The influence of land abandonment on forest disturbance regimes: a global review

Landscape Ecology - Since the nineteenth century, rural areas have experienced progressive abandonment mostly due to socioeconomic changes, with direct and indirect effects on forest disturbance...     

Activity of extracts from wild edible herbs against postharvest fungal diseases of fruit and vegetables

The use of plant extracts could be a useful alternative to synthetic fungicides in the management of rot fungi during postharvest handling of fruit and vegetables. The aim of this study was to assess the in vitro and in vivo activity of extracts obtained from nine wild edible herbaceous species (Borago officinalis, Orobanche crenata, Plantago coronopus, P. lanceolata, Sanguisorba minor, Silene vulgaris, Sonchus asper, Sonchus oleraceus, and Taraxacum officinale) against some important postharvest pathogens, i.e. Botrytis cinerea, Monilinia laxa, Penicillium digitatum, P. expansum, P. italicum, Aspergillus carbonarius, and A. niger. Phenolic composition of all extracts was evaluated by HPLC. Several derivatives of caffeic acid, of the flavones apigenin and luteolin, and of the flavonols kaempferol and quercetin, were identified. Extracts from S. minor and O. crenata showed the highest efficacy in all the trials. In particular, S. minor completely inhibited in vitro the conidial germination of M. laxa, P. digitatum, P. italicum, and A. niger and strongly reduced those of B. cinerea; O. crenata extract showed a lower but still significant reduction of conidial germination on all the tested fungi. Moreover, the extracts from both species were effective in reducing the germ tube elongation also when a slight inhibition of conidial germination was observed. In many cases, a dose effect was observed, with an increase of antifungal activity as the phenolic concentration increased. In trials performed on wounded fruit, S. minor extract completely inhibited brown rot on apricots and nectarines; O. crenata extract strongly reduced grey mould, brown rot, and green mould on table grapes, apricots and nectarines, and oranges, respectively. The inhibition efficacy of extracts was ascribed to the presence of some caffeic acid derivatives and/or flavonoids. HPLC phenolic analyses provided useful information to identify the possible active compounds.     

Evolution of clinical, haematological and biochemical findings in young dogs naturally infected by vector-borne pathogens

Longitudinal studies evaluating the evolution of clinical, haematological, biochemical findings in young dogs exposed for the first time to multiple vector-borne pathogens have not been reported. With the objective of assessing the evolution of clinical, haematological and biochemical findings, these parameters were serially monitored in naturally infected dogs throughout a 1-year follow-up period. Young dogs, infected by vector-borne pathogens based on cytology or polymerase chain reaction, were examined clinically and blood samples were obtained at seven different follow-up time points. Dogs were randomized to group A (17 dogs treated with a spot-on formulation of imidacloprid 10% and permethrin 50%) or to group B (17 dogs untreated). In addition, 10 4-month-old beagles were enrolled in each group and used as sentinel dogs. At baseline, Anaplasma platys was the most frequently detected pathogen, followed by Babesia vogeli, Bartonella spp., Ehrlichia canis and Hepatozoon canis. Co-infections with A. platys and B. vogeli, followed by E. canis and B. vogeli, A. platys and H. canis and A. platys and Bartonella spp. were also diagnosed. In dogs from group B, abnormal clinical signs were recorded at different time points throughout the study. No abnormal clinical signs were recorded in group A dogs. Thrombocytopenia was the most frequent haematological alteration recorded in A. platys-infected dogs, B. vogeli-infected dogs and in dogs co-infected with A. platys and B. vogeli or A. platys and Bartonella spp. Lymphocytosis was frequently detected among dogs infected with B. vogeli or co-infected with A. platys and B. vogeli. Beagles were often infected with a single pathogen rather than with multiple canine vector-borne pathogens. There was a significant association (p<0.01) between tick infestation and A. platys or B. vogeli, as single infections, and A. platys and B. vogeli or A. platys and Bartonella spp. co-infections. This study emphasizes the clinical difficulties associated with assigning a specific clinical sign or haematological abnormality to a particular canine vector-borne disease.     

Mitochondrial cytochrome c oxidase subunit 1 (cox1) gene sequence of Spirocerca lupi (Nematoda, Spirurida): avenues for potential implications

Canine spirocercosis is a life-threatening parasitosis caused by Spirocerca lupi (Nematoda, Spirurida) that is presently emerging in several countries. This study characterised an informative region within the mitochondrial (mtDNA) gene encoding for the cytochrome c oxidase subunit 1 (cox1) of S. lupi by Polymerase Chain Reaction (PCR)-coupled sequencing. Specimens from five different countries in Europe, Asia and Africa were examined and two different sequence variants of cox1 (i.e. haplotypes) were determined, displaying nucleotidic variation at 6 of 689 positions. All of these positions were invariable among all the parasite individuals from Europe (haplotype 1) and among the African and Asian individuals (haplotype 2), but differed between Europe and Asia/Africa. The S. lupi cox1 sequences were consistent with those of other common Spirurida previously reported at both nucleotidic and phylogenetic levels. This study provides molecular information essential for identification of the nematode, irrespective of its life cycle stage. Crucial implications for the specific molecular diagnosis of clinical spirocercosis and investigation of the evolution, population genetics, ecology and epidemiology of S. lupi are discussed.     

