Making more with standard ecotoxicological tests: Using sets of behavioural markers to test the effect of endosulfan on amphibian tadpoles

peer reviewe

Five thousand years of tropical lake sediment DNA records from Benin

Until now, sedimentary DNA (sedDNA) studies have only focused on cold and temperate regions were DNA is relatively well preserved. Consequently, the tropics, where vegetation is hyperdiverse and natural archives are rare, have been neglected and deserve attention. In this study, we used next-generation sequencing to barcode sedDNA from Lake Sele, localized in the tropical lowlands of Benin (Africa), and compared the taxonomic diversity detected by DNA analyses with pollen assemblages. Plant sedDNA was successfully amplified from 33 of the 34 successfully extracted samples. In total, 43 taxa were identified along the 5,000 years spanned by the sediment: 22 taxa were identified at the family level and 21 at the genus level. The plant diversity recovered through sedDNA from Lake Sele showed a specific local signal and limited overlapping with pollen. Introduced plants, grown and cultivated close to the water, such as sweet potato, were also well recorded by sedDNA. It appears, therefore, to be a promising approach to studying past diversity in tropical regions, and could help in tracking the introduction and history of agriculture. This is the first time this method has been used in the field of domestication and dissemination of several specific crops, and the results are very encouraging

Predicting the prices of cards in the game Magic with machine learning

V tem diplomskem delu smo preučevali trende gibanja cen pri kartah igre Magic: The Gathering in pri tem uporabili najbolj primerne metode strojnega ućenja. Cilj je bil izdelati napovedni model za cene kart. Naša naloga je bila identiciranje pomembnih virov, pridobivanje potrebnih podatkov, njihova pretvorba v računalniku razumljivo obliko ter izbira primernega algoritma. Model, ki smo ga ustvarili, se je izkazal za zanesljivega s 61% točnostjo napovedi gibanja cene pri zelo redkih kartah, medtem ko smo pri redkih kartah dosegli le 52% točnost, kar ni preseglo niti privzete točnosti. Pri nalogi smo uporabili metodo podpornih vektorjev ter si pomagali z orodjem Weka. S podatki, ki smo jih pridobili, smo naredili še nekaj poizkusov in tako poiskali nekaj novih odvisnosti med podatki, ki jih prej nismo poznali.This thesis is a study of Magic: The Gathering card price fluctuations using the most appropriate machine learning methods. The goal was to construct a predictive model for card prices. This required us to identify crucial attributes, gather necessary data, convert it to a machine-readable format and select a suitable learning algorithm for the task. The resulting model was effective, attaining a 61 % price trend accuracy with mythic rare cards, while it was less successful with rare cards with only 52% accuracy, which failed to beat default accuracy. Support vector machines algorithms and the machine learning toolbox Weka were used to achieve these results, which were applied in further experiments that led to the discovery of previously unknown data dependencies

Towards the end of facultative paedomorphosis in Balkan newts? A focus on Montenegrin populations

peer reviewe

From introduction to the establishment of alien species: bioclimatic differences between presence and reproduction localities in the slider turtle

ABSTRACT Aim Understanding the factors determining the transition from introduction of aliens to the establishment of invasive populations is a critical issue of the study of biological invasions, and has key implications for management. Differences in fitness among areas of introduction can define the zones where aliens become invasive. The American slider turtle Trachemys scripta has been introduced worldwide, and has negative effects on freshwater communities, but only a subset of introduced populations breed successfully. We used species distribution models to assess the factors influencing the slider distribution in Italy, by analysing bioclimatic features that can cause the transition from presence of feral adults to breeding populations. We also evaluated whether climate change might increase the future suitability for reproduction. Location Central and Northern Italy. Methods The distribution of slider turtle was obtained from the literature, unpublished reports and field surveys. We used Maxent to build bioclimatic models. Results Reproductive populations are associated to a clear bioclimatic envelope with warmer climate, more solar radiation and higher precipitations than populations where reproduction is not observed. Several Mediterranean areas currently have climatic features suitable for sliders. Scenarios of climate change predict the expansion of these areas. In the near future (2020), the proportion of populations in areas suitable for reproduction will dramatically increase. Main conclusion Our study shows that bioclimatic differences can determine the areas where aliens become invaders. Management should be focused to these source areas. However, climate change can increase fitness in the future, and therefore the interactions between climate change and fitness can boost the invasiveness of this alien species

Appendix A. A table showing significance of ecological thresholds in newt species, evaluated after removing from the data set ponds with fish.

A table showing significance of ecological thresholds in newt species, evaluated after removing from the data set ponds with fish

Cumulative effects of road de-icing salt on amphibian behavior

Despite growing evidence of the detrimental effect of chemical substances on organisms, limited research has focused on changes in behavioral patterns, in part due to the difficulties to obtain detailed quantitative data. Recent developments in efficient computer-based video analyses have allowed testing pesticide effects on model species such as the zebrafish. However, these new techniques have not yet been applied to amphibians and directly to conservation issues, i.e. to assess toxicological risks on threatened species. We used video tracking analyses to test a quantitative effect of an environmental contaminant on the locomotion of amphibian tadpoles (Rana temporaria) by taking into account cumulative effects. Because recent research has demonstrated effects of de-icing salts on survival and community structure, we used sodium chloride in our experimental design (25 replicates, 4 concentrations, 4 times) to test for an effect at the scale of behavior at environmentally relevant concentrations. Analysis of 372 1-hr video-tracks (5 samples per sec) showed a complex action of salts on behavioral patterns with a dose and cumulative response over time. Although no effects were found on mortality or growth, the highest salt concentrations reduced the speed and movement of tadpoles in comparison with control treatments. The reduced locomotor performance could have detrimental consequences in terms of tadpoles’ responses to competition and predation and may be an indicator of the low concentration effect of the contaminant. On one hand, this study demonstrates the usefulness of examining behavior to address conservation issues and understand the complex action of environmental factors and, more particularly, pollutants on organisms. On the other hand, our results highlight the need of new computerized techniques to quantitatively analyze these patterns

Data from: Genetic and ecological data reveal species boundaries between viviparous and oviparous lizard lineages

Identification of cryptic species is an essential aim for conservation biologists to avoid premature extinctions of ‘unrecognized’ species. Integrating different types of data can undoubtedly aid in resolving the issue of species delimitation. We studied here two lineages of the common lizard Zootoca vivipara that display different reproductive mode (the viviparous Z. v. vivipara and the oviparous Z. v. carniolica) and that overlap their distributional ranges in the European Alps. With the purpose of delimiting species’ boundaries, we analyzed their ecological, genetic and natural history features. More than 300 samples were collected and analyzed at cytochrome b and 11 microsatellites loci for investigating genetic variation, population structure, individual relatedness and evolutionary histories of the two lineages. Additionally, we compared their ecological niches using eight ecological variables. Genetic data showed contrasting patterns of genetic structure between the two lineages, different demographic dynamics and no hybridization events. Also strong ecological differences (such as temperature) emerged between the two lineages, and niche overlap was limited. Taken together, these results indicate that Z. v. vivipara and Z. v. carniolica should be recognized as two separate species, and particular conservation consideration should be given to the oviparous lineage that tends to live in areas threatened by increasing impact of human activities. However, recent and rapid climate warming might determine an increasing risk for the persistence of the viviparous lineage, being adapted to cold environments