Population dynamics of the mycoparasite, sporidesmium sclerotivorum, and its host, sclerotinia minor, in soil

The infection and survival of sclerotia of Sclerotinia minor and the production ofmacroconidia of the mycoparasite, Sporidesmium sclerotivorum, were studied in vitro when each fungus was added to soil at various initial inoculum densities. The rate at which S. sclerotivorum invaded host sclerotia and caused their decay varied with the amount of the mycoparasite added to soil. The results suggest that approximately 5 macroconidia of the mycoparasite g^?1 of soil are needed to successfully infect sclerotia and bring about their decay, when soils are sampled and mixed every 2 weeks. The rate at which S. sclerotivorum infects sclerotia of S. minor and causes their decay is also dependent on the initial inoculum density of the host. Each infected sclerotium supports the production of about 15,000 new macroconidia in soil regardless of the initial inoculum density of the host. It is concluded that successful biological control by S. sclerotivorum is dependent on the soil population of both the host and the mycoparasite.     

Translocations of eight species of burrow-nesting seabirds (genera Pterodroma, Pelecanoides, Pachyptila and Puffinus: Family Procellariidae)

Development of seabird translocation techniques is required to meet species recovery objectives, to improve conservation status, and to restore ecological processes. During 1997-2008 we undertook translocation trials on eight petrel species of four genera within the New Zealand region: common diving petrel (Pelecanoides urinatrix), fairy prion (Pachyptila turtur), grey-faced petrel (Pterodroma macroptera gouldi), Pycroft’s petrel (Pterodroma pycrofti), Chatham petrel (Pterodroma axillaris), Chatham Island taiko (Magenta petrel; Pterodroma magentae), fluttering shearwater (Puffinus gavia), and Hutton’s shearwater (Puffinus huttoni). A total of 1791 chicks within 5 weeks of fledging were moved up to 240 km, placed in artificial burrows and hand-fed until they fledged. Of these, 1546 fledged, and so far at least 68 have returned as adults to the translocation sites. Most birds were crop-fed a puree based on tinned sardines and fresh water. This diet worked well for all species regardless of their typical natural diet (planktonic crustaceans, squid, or fish) with all species fledging above or close to mean natural fledging weights.     

肉鸡H9N2亚型禽流感病毒全基因测序及遗传进化分析

根据GenBank登陆的H9N2亚型禽流感病毒（AIV）的全基因序列,设计11对引物,运用RT-PCR方法扩增A／Chicken／Zhejiang／HJ／2007(H9N2)毒株8个基因片段,并克隆到pMD18-T载体中进行序列测定。基因序列比较及遗传进化分析结果表明,所克隆的8个基因片段均有HJ毒株完整的开放阅读框（ORF）,其血凝素（HA）基因蛋白裂解位点的氨基酸组成为-PSKSSR*G-,为不连续的碱性氨基酸,符合低致病性AIV HA基因裂解位点的序列特征;与QA/HK/G1/97的进化关系较近,处在同一分支。其神经氨酸酶（NA）基因在63、64、65位点上有3个氨基酸（T、E、I）缺失,在遗传进化上属于常见的CK/BJ/1/94（DK/HK/Y280/97）群系。核蛋白（NP）基因整合有同地分离的H5N1亚型流感病毒NP基因片段,进化关系较近。基质蛋白（M）基因与1999年香港感染儿童的两株流感病毒（HK/1073/99和HK/1074/99）进化关系属于同一分支。非结构蛋白（NS）基因与近年来分离的猪源H9N2亚型流感病毒进化关系相近,和1998年首次报道的猪源H9N2亚型流感病毒（SW/HK/9/98）处在同一进化分支。聚合酶蛋白（PA、PB2、PB1）中,PB1从33-47位存在15个连续碱基缺失,是首次报道该基因ORF内存在缺失,从遗传进化上和近年来分离的H5N1亚型流感病毒处在同一分支上;PA基因从遗传进化上和PB1基因类似;PB2基因与常见的流感病毒毒株的遗传进化关系较远,在相应的进化树另成分支。因此,A／Chicken／Zhejiang／HJ／2007(H9N2)是由不同流感病毒基因亚系间发生自然重排的产物。     

