11 research outputs found

    No signs of inbreeding despite long-term isolation and habitat fragmentation in the critically endangered Montseny brook newt (Calotriton arnoldi)

    Get PDF
    Endemic species with restricted geographic ranges potentially suffer the highest risk of extinction. If these species are further fragmented into genetically isolated subpopulations, the risk of extinction is elevated. Habitat fragmentation is generally considered to have negative effects on species survival, despite some evidence for neutral or even positive effects. Typically, non-negative effects are ignored by conservation biology. The Montseny brook newt (Calotriton arnoldi) has one of the smallest distribution ranges of any European amphibian (8 km2) and is considered critically endangered by the International Union for Conservation of Nature. Here we apply molecular markers to analyze its population structure and find that habitat fragmentation owing to a natural barrier has resulted in strong genetic division of populations into two sectors, with no detectable migration between sites. Although effective population size estimates suggest low values for all populations, we found low levels of inbreeding and relatedness between individuals within populations. Moreover, C. arnoldi displays similar levels of genetic diversity to its sister species Calotriton asper, from which it separated around 1.5 million years ago and which has a much larger distribution range. Our extensive study shows that natural habitat fragmentation does not result in negative genetic effects, such as the loss of genetic diversity and inbreeding on an evolutionary timescale. We hypothesize that species in such conditions may evolve strategies (for example, special mating preferences) to mitigate the effects of small population sizes. However, it should be stressed that the influence of natural habitat fragmentation on an evolutionary timescale should not be conflated with anthropogenic habitat loss or degradation when considering conservation strategies

    Elementy edukacji prośrodowiskowej w nowej podstawie programowej przedmiotu chemia oraz w wybranych podręcznikach do nauczania chemii dla III i IV etapu kształcenia

    No full text
    In 2009 the Ministry of National Education introduced a new core curriculum for general education in Poland which completely transformed environmental education at ISCED 2 (Polish: gimnazjum, junior high school) and ISCED 3 (post-gimnazjum, senior high schools of different types) stages. Considering the immense impact of chemical substances on the state of global nature, the curriculum for chemistry plays a pivotal role in the development of environmental knowledge and pro-environmental attitudes among students in Polish schools. There is no doubts that not only are chemistry textbooks the basic source of scientific knowledge for students, but they also inspire teachers during class preparation. The educational reform created a need for updating chemistry textbooks according to new core curriculum. The aim of this work was to investigate the coherence between elements of environmental education required by core curriculum and the depiction of these issues proposed in textbooks. Textbooks of major Polish educational publishers for junior and senior secondary schools at basic level were analyzed. The results of this study show that all examined textbooks are coherent with environmental issues included in the program fundamentals, but they also give additional pieces of information when needed, even when such content is not precisely defined in the core curriculum (eg organic chemical waste problems). The comparison of selected textbooks provided information on the present state of education reform implementation and on what could be improved or clarified in the new core curriculum regarding environmental problems.W 2009 roku Ministerstwo Edukacji Narodowej wprowadziło nową podstawę programową kształcenia ogólnego w Polsce, która przekształciła całkowicie edukację środowiskową na III (gimnazjum) i IV (szkoły ponadgimnazjalne) etapie kształcenia. Biorąc pod uwagę ogromny wpływ substancji chemicznych na stan środowiska naturalnego, podstawa programowa przedmiotu chemia pełni istotną rolę w rozwijaniu wiedzy środowiskowej oraz postaw prośrodowiskowych wśród uczniów polskich szkół. Bez wątpienia, podręczniki chemiczne są nie tylko podstawowym źródłem wiedzy naukowej dla uczniów, ale także inspiracją dla nauczycieli przygotowujących zajęcia lekcyjne. Reforma edukacyjna narzuciła konieczność zaktualizowania podręczników do nauki chemii zgodnie z nową podstawą programową. Celem niniejszej pracy było zbadanie spójności elementów edukacji prośrodowiskowej wymaganych w nowej podstawie programowej z omówieniem tych zagadnień zaproponowanym w wybranych podręcznikach. Analizie poddano podręczniki dla szkół gimnazjalnych i ponadgimnazjalnych (zakres podstawowy) wydane przez największe polskie wydawnictwa edukacyjne. Wyniki tego badania wskazują, że wszystkie analizowane podręczniki są zgodne z treściami kształcenia prośrodowiskowego zawartymi w podstawie programowej, a jeśli to konieczne, zawierają także dodatkowe wiadomości nieujęte podstawą programową (np. problemy z odpadami związków organicznych). Porównanie M. Musialik, M.M. Chrzanowski, I. Buczek, E.B. Arèvalo-Garcia and B. Ostrowska 142 wybranych podręczników dostarczyło informacji o stanie obecnym wdrażania reformy edukacyjnej oraz o elementach nowej podstawy programowej dotyczących problemów środowiskowych, które warto poprawić lub uściślić

    The soft-X-ray emission of Ark 120. XMM-Newton, NuSTAR, and the importance of taking the broad view

