Comprehensive assessment on the ecological stress of rapid land urbanization per proportion, intensity, and location

Aiming at assessing the ecological stress of land urbanization comprehensively,three perspectives are considered and combined,i.e.the amount effect with the proportion of construction lands as the indicator,the intensity effect per the density of environmental pollutant emissions,and the location effect based on their spatial distribution in the heterogeneous landscape.The quantitative results of Southern Jiangsu case in Eastern China show the single-perspective ecological stress are spatially different;the proportion effect is higher in city propers which are more densely populated and industrialized.However,the intensity effect is more significant for units along the Yangtze river where heavy industries are gathered,while the location effect is higher in“ecologically suitable”regions.As the integration of proportion,intensity,and location effects,the comprehensive stress differs across Southern Jiangsu and are also different with the single-perspective results.Dominant stressors of each unit are spatially distinct,which benefits policymakers in targeting their objectives as per primary influencing factors.It is concluded that the comprehensive assessment could efficiently reveal the spatial differentiation of the ecological effects of land urbanization and also the differentiated role of different factors for each unit.

Planktonic protist communities in semi-enclosed mariculture waters: temporal dynamics of functional groups and their responses to environmental conditions

The functional groups of planktonic protist communities and their responses to the changes of environmental conditions were investigated in a semi-enclosed shrimp-farming pond in Qingdao,Shandong Province,China,during a six-month study period （a complete shrimp-culture cycle） from May to October 2002.The results reveal that： （1） the protist communities represented five trophic and functional groups of the species identified,about 60% were photoautotrophs,20% algivores,12% bacterivores,5% raptors and about 3% non-selectives;（2） the photoautotrophs,algivores and bacterivores were the primary contributors to the changes in the protist communities in short temporal scales,the succession of dominance typically being bacterivores→photoautotrophs→algivores,with the raptors dominating the protist communities in a single sample （early June）;（3） the photoautotrophs and non-selectives were the primary contributors to the peak of protist abundance in early October whereas the photoautotrophs,bacterivores,raptors and non-selectives mainly gave rise to two bimodal peaks of biomass in July and October respectively;（4） five functional groups of protist communities represented significant correlations with water nutrients （i.e.,NH 3-N,NO 3-N,and PO 4 ）,either alone or in combination with temperature,of which algivores and raptors were strongly correlated with phosphate and the concentration of Chl a,while bacterivores were strongly related to nitrogen and the concentration of bacteria.These findings confirm that planktonic protists are potentially useful bioindicators of water quality in the semi-enclosed mariculture system.

Genetic variation at the p53 locus of two ecologically divergent Microtus pine voles:identification of molecular markers for species assignment

The Lusitanian(Microtus lusitanicus)and the Mediterranean(Microtus duodecimcostatus)pine voles are recently diverged sister species endemic of the Iberian Peninsula that can be identified with ecological and morphological characters,but in areas where the 2 species co-occur,species designation may be difficult.Genetic discrimination between M.lusitanicus and M.duodecimcostatus has not been achieved yet possibly because of their estimated re-cent split and an evolutionary history that includes inter-species geneflow.Following our previous observations on exons 5–7 of the p53 gene,here we analyze the potential use of the p53 genomic region as a discrimination marker of these species by extending our analyses to several kb upstream and downstream of the p53 gene and charac-terizing the degree of genetic differentiation in 7 markers within this region.Additionally,we fully sequenced the P53 protein of both species.We observed:(i)generally high differentiation in this region;(ii)M.duodecimcostatus showed in general higher values of nucleotide and haplotype diversities;(iii)the concatenated phylogenetic tree separates the 2 species;(iv)the 2 P53 proteins only differ in 1 amino acid;(v)4 of the markers,2 in p53,one in Atp1b2,and another in Wrap53,contain species-specific genetic variation thus allowing a reliable discrimination between specimens from both species,irrespective of sampling location or introgression status.We provide ad-ditional data on the putative role of p53 in the evolution of these species and present researchers with a fast and cost-effective resource for M.lusitanicus and M.duodecimcostatus identification.