Incipient Forest Decline in the Province of Trento (Northern Italy). Preliminary Sem Observations and Consideration of Inorganic Components of Leaves and Roots

One year old needles of both healthy and damaged silver fir and Norway spruce from the area of Trento (Northern Italy) were observed by SEM. Needles of damaged trees show quite evident structural alterations of epidermis, expecially epicuticular waxes. Roots and needles of both fir and spruce are also tested for their metal content. Evidence is reported of an increasing concentration of Fe, Mg and Ca in roots of plants grown on alkali soil. Ca, and to a lesser extent Fe, Al and Pb, appears to be more present in old needles, whereas K and Mg exhibit higher amounts in young needles. Some indications are found between damage and the content of some metals such as Mg and Mn in needles.     

Applying the concept of agrodiversity to indigenous soil and water conservation practices in eastern Kenya

Agrodiversity – the diversity of cropping systems, crop species and farm management practices has received increasing attention in recent years as a way of spreading risk and supporting food security in resource-poor farming systems. This paper discusses the dynamic aspects of indigenous soil and water conservation (ISWC) practices in a semi-arid part of Kenya. The objective is to show the range of sources of variability and diversity that prevail in this environment, the responses of farmers to this variability, and the way farmers' rationalise the heterogeneity of soil and water management practices. Methods used included participatory surveys and evaluations, on-farm monitoring, soil and rainfall data analyses, and questionnaire surveys. Sources of variability affecting cropping systems and land management practices included rainfall, soil fertility, farmer resource level and farm productivity. A decision-tree was developed to examine how biophysical and socio-economic variability affected farmers' choice of ISWC. Different ISWC structures dominated on sandy and stony soils, respectively. Low resource farmers tended to choose cheaper and less labour demanding techniques, and constructed smaller ISWC structures than better endowed farmers. The largest diversity of ISWC practices was found on newly-opened land with mixed soils. Moreover, on-farm productivity levels indicated that costly investments in SWC are unfeasible, as this would further increase the risk for negative returns to farming. The wider implications of the results are that SWC interventions in marginal areas should build on the existing agrodiversity and an understanding of the complex interactions between environmental and socio-economic factors that give rise to differences in farming systems and land management practices.     

Egg testosterone affects wattle color and trait covariation in the ring-necked pheasant

Transfer of maternal hormones to the eggs is a major source of offspring phenotypic variation. The developmental and organizational effects of egg hormones can extend into adulthood and affect behavioral and morphological traits involved in sexual and reproductive behavior, with important consequences for offspring fitness. In this study, we injected testosterone (T) in egg albumen of captive ring-necked pheasant (Phasianus colchicus) eggs. We then assessed the consequences for chick growth, cell-mediated immunity, and multiple male secondary sexual traits at maturity by comparison with a control group. We also compared the covariation between traits in the two experimental groups. We found that control males had redder wattles than males from T-injected eggs, suggesting that attractiveness and reproductive success of the offspring might vary depending on maternal transfer of T to the eggs. T treatment also modified the covariation between cell-mediated immunity and wattle coloration and between the area of the wattle and the expression of another secondary sexual trait, the ear tufts. These effects are likely to translate into fitness differences among the offspring if mate acquisition depends on the simultaneous expression of several traits that are differentially affected by the same maternal contribution. Maternal effects mediated by egg hormones might affect the fitness of the offspring not only by directional modification of phenotypic traits, but also by facilitating or inhibiting their covariation. This suggests the possibility that female choice based on the relative expression of multiple secondary sexual traits exerts a pressure on how maternal transfer of androgens contributes to developmental programs.     

Assessing health risk from benzene pollution in an urban area

A health hazard, specifically the leukaemia risk, is evaluatedfrom different sources of benzene exposure with relation to apopulation living in an urban area of Italy. The population exposure is calculated for a reference year by sexand lyfestyle, with respect to smokers and non smokers. Potentialhealth risk is therefore quantified by means of mathematicalmodels and the relative significance of the different sources is described. The results of the analysis are useful for the identification ofappropriate risk reduction strategies to minimize exposure, inparticular when resulting from lifestyle and personal activities.     

