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River flow regulation, fragmentation, and changes in water quality caused by dams have varying effects on aquatic biodiversity and ecosystem functions, but are not clearly resolved in boreal ecosystems. We adopted a multiscale approach to quantify fish community trajectories over 20 years using a network of sites spread across four reservoirs in two hydroelectricity complexes in northern Quebec, where other anthropogenic factors have been negligible. Across three spatial scales, we found little evidence of directional temporal trends in diversity relative to reference sites. Using beta-diversity analyses, we also detected a high degree of stability in fish composition over time and space at the complex and reservoir scales. However, changes in species assemblage following impoundment were detected at the scale of the sampling station. At this scale, we found that some species consistently benefited (coregonids and pikes) from impoundment, whereas others were detrimentally affected (suckers and one salmonid). Overall, we conclude that examining different scales is key when trying to understand the impacts of humans on biodiversity and in formulating management recommendations. La regulation du debit des rivieres, la fragmentation et les variations de la qualite de l'eau causees par les barrages ont des effets variables sur la biodiversite aquatique et les fonctions des ecosystemes, cependant, la comprehension de ces processus dans les ecosystemes boreaux est limitee. Nous avons adopte une approche a multi-echelles pour quantifier les trajectoires de communautes de poissons sur une periode de 20 ans en utilisant un reseau de sites repartis dans quatre reservoirs et deux complexes hydroelectriques dans le nord du Quebec, ou les effets d'autres facteurs anthropiques ont ete negligeables. Nous avons trouve peu d'indices de tendances temporelles directionnelles de la diversite par rapport a des sites de reference. En utilisant des analyses de la diversite beta, nous avons en outre detecte un degre eleve de stabilite de la composition de poissons dans le temps et l'espace a l'echelle du complexe et du reservoir, et ce aux trois echelles spatiales. Des variations dans l'assemblage des especes de poissons apres l'endiguement ont toutefois ete decelees a l'echelle de la station d'echantillonnage. A cette echelle, nous avons constate que l'endiguement s'avere avantageux pour certaines especes (coregonides et brochets), mais nefaste pour d'autres especes (meuniers et un salmonide). Globalement, nous concluons que l'examen a differentes echelles revet une importance cle pour la comprehension des impacts des humains sur la biodiversite et pour la formulation de recommandations de gestion. [Traduit par la Redaction], Introduction In response to increased demand for energy, many large hydroelectric dams are currently in operation or are being constructed (Grill et al. 2015; Winemiller et al. 2016). Dams such [...]

Forest attributes such as volume or basal area are concentrated at tree locations and are absent elsewhere. It is, therefore, more meaningful to consider the amount of forest attributes at a prefixed spatial grain, within regular plots of prefixed size centered at the points of the study area. In this way, the diversity of attributes within plots also can be considered and quantified by suitable indexes, giving rise to a diversity surface defined on the continuum of points constituting the area. We analyze the estimation of diversity surfaces when a sample of plots is selected by a probabilistic sampling scheme and diversity within nonsampled plots is estimated using an inverse distance weighting interpolator. We discuss the design-based asymptotic properties of the resulting maps when the survey area remains fixed and the number of sampled points increases. Because diversity surfaces share suitable mathematical properties, if the schemes adopted to select sample points ensure an even coverage of the study areas avoiding large portions of non-sampled zones, it can be proven that the estimated maps approach the true maps. Key words: diversity maps, inverse distance weighting interpolator, design-based consistency, spatial simulation, case study. Les attributs de la foret comme le volume ou la surface terriere sont concentres a l'emplacement des arbres et sont absents ailleurs. Par consequent, il est plus significatif de considerer la quantite des attributs de la foret a une resolution spatiale predeterminee, dans des parcelles regulieres de taille predeterminee, centrees sur les points de la zone d'etude. De cette maniere, la diversite des attributs au sein des parcelles peut egalement etre prise en compte et quantifiee a l'aide d'indices appropries, donnant lieu a une surface de diversite definie sur le continuum de points constituant la superficie a l'etude. Nous analysons l'estimation des surfaces de diversite lorsqu'un echantillon de parcelles est selectionne au moyen d'un plan d'echantillonnage probabiliste et que la diversite au sein de parcelles non echantillonnees est estimee a l'aide d'un interpolateur pondere par l'inverse de la distance. Nous discutons des proprietes asymptotiques des cartes obtenues, qui resultent du plan d'experience, lorsque la zone d'inventaire demeure fixe et que le nombre de points echantillonnes augmente. Puisque les surfaces de diversite partagent des proprietes mathematiques appropriees, si les plans d'echantillonnage adoptes pour selectionner les points d'echantillonnage assurent une couverture uniforme des zones d'etude, en evitant de laisser de larges portions non echantillonnees, on peut demontrer que les cartes estimees se rapprochent des vraies cartes. [Traduit par la Redaction] Mots-cles : cartes de diversite, interpolateur pondere par l'inverse de la distance, coherence basee sur la conception du plan d'experience, simulation spatiale, etude de cas., Introduction Spatially explicit estimates are needed in many environmental and ecological applications for making maps: the increasing practical demand is for information on the spatial distribution of environmental and ecological [...]