KINETICS OF ION EXCHANGE IN SOIL ORGANIC MATTER. IV. ADSORPTION AND DESORPTION OF Pb2+, Cu2+, Cd2+, Zn2+ AND Ca2+ BY PEAT

The equilibria as well as the rates of adsorption and desorption of the ions Pb²⁺, Cu²⁺, Cd²⁺, Zn²⁺, and Ca²⁺ by soil organic matter were determined in batch experiments as a function of the amount of metal ions added to an aqueous suspension of HCl-washed peat. Simultaneous determination of the metal ions and hydrogen ions in the solution by atomic absorption spectrophotometry and pH-measurements showed that the adsorption of one divalent metal ion by peat was coupled with the release of two hydrogen ions. Since this equivalent ion-exchange process causes a corresponding increase of the electric conductivity of the solution, the rates of the adsorption and desorption processes were determined by an immersed conductivity electrode. The distribution coefficients show that the selective order for the metal adsorption by peat is Pb²⁺ > Cu²⁺ > Cd²⁺≌ Zn²⁺ > Ca²⁺ in the pH range of 3·5 to 4·5. The slope of -2, as observed in a double logarithmic plot of the distribution coefficients versus the total solution concentration confirms the equivalence of the ion-exchange process of divalent metal ions for monovalent H₃O⁺ -ions in peat. The absolute rates of adsorption, as well as the rates for the fractional attainment of the equilibrium, increase with increasing amounts of metal ions added. This behaviour is also observed for the subsequent desorption of the metal ions by H₃O⁺-ions. At a given amount of metal ions added, the absolute rates of adsorption decrease in the order Pb²⁺ > Cu²⁺ > Cd²⁺ > Zn²⁺ > Ca²⁺, while the rates for the fractional attainment of the equilibrium decrease in the order Ca²⁺ > Zn²⁺≌ Cd²⁺ > Pb²⁺ > Cu²⁺. The half times for adsorption and desorption were in the range of 5 to 15 sec.     

Lotononis angolensis forms nitrogen fixing, lupinoid nodules with phylogenetically unique, fast-growing, pink-pigmented bacteria, which do not nodulate L. bainesii or L. listii

Root-nodule bacteria that nodulate the legume genus Lotononis are being investigated to develop new forage species for agriculture. Bacteria isolated from nodules of Lotononis angolensis were fast-growing, highly mucoid and pink-pigmented, and on the basis of 16S rRNA phylogeny <94% related to other genera in the Alphaproteobacteria. Root-nodule bacteria isolated from other Lotononis species (L. bainesii, L. solitudinis and L. listii) resembled the more common dry, slow-growing, pink-pigmented rhizobia previously described for L. bainesii. These isolates could be attributed to the Methylobacterium genus, although not to the type species Methylobacterium nodulans. Further differences were uncovered with nodulation studies revealing that nodule isolates from L. angolensis were effective at nitrogen fixation on their host plant, but could nodulate neither L. bainesii nor L. listii. Reciprocal tests showed isolates from L. bainesii, L. listii and L. solitudinis were incapable of nodulating L. angolensis effectively. Nodule morphology for L. bainesii, L. angolensis and L. listii was characteristically lupinoid, with little structural divergence between the species, and with nodules eventually enclosing the entire root.     

The trout cod, Maccullochella macquariensis, a rare freshwater fish of Eastern Australia

Maccullochella macquariensis is a rare freshwater percichthyid fish that was formerly found in many localities throughout the Murray-Darling River system of eastern Australia. It is now restricted to two isolated habitats in Victoria. This paper gives an account of the species and its distribution, catalogues the known museum specimens, and provides photographs of representative individuals.     

Status and conservation of the grey seal, Halichœrus grypus, in France

We investigated the status of the grey seal in the Molène archipelago, western Brittany, where a Marine National Park is planned. We combined regular censuses, photo-identification and satellite telemetry to investigate trends in grey seal abundance, site fidelity, individual movements and haulout site use. Individual movements and seasonal variations in abundance suggest that the seals used the Molène archipelago alternatively with other haulout sites of the South-west British Isles during their annual cycle. Nine out of 16 seals fitted with Satellite Relay Data Loggers (SRDLs) moved to the Isles of Scilly, English Cornwall, Wales or the Channel islands. On average the seals spent 85% of their time Near Haulout, 56.8% of which in the Molène archipelago. Overall the seals spent 66% of their tracking time within the boundaries of the Marine National Park. From 1997 to 2000 in the Molène archipelago, we observed a peak in number during the moulting season (mean = 49.8 seals) and a lower abundance during the breeding season (mean = 38.3 seals). The sex ratio was strongly skewed towards males during the moult (between 3.1 and 5.3-1), and was close to 1:1 during the summer. Inter-annual site fidelity outside the breeding season was very high, varying from 70% to 95% of identified seals, suggesting that the observed movements constitute rotations rather than random dispersion. From 1991/1994 to 1997/2000, the mean number of seals counted at haulout sites increased by 7%, close to the rates of increase observed in the core population of the British Isles at the same period. The Marine National Park may be too restricted for the overall conservation of the population but management plans should be aimed at preserving the characteristics of the habitat for the grey seal.     

Surface water and ground-water thresholds for maintaining Populus-Salix forests, San Pedro River, Arizona

Ground-water and surface flow depletions are altering riparian ecosystems throughout the southwestern United States, and have contributed to the decline of forests of the pioneer trees Populus fremontii (Fremont cottonwood) and Salix gooddingii (Goodding willow). On some rivers, these forests have been replaced by shrublands of Tamarix ramosissima (tamarisk), a drought-tolerant species from Eurasia. The physiological response of these three riparian plant species to decreases in water availability is well studied, but little attention has been given to shifts in community and population structure in response to declines in surface flow and ground-water levels. Based on study of 17 sites spanning a hydrologic gradient, this research identified hydrologic thresholds above which P. fremontii-S. gooddingii maintain tall dense stands with diverse age classes, and above which they are more abundant than T. ramosissima stands along the San Pedro River in Arizona. Surface flow permanence was the hydrologic variable that explained most of the variance in species abundance and relative importance, with inter-annual ground-water fluctuation and depth to ground water also contributing. P. fremontii and S. gooddingii were dominant over T. ramosissima at sites where surface flow was present more than 76% of the time, inter-annual ground-water fluctuation was less than 0.5 m, and average maximum depth to ground water was less than 2.6 m, during a two-year period of data collection. Because T. ramosissima is a shrub species with smaller leaves and lower canopy heights than P. fremontii and S. gooddingii, these shifts in species composition corresponded to decreases in maximum canopy height and upper stratum (above 8 m) vegetation volume as site water availability declined. As well, sites with deeper water tables and more intermittent flows had greater areal coverage of shrublands and less of woodlands. The altered vegetation structure along dewatered rivers may lower wildlife habitat quality. This study provides river managers with quantitative hydrologic guidelines for conserving tall dense P. fremontii-S. gooddingii stands and emphasizes the importance of maintaining long-term hydrologic conditions that are favorable to these species. The study also has implications for riparian restoration and invasive species management by suggesting that desired outcomes may be achieved through restoration of physical processes.     

入侵植物豚草与本地植物马唐对土壤肥力与酶活性影响的比较

通过同质园试验比较研究了外来入侵植物豚草与本地植物马唐对土壤肥力及3大类酶活性的影响.结果表明: 与本地植物及空白对照相比, 豚草显著提高了入侵地的土壤有效养分含量, 特别是有效钾含量是空白对照区和本地植物马唐区的3.6倍和1.3倍.与空白对照区和本地植物马唐种植区相比, 豚草种植区的土壤酶活性亦显著提高.外来入侵植物豚草在入侵地形成新的关系过程中, 比本地植物马唐能更快地提高土壤有效养分含量及酶活性, 从而实现较短时间内通过提高土壤肥力, 形成对自身生长有利的土壤环境来帮助其竞争入侵.     

Numbers of nesting frigatebirds, Fregata minor and F. ariel, on Aldabra Atoll nature reserve,Seychelles

Aldabra Atoll, a strict Nature Reserve and major breeding station of lesser and greater frigatebirds, may be developed for tourism. Determining whether this affects the frigate breeding populations is complicated by their extended annual laying seasons and the biennial breeding periodicity of individuals rearing fledgelings. This study, using a census method incorporating adjustments for seasonal changes in nest numbers, changes in nest ownership and replacement laying, indicates that there are at least 4000 pairs of greater frigatebirds and 6000 pairs of lesser frigatebirds annually involved in breeding activities. There is some evidence that more male than female greater frigatebirds attempt to pair each season. Comparison with an earlier census suggests that severe human disturbance induces curtailment of laying seasons, major changes in nest distribution and prevents many birds from breeding.     

Microbial CO2 production, CH4 dynamics and nitrogen in a wetland soil (New York State, USA) associated with three plant species (Typha, Lythrum, Phalaris)

Plants furnish soil with organic carbon (OC) compounds that fuel soil microorganisms, but whether individual plant species – or plants with unique traits – do so uniquely is uncertain. We evaluated soil microbial processes within a wetland in which areas dominated by a distinct plant species (cattail –Typha sp.; purple loosestrife –Lythrum salicaria L.; reed canarygrass –Phalaris arundinacea L.) co‐mingled. We also established an experimental plot with plant shoot removal. The Phalaris area had more acidic soil pH (7.08 vs. 7.27–7.57), greater amount of soil organic matter (19.0% vs. 9.0–11.5%), and the slowest production rates of CO₂ (0.10 vs. 0.21–0.46 μmol kg⁻¹ s⁻¹) and CH₄ (0.040 vs. 0.054–0.079 nmol kg⁻¹ s⁻¹). Nitrogen cycling was dominated by net nitrification, with similar rates (17.2–18.9 mg kg⁻¹ 14 days⁻¹) among the four sampling areas. In the second part of the study, we emplaced soil cores that either allowed root in‐growth or excluded roots to evaluate how roots directly affect soil CO₂ and CH₄. The three plant species had similar amounts of root growth (ca 290 g m⁻² year⁻¹). Fungal biomass was similar in soils with root in‐growth versus root exclusion, regardless of dominant plant species. Rates of soil CO₂ production did not differ with root in‐growth versus root exclusion, and added glucose increased CO₂ production rates by only 35%. Root in‐growth did lead to greater rates of CH₄ production; albeit, addition of glucose had much greater effect on CH₄ production (1.24 nmol kg⁻¹ s⁻¹) compared with controls without added glucose (0.058 nmol kg⁻¹ s⁻¹). Our data revealed relatively few subtle differences in soil characteristics and processes associated with different plant species; albeit, roots had little effect, even inhibiting some microbial processes. This research highlights the need for both field and experimental studies in long‐established monocultures of plant species to understand the role of plant biodiversity in soil function.     