    Get PDF
    We present simultaneous XMM-Newton and NuSTAR observations of the `bare' Seyfert 1 galaxy, Ark 120, a system in which ionized absorption is absent. The NuSTAR hard X-ray spectral coverage allows us to constrain different models for the excess soft X-ray emission. Among phenomenological models, a cutoff power law best explains the soft X-ray emission. This model likely corresponds to Comptonization of the accretion disk seed UV photons by a population of warm electrons: using Comptonization models, a temperature of ~0.3 keV and an optical depth of ~13 are found. If the UV-to-X-ray optxagnf model is applied, the UV fluxes from the XMM-NewtonNewton Optical Monitor suggest an intermediate black hole spin. Contrary to several other sources observed by NuSTAR, no high energy cutoff is detected, with a lower limit of 190 keV.Comment: 6 pages. Accepted for publication in MNRA

    Connectivity in grey reef sharks (Carcharhinus amblyrhynchos) determined using empirical and simulated genetic data

    Get PDF
    Grey reef sharks (Carcharhinus amblyrhynchos) can be one of the numerically dominant high order predators on pristine coral reefs, yet their numbers have declined even in the highly regulated Australian Great Barrier Reef (GBR) Marine Park. Knowledge of both large scale and fine scale genetic connectivity of grey reef sharks is essential for their effective management, but no genetic data are yet available. We investigated grey reef shark genetic structure in the GBR across a 1200km latitudinal gradient, comparing empirical data with models simulating different levels of migration. The empirical data did not reveal any genetic structuring along the entire latitudinal gradient sampled, suggesting regular widespread dispersal and gene flow of the species throughout most of the GBR. Our simulated datasets indicate that even with substantial migrations (up to 25% of individuals migrating between neighboring reefs) both large scale genetic structure and genotypic spatial autocorrelation at the reef scale were maintained. We suggest that present migration rates therefore exceed this level. These findings have important implications regarding the effectiveness of networks of spatially discontinuous Marine Protected Areas to protect reef sharks

    Genetic structure and signatures of selection in grey reef sharks (Carcharhinus amblyrhynchos)

    No full text
    With overfishing reducing the abundance of marine predators in multiple marine ecosystems, knowledge of genetic structure and local adaptation may provide valuable information to assist sustainable management. Despite recent technological advances, most studies on sharks have used small sets of neutral markers to describe their genetic structure. We used 5517 nuclear single-nucleotide polymorphisms (SNPs) and a mitochondrial DNA (mtDNA) gene to characterize patterns of genetic structure and detect signatures of selection in grey reef sharks (Carcharhinus amblyrhynchos). Using samples from Australia, Indonesia and oceanic reefs in the Indian Ocean, we established that large oceanic distances represent barriers to gene flow, whereas genetic differentiation on continental shelves follows an isolation by distance model. In Australia and Indonesia differentiation at nuclear SNPs was weak, with coral reefs acting as stepping stones maintaining connectivity across large distances. Differentiation of mtDNA was stronger, and more pronounced in females, suggesting sex-biased dispersal. Four independent tests identified a set of loci putatively under selection, indicating that grey reef sharks in eastern Australia are likely under different selective pressures to those in western Australia and Indonesia. Genetic distances averaged across all loci were uncorrelated with genetic distances calculated from outlier loci, supporting the conclusion that different processes underpin genetic divergence in these two data sets. This pattern of heterogeneous genomic differentiation, suggestive of local adaptation, has implications for the conservation of grey reef sharks; furthermore, it highlights that marine species showing little genetic differentiation at neutral loci may exhibit patterns of cryptic genetic structure driven by local selection

    Population expansion and genetic structure in Carcharhinus brevipinna in the southern Indo-Pacific

    Get PDF
    Background: Quantifying genetic diversity and metapopulation structure provides insights into the evolutionary history of a species and helps develop appropriate management strategies. We provide the first assessment of genetic structure in spinner sharks (Carcharhinus brevipinna), a large cosmopolitan carcharhinid, sampled from eastern and northern Australia and South Africa.\ud \ud Methods and Findings: Sequencing of the mitochondrial DNA NADH dehydrogenase subunit 4 gene for 430 individuals revealed 37 haplotypes and moderately high haplotype diversity (h = 0.6770 ±0.025). While two metrics of genetic divergence (Φ(ST) and F(ST)) revealed somewhat different results, subdivision was detected between South Africa and all Australian locations (pairwise Φ(ST), range 0.02717–0.03508, p values ≤ 0.0013; pairwise F(ST) South Africa vs New South Wales = 0.04056, p = 0.0008). Evidence for fine-scale genetic structuring was also detected along Australia's east coast (pairwise Φ(ST) = 0.01328, p < 0.015), and between south-eastern and northern locations (pairwise Φ(ST) = 0.00669, p < 0.04).\ud \ud Conclusions: The Indian Ocean represents a robust barrier to contemporary gene flow in C. brevipinna between Australia and South Africa. Gene flow also appears restricted along a continuous continental margin in this species, with data tentatively suggesting the delineation of two management units within Australian waters. Further sampling, however, is required for a more robust evaluation of the latter finding. Evidence indicates that all sampled populations were shaped by a substantial demographic expansion event, with the resultant high genetic diversity being cause for optimism when considering conservation of this commercially-targeted species in the southern Indo-Pacific
    corecore