Factors affecting the contents of iridoid oleuropein in olive leaves (Olea europaea L.)

In this study, for the first time, the impact of the genetic factor on the contents of oleuropein in olive leaves was not only evaluated but the influence exerted by the color/age of leaves (green, green-yellowish, and yellow) and the collecting period (spring or autumn) was also evaluated. A repetitive high-resolution gas chromatographic quantitation method and an accurate high-performance liquid chromatographic method were developed. These analytical methods gave results showing a highly linear relationship. Samples of olive leaves were taken from seven major Italian olive cultivars, such as Dritta, Leccino, Caroleo, Coratina, Castiglionese, Nebbio, and Grossa di Cassano. Such a vegetal raw material could actually be exploited for recovering oleuropein, considered to be a high-added value molecule. This could be converted into hydrxytyrosol, a compound known to possess strong bioactive properties. Olive leaves showed considerable contents of oleuropein, which with some cultivars were even higher with respect to those present in the corresponding olive fruits (reported in the literature). The amounts of oleuropein in the collected leaves were markedly modified by the color/age and genetic factors, whereas meaningless variations were ascribable to the quantitation method and the collecting period factors. Various chemometrics, applied to the obtained analytical data, appeared to be effective in discriminating the samples on the basis of the above-examined experimental factors, thus confirming how these should be taken into account in future industrial recovery of oleuropein from olive leaves.     

Bird communities following high-severity fire: Response to single and repeat fires in a mixed-evergreen forest,Oregon, USA

Fire is a widespread natural disturbance agent in most conifer-dominated forests. In light of climate change and the effects of fire exclusion, single and repeated high-severity (stand-replacement) fires have become prominent land management issues. We studied bird communities using point counting in the Klamath-Siskiyou ecoregion of Oregon, USA at various points in time after one or two high-severity fires. Time points included 2 and 3 years after a single fire, 17 and 18 years after a single fire, 2 and 3 years after a repeat fire (15 year interval between fires), and >100 years since stand-replacement fire (mature/old-growth forest). Avian species richness did not differ significantly among habitats. Bird density was highest 17 and 18 years after fire, lowest 2 years after fire, and intermediate in repeat burns and unburned forest. Bird community composition varied significantly with habitat type (A = 0.24, P < 0.0001) with two distinct gradients in species composition relating to tree structure (live to dead) and shrub stature. Using indicator species analysis, repeat burns were characterized by shrub-nesting and ground-foraging bird species while unburned mature forests were characterized by conifer-nesting and foliage-gleaning species. Bird density was not related to snag basal area but was positively related to shrub height. Contrary to expectations, repeated high-severity fire did not reduce species richness, and bird densities were greater in repeat burns than in once-burned habitats. Broad-leaved hardwoods and shrubs appear to play a major role in structuring avian communities in the Klamath-Siskiyou region. In light of these results, extended periods of early seral broadleaf dominance and short-interval high-severity fires may be important to the conservation of avian biodiversity.     

Multivariate approach to evaluate the penetrometer resistance in different tillage systems

At present, the penetrometer is the most widely used instrument for assessing in situ soil strength, one of the extrinsic factors affecting plant growth and crop productivity. In this paper we propose a method that discriminates penetrometer resistance due to different soil treatments, by means of Principal Component (PC) analysis. We hypothesized and demonstrated that penetrometer resistance values measured at different soil depths are correlated among themselves (multicollinearity). Considering measurements at each depth as different variables, PC analysis restructured data sets containing these correlated variables into a smaller number of components, whose scores were utilized in univariate analysis of variance (ANOVA) to test differences among imposed soil treatments. We applied the procedure to penetrometer resistance values measured by means of a hand-held cone penetrometer in two long-term experiments conducted in southern Italy, on durum wheat (Triticum durum Desf.) under continuous cropping. In the first trial, four different soil tillage treatments were compared; in the second, two different tillages and two residue management systems were examined. In both trials, PC analysis reduced the original 14 depths of measurements into only 4 PC's, based on correlations of their resistance values, explaining more than 80% of the total variation. Furthermore, ANOVA applied to the scores of each PC, clearly indicated treatment effects on soil strength.

The proposed method has thus allowed assemblage a posteriori of penetration resistance data into only a few significative intervals, using correlations among the measurements made at the different depths. This way, the possible resistance differences due to tillage and/or management treatments have been more easily and more unambiguously showed.