紫花苜蓿、黑麦草和狼尾草对Cu、Pb复合污染土壤修复能力的研究

随着经济和社会的发展,土壤重金属污染对粮食安全及人类的身体健康构成了巨大的威胁,而目前对于土壤重金属污染的治理主要以植物修复为主。为了寻找适宜修复Cu、Pb复合污染土壤的牧草,采用盆栽试验法,将试验的植物设置9组处理:1组对照组(CK),不添加任何重金属盐;4组单一污染,即单一Cu低(Cu1,200 mg×kg-1)、高浓度(Cu2 400 mg×kg-1),单一Pb低(Pb1 300 mg×kg-1)、高浓度(Pb2 800 mg×kg-1);4组Cu、Pb复合污染(Cu1Pb1、Cu1Pb2、Cu2Pb1、Cu_2Pb_2)。通过比较紫花苜蓿(Medicago sativa)、黑麦草(Lolium perenne)、狼尾草(Pennisetum alopecuroides)的适应能力和富集特征,研究了这3种常见牧草植物对受Cu、Pb复合污染土壤的修复效果。结果表明:1)紫花苜蓿地上部和根部生物量均在Pb1处理组时最大,显著高于其他处理组;黑麦草地上部生物量在Cu1Pb1处理组最大,根部生物量在Pb1处理组最大;狼尾草地上部生物量在Cu_2Pb_2处理组最大,根部生物量在Cu2处理组最大。2)Cu单一污染下,狼尾草抗性系数最大;Pb单一污染下,紫花苜蓿抗性系数最大;Cu-Pb复合污染下,狼尾草的抗性系数较大。高浓度Cu处理组3种牧草植物的地上部生物量、根部生物量和抗性系数均呈现:狼尾草黑麦草紫花苜蓿,且狼尾草显著大于黑麦草和紫花苜蓿。3)种植3种牧草植物后,土壤重金属Cu、Pb含量均有所降低。在一定浓度下,土壤Cu-Pb重金属间会相互促进对方在牧草植物中的吸收。4)3种牧草中紫花苜蓿地上部对Cu的富集系数在Cu_2Pb_2处理组最大,达1.61;黑麦草根部对Cu的富集系数在Cu_2Pb_2处理组最大,达3.80;3种牧草地上部和根部对Pb的富集系数只在黑麦草根部的Cu1Pb1处理组时大于1,达1.46。5)黑麦草对Pb的吸收能力较强,且主要积累在根系;紫花苜蓿对Cu-Pb复合污染综合修复效果最好。紫花苜蓿和黑麦草分别在Cu-Pb复合污染和Pb单一污染土壤中对Pb的转运系数大于1,分别为2.72和2.06,反映其对土壤中的Pb具有富集潜力。综合表明,黑麦草对重金属Pb具有较强的耐性,在Pb单一污染土壤的植物修复及尾矿废弃地的植被重建中,可优先作为选择的材料;紫花苜蓿对重金属Cu、Pb均具有较强的耐性,在重金属Cu单一或Cu-Pb复合污染土壤的植物修复及尾矿废弃地的植被重建中,可优先作为选择的材料。     

Wood, nematodes, and the nematode-trapping fungus Arthrobotrys oligospora

Researchers have proposed that Arthrobotrys oligospora and related fungi trap soil nematodes to obtain nitrogen and thereby compete saprophytically for carbon and energy in nitrogen-poor environments, including litter and wood. The current study tested two hypotheses concerning this model. The first was that wood decomposition would be enhanced if both large numbers of nematodes (a potential nitrogen supply) and A. oligospora (a cellulolytic organism that can use that N supply) were present. The second was that A. oligospora trapping activity would increase if large numbers of nematodes were added to soil containing abundant carbon (a wood dowel or chip). Although the first hypothesis was supported by an in vitro experiment on agar (A. oligospora degraded much more wood when nematodes were present), neither hypothesis was supported by an experiment in vials containing field soil. In soil, wood decomposition was unaffected by the addition of A. oligospora or large numbers of nematodes. Whereas A. oligospora trapped virtually all nematodes added to agar cultures, it trapped few or no nematodes added to soil. Given that the fungal isolate was obtained from the same soil and that the fungus increased to large numbers (>1×10³ propagules g⁻¹ soil), the failure of A. oligospora to trap nematodes in soil is difficult to explain. Soil nitrate levels, however, were high (71 mg kg⁻¹), and it is possible that with lower nitrate levels, trapping in soil might be stimulated by wood and nematodes.     

作为颗粒运移的示踪剂的土壤7Be, 137Cs, 226Ra和228Ra的地球化学种类

A brunisolic soil collected from an erosive forest land(HF-1-1) and a yellow soil from and accumulative shallow basin(HF-6-1) in the watershed of Lake Hongfeng (HF) were used for activity measurements of ^7Be,^137Cs,^226Ra and ^228Ra in different geochemical speciation.More than 85% of ^7Be,^137Cs,^226Ra and 228Ra in the soils were bound to organic Fe-Mn oxy-hydroxide and residual fractions.They could move with soil particlesw and be used as tracers for the erosion and /or accumulation of soil particles.^7Be gohemical specition in the soils agreed with its trace for seasonal particle transport.^137Cs geohemial speciaiton was suitable for tracing soil particle accumulation and for sediment aating.^226Ra and ^228Ra were ombined in crystalline skeleton of clay minerals and mainly remained as residues in the soils and little was bound to the soluble,exchangeable and carbonate fractions.The differentiation of ^226 Ra/^228Ra activity ratios in different geoheical fractions in the soils could be used as a parameter to trace accumulation and /or erosion of soil particles.     

