Vanesa Arzamendia

Detecting areas of endemism with a taxonomically diverse data set: plants, mammals, reptiles, amphibians, birds, and insects from Argentina

The idea of an area of endemism implies that different groups of plants and animals should have largely coincident distributions. This paper analyses an area of 1152 000 km2, between parallels 21 and 32°S and meridians 70 and 53°W to examine whether a large and taxonomically diverse data set actually displays areas supported by different groups. The data set includes the distribution of 805 species of plants (45 families), mammals (25 families), reptiles (six families), amphibians (five families), birds (18 families), and insects (30 families), and is analysed with the optimality criterion (based on the notion of endemism) implemented in the program NDM/VNDM. Almost 50% of the areas obtained are supported by three or more major groups; areas supported by fewer major groups generally contain species from different genera, families, or orders.

Biología reproductiva de la serpiente semiacuática Liophis semiaureus (Serpentes, Colubridae) en el nordeste de Argentina

Las serpientes tienen una notable flexibilidad y diversidad en sus tacticas reproductivas, a pesar de ello, los estudios acerca de la biologia reproductiva de especies sudamericanas en zonas subtropicales-templadas son escasos. Se analizo la biologia reproductiva de Liophis semiaureus en el nordeste de Argentina, incluyendo la madurez y dimorfismo sexual, fecundidad y ciclo reproductivo. Las hembras maduras fueron significativamente mas largas, presentaron mayor peso corporal y alcanzaron la madurez sexual a una longitud mayor que los machos. Los machos tuvieron colas mas largas que las hembras. El ciclo reproductivo fue estacional con mayor actividad en los periodos templados del ano aunque previos a la epoca de inundaciones. Liophis semiaureus invirtio mas energia en la reproduccion que en el crecimiento, lo que posibilita que comiencen a reproducirse con tamanos mas pequenos con respecto a otras poblaciones, sin retrasar su reproduccion hasta alcanzar mayores tamanos. Esta puede ser una estrategia ventajosa en climas estacionales. Las caracteristicas reproductivas y de dimorfismo sexual en L. semiaureus se encontrarian influenciadas por aspectos filogeneticos, geograficos y ecologicos, lo que determina que la especie responda de manera general al patron reproductivo del grupo taxonomico pero con particularidades propias determinadas por los factores geograficos y los requerimientos ecologicos.

Temperate snake community in South America: is diet determined by phylogeny or ecology?

Communities are complex and dynamic systems that change with time. The first attempts to explain how they were structured involve contemporary phenomena like ecological interactions between species (e.g., competition and predation) and led to the competition-predation hypothesis. Recently, the deep history hypothesis has emerged, which suggests that profound differences in the evolutionary history of organisms resulted in a number of ecological features that remain largely on species that are part of existing communities. Nevertheless, both phylogenetic structure and ecological interactions can act together to determine the structure of a community. Because diet is one of the main niche axes, in this study we evaluated, for the first time, the impact of ecological and phylogenetic factors on the diet of Neotropical snakes from the subtropical-temperate region of South America. Additionally, we studied their relationship with morphological and environmental aspects to understand the natural history and ecology of this community. A canonical phylogenetical ordination analysis showed that phylogeny explained most of the variation in diet, whereas ecological characters explained very little of this variation. Furthermore, some snakes that shared the habitat showed some degree of diet convergence, in accordance with the competition-predation hypothesis, although phylogeny remained the major determinant in structuring this community. The clade with the greatest variability was the subfamily Dipsadinae, whose members had a very different type of diet, based on soft-bodied invertebrates. Our results are consistent with the deep history hypothesis, and we suggest that the community under study has a deep phylogenetic effect that explains most of the variation in the diet.