The purpose of this study was to determine whether the A horizon (topsoil) exhibits stratification across two depths, 1 cm and 4 cm. Two sites in San Antonio, TX, were chosen to address this question. The first was on the campus of the University of the Incarnate Word. The second was adjacent to the university in the Headwaters Sanctuary. At each locality, soil samples were analyzed in order to examine the morphological diversity of bacteria across site and depth. Preliminary results suggest that the bacterial biodiversity is different when depths are considered as a single entity versus individually. These finding have implications for investigations into soil biodiversity and suggest that in order to gain an accurate estimate of bacterial biodiversity in topsoil multiple depths within this layer of soil should be examined. Keywords: 16S rRNA, biodiversity, bacteria, topsoil, stratification, A horizon, In any ecosystem, terrestrial or aquatic, microorganisms, such as bacteria or fungi, are the most prevalent and diverse organisms present (Whitman et al. 1998; Torsvik et al. 2002; Kemp & [...]

To identify stable and productive Eucalyptus urophylla S.T. Blake families across diverse climate zones in Brazil, we evaluated growth and survival of 322 open-pollinated families derived from 13 genetically improved seed sources in 10 trials across the country. Survival and growth data were analyzed using linear mixed models and REML/BLUP. Survival ranged from 51% to 92%, and the mean annual increment varied from 19 to 46 [m.sup.3] x [ha.sup-1] x [year.sup.-1]. Although planted in suitable climatic zones, some trials had low survival and (or) productivity. Conversely, the highest productivity was recorded in a zone considered to be of low suitability. These results show the importance of assessing the climatic requirements of eucalypts beyond those determined from analyses of their natural distribution, especially when testing already improved seed sources. A number of productive and stable families were identified based on analysis of the interaction between genotype and environment, and from these, 144 individuals were selected and had their genetic diversity estimated using 19 microsatellite DNA markers. The genetic diversity of these selected trees was equivalent to that observed in previous studies of natural populations of E. urophylla, indicating that breeding programs of E. urophylla in Brazil still retain high levels of diversity for sustainable genetic gains.Key words: genotype-environment interaction, productivity and stability, family selection, genetic diversity, abiotic and biotic stress.De facon a identifier des familles d'Eucalyptus urophylla S.T. Blake stables et productives pour diverses zones climatiques du Bresil, nous avons evalue la croissance et la survie de 322 familles a pollinisation libre provenant de 13 sources de semences genetiquement ameliorees deployees dans 10 stations reparties dans tout le pays. Les donnees de survie et de croissance ont ete analysees a l'aide de modeles lineaires mixtes et d'approches par le maximum de vraisemblance restreinte et par le meilleur predicteur lineaire non biaise. La survie variait de 51 a 92 % et l'accroissement annuel moyen de 19 a 46 [m.sup.3]x[ha.sup.-1]x[an.sup.-1]. Bien que les familles aient ete plantees dans des zones climatiques favorables, la survie ou la productivite etaient faibles dans certaines stations. A l'inverse, la plus forte productivite a ete observee dans une zone consideree comme etant peu favorable. Ces resultats montrent l'importance d'evaluer les exigences climatiques des eucalyptus au-dela de celles qui sont determinees par l'analyse de leur repartition naturelle, surtout lorsqu'on teste des sources de semences deja ameliorees. Un certain nombre de familles productives et stables ont ete identifiees sur la base de l'analyse de l'interaction entre le genotype et l'environnement. Parmi celles-ci, 144 individus ont ete selectionnes pour estimer leur diversite genetique a l'aide de 19 marqueurs d'ADN microsatellites. La diversite genetique de ces arbres selectionnes etait equivalente a celle observee lors d'etudes precedentes portant sur les populations naturelles d'E. urophylla, ce qui indique que les programmes de selection d'E. urophylla au Bresil conservent toujours des niveaux eleves de diversite pour des gains genetiques durables. [Traduit par la Redaction]Mots-cles : interaction entre la genetique et l'environnement, productivite et stabilite, selection de familles, diversite genetique, stress biotiques et abiotiques., IntroductionEucalyptus urophylla S.T. Blake (Timor mountain gum) is one of the most economically important forest trees in the world, planted both as a pure species and in hybrid combinations (Denison [...]

