Impact of land-use type and harvesting on population structure of a non-timber forest product-providing tree in a semi-arid savanna, West Africa

Non-timber forest products (NTFPs) strongly contribute to livelihood security in the semi-arid tropics. Main factors determining the populations of NTFP-providing species are human activities. This study examined the impact of land-use, combined with rates and patterns of debarking and chopping on a NTFP-providing tree (Anogeissus leiocarpa) in Burkina Faso. We compared stands in a protected area (W National Park) with those of its surrounding communal area (fallows, croplands) in order to (i) obtain an indication on the status of the population, (ii) assess its harvesting tolerance, (iii) estimate the sustainability of present management, and (iv) derive which additional management strategies may foster its conservation. Our results reveal that the stands of A. leiocarpa are in healthy states in fallows and in the park. In croplands, the absence of saplings gives evidence of a declining population. Nearly all individuals of A. leiocarpa were harvested in croplands and fallows, while the number of harvested individuals in the park was negligible. Intensity of debarking and chopping was tree size-specific. The sprouting ability significantly increased with higher chopping intensity. We conclude that despite the land-use impact and the intense harvesting, stands of A. leiocarpa are still well preserved due to the species life history (fast growing and high sprouting) and due to indirect positive influences of human activities by providing better environmental conditions for its recruitment. Thus, the population of A. leiocarpa is not at risk to over-harvesting and land-use even though it is not protected.     

Soil chemical properties and microbial biomass after 16 years of no-tillage farming on the Loess Plateau, China

Data from a 16-year field experiment conducted in Shanxi, on the Chinese Loess Plateau, were used to compare the long-term effects of no-tillage with straw cover (NTSC) and traditional tillage with straw removal (TTSR) in a winter wheat (Triticum aestivum L.) monoculture. Long-term no-tillage with straw cover increased SOM by 21.7% and TN by 51.0% at 0–10 cm depth and available P by 97.3% at 0–5 cm depth compared to traditional tillage. Soil microbial biomass C and N increased by 135.3% and 104.4% with NTSC compared to TTSR for 0–10 cm depth, respectively. Under NTSC, the metabolic quotient (CO₂ evolved per unit of MBC) decreased by 45.1% on average in the top 10 cm soil layer, which suggests that TTSR produced a microbial pool that was more metabolically active than under NTSC. Consequently, winter wheat yield was about 15.5% higher under NTSC than under TTSR. The data collected from our 16-year experiment show that NTSC is a more sustainable farming system which can improve soil chemical properties, microbial biomass and activity, and thus increase crop yield in the rainfed dryland farming areas of northern China. The soil processes responsible for the improved yields and soil quality, in particular soil organic matter, require further research.     

Molecular analysis of the Arbuscular mycorrhiza symbiosis

The molecular analysis of the arbuscular mycorrhizal (AM) symbiosis started at the beginning of this decade. The paper summarises the work of the ‘Laboratorium für Molekulare Genetik arbuskulärer Mykorrhiza’ at the MPI für terrestrische Mikrobiologie in Marburg on three major topics. Firstly, the plant response to the mycorrhizal colonisation was analysed using both, targeted and non‐targeted approaches. As an example, the localisation of the gst1 mRNA in potato mycorrhiza is shown. Second, molecular techniques were established to analyse gene expression of the fungal partner of the symbiosis. We present a differential RNA display analysis of spore germination in two AM fungi and the cloning of a gene from Glomus mosseae that shows expression at all stages of the fungal life cycle. In the last part, we introduce the work we are carrying out with a new root endophytic fungus, Piriformospora indica. Infection experiments on maize showed that despite the fungus performs as a root necrotroph, it has a positive effect on plant growth.     

Efficacy of Common Aquaculture Compounds for Disinfection of Flavobacterium columnare and F. psychrophilum

Flavobacterium columnare and F. psychrophilum are important pathogens of the aquaculture industry, and thus disinfection of aquaculture systems and equipment is essential for disease control. This study examined commercially available compounds in vitro for their ability to eliminate these two species of Flavobacterium from the water. The compounds evaluated included Clorox, ethanol, Roccal, Lysol, iodine, formalin, Chloramine-T, glutaraldehyde, potassium permanganate, sodium chloride, and Virkon Aquatic. In this study, 70% ethanol, 50% ethanol, Clorox, Roccal, Lysol, iodine, glutaraldehyde, Chloramine-T, and Virkon Aquatic reduced the number of bacteria of both species to zero within one minute of contact time. Formalin and 30% ethanol also killed both species of bacteria, but required a longer contact time. Potassium permanganate killed F. columnare within one minute, but did not reduce the numbers of F. psychrophilum even after one hour of contact time. Sodium chloride was not effective.     

