Effects of insect-resistant transgenic cotton on ground-dwelling beetle assemblages(Coleoptera)

We compared the ground-dwelling beetle assemblages under four scenarios in which transgenic Bt（Cry 1Ac） cotton（33B）,transgenic Bt（Cry 1Ac）＋CpTI cotton（SGK321）,conventional cotton（33）,conventional cotton（Shiyuan 321） in North China.During the survey in two years（2009-2010）,24 ground beetle species were captured with pitfall traps in 20 plots which included five replicates for each cotton type.No significant difference was observed in the number of ground beetle species captured,activity density,evenness and Shannon-Wiener diversity among the four cotton varieties.Chlaenius posticalis was less abundant in transgenic Bt＋CpTI cotton（SGK321） fields than its conventional cotton（Shiyuan 321）,but more abundant in transgenic Bt cotton（33B） fields compared with its conventional cotton（33）.There was no significant difference for other abundant species between in transgenic cotton and in conventional cotton fields.Based on non-metric multidimensional scaling（NMDS） analysis,ground-dwelling beetle assemblages were similar in transgenic and conventional cotton over the two years,but the ground-dwelling beetle assemblages in transgenic cotton 33 B significantly differed from that in the conventional cotton（strain 33） in 2010.No strong evidence that the transgenic cotton effect on ground-dwelling beetle assemblages was found in this study.

Soil and Vegetation Seasonal Changes in the Grazing Andean Mountain Grasslands

Andean grasslands ecosystems are fragile environments with rigorous climatologic conditions and low and variable food for the grazing. The Apolobamba area is located in the Bolivian Andean Mountains. Its high grasslands provide a natural habitat for wild and domestic camelids such as vicuna(Vicugna vicugna) and alpaca(Lama pacos). The botanical diversity plays an essential role in maintaining vital ecosystem functions. The objectives of this research were to determine the seasonal changes in soil properties, to study the vegetation changes during the wet and dry seasons and the influence of soil properties and camelid densities on the vegetation in the Apolobamba grasslands. Four zones with different vicuna populations were selected to be studied. The following soil parameters were determined: total organic carbon, total nitrogen, available phosphorous, cation exchange capacity, exchangeable cations, pH and texture. The vegetation season changes were studied through botanical identification, above-ground biomass, plant cover and species richness. Results showed that some soil properties such as C/N ratio, CEC, silt and clay percentages kept stable against the seasonal changes. Generally, soil nutrients were relatively higher during the dry season in the surface and subsurface. The results did not point out the predominant vegetation growth during the wet season. The seasonal vegetation growth depended on each species. Thegood soil fertility corresponded to the highest plant cover. Soil fertility presented no influence on the above-ground biomass of the collected species. The negative influence of camelid grazing on soil properties could not be assessed. However, overgrazing could affect some plant species. Therefore, protection is needed in order to preserve the biodiversity in the Andean mountain grasslands.