The Amazon is one of the few independent centres of plant domestication in the world, yet archaeological and ethnographic evidence suggest a relatively recent transition to agriculture there. In order to make sense of this time lag, the authors propose the use of the concept of familiarisation ' instead of 'domestication', to explain Amazonian plant management, and the long-term relationship betiveen plants and people in the region. This concept allows them to cast a fresh eye over ancient and contemporary patterns of plant cultivation and management that may be distinct to the ones described for the Old World.Keywords: Amazonia, plant domestication, cultivation, familiarisation, It is widely accepted that Amazonia was an independent centre of plant domestication (Piperno 2011; Clement et al. 2015). Archaeological and ethnographic data on plant cultivation and management in this [...]

Ectomycorrhizal (ECM) fungi are obligate symbionts of dominant vascular plants, liverworts and hornworts. There are reports of about 20,000 to 25,000 ECM fungi that promote plant growth by facilitating enhanced water and nutrient absorption, and provide tolerance to environmental stresses. These below-ground fungi play a key role in terrestrial ecosystems as they regulate plant diversity, nutrient and carbon cycles, and influence soil structure and ecosystem multifunctionality. Because ECM fungi are obligate root symbionts, host plant can have a strong effect on ECM species richness and community composition. The biogeographic pattern and detailed functioning and regulation of these mycorrhizosphere processes are still poorly understood and require detailed study. More recent researches have placed emphasis on a wider, multifunctional perspective, including the effects of ectomycorrhizal symbiosis on plant and microbial communities, and on ecosystem processes. Over the years the main focus in ECM research has been on the study of diversity and specificity of ECM strains, the role of ECM in regeneration of degraded ecosystem, the growth and establishment of seedlings through nutrient acquisition and the mediation of plant responses to various types of stress. In this review, recent progresses in ectomycorrhizal biology are presented, especially the potential role of ECM symbioses in resistance or tolerance to various biotic and abiotic stresses, and in maintinance of plant diversity for proper ecosystem functioning. Keywords Ectomycorrhizal symbiosis * Ecosystem * Evolution * ECM diversity * Afforestation, Introduction It was Albert Bernard Frank (1885), a forest pathologist, who for the first time introduced the term mycorrhiza. In Greek language 'mykes' refers to Fungus and 'rhiza' refers to [...]

