Biological and Artificial Matrixes as PAH Accumulators: An Experimental Comparative Study

In order to find out a new effective accumulator of polycyclic aromatic hydrocarbons (PAHs) useful for monitoring studies on a large scale and low costs, the accumulation capacity of both biological and artificial matrixes (mosses and polyester fibers, respectively) has been tested. For this purposes, Hypnum cupressiforme and dacron® were exposed to pollution airborne in two sites located nearby an active iron industry and in center of the town of Trieste, where high PAH pollution spots, due to vehicular traffic, are usually detected. The samplers were exposed in six sampling sessions for 21 days. The results obtained were compared with data collected by active PAH samplers, usually employed for official widespread monitoring. The level of correlation between the data sets was calculated. Furthermore, a repeatability study of data was performed. According to the results, both matrixes are good PAH accumulators, though they show different skills.     

Using a Chlorophyll Meter to Optimize Nitrogen Fertilizer Application for Intensively-Managed Small-Grain Cereals

Most methods used to estimate N status require collection, processing and analysis of soil and/or plant tissue samples. In this study, leaf chlorophyll content of cereals, determined in the field with a portable chlorophyll meter (Minolta SPAD-502), was used to predict N availability of wheat ( Triticum aestivum L.), barley ( Hordeum vulgare L.), oats ( Avena sativa L.) and rye ( Secale cereale L.). The results indicated that accurate nitrogen (N) fertilizer recommendations based on chlorophyll content have both environmental and economic advantages. Determination of leaf chlorophyll content with a chlorophyll meter accurately indicated plant N status allowing N fertilizer requirement to be accurately determined and resulting in increased N uptake efficiency. Applying N fertilizer on this basis improved production economics and improved physical input-output ratio during grain yield formation. Using a chlorophyll meter, responsive and non-responsive categories can be determined at the stage of maximum number of florets per ear primordium (Zadoks' GS 37-41) and at pollination (i.e. pollen grains on well-developed stigmatic hairs, GS 52-58).     

Do enchytraeid worms and habitat corridors facilitate the colonisation of habitat patches by soil microbes?

Due to their high abundance and ubiquitous existence, microbes are considered to be efficient colonisers of newly established habitats. To shed light on the dispersal mechanisms of soil microbes, a controlled microcosm experiment was established. In these microcosms, the dispersal of microbes from a source humus patch to originally sterile humus patches (embedded in a mineral soil matrix) was followed for 16 months, applying 16S and 18S ribosomal DNA-based PCR-DGGE molecular methods. Specifically, the role of enchytraeid worms and habitat (humus) corridors as possible facilitators of microbe dispersal was studied. The results showed that enchytraeid worms function efficiently as vectors for horizontal dispersal of saprophytic fungi in soil. Some of the fungi also proved to disperse through the corridors by vegetative growth, although this dispersal was inefficient as compared to dispersal with the enchytraeids. Virtually no saprophytic fungi were able to disperse through the mineral soil matrix in the absence of both enchytraeid worms and corridors. Unlike soil fungi, the dispersal of soil bacteria was not affected by any of the studied factors. The results of the present experiment provide direct evidence of the crucial role of soil fauna in aiding the horizontal dispersal of soil fungi. The role of enchytraeids as a functionally important species in boreal forest soils is further emphasized, since bringing microbes into contact with new resources is likely to enhance the rate of decomposition in soils.     

Role of adenine nucleotide translocator 1 in mtDNA maintenance

Autosomal dominant progressive external ophthalmoplegia is a rare human disease that shows a Mendelian inheritance pattern, but is characterized by large-scale mitochondrial DNA (mtDNA) deletions. We have identified two heterozygous missense mutations in the nuclear gene encoding the heart/skeletal muscle isoform of the adenine nucleotide translocator (ANT1) in five families and one sporadic patient. The familial mutation substitutes a proline for a highly conserved alanine at position 114 in the ANT1 protein. The analogous mutation in yeast caused a respiratory defect. These results indicate that ANT has a role in mtDNA maintenance and that a mitochondrial disease can be caused by a dominant mechanism.     

Cost-effective strategies to conserve boreal forest biodiversity and long-term landscape-level maintenance of habitats

Setting aside parcels of land is the main conservation strategy to reduce the rate of biodiversity loss worldwide. Because funding for biological conservation is limited, it is important to distinguish the most efficient ways to use it. Here, we assess implications of alternative measures to conserve biodiversity in managed boreal forest landscapes. We calculated four alternative spatio-temporal scenarios and compared these to the current management regime over 100-year time period. In the alternative scenarios, a fixed amount of funding was invested in (1) permanent large reserves (each tens of ha in size), (2) permanent small reserves (each a few ha in size), (3) temporary small reserves (based on 10-year contracts with private land owners), and (4) green-tree retention (small groups of trees retained on clear-cuts). To assess biodiversity implications, we used habitat suitability indices to calculate overall habitat availability for five groups of red-listed and habitat-specific species associated with decaying spruce logs. The possibilities for timber harvests did not differ among the scenarios, but biodiversity performance was different. The scenarios with permanent reserves tended to outperform other scenarios, suggesting that conservation policies based on permanent reserves are the most cost-efficient in the long term. Results, however, varied among time scales and species groups. In the short term, a strategy of investment in temporary small reserves was the most efficient. Habitat for species associated with old spruce dead-wood and preferring shade was rare throughout all simulations, and therefore, it is likely that these species cannot be sustained in managed forests. Species that live on fresh dead-wood and are associated with forest edges coped well in all scenarios suggesting that such species will persist in managed landscapes without additional conservation efforts. Explicit definition of conservation objectives and time frames for conservation action are thus prerequisites for successful conservation planning.     

Soil decomposer community as a model system in studying the effects of habitat fragmentation and habitat corridors

Due to the practical difficulties of experimental study of habitat fragmentation and habitat corridors at the landscape scale, the use of smaller-scale model systems has been offered as a feasible alternative to uncover the ecological phenomena taking place in fragmented environments. In this mini-review, we consider the applicability of the soil decomposer community as such a model system. For the most part, this article is based on the few studies that have explicitly addressed this question by experimental manipulations of the natural habitat of soil decomposer community. However, to broaden the view, we also capitalize upon studies focusing on the effects of isolation and soil use changes on soil organisms and on dispersal of soil fauna, all of these being considered as factors determining the sensitivity of organisms to habitat fragmentation. Since usability of a model system by definition depends on the possibility of applying the results to other (usually larger scale) systems, we discuss the characteristics of the soil decomposer community also from this point of view.The existing data suggest that soil organisms, in general, are not sensitive to habitat fragmentation even in small scale. Because of this, and the unique features of the belowground environment and its biota combined with gaps in the knowledge of the life history characteristics of soil organisms, the soil decomposer community is not ideal for predicting the implications of habitat fragmentation and habitat corridors on threatened species. Despite this, we still believe that there are lessons to be learned by studying the effects of habitat fragmentation on this important community of organisms, especially in combination with the consequences of ongoing climate change.