A national level forest resource assessment for Burkina Faso - A field based forest inventory in a semiarid environment combining small sample size with large observation plots

Even though considerable parts of the global tropical forests are located in Africa, reliable data on African forest resources is limited. While this is widely recognized for tropical moist forests, it also holds for tropical dry forests. To partially fill the gap a forest inventory was carried out in Burkina Faso, West Africa. In this paper we present a methodological approach and sample based estimates of the tree and forest resources including estimates of (1) land cover classes, (2) species composition, and (3) above ground tree carbon stocks. Following the land classification of the Food and Agriculture Organization of the United Nations (FAO), the forest cover of Burkina Faso was estimated as 42.6% (116,847 km²). For the classes “other wooded land”, “other land” and “other land with tree cover” the estimates were 1.6%, 53.6%, and 9.1%, respectively. We found notable differences to the estimates published by FAO, in particular when considering the classes “forest” and “other wooded land” separately, but lesser so when the two classes are combined. That points to a major issue in applying these class definitions in semiarid environments. Given the relatively small sample size (n = 46 field observed plots), relative standard errors (SE%) of area estimates are high (around 9% for the larger area classes). Aboveground tree carbon stocks were estimated to be 6.640, 5.580 and 7.222 Mg ha⁻¹ for “forest”, “other wooded land” and “other land with tree cover”, respectively (SE% around 18% for all three estimates). Availability of biomass models is very limited for all classes, in particular when it comes to shrubs. Furthermore, it was estimated that the most abundant tree species in Burkina Faso is Vittelaria paradoxa, the “shea butter tree” which is a multi-use tree species of high relevance for rural livelihoods.To our knowledge this study is the first field-based forest inventory on national level in Burkina Faso where the estimation of errors was possible on statistical grounds, and done. The results of this study revealed major issues that should be taken into account when doing similar studies, including carbon monitoring and accounting: increasing the sample size will lead to smaller standard errors (at a higher costs, of course), but will not solve the crucial points (1) of non-availability of suitable biomass models, in particular for shrub lands and (2) of implementation issues regarding the definition of land cover types.     

Environment and tree size controlling stem sap flux in a perhumid tropical forest of Central Sulawesi,Indonesia

• Introduction   

We studied stem sap flux density in seven common tree species in a perhumid tropical rainforest at pre-montane elevation in Sulawesi with the aims (1) to analyse the among-species variation in flow patterns, (2) to search for an assumed convergence in the response to controlling environmental factors, and (3) to investigate the effect of tree size on xylem flux.     

Comparison of conventional eight-point crown projections with LIDAR-based virtual crown projections in a temperate old-growth forest

Introduction   

Sight-based field measurements of tree crown projection area and canopy height are common praxis in forest science but difficult to validate. We quantified their measurement errors based on the virtual representation of an 11-species old-growth forest provided by high-resolution terrestrial LIDAR (light detection and ranging) measurements.     

Cytochrome P450 mediated pyrethroid resistance in European populations of Meligethes aeneus (Coleoptera: Nitidulidae)

Pollen beetle, Meligethes aeneus (Coleoptera: Nitidulidae) is a major pest on several million hectares in European winter oilseed rape cultivation. Synthetic pyrethroids have been successfully used for many years to keep them under economic damage thresholds. Recently wide-spread resistance development to pyrethroids in pollen beetle populations was described in many European countries, including Germany, France, Poland, Denmark and others. Resistance monitoring is conducted by incubating beetles for 24 h in glass vials coated with different concentrations of lambda-cyhalothrin. Using such an assay format we were able to show cross-resistance to other pyrethroids, such as deltamethrin, cypermethrin, and to a somewhat lower extent bifenthrin, etofenprox and tau-fluvalinate. Here we also investigated in more detail in 27 different populations the biochemical mechanism of pyrethroid resistance. Synergism experiments revealed a high synergistic potential for piperonyl butoxide in vivo, whereas other compounds such as S,S,S-tributylphosphorotrithioate and diethylmaleimide failed to suppress pyrethroid resistance. Incubating microsomal fractions of pollen beetle with deltamethrin and subsequent LC–MS/MS analysis revealed 4-OH-deltamethrin as the major metabolite. Metabolite formation in vitro and pyrethroid resistance in vivo is correlated and inhibition trials with piperonyl butoxide, tebuconazole and aminobenzotriazole suggest the involvement of cytochrome P450′s. Furthermore we were able to show cross-resistance to tau-fluvalinate which is supported by the competitive inhibition of 4-OH-deltamethrin formation by increasing concentrations of tau-fluvalinate in microsomal hydroxylation assays. Although we provided clear experimental evidence for an oxidative mechanism of resistance in numerous populations, other mechanisms might be involved based on the data discussed.     

Pyrethroid resistance and thiacloprid baseline susceptibility of European populations of Meligethes aeneus (Coleoptera: Nitidulidae) collected in winter oilseed rape

BACKGROUND: Pollen beetle, Meligethes aeneus F. (Coleoptera: Nitidulidae), is a major pest in European winter oilseed rape. Recently, control failures with pyrethroid insecticides commonly used to control this pest have been reported in many European countries. For resistance management purposes, the neonicotinoid insecticide thiacloprid was widely introduced as a new mode of action for pollen beetle control. RESULTS: A number of pollen beetle populations collected in Germany, France, Austria, Great Britain, Sweden, Denmark, Finland, Poland, Czech Republic and Ukraine were tested for pyrethroid resistance using lambda‐cyhalothrin‐coated glass vials (adult vial test). Most of the populations tested exhibited substantial levels of resistance to lambda‐cyhalothrin, and resistance ratios ranged from < 10 to > 2000. A similar resistance monitoring bioassay for the neonicotinoid insecticide thiacloprid was developed and validated by assessing baseline susceptibility data for 88 European pollen beetle populations. A variation of less than fivefold in response to thiacloprid was detected. The thiacloprid adult vial bioassay is based on glass vials coated with an oil‐dispersion‐based formulation of thiacloprid, resulting in a much better bioavailability compared with technical material. Analytical measurements revealed a > 56 and 28 day stability of thiacloprid and lambda‐cyhalothrin in coated glass vials at room temperature, respectively. No cross‐resistance between thiacloprid and lambda‐cyhalothrin based on log‐dose probit–mortality data was detected. CONCLUSION: Pyrethroid resistance in many European populations of M. aeneus was confirmed, whereas all populations are susceptible to thiacloprid when tested in a newly designed and validated monitoring bioassay based on glass vials coated with oil‐dispersion‐formulated thiacloprid. Based on the homogeneous results, it is concluded that thiacloprid could be an important chemical tool for pollen beetle resistance management strategies in European winter oilseed rape. Copyright © 2011 Society of Chemical Industry     

Accurate determination of oosporein in fungal culture broth by differential pulse polarography

A simple and accurate differential pulse polarographic method has been developed for the determination of oosporein in the culture broth of the fungus Beauveria brongniartii. This hydroxybenzoquinone derivative is the only major secondary metabolite secreted by this entomopathogenic fungus, which is used as biological pest control agent (BCA) against Melolontha melolontha larvae. It can be found in the host organism as well as in the formulated product. The polarographic behavior of oosporein was examined in various buffer systems over the pH range 3-10. In Britton-Robinson buffer/methanol solution (3:7 v/v, pH 5.5) the differential pulse polarograms exhibited reproducible peaks at E(p) = -0.18 V vs silver/silver chloride/potassium chloride (3 M). Under these conditions, a plot of peak height vs concentration of oosporein was found to be linear over the range 5.9 x 10(-)(7) to 2.5 x 10(-)(5) M (0.18-7.74 microg mL(-)(1); r = 0.9998). The detection limit was calculated to be 54 ng mL(-)(1). To evaluate the concentration of oosporein, the standard addition method was applied. The analysis of oosporein in the culture broth led to a mean value of 524.9 microg mL(-)(1) broth with a relative standard deviation (S(rel)) of +/-2.6%. The proposed polarographic method is accurate, not time-consuming, and it is of low cost because no separation steps are necessary.     

The N transformation mechanisms for rapid nitrate accumulation in soils under intensive vegetable cultivation

Purpose  

Rapid soil degradation occurring under intensive vegetable cultivation, an increasingly common agricultural strategy in China, is characterized by soil acidification, salinity, and NO₃⁻ accumulation. However, to date, the reasons for rapid NO₃⁻ accumulation in soils at the nitrogen (N) levels have not been completely understood. In this study, we explored the underlying mechanisms for rapid NO₃⁻ accumulation in soils used for intensive vegetable cultivation and implications of altered gross N transformation rates on soil properties and sustainable cultivation.     

Epidemiological enquiries in two Q fever outbreaks in a community of Baden-Württemberg during 2008 and 2009

In 2008 and 2009, two consecutive outbreaks of Q fever in humans were recorded in the district of Freudenstadt, northern Black Forrest, Baden-Württemberg, Germany. In 2008, a total of 41 persons from a single local community fell ill and were found infected with Coxiella burnetii. Although comprehensive diagnostic and epidemiological outbreak investigations were conducted and control measures taken which included vaccination of ruminants at risk in three parts of the affected community, re-occurrence of the disease in 2009 with further 29 confirmed human Q fever cases could not be prevented. While the origin of infection of the first outbreak was probably a flock of 550 sheep moved in the surrounding of the affected villages, the source of infection for the consecutive outbreak in 2009 could not be identified. It seems possible that meadows contaminated with infectious placenta or birth fluids represented the sources of infection.     

Phenotypic and genotypic properties of Staphylococcus aureus subsp. anaerobius isolated from lymph node abscesses of goats

In the present study 20 staphylococci isolated from lymph node abscesses of 19 goats of two herds in Western Poland could be identified as Staphylococcus aureus subsp. anaerobius. All 20 strains grew under microaerobic conditions, were negative in the catalase test, showed the typical phenotypic properties of 5. aureus and could genotypically be identified by a positive sa442, 235 rDNA, nuc, coa and spa PCR reaction. The variable regions of the coa and spa gene of the 20 strains appeared with uniform amplicon sizes, respectively. All 20 strains were negative for 12 additionally investigated enterotoxin encoding genes, tst and ssl7 and positive for the gene cap8. Identical properties could be observed for S. aureus subsp. anaerobius DSM 20714. Amplification and sequencing of kat gene of a single Staphylococcus aureus subsp. anaerobius strain of the present study and S. aureus subsp. anaerobius DSM 20714 revealed a complete identity of the kat sequences of both strains and a katB sequence obtained from GenBank (AJ000471). The bacteria were additionally investigated for relatedness by macrorestriction analysis of chromosomal DNA with subsequent pulsed-field gel electrophoresis (PFGE), yielding, corresponding to the above mentioned PCR results, identical PFGE patterns for all 20 Staphylococcus aureus subsp. anaerobius strains isolated in Western Poland and the S. aureus subsp. anaerobius reference strain DSM 20714.This indicates the clonal identity of the strains isolated in Western Poland and the S. aureus subsp. anaerobius reference strain. The route of infection of the two herds in Western Poland with a bacterial clone originally isolated in Spain remains unclear.