This paper examines the relationship between immigrants' genetic diversity and economic development in the United States during the late nineteenth and the beginning of the twentieth centuries, a period commonly referred to as the age of mass migration from Europe to the New World. Our panel model estimates show that during this period, immigrants' genetic diversity is significantly positively correlated with measures of U.S. counties' economic development. There exists also a significant positive relationship between immigrants' genetic diversity in 1870 and contemporaneous measures of U.S. counties' average income. (JEL J11, O51, Z13), I. INTRODUCTION Genetic diversity has been attributed an important role in explaining why there still exist persistent disparities in economic development across the globe (Ashraf and Galor 2016; Spolaore and [...]

Advances in biotechnology mean that it may soon be possible to recreate previously extinct species. This has led to an emerging debate within bioethics about whether we ought to reintroduce extinct species into our ecosystems. In this paper, we discuss the role that biodiversity could play in this debate. Many believe that biodiversity is a good that should be protected. We argue that if biodiversity is a good, then this suggests it should also be promoted, including by reintroducing previously extinct species. We begin by outlining different ways in which biodiversity could be conceptualized, and then analyze various accounts of its value. We suggest no approach justifies an asymmetry between 'protecting' biodiversity by conserving species alive today, and 'creating' biodiversity by introducing previously extinct species. This suggests that if we have reasons stemming from biodiversity to protect species from extinction, we will have similar reasons to reintroduce previously extinct species. We close by asking whether arguments from biodiversity speak in favor of introducing some novel species into the ecosystem., Author(s): Christopher Gyngell [sup.1] , Julian Savulescu [sup.1] [sup.2] Author Affiliations: (1) Oxford Uehiro Centre for Practical Ethics, Oxford University, 0000 0004 1936 8948, grid.4991.5, , Oxford, UK (2) School [...]

In spring 2016, highly pathogenic avian influenza (HPAI) outbreaks caused by the H5N8 subtype of clade 2.3.4.4 (group B) were reported in migratory wild birds in Qinghai Lake, China (1), [...]

Abstract: The emergence of next generation sequencing has increased by several orders of magnitude the amount of data available for phylogenetics. Reduced representation approaches, such as restriction-sited associated DNA sequencing [...]

ABSTRACT Understanding the population structure of a commercially fished species and how those populations change over time is essential for proper management. Although the blue crab Callinectes sapidus (Rathbun, 1896) [...]

We analyzed data from a woodland site for a 59-year period to determine whether changes in bird populations are related to changes in the diversity and relative abundance of woody plant species even when vegetation structure, degree of forest fragmentation in the surrounding landscape, and regional changes in bird populations are taken into account. Principal component analyses generated vegetation factors encompassing variables such as total basal area, shrub density, basal area of common tree species, and measures of tree and shrub species diversity. We also calculated a forest edge/forest area index based on GIS analysis of the landscape within 2 km of the study site. Poisson regression models revealed relationships between these covariates and population changes for 19 bird species and for seven groups of species characterized by similar migration strategies or habitat requirements. All groups of habitat specialists showed a positive relationship with the first vegetation factor, which indicates that they declined as total basal area and dominance of oaks and maples increased and as tree and shrub diversity decreased. This suggests that floristic diversity may be important for determining habitat quality. Bird species associated with the shrub layer and with hemlock stands showed positive relationships with the second vegetation factor, suggesting that the recent decline in eastern hemlocks (Tsuga canadensis) because of hemlock woolly adelgid (Adelges tsugae) had an adverse impact on these species. Forest migrants, shrub-layer specialists, long-distance migrants and permanent residents showed negative relationships with the forest edge/forest interior index, indicating that conservation efforts to protect bird communities should take the wider landscape into account. The strongest relationship for most species and species groups was with the first vegetation factor, which suggests that species composition and diversity of trees and shrubs may be especially important in determining abundance of many forest birdspecies. Received 26 June 2015. Accepted 4 February 2016. Key words: bird population declines, forest birds, forest fragmentation, hemlock decline, tree species composition., Long-term monitoring of populations at particular study sites can provide new insights about the main drivers of population change, particularly if the environment within and around the site is monitored. [...]