Influence of floor surface and access to pasture on claw health in dairy cows kept in cubicle housing systems

In this study, the effects on the claw health of dairy cows of three different floor types and access to pasture were investigated on 35 farms. The farms were fitted with a given floor type in the indoor walking area of a cubicle housing system: a solid rubber, mastic asphalt or slatted concrete floor. Because we chose farms on which the given floor type was in good condition, the data presented show what can be achieved on these types of floors under ideal circumstances. Cows on half of the farms per floor type had access to pasture during the grazing period. Each farm was visited three times at approx. 6-month intervals at the end of the winter indoor-housing period and at the end of the summer period, i.e. after the period with access to pasture on half of the farms. During each visit, the claw health of the same 10 cows per farm was assessed on the occasion of routine claw trimming. The proportion of cows with haemorrhages increased from mastic asphalt to rubber and slatted concrete floors. A lower proportion of cows kept on mastic asphalt was affected by white-line fissures and needed intermittent claw-trimming, an indicator for lameness. Cows housed in cubicle systems with slatted concrete floors were at the lowest risk of having heel-horn erosions. Access to pasture was associated with a lower incidence of slight white-line fissures and dermatitis digitalis. A higher proportion of cows with sole haemorrhages and sole ulcers were found on all floor types at the end of the summer period than at the end of the winter indoor-housing period. Floor type did not influence the presence of sole ulcers and deep white-line fissures. In conclusion, the effect of floor type on claw health was slight, and none of the investigated floor types was clearly superior to the others. Access to pasture was not effective in reducing the presence of most types of claw lesions associated with the floor type used in the indoor walking area.     

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Simulation of climate-change scenarios to explain Usutu-virus dynamics in Austria

The emergence and spread of infectious diseases in mid-latitudes, so far mainly observed in the tropics, considerably increase under the current situation of climate change. A recent example is the Usutu virus (USUV) outbreak in Austria. USUV is closely related to the West Nile virus in the U.S. and caused mass mortalities mainly of blackbirds (Turdus merula). The USUV flavivirus persists in a natural transmission cycle between vectors (mosquitoes) and host reservoirs (birds) and leads - once endemic in a population - to periodic outbreaks. In an epidemic model to explain the USUV dynamics in Austria 2001-2005, USUV dynamics were mainly determined by an interaction of bird immunity and environmental temperature. To investigate future scenarios, we entered temperature predictions from five global climate models into the USUV model and also considered four different climate-warming scenarios defined by the I ntergovernmental Panel on Climate Change, IPCC (20 different model-scenario combinations). We downscaled the 20 time series of predicted temperatures (through the year 2100) to represent the region around Vienna. Our simulations predict that USUV will persist in the host population after the epidemic peak observed in 2003. USUV-specific annual blackbird-mortality time series predict that the outbreak frequency increases successively from the beginning to the end of the century. Simulations of worst-case scenarios result in an endemic equilibrium with a decline of the blackbird population of about 24%. Additionally we calculated the annually averaged basic reproduction number for the period 1901-2100. The latter depict that undetected major outbreaks before 2000 were unlikely, whereas it is likely that the USUV becomes endemic after 2040.     

Toxicological and analytical investigations of noni (Morinda citrifolia) fruit juice

Morinda citrifolia (noni) is known to contain genotoxic anthraquinones in the roots. Because of the widespread use of noni juice, the possible genotoxic risk was examined through a battery of short-term tests. Noni juice was also chemically analyzed for the possible presence of anthraquinones. Noni juice extract in the Salmonella microsome assay showed a slight mutagenic effect in strain TA1537, due to the presence of flavonoids. No mutagenicity was observed in the mammalian mutagenicity test with V79 Chinese hamster fibroblasts. Rats treated with a noni juice concentrate did not show DNA repair synthesis (UDS) in primary rat hepatocytes, nor could DNA adducts or DNA strand breaks be observed. HPLC analysis of noni juice for anthraquinones was negative, with a sensitivity of <1 ppm. In summary, chemical analysis and genotoxicity tests reveal that noni juice does not have a genotoxic potential and that genotoxic anthraquinones do not exist in noni juice.