Zhao Hui-yan

Time structure and dynamics of the insect communities in bush vegetation restoration areas of Zhifanggou watershed in Loess hilly region

Abstract The insects were investigated in Zhifanggou watershed, Ansai County, Shaanxi Province, China. The results showed that the insect species varied spatially in the following order: the natural bush forests, the mixed forests and the simple forests. The individual number of insects in Caragana korshinskii was the highest, followed by mixed forests and Hippaphae rhamnoides, and the change range of the insect individuals in the natural bush forests was the smallest. The species number of insects with seasonal changes and the individual number of insects in various types of vegetation can be described by the Univariate cubic equation. The order of the diversity index of the insect communities in various types of vegetation from May to September was the natural bush forests, the mixed forests and the simple forests. The change ranges of the evenness values of the simple forests and the mixed forests were higher, and that of the natural bush forests was smaller. The reverse trend was assumed between the dominance values and the evenness values in the time course. Moreover, the main factors and temporal patterns of the insect communities in the natural bush forests were more complicated, fluctuative and obvious than those in the mixed forests and the simple forests by using the principal component analysis.

A MODEL TO ANALYZE WEATHER IMPACT ON APHID POPULATION DYNAMICS: AN APPLICATION ON SWALLOWTAIL CATASTROPHE MODEL

Acidified and non acidified samples of wastewaters from the Etoudi’s slaughterhouse (Yaounde, Cameroon) were analyzed before and after having been exposed to an electric discharge in a cold plasma reactor at different exposure times. Analyses reveal that untreated and non acidified wastewaters (pH = 7.8) contain 230.4 mgL-1 of phosphate (PO4 3-) and 479.6 mgL-1 of nitrate (NO3 -) ions. Exposure of these wastewaters to the gliding discharge (“glidarc”) operated in humid air induces PO4 3- and NO3 - concentrations abatement by 41.55% for phosphates and 86.24% for nitrates within 20 min of exposure for a gas flow rate of 800 Lh-1,which confirms the efficiency of the glidarc treatment in humid air in case of waste treatments. On the other hand, exposure of acidified wastewaters (pH = 2.2) to the glidarc in the same conditions showed that PO4 3- andNO3 - concentrations increase with exposure time; this result is in conformity with oxidation phenomena induced by the glidarc and previously presented by several authors. From these results the efficiency of the “glidarc” technique in degrading phosphates and nitrates in basic medium was proven.