Background Arcobacter constitute emerging food- and waterborne pathogens causing gastroenteritis in humans, but the underlying mechanisms are only incompletely understood. We therefore characterized Arcobacter isolates derived from human stool samples that had been collected during a prospective prevalence study in Germany in vitro. Thirty-six bacterial isolates belonging to the species A. butzleri (n = 24), A. cryaerophilus (n = 10) and A. lanthieri (n = 2) were genotyped by ERIC-PCR, the presence of 10 putative virulence genes was assessed and cytotoxic effects on the human intestinal cell line HT-29/B6 were analyzed applying the WST-assay. Results Genotyping revealed high genetic diversity within the species A. butzleri, A. cryaerophilus and A. lanthieri. Both, A. butzleri and A. lanthieri encoded for a large number of putative virulence genes, while fewer genes were detectable in A. cryaerophilus isolates. Notably, the three cytolethal distending toxin (CDT) genes cdtA, cdtB and cdtC were abundant in both A. lanthieri isolates. Furthermore, all A. butzleri and A. lanthieri, but only one of the A. cryaerophilus isolates exerted cytotoxic effects. Conclusions Our study provides evidence for the abundance of putative virulence genes in Arcobacter isolates and prominent cytotoxic effects of A. butzleri and A. lanthieri in vitro. The presence of cdtA, cdtB, cdtC in A. lanthieri points towards CDT secretion as potential mechanism underlying cytotoxicity as opposed to A. butzleri. However, the association of the Arcobacter virulence factors detected and human morbidity should be addressed in future studies. Keywords: Arcobacter, Human, Cytotoxicity, Virulence genes, Genotyping, Author(s): Vanessa Brückner[sup.1], Ulrike Fiebiger[sup.2], Ralf Ignatius[sup.2,3], Johannes Friesen[sup.3], Martin Eisenblätter[sup.4], Marlies Höck[sup.5], Thomas Alter[sup.1], Stefan Bereswill[sup.2], Markus M. Heimesaat[sup.2] and Greta Gölz[sup.1] Background Arcobacter constitute Gram-negative, motile bacilli belonging [...]

Despite the crucial role of epibenthic primary producers (cyanobacteria, green and red algae), no diversity curves for calcimicrobes and calcareous algae are available to assess the pyramiding paleoecology characterizing the [...]

White-nose syndrome is rapidly spreading in eastern North America, causing mass mortality of hibernating bats. We characterized levels of genetic diversity and population structure of the little brown bat (Myotis lucifugus (Le Conte, 1831)) in eastern Canada to infer the extent to which oceanic straits may be barriers to movement. To quantify metrics of gene flow and infer movement dynamics, we genotyped 679 M. lucifugus at nine nuclear microsatellites (nDNA) and sequenced a portion of the mitochondrial DNA (mtDNA). We found high levels of genetic diversity and little population structure, with [approximately equal to]13-fold higher differentiation of mtDNA than nDNA markers, suggesting that structuring patterns largely result from female philopatry. Discriminant analysis of principle components suggested that the subtle underlying structure was not concordant with sampling site. Regional differentiation ([F.sub.ST], [D.sub.est], Mantel test residuals) is mostly consistent with genetic isolation by distance. However, samples from Newfoundland showed genetic differentiation over and above the effects of distance, lower levels of genetic diversity, and less genetic connectivity with other sampled regions. Despite this, oceanic straits in the Gulf of Saint Lawrence do not appear to create an impenetrable barrier to movement, therefore it may be possible for white-nose syndrome to spread to Newfoundland. Key words: Myotis lucifugus, little brown bat, population structure, geographic barrier, white-nose syndrome. Le syndrome du museau blanc se propage rapidement dans l'est de l'Amerique du Nord, entrainant une mortalite massive des chauves-souris hibernantes. Nous avons caracterise les degres de diversite genetique et la structure de la population du vespertilion brun (Myotis lucifugus (Le Conte, 1831)) dans l'est du Canada afin d'inferer la mesure dans laquelle les detroits oceaniques pourraient constituer des barrieres aux deplacements. Pour quantifier le flux genetique et inferer la dynamique des deplacements, nous avons effectue le genotypage de 679 M. lucifugus en neuf microsatellites nucleaires (ADNn) et le sequencage d'une portion d'ADN mitochondrial (ADNmt). Nous avons observe des degres eleves de diversite genetique et peu de structure de la population, les marqueurs d'ADNmt presentant une differentiation [approximately equal to]13 fois superieure a celle des marqueurs d'ADNn, ce qui donne a penser que les motifs de structuration decoulent en bonne partie de la philopatrie des femelles. L'analyse discriminante des composantes principales suggere que la subtile structure sous-jacente n'est pas reliee au lieu d'echantillonnage. La differentiation regionale ([F.sub.ST], [D.sub.est], residus du test de Mantel) refleterait principalement un isolement genetique par la distance. Toutefois, des echantillons provenant de Terre-Neuve presentment une differentiation genetique allant au-dela des seuls effets de la distance, des degres de diversite genetique plus faibles et moins de connectivite genetique avec les autres regions echantillonnees. Les detroits oceaniques dans le golfe du Saint-Laurent ne semblent neanmoins pas constituer une barriere impenetrable aux deplacements, de sorte qu'il est possible que le syndrome du museau blanc se propage a Terre-Neuve. [Traduit par la Redaction] Mots-cles: Myotis lucifugus, vespertilion brun, structure de la population, barriere geographique, syndrome du museau blanc., Introduction While many species have patterns of population structure consistent with isolation by distance (IBD) on mainlands (Allendorf and Luikart 2007), the extent to which oceanic straits impede movement between [...]

A major challenge in theoretical ecology is understanding how natural microbial communities support species diversity (1-8), and in particular how antibiotic-producing, -sensitive and -resistant species coexist (9-15). While cyclic 'rock-paper-scissors' interactions can stabilize communities in spatial environments (9-11), coexistence in unstructured environments remains unexplained (12,16). Here, using simulations and analytical models, we show that the opposing actions of antibiotic production and degradation enable coexistence even in well-mixed environments. Coexistence depends on three-way interactions in which an antibiotic-degrading species attenuates the inhibitory interactions between two other species. These interactions enable coexistence that is robust to substantial differences in inherent species growth rates and to invasion by 'cheating' species that cease to produce or degrade antibiotics. At least two antibiotics are required for stability, with greater numbers of antibiotics enabling more complex communities and diverse dynamic behaviours ranging from stable fixed points to limit cycles and chaos. Together, these results show how multi-species antibiotic interactions can generate ecological stability in both spatially structured and mixed microbial communities, suggesting strategies for engineering synthetic ecosystems and highlighting the importance of toxin production and degradation for microbial biodiversity., Antibiotic-producing species are common in natural microbial communities (13,17,18). Ecological models of antibiotics typically assume pairwise species relationships, where antibiotic producers inhibit sensitive species more than resistant species. These pairwise [...]

Byline: A. Sheikh, M. M. M. Ahmed, M. H. Z. Mutwakil, K. S. Saini, F. A. S. Alsulaimany, A. A EL Hanafy and J. S. M. Sabir Abstract Microsatellites are [...]

Byline: S. Joezy-Shekalgorabi, A. Maghsoudi, A. Taheri-Yeganeh and B. Rajabi-Marand Abstract In the current research, genetic diversity of Iranian Adani dairy goat was assessed utilizing pedigree analysis. Pedigree records from [...]