A field investigation was conducted at the Shenyang Experimental Station of Ecology, Chinese Academy of Sciences, in an aquic brown soil of Northeast China under three land use types (cropland, abandoned cropland, and...A field investigation was conducted at the Shenyang Experimental Station of Ecology, Chinese Academy of Sciences, in an aquic brown soil of Northeast China under three land use types (cropland, abandoned cropland, and woodland) in order to evaluate whether the vertical distribution and seasonal fluctuation for the number of total nematodes and trophic groups could reflect soil ecosystem differences and to determine the relationships between soil chemical properties and soil nematodes. The majority of soil nematodes were present in the 0-20 cm soil layers, and for these land use types plant parasites were the most abundant trophic group. In the abandoned cropland the numbers of plant parasites reached a peak on the August sampling date, whereas the cropland and woodland peaked on the October sampling date. Meanwhile, in all land use types the number of total nematodes, bacterivores, plant parasites, and omnivores-predators was negatively (P < 0.05, except for bacterivores in cropland, which was not significant) correlated with bulk density, and positively (P < 0.05, except for fungivores in abandoned cropland, which was not significant) correlated with total organic carbon and total nitrogen.展开更多
Vertical and seasonal distributions of flying beetles were investigated in asuburban temperate deciduous forest in Kanazawa, Japan using water pan traps to determine the abundance and composition among vertical strata...Vertical and seasonal distributions of flying beetles were investigated in asuburban temperate deciduous forest in Kanazawa, Japan using water pan traps to determine the abundance and composition among vertical strata, change in the abundance and composition through seasons and determinant factors in generating the distributions. Traps were placed at three levels (0.5 m, 10 m, and 20 m above ground) on a tower. Samplings were carried out seasonally from May to November in 1999 and 2000. Variations in the abundance of flying beetles were observed from different layers. The results showed that the abundance and composition of flying beetles varied among strata and seasons. In both 1999 and 2000,Elateridae was consistently most abundant in the bottom layer, while Attelabidae and Cantharidae were most abundant in the upper layer. In 1999, Eucnemidae and overall scavengers were most abundance in the bottom layer, but results were not consistent with those in 2000. In general, the abundance of herbivores reaches a peak in the early season(May/June) and decreases in the following months. Peaks of abundance in predators vary vertically. In the bottom layer a peak was observed in the early season (May/June), while in the upper layer this was observed in July. Scavengers had two peaks, in May/June and September. These patterns indicated that vertical distributions in the abundance of differentfeeding guilds varied through seasons.展开更多
Long-term forecasts of pest pressure are central to the effective managementof many agricultural insect pests. In the eastern cropping regions of Australia, seriousinfestations of Helicoverpa punctigera (Wallengren) a...Long-term forecasts of pest pressure are central to the effective managementof many agricultural insect pests. In the eastern cropping regions of Australia, seriousinfestations of Helicoverpa punctigera (Wallengren) and H. armigera (Hiibner)(Lepidoptera:Noctuidae) are experienced annually. Regression analyses of a long series of light-trap catches ofadult moths were used to describe the seasonal dynamics of both species. The size of the springgeneration in eastern cropping zones could be related to rainfall in putative source areas in inlandAustralia. Subsequent generations could be related to the abundance of various crops inagricultural areas, rainfall and the magnitude of the spring population peak. As rainfall figuredprominently as a predictor variable, and can itself be predicted using the Southern OscillationIndex (SOI), trap catches were also related to this variable. The geographic distribution of eachspecies was modelled in relation to climate and CLIMEX was used to predict temporal variation inabundance at given putative source sites in inland Australia using historical meteorological data.These predictions were then correlated with subsequent pest abundance data in a major croppingregion. The regression-based and bio-climatic-based approaches to predicting pest abundance arecompared and their utility in predicting and interpreting pest dynamics are discussed.展开更多
基金Supported by the National Natural Science Foundation of China (No. 30570337).
文摘A field investigation was conducted at the Shenyang Experimental Station of Ecology, Chinese Academy of Sciences, in an aquic brown soil of Northeast China under three land use types (cropland, abandoned cropland, and woodland) in order to evaluate whether the vertical distribution and seasonal fluctuation for the number of total nematodes and trophic groups could reflect soil ecosystem differences and to determine the relationships between soil chemical properties and soil nematodes. The majority of soil nematodes were present in the 0-20 cm soil layers, and for these land use types plant parasites were the most abundant trophic group. In the abandoned cropland the numbers of plant parasites reached a peak on the August sampling date, whereas the cropland and woodland peaked on the October sampling date. Meanwhile, in all land use types the number of total nematodes, bacterivores, plant parasites, and omnivores-predators was negatively (P < 0.05, except for bacterivores in cropland, which was not significant) correlated with bulk density, and positively (P < 0.05, except for fungivores in abandoned cropland, which was not significant) correlated with total organic carbon and total nitrogen.
文摘Vertical and seasonal distributions of flying beetles were investigated in asuburban temperate deciduous forest in Kanazawa, Japan using water pan traps to determine the abundance and composition among vertical strata, change in the abundance and composition through seasons and determinant factors in generating the distributions. Traps were placed at three levels (0.5 m, 10 m, and 20 m above ground) on a tower. Samplings were carried out seasonally from May to November in 1999 and 2000. Variations in the abundance of flying beetles were observed from different layers. The results showed that the abundance and composition of flying beetles varied among strata and seasons. In both 1999 and 2000,Elateridae was consistently most abundant in the bottom layer, while Attelabidae and Cantharidae were most abundant in the upper layer. In 1999, Eucnemidae and overall scavengers were most abundance in the bottom layer, but results were not consistent with those in 2000. In general, the abundance of herbivores reaches a peak in the early season(May/June) and decreases in the following months. Peaks of abundance in predators vary vertically. In the bottom layer a peak was observed in the early season (May/June), while in the upper layer this was observed in July. Scavengers had two peaks, in May/June and September. These patterns indicated that vertical distributions in the abundance of differentfeeding guilds varied through seasons.
文摘Long-term forecasts of pest pressure are central to the effective managementof many agricultural insect pests. In the eastern cropping regions of Australia, seriousinfestations of Helicoverpa punctigera (Wallengren) and H. armigera (Hiibner)(Lepidoptera:Noctuidae) are experienced annually. Regression analyses of a long series of light-trap catches ofadult moths were used to describe the seasonal dynamics of both species. The size of the springgeneration in eastern cropping zones could be related to rainfall in putative source areas in inlandAustralia. Subsequent generations could be related to the abundance of various crops inagricultural areas, rainfall and the magnitude of the spring population peak. As rainfall figuredprominently as a predictor variable, and can itself be predicted using the Southern OscillationIndex (SOI), trap catches were also related to this variable. The geographic distribution of eachspecies was modelled in relation to climate and CLIMEX was used to predict temporal variation inabundance at given putative source sites in inland Australia using historical meteorological data.These predictions were then correlated with subsequent pest abundance data in a major croppingregion. The regression-based and bio-climatic-based approaches to predicting pest abundance arecompared and their utility in predicting and interpreting pest dynamics are discussed.
