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Invasive plants alter community structure, threatening ecosystem function and biodiversity, but little information is available on whether invasive species richness responds to environmental conditions in the same way that richness of native plants does. We surveyed submerged and floating-leaved plants in 99 Connecticut (northeast USA) lakes and ponds, collecting quantitative data on abundance and frequency. We used multiple linear and logistic regression to determine which environmental conditions were correlated with species richness of invasive and native plants. Independent variables included lake area, maximum depth, pH, alkalinity, conductivity, phosphorus concentration, productivity, and dominance (the proportional abundance of the most abundant and frequently found species), plus two estimates of human activity. Species richness of both native and invasive richness was correlated with alkalinity and human activity. Native richness also increased with water clarity, lake area, and productivity; invasive species richness also rose with pH. We found no evidence that richness of one group affected richness of the other. We also investigated patterns of dominance and found that native plants were as likely to become dominant as invasive species. Dominance occurred overwhelmingly in shallow lakes with high productivity. Key words: abiotic conditions, biodiversity, community structure, dominance, lakes, macrophyte. Les plantes envahissantes modifient la structure des communautes en menacant les fonctions des ecosystemes et leur biodiversite, mais on connait peu de chose a savoir si la richesse en especes envahissantes reagit aux conditions du milieu de la meme facon que la richesse en plantes indigenes. Les auteurs ont suivi les plantes submergees et a feuilles flottantes dans 99 lacs et etang du nord-est des Etats-Unis, en reunissant les donnees d'abondance et de frequence. Ils ont utilise la regression lineaire multiple et logistique pour determiner quelles conditions environnementales montrent une correlation avec les richesses en especes des plantes envahissantes et indigenes. Les variables independantes comprennent la surface des lacs, la profondeur maximum, le pH, l'alcalinite, la conductivite, la teneur en phosphore, la productivite et la dominance (l' abondance proportionnelle des especes les plus frequentes et les plus abondantes), ainsi que deux valeurs estimees pour l'activite humaine. La richesse en especes indigenes aussi bien qu'en especes envahissantes montre une correlation avec l'alcalinite et l'activite humaine. La richesse en especes indigenes augmente egalement avec la clarte de l'eau, la surface du lac et la productivite; la richesse en especes adventices augmente aussi avec le pH. On ne percoit aucune preuve que la richesse d'un groupe affecte la richesse de l'autre. Les auteurs ont egalement examine le patron de la dominance pour constater que les plantes indigenes ont autant de chance de devenir dominantes que les especes envahissantes. On retrouve la dominance surtout dans les lacs peu profonds a forte productivite. Mots-cles : conditions abiotiques, biodiversite, structure des communautes, dominance, lacs, macrophytes. [Traduit par la Redaction], Introduction Invasive plants are an economic and ecological problem in many aquatic systems (Pimentel et al. 2005). They can dominate lakes, interfering with recreation and reducing real estate values (Bergstrom [...]

As the science community has recognized the vital role of communicating to the public, science communication training has proliferated. The development of rigorous, comparable approaches to assessment of training has not kept pace. We conducted a fully controlled experiment using a semester-long science communication course, and audience assessment of communicator performance. Evaluators scored the communication competence of trainees and their matched, untrained controls, before and after training. Bayesian analysis of the data showed very small gains in communication skills of trainees, and no difference from untrained controls. High variance in scores suggests little agreement on what constitutes "good" communication. [ABSTRACT FROM AUTHOR]

The article discusses the significance of knowing and understanding the truth about U.S. slavery before going to the reconciliation process. The author believes that acknowledging that a mistake was done and apologizing for it, are necessary, but these are not enough conditions for reconciliation. He said that both an apology and attempt to correct the wrong done in the past through reparations are needed to achieve reconciliation. However in the case of U.S. slavery which happened more than 100 years ago, he argues, that it is premature to think about reparations because the nation doesn't know enough of slavery, therefore, it also doesn't know what it has to apologize for, and any apology which is not based on full understanding of the mistakes done would just be meaningless.