Las especies amenazadas como hipótesis: problemas y sesgos en su categorización ejemplificados con las serpientes de la Argentina

Threatened species are those that have a high probability of extinction or are close to this situation to continue direct pressure on them or their habitats. From this definition we analyze problems and biases in the categories of threat of Argentine snakes, showing examples where taxonomic changes (Linnaean shortfall), gaps in knowledge about the distribution of species (Wallacean shortfall), or bio-ecological aspects (Haeckelean shortfall) generate biases in the allocation of its conservation status. We proposed that endangered species should be listed as hypothesis, by analyzing scientifically quantitative and / or qualitative information about its geographic distribution, size and population trend and bio-ecological characteristics that make them vulnerable against anthropogenic effects. As a result, will be reject or not its

Is xenodontine snake reproduction shaped by ancestry, more than by ecology?

Abstract One of the current challenges of evolutionary ecology is to understand the effects of phylogenetic history (PH) and/or ecological factors (EF) on the life‐history traits of the species. Here, the effects of environment and phylogeny are tested for the first time on the reproductive biology of South American xenodontine snakes. We studied 60% of the tribes of this endemic and most representative clade in a temperate region of South America. A comparative method (canonical phylogenetic ordination—CPO) was used to find the relative contributions of EF and PH upon life‐history aspects of snakes, comparing the reproductive mode, mean fecundity, reproductive potential, and frequency of nearly 1,000 specimens. CPO analysis showed that PH or ancestry explained most of the variation in reproduction, whereas EF explained little of this variation. The reproductive traits under study are suggested to have a strong phylogenetic signal in this clade, the ancestry playing a big role in reproduction. The EF also influenced the reproduction of South American xenodontines, although to a lesser extent. Our finding provides new evidence of how the evolutionary history is embodied in the traits of living species.

Descriptive bioregionalisation and conservation biogeography: what is the true bioregional representativeness of protected areas?

Abstract. Conservation biogeography involves the application of biogeographical principles and methods to conservation issues, including the design of protected areas. Bioregionalisation has been central in the implementation of main global conservation strategies, providing the basis for prioritising protected areas and evaluating their representativeness and effectiveness in conservation actions. Traditionally, experts established these bioregionalisations without repeatable methodologies and using only qualitative evidence, which has set constraints in their usefulness. We compared three descriptive bioregionalisations commonly used for conservation decision-making, with a regionalisation produced using quantitative methods (endemicity analysis), so as to assess biases and differences in the representativeness of the existing protected-area system of Argentina. Areas of endemism were detected using NDM/VNDM quantitative methodology on a database consisting of 19 250 distribution records of 116 taxa of snakes, and the results were compared with previous descriptive regionalisations. We recovered 9 quantitative bioregionalisation units (QBU) v. 6–8 descriptive bioregionalisation units (DBU) proposed by previous authors. From this comparison, the following was found: (1) we discovered three new QBU not considered by any previous DBU; (2) other three areas proposed by DBU are not supported by our endemicity analysis; (3) we detected differences comparing the representativeness of protected areas between descriptive v. quantitative bioregionalisations, leaving the first, some areas of conservation relevance largely unprotected. Moreover, DBU were characterised by a high degree of uncertainty and biases, such as the consideration of probably artificial units, the non-recognition of some natural units and mistakes in the representativeness of protected areas. We emphasise the importance of applying quantitative biogeographic methods to identify bioregionalisation units and its fundamental role in conservation biogeography so as to optimise protected-area efficiency and other territorial conservation strategies.

Distribution and natural history notes on Tachymenis chilensis chilensis (Schlegel, 1837) (Reptilia: Serpentes: Dipsadidae) in Argentina

We revisit the distribution and natural history data of Tachymenis chilensis chilensis (Schlegel, 1837) in Argentina based on compiled and novel records, extending its northern and southern distribution from the previously known localities in Argentina. We recorded two prey items in Argentinean populations: Rhinella rubropunctata , reported for the first time, and Liolaemus pictus . Tachymenis c. chilensis is mainly found in forested habitats, generally near wetlands with abundant populations of amphibians. The latitudinal range occupied by T. c. chilensis in Argentina is similar to that in Chile, but its northern distribution limit reaches the lowest latitudes in Chile. This is probably due to the higher humidity levels in the western slopes of the Andes and the barrier effect of the highest mountain ranges in this area.