Bioremediation of petroleum‐impacted soils from investigation‐derived wastes

Optimal conditions for bioremediation of investigation‐derived wastes from petroleum‐impacted soils (PIS) were determined through biotreatability experiments. The PIS was collected as extruded cores obtained during sample drilling. These samples were processed into workable media prior to treatment in bioreactors. Soil moisture content in the bioreactors was adjusted to 30 percent, 40 percent, 50 percent (control), and 60 percent, dry‐weight basis, and nutrient levels were adjusted by applying fertilizer, yielding carbon (C) to nitrogen (N) ratios of 20:1, 10:1, and 5:1, versus a control C:N ratio of 140:1. Temperature, pH, viable bacterial plate counts, contaminant degradation rate, and microbial respiration were monitored. Concentrations of three selected branched alkanes in the aviation fuel contaminant, measured by gas chromatography, decreased for most treatments. The greatest degradation occurred with a moisture content of 40 percent and C:N ratio of 5:1. Increased contaminant degradation was consistent with increased microbial activity measured by respiration. There was poorer correlation between contaminant degradation and viable plate counts, which suggests that respirometry is a better measure of activity of the microbial population responsible for contaminant degradation. General plate counts, which enumerate only a fraction of the total population, may not be a reliable quantitative indicator of the actual microorganism population that is responsible for degradation. © 2003 Wiley Periodicals, Inc.     

Nestling rearing is antioxidant demanding in female barn swallows (Hirundo rustica)

Reproduction is a demanding activity, since organisms must produce and, in some cases, protect and provision their progeny. Hence, a central tenet of life-history theory predicts that parents have to trade parental care against body maintenance. One physiological cost thought to be particularly important as a modulator of such trade-offs is oxidative stress. However, evidence in favour of the hypothesis of an oxidative cost of reproduction is contradictory. In this study, we manipulated the brood size of wild barn swallows Hirundo rustica soon after hatching of their nestlings to test whether an increase in nestling rearing effort translates into an increased oxidative damage and a decreased antioxidant protection at the end of the nestling rearing period. We found that, while plasma oxidative damage was unaffected by brood size enlargement, females rearing enlarged broods showed a decrease in plasma non-enzymatic antioxidants during the nestling rearing period. This was not the case among females rearing reduced broods and among males assigned to either treatment. Moreover, individuals with higher plasma oxidative damage soon after the brood size manipulation had lower plasma non-enzymatic antioxidants at the end of the nestling rearing period, suggesting that non-enzymatic antioxidants were depleted to buffer the negative effects of high oxidative damage. Our findings point to antioxidant depletion as a potential mechanism mediating the cost of reproduction among female birds.     

Relevance of wound-activated compounds produced by diatoms as toxins and infochemicals for benthic invertebrates

Plants evolve the production of wound-activated compounds (WACs) to reduce grazing pressure. In addition, several plant-produced WACs are recognized by various invertebrates, playing the role of infochemicals. Due to co-evolutionary processes, some invertebrates recognize plant infochemicals and use them to identify possible prey, detect the presence of predators or identify algae containing various classes of toxic metabolites. Different metabolites present in the same algae can play the role of toxins, infochemicals or both simultaneously. We investigated the infochemical activity of compounds extracted from three diatoms epiphytes of the seagrass Posidonia oceanica, by conducting choice experiments on invertebrates living in the same community or in close proximity. Furthermore, the specific toxicity of the extracts obtained from the same algae was tested on sea urchin embryos using a standard bioassay procedure, to detect the presence of toxins. The comparison of the two effects demonstrated that invertebrates are subjected to diatom wound-activated toxicants when these algae are not associated with their own habitat, but they are able to recognize volatile infochemicals derived from diatoms associated with their habitats. The specific toxicity of WACs was shown to be inversely correlated to the perceptive ability of invertebrates towards volatile compounds liberated by the same algae. Hence, when the recognition of specific algae by a given invertebrate species evolves, their detrimental effects on the receiving organism may be lost.