A size‐age model based on bootstrapping and Bayesian approaches to assess population dynamics of Anguilla anguilla L. in semi‐closed lagoons

A size‐age modelling technique is presented for assessing the vital rates, stock and recruitment of eel populations in semi‐closed lagoons with fully monitored migration of silver eels. Data for yellow and silver European eels (Anguