TOLD LIKE IT IS! AN EVALUATION OF AN INTEGRATED ORAL DEVELOPMENT PILOT PROJECT

Much established pedagogical and CALL (computer-assisted language learning) research advocates an integrated constructivist approach to the use of technology in language learning. This paper reports on a pilot project delivered to first year undergraduate French students. The project aim was to deliver a blend of collaborative and individual learning through a combination of CALL programs and online activities alongside traditional face-to-face conversation classes. Using quantitative analysis of a pre- and posttest and a variety of questionnaires, this project assessed student progress in developing oral skills across two groups, one (the treatment group) using technology and the other (the comparison group) being a traditional conversation class. Each group covered the same content and underwent the same assessment procedures. In addition, through qualitative analysis measures, the project evaluated the role played by additional variables in the learning process, as well as student and staff reactions to the two approaches. The study concludes by showing that while progress was made by both groups, the progress made by those not using technology was significantly greater than that made by students using technology over a short-term study. It also highlights the need for developing pedagogy to ensure that CALL-based teaching goes beyond rehearsal activity to achieve message-orientated communication

Herbivores and nutrients control grassland plant diversity via light limitation

Human alterations to nutrient cycles[superscript 1,2] and herbivore communities³⁻⁷ are affecting global biodiversity dramatically². Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems[superscript 8,9]. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light.This is the publisher’s final pdf. The published article is copyrighted by the Nature Publishing Group and can be found at: http://www.nature.com/nature/index.htm

Predicting invasion in grassland ecosystems: is exotic dominance the real embarrassment of richness?

Invasions have increased the size of regional species pools, but are typically assumed to reduce native diversity. However, global-scale tests of this assumption have been elusive because of the focus on exotic species richness, rather than relative abundance. This is problematic because low invader richness can indicate invasion resistance by the native community or, alternatively, dominance by a single exotic species. Here, we used a globally replicated study to quantify relationships between exotic richness and abundance in grass-dominated ecosystems in 13 countries on six continents, ranging from salt marshes to alpine tundra. We tested effects of human land use, native community diversity, herbivore pressure, and nutrient limitation on exotic plant dominance. Despite its widespread use, exotic richness was a poor proxy for exotic dominance at low exotic richness, because sites that contained few exotic species ranged from relatively pristine (low exotic richness and cover) to almost completely exotic-dominated ones (low exotic richness but high exotic cover). Both exotic cover and richness were predicted by native plant diversity (native grass richness) and land use (distance to cultivation). Although climate was important for predicting both exotic cover and richness, climatic factors predicting cover (precipitation variability) differed from those predicting richness (maximum temperature and mean temperature in the wettest quarter). Herbivory and nutrient limitation did not predict exotic richness or cover. Exotic dominance was greatest in areas with low native grass richness at the site- or regional-scale. Although this could reflect native grass displacement, a lack of biotic resistance is a more likely explanation, given that grasses comprise the most aggressive invaders. These findings underscore the need to move beyond richness as a surrogate for the extent of invasion, because this metric confounds monodominance with invasion resistance. Monitoring species’ relative abundance will more rapidly advance our understanding of invasions.This is the publisher’s final pdf. The published article is copyrighted by John Wiley & Sons Ltd and can be found at: http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-2486

Microbial dynamics in coastal waters of East Antarctica:bacterial production and nanoflagellate bacterivory

Bacterial production and heterotrophic nanoflagellate (HNAN) bacterivory were determined concurrently with measurements of abundance and biomass at weekly intervals between 30 December 1993 and 11 February 1994 at a shallow, coastal location in Prydz Bay, eastern Antarctica. Bacterial production was measured by [3H]thymidine incorporation and HNAN bacterivory by the uptake of fluorescently labelled bacteria. Bacterial abundance, biomass and production ranged from 2 to 8 x 108 l-1, 13 to 64 µg C l-1 and 8 to 14 µg C l-1 d-1, respectively, with maximum values recorded in mid January. The HNAN community comprised choanoflagellate, non-collared and colonial taxa, with non-collared forms dominating abundance and biomass in late January and early February. Total HNAN abundance and biomass ranged from 1.6 to 4.2 x 106 l-1 and 8 to 16 µg C l-1, respectively. HNAN cellular ingestion and clearance rates differed between taxa with maximum rates of 8.28 particles cell-1 h-1 and 9.32 nl cell-1 h-1 recorded for large non-collared forms. During the study period the HNAN community grazed 0.9 to 4.7 µg bacterial C l-1 d-1, equivalent to 3 and 12% of bacterial biomass, and 10 and 36% of daily bacterial production; however, these values are likely to be minimal estimates and grazing impact may have been higher on occasion. Choanoflagellates were responsible for much of the grazing impact at the beginning of the study period, while non-collared HNAN were the dominant grazers in late January and early February. The HNAN community therefore appears to graze substantial bacterial production in Antarctic coastal waters during the austral summer, although alternative sources of bacterial mortality are likely to be of importance

A qualitative and quantitative evaluation of the effects of CALL platforms, programs and pedagogy on second language acquisition

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Guest editorial

This special issue presents selected papers on tree domestication from the Second World Agroforestry Congress, held in Nairobi between 23 and 28 August 2009. Over the last seventeen years agroforestry tree domestication has emerged as a key component of agroforestry, aimed at enriching farming systems with tree species producing high-value products for domestic use and for trade. This approach to improving the livelihoods of smallholder farmers is a crucial step for the alleviation of poverty, malnutrition and hunger, by generating farm income, enriching diets with nutritious fruits, nuts, etc., and creating employment through processing, value-adding and trade

Temporal patterns of protozooplankton abundance and their food in Ellis Fjord, Princess Elizabeth Land, Eastern Antarctica

The abundance and biomass of ciliates, dinoflagellates and heterotrophic and phototrophic nanoflagellates were determined at three sites along an ice-covered Antarctic fjord between January and November 1993. The water column showed little in the way of temperature and salinity gradients during the study period. In general, the protozooplankton exhibited a seasonal variation which closely mirrored that of chlorophyllaand bacterioplankton. The fjord mouth, which was affected by the greatest marine influences, consistently had the highest densities of ciliates and the most diverse community, with up to 18 species during the sampling period. Small aloricate ciliates were present throughout the year withStrobilidiumspp. being dominant during the winter. Larger loricate and aloricate ciliates became more prominent during January and November, along with the autotrophic ciliateMesodinium rubrumand two mixotrophic species (Strombidium wulffiand a type resemblingTontonia) suggesting evidence of species successions. Data on dinoflagellates were less extensive, but these protists showed greatest species diversity in the middle reaches of the fjord. A total of 13 species of dinoflagellate was recorded. Ciliates made a significant contribution to the biomass of the microbial community in summer, particularly in the middle and at the seaward end of the fjord. In winter, heterotrophic flagellates (HNAN) and phototrophic nanoflagellates (PNAN) were the dominant component of protistan biomass. In terms of percentage contribution to the microbial carbon pool, bacteria dominated during winter and spring. To the authors’ knowledge, this is the first seasonal study of an Antarctic fjord. The Ellis Fjord is very unproductive compared to lower latitude systems, and supports low biomass of phytoplankton and microbial plankton during most of the year. This relates to severe climatic and seasonal conditions, and the lack of allochthonous carbon inputs to the system. Thus, high latitude estuaries may differ significantly from lower latitude systems, which generally rank among the most productive aquatic systems in the world