Distribution, based on two of our studies about modelling distribution we indicated that Boa constrictor occidentalis and Epicrates alvarezi are regional endemisms of the Chaco and that Epicrates crassus is a microendemism in the Paranaense rainforest. You should notice that this criterion focuses in the distribution in Argentina, so the species could not fall in these levels when all its distribution is considered. Regarding its Ecological specificity, studies about habitat use in Boa constrictor occidentalis performed by our group indicated that the species is a habitat specialist strongly associated to forest patches for thermoregulation, being these habitat requirements stronger in the breeding season. Since there are not specific studies for the Epicrates species based on what we know about its distribution, but also on our studies in Boa constrictor occidentalis we infer that they are also specialists in habitat and microhabitat. Regarding Antropogenic effect in this criterion we indicated the higher classification for Boa and Epicrates since in our studies we demonstrated that habitat modification (deforestation and/or degradation) influences the capability of dispersion of the individuals, isolating the populations, and also affecting the acquisition of resources. Regarding its reproductive behavior, landscape modifications affect body condition, cutch size and testicular volume. But also the spatial pattern of vegetation influences the distribution of males and females in the breeding season. So, forest loss constrains reproduction. Regarding Reproductive potential: although clutch size could be large in the genus Boa, studies of our work team indicated that character, together with reproductive frequency, are plastic and could be affected by resource availability (like food intake in the season previous to the reproductive season since they are capital breeders, thermoregulation sites, mates, etc.), and reproductive frequency can change from biannual to triannual, or the clutch size could be reduced. Hence, for Boa and Epicrates the level was indicated between 5 to 10 offspring per year on average. Regarding abundance our experience in the field searching for boas in the Chaco helps us to indicate that although despite Epicrates alvarezi is well represented in Museum collections in Argentina, in the field it is scarce and difficult to find despite being properly searched. As a result of this analysis the four species of boas distributed in Argentina, presented some of the categories of threat. Being Epicrates crassus endangered, Boa constrictor occidentalis and Epicrates alvarezi threatened and Eunectes notaeus vulnerable. Notice that none of these boas has been categorized by the IUCN yet. After this classification we proposed Conservation actions for each species. But in general the following main ideas prevail: The mere presence of the species does not reflect the status of its populations, above all if we deal with a long-lived species. It is necessary to efficiently control deforestation and degradation, promote the protection of forest remnants and establish ecological corridors to ensure connectivity within the ecological region. New studies should be performed integrating species and environments with an ecosystemic approach. More interaction and exchange of information is needed between governmental authorities, natural resource managers, research groups and scientific societies. Regarding this last point, although the development of this categorization was not sponsored or supported by any governmental organism, a decree was passed by the National Environmental Agency establishing that our categorization is the valid one for the herpetofauna of Argentina. To conclude I want to stress the fact that establishing an accurate conservation status for a species is not possible without thorough studies about its biology.