Statewide modeling of bobcat, Lynx rufus, habitat in Illinois, USA

We used sighting location and remotely sensed habitat data, multivariate statistical techniques, and a geographic information system to model bobcat (Lynx rufus) habitat in Illinois, thereby providing state wildlife managers with information to review the listing of bobcats as a state-threatened species and contribute to the development of a statewide management plan. We used canonical discriminant function analysis to model presence/absence and relative abundance of bobcats statewide. These models suggested that bobcats occurred in moderate to high abundance in 23 of 98 counties statewide (23%). We used stepwise logistic regression (SLR) analysis to model statewide habitat suitability. Spatial modeling of the SLR equation predicted that 29% of Illinois contained suitable habitat classified as P>0.50. Models were accurate when validated with an independent data set and indicated the importance of woods-related habitat variables to bobcats. In conclusion, these models provided tools to rapidly assess status that contributed to delisting bobcats as a threatened species in Illinois and provided further information to guide conservation efforts.     

LC/DAD/ESI/MS method for the determination of imidacloprid, thiacloprid, and spinosad in olives and olive oil after field treatment

The behavior in the field and the transfer from olives to olive oil during the technological process of imidacloprid, thiacloprid, and spinosad were studied. The extraction method used was effective in extracting the analytes of interest, and no interfering peaks were detected in the chromatogram. The residue levels found in olives after treatment were 0.14, 0.04, and 0.30 mg/kg for imidacloprid, thiacloprid, and spinosad, respectively, far below the maximum residue levels (MRLs) set for these insecticides in EU. At the preharvest interval (PHI), no residue was detected for imidacloprid and thiacloprid, while spinosad showed a residue level of 0.04 mg/kg. The study of the effect of the technological process on pesticide transfer in olive oil showed that these insecticides tend to remain in the olive cake. The LC/DAD/ESI/MS method showed good performance with adequate recoveries ranging from 80 to 119% and good method limits of quantitation (LOQs) and of determination (LODs). No matrix effect was detected.     

Pollutant (Zn,PO4, NO2, PAH, γ-BHC,coprostanol) transport and its modeling in a small stream

The response of a lotic ecosystem to an instantaneous release of pollutants (Zn, PO₄, NO₂, PAH, γ-BHC, and coprostanol) which were included in a slug of treated sewage, was investigated. The impulse response concentration curve of pollutants was used to determine the dispersion coefficient. A mathematical model was obtained by solving the one dimensional mass transport equation with an exponential decay by a multistage implicit finite difference method and optimization of the decay constant.     

Influence of Glomus etunicatum/Zea mays mycorrhiza on atrazine degradation, soil phosphatase and dehydrogenase activities, and soil microbial community structure

The effects of an arbuscular mycorrhizal (AM) fungus (Glomus etunicatum) on atrazine dissipation, soil phosphatase and dehydrogenase activities and soil microbial community structure were investigated. A compartmented side-arm (‘cross-pot’) system was used for plant cultivation. Maize was cultivated in the main root compartment and atrazine-contaminated soil was added to the side-arms and between them 650 or 37 μm nylon mesh was inserted which allowed mycorrhizal roots or extraradical mycelium to access atrazine in soil in the side-arms. Mycorrhizal roots and extraradical mycelium increased the degradation of atrazine in soil and modified the soil enzyme activities and total soil phospholipid fatty acids (PLFAs). Atrazine declined more and there was greater stimulation of phosphatase and dehydrogenase activities and total PLFAs in soil in the extraradical mycelium compartment than in the mycorrhizal root compartment when the atrazine addition rate to soil was 5.0 mg kg⁻¹. Mycelium had a more important influence than mycorrhizal roots on atrazine degradation. However, when the atrazine addition rate was 50.0 mg kg⁻¹, atrazine declined more in the mycorrhizal root compartment than in the extraradical mycelium compartment, perhaps due to inhibition of bacterial activity and higher toxicity to AM mycelium by atrazine at higher concentration. Soil PLFA profiles indicated that the AM fungus exerted a pronounced effect on soil microbial community structure.