Species distribution models and empirical test: Comparing predictions with well-understood geographical distribution of Bothrops alternatus in Argentina

Abstract Species distribution models (SDMs) estimate the geographical distribution of species although with several limitations due to sources of inaccuracy and biases. Empirical tests arose as the most important steps in scientific knowledge to assess the efficiency of model predictions, which are poorly rigorous in SDMs. A good approach to the empirical distribution (ED) of a species can be obtained from comprehensive empirical knowledge, that is, well‐understood distributions gathered from large amount of data generated with appropriate spatial and temporal samples coverage. The aims of this study were to (a) compare different SDMs predictions with an ED; and (b) evaluate if fuzzy global matching (FGM) could be used as an index to compare SDMs predictions and ED. Six algorithms with 5 and 20 variables were used to assess their accuracy in predicting the ED of the venomous snake Bothrops alternatus (Viperidae). Its entire distribution is known, thanks to thorough field surveys across Argentina, with 1,767 records. ED was compared with SDMs predictions using Map Comparison Kit. SDMs predictions showed important biases in all methods used, from 70% sub‐estimation to 40% over‐estimation of ED. BIOCLIM predicted ≈31% of B. alternatus ED. DOMAIN predicted 99% of ED, but over‐estimated 40% of the area. GLM with five variables calculated 75% of ED, while Genetic Algorithm for Rule‐set Prediction showed ≈60% of ED; the last two presenting overpredictions in areas with favorable climatic conditions but not inhabited by the species. MaxEnt and RF were the only methods to detect isolated populations in the southern distribution of B. alternatus. Although SDMs proved useful in making predictions about species distribution, predictions need validation with expert maps knowledge and ED. Moreover, FGM showed a good performance as an index with values similar to True Skill Statistic, so that it could be used to relate ED and SDMs predictions.

Urbanization impacts on the trophic guild composition of bird communities

ABSTRACT Urbanization transforms the landscape and generates loss of pristine habitats. We investigated the urbanization effect on bird communities in a growing South American city (Santa Fe, Argentina) and hypothesized that if habitat structure and human disturbance change along an urban gradient, the richness and abundance of trophic guilds should also vary accordingly. We placed 50 transects 100 m long × 50 m wide in five districts with different levels of urbanization, determined by habitat structure variables. We recorded the number and abundance of species and the amount of pedestrians and vehicles passing through each transect. We recorded 23% of all bird species known for the Santa Fe province and categorized them within 19 trophic guilds. The percentage of area covered by herbaceous vegetation, water bodies and trees and shrubs had a positive relationship with the richness and abundance of most of trophic guilds (hawking aerial, terrestrial, bark and foliage insectivores; terrestrial and generalized granivores; generalized, aquatic diving and foliage omnivores; hawking aerial, aquatic diving and striding carnivores; nectarivores; and aquatic filters). Pavement surface and human disturbance variables had a negative relationship with the richness, and high buildings and pavement surface had a positive relationship with the abundance of terrestrial omnivores and coursing aerial insectivores. Variation partitioning revealed that habitat structure and human disturbance were better predictors of the richness than the abundance of each trophic guild. Results showed that trophic guilds associated to vegetation strata were seen to increase their richness and abundance towards green areas, even if they presented generalist or specialist habits. Urban planners should conserve or manage the surrounded natural spaces when the growth of the city is directed to these areas and increase the availability of environmental features within the urban matrix.

New southern record of Erythrolamprus reginae (Linnaeus, 1758) (Serpentes: Dipsadidae), a vulnerable species in Argentina

I present the first record of the tropical snake Erythrolamprus reginae from Entre Rios province as the southernmost record from Argentina and South America. This record extends the range of this species by 510 km airline south of known localities in Corrientes province. Geographical distribution in Argentina and Paraguay is provided. This record confirms the presence of E. reginae in seasonally flooded gallery forest bordering the Uruguay River, a biogeographical corridor for tropical biota invading temperate latitudes.