秦皇岛市4种常见绿化植物滞尘效应研究

通过对秦皇岛市4种常见绿化植物的叶片滞尘量、单株滞尘能力及相关因素的研究,发现绿化植物单位叶面积的滞尘量最大可以相差2.5倍左右,树种叶片滞尘能力的大小排序为：国槐＞悬铃木＞金银木＞连翘,单株滞尘能力的大小排序为：悬铃木＞国槐＞金银木＞连翘;绿化植物的滞尘量与环境中粉尘含量成正比,树木滞尘能力还与叶片表面性状、叶面积指数及植物所处环境等因素有关。     

外来赤潮生物入侵现状及对赤潮灾害的影响研究

外来赤潮生物入侵加剧了我国近海海域的赤潮灾害。根据2004—2013年的数据统计,分别从赤潮生物优势种、频率、海域分布和赤潮面积4个方面分析了外来赤潮生物对我国近海赤潮灾害的影响,并着重从外来赤潮生物入侵早期预警系统建设、压舱水排放管理和赤潮灾害防治技术3个方面提出应对措施。     

Responses of a soil bacterium, Pseudomonas chlororaphis O6 to commercial metal oxide nanoparticles compared with responses to metal ions

The toxicity of commercially-available CuO and ZnO nanoparticles (NPs) to pathogenic bacteria was compared for a beneficial rhizosphere isolate, Pseudomonas chlororaphis O6. The NPs aggregated, released ions to different extents under the conditions used for bacterial exposure, and associated with bacterial cell surface. Bacterial surface charge was neutralized by NPs, dependent on pH. The CuO NPs were more toxic than the ZnO NPs. The negative surface charge on colloids of extracellular polymeric substances (EPS) was reduced by Cu ions but not by CuO NPs; the EPS protected cells from CuO NPs-toxicity. CuO NPs-toxicity was eliminated by a Cu ion chelator, suggesting that ion release was involved. Neither NPs released alkaline phosphatase from the cells’ periplasm, indicating minimal outer membrane damage. Accumulation of intracellular reactive oxygen species was correlated with CuO NPs lethality. Environmental deposition of NPs could create niches for ion release, with impacts on susceptible soil microbes.     

Quantitative Determination of Rarity of Freshwater Fishes and Implications for Imperiled‐Species Designations

Abstract: Conserving rare species and protecting biodiversity and ecosystem functioning depends on sound information on the nature of rarity. Rarity is multidimensional and has a variety of definitions, which presents the need for a quantitative classification scheme with which to categorize species as rare or common. We constructed such a classification for North American freshwater fishes to better describe rarity in fishes and provide researchers and managers with a tool to streamline conservation efforts. We used data on range extents, habitat specificities, and local population sizes of North American freshwater fishes and a variety of quantitative methods and statistical decision criteria, including quantile regression and a cost‐function algorithm to determine thresholds for categorizing a species as rare or common. Species fell into eight groups that conform to an established framework for rarity. Fishes listed by the American Fisheries Society (AFS) as endangered, threatened, or vulnerable were most often rare because their local population sizes were low, ranges were small, and they had specific habitat needs, in that order, whereas unlisted species were most often considered common on the basis of these three factors. Species with large ranges generally had few specific habitat needs, whereas those with small ranges tended to have narrow habitat specificities. We identified 30 species not designated as imperiled by AFS that were rare along all dimensions of rarity and may warrant further study or protection, and we found three designated species that were common along all dimensions and may require a review of their imperilment status. Our approach could be applied to other taxa to aid conservation decisions and serve as a useful tool for future revisions of listings of fish species.     

Vulnerability of Rehabilitated Agricultural Production Systems to Invasion by Nontarget Plant Species

Vast areas of arable land have been retired from crop production and “rehabilitated” to improved system states through landowner incentive programs in the United States (e.g., Conservation and Wetland Reserve Programs), as well as Europe (i.e., Agri-Environment Schemes). Our review of studies conducted on invasion of rehabilitated agricultural production systems by nontarget species elucidates several factors that may increase the vulnerability of these systems to invasion. These systems often exist in highly fragmented and agriculturally dominated landscapes, where propagule sources of target species for colonization may be limited, and are established under conditions where legacies of past disturbance persist and prevent target species from persisting. Furthermore, rehabilitation approaches often do not include or successfully attain all target species or historical ecological processes (e.g., hydrology, grazing, and/or fire cycles) key to resisting invasion. Uncertainty surrounds ways in which nontarget species may compromise long term goals of improving biodiversity and ecosystem services through rehabilitation efforts on former agricultural production lands. This review demonstrates that more studies are needed on the extent and ecological impacts of nontarget species as related to the goals of rehabilitation efforts to secure current and future environmental benefits arising from this widespread conservation practice.     

Bumblebee Vulnerability: Common Correlates of Winners and Losers across Three Continents

Abstract:  It is widely agreed that in many parts of the world some bumblebee ( Bombus ) species have declined, and that this has often been driven by land-use changes that cause reductions in the abundance of food plants. There is much less agreement about how changes in food plants affect some bumblebee species more than others. We sought to identify which species' characteristics are generally associated with the relative winners and losers by comparing the 3 independent bumblebee faunas from parts of Britain, Canada, and China. Using available survey data, we assessed species characteristics, including competition with congeners, climatic specialization, proximity to climatic range edge, food specialization, phenology, body size, and range size. Results of our meta-analysis of correlations showed support for the hypotheses that decline susceptibility is generally greater for species that have greater climatic specialization, for species in areas where they occur closest to the edges of their climatic ranges, and for species that have queens that become active later in the year. The latter characteristic may render a species at a particular disadvantage when they have long colony cycles if there are losses of food plants in mid to late colony development.     

Incomes,Attitudes, and Occurrences of Invasive Species: An Application to Signal Crayfish in Sweden

This article analyzes and carries out an econometric test of the explanatory power of economic and attitude variables for occurrences of the nonnative signal crayfish in Swedish waters. Signal crayfish are a carrier of plague which threatens the native noble crayfish with extinction. Crayfish are associated with recreational and cultural traditions in Sweden, which may run against environmental preferences for preserving native species. Econometric analysis is carried out using panel data at the municipality level with economic factors and attitudes as explanatory variables, which are derived from a simple dynamic harvesting model. A log-normal model is used for the regression analysis, and the results indicate significant impacts on occurrences of waters with signal crayfish of changes in both economic and attitude variables. Variables reflecting environmental and recreational preferences have unexpected signs, where the former variable has a positive and the latter a negative impact on occurrences of waters with signal crayfish. These effects are, however, counteracted by their respective interaction effect with income.     

Interactions Among the Copper Species and Forms in Sea Water/Sediments and Copper Bioaccumulation in Oysters

Abstract

Earlier papers indicated that the first incident of green discoloration in oysters (Crassostrea gigas) and the mass mortality observed in 1986 along the Taiwan Erhjin Chi coastal area were caused by the higher contents of total copper and copper species (mainly bioavailable and free ion) in sea water. the copper in sea water would be sorbed by suspended matter and transferred to sediments, and the copper in the sediments would also be desorbed to sea water. Processes of copper adsorption and desorption are the major factors influencing the contents of total copper and copper species in sea water and sediments. in this study, the Erhjin Chi sediments were mixed with sea water by a shaker technique. When the mixture was shaken for one hour, analogous to tidal mixing in estuaries, only copper desorption from sediments was observed. If the shaking time is increased for more than 3 hours, the copper released from the sediments was resorbed to the remaining solid phases. the higher the contents of mud (91.71%) and total copper (701 mg kg^?1) in sediments, the higher the copper desorption rate (1.86 ppm hr^?1) and copper adsorption rate (0.50 ppm hr^?1) were observed. in sediments containing lower mud (0.80%) and lower copper (43.5 mg kg^?1), the copper desorption and adsorption rates were 0.83 ppm hr^?1 and 0.22 ppm hr^?1, respectively. the interactions among the total copper and copper species in sea water and sediments, chemical and ecological parameters, and copper bioaccumulation in oysters in the Erhjin Chi estuarine and coastal area are also discussed.     

Using Multi-Scale Sampling and Spatial Cross-Correlation to Investigate Patterns of Plant Species Richness

Land managers need better techniques to assess exoticplant invasions. We used the cross-correlationstatistic, I _YZ, to test for the presence ofspatial cross-correlation between pair-wisecombinations of soil characteristics, topographicvariables, plant species richness, and cover ofvascular plants in a 754 ha study site in RockyMountain National Park, Colorado, U.S.A. Using 25 largeplots (1000 m²) in five vegetation types, 8 of 12variables showed significant spatial cross-correlationwith at least one other variable, while 6 of 12variables showed significant spatial auto-correlation. Elevation and slope showed significant spatialcross-correlation with all variables except percentcover of native and exotic species. Percent cover ofnative species had significant spatialcross-correlations with soil variables, but not withexotic species. This was probably because of thepatchy distributions of vegetation types in the studyarea. At a finer resolution, using data from ten1 m² subplots within each of the 1000 m² plots, allvariables showed significant spatial auto- andcross-correlation. Large-plot sampling was moreaffected by topographic factors than speciesdistribution patterns, while with finer resolutionsampling, the opposite was true. However, thestatistically and biologically significant spatialcorrelation of native and exotic species could only bedetected with finer resolution sampling. We foundexotic plant species invading areas with high nativeplant richness and cover, and in fertile soils high innitrogen, silt, and clay. Spatial auto- andcross-correlation statistics, along with theintegration of remotely sensed data and geographicinformation systems, are powerful new tools forevaluating the patterns and distribution of native andexotic plant species in relation to landscape structure.     

Research On Zooplankton in the Gulf of Rapallo

Zooplankton samples, collected in autumn 1996 from two stations in the Gulf of Rapallo, Ligurian Sea (Rapallo Harbour and Prelo Bay, which is a more open site with lower human impacts) were analysed. at both stations, the community was dominated by copepods (mainly juveniles and adults of different species of Acartia and Oithona) and meroplankton (mainly polychaete larvae). Total zooplankton abundance in the harbour waters was significantly higher than in the nearby bay. the occurrence of Acartia grani in Rapallo Harbour and Pteriacartia josephinae in Prelo Bay is noteworthy, as they are reported for the first time in the Ligurian Sea, and A. grani has not previously been recorded to the Italian coastline. A three-day benthic chamber experiment aimed to quantify nutrient fluxes between the sediment and water column was performed in the Rapallo Harbour: the profound effects of confinement on the composition and abundance of zooplankton within the incubation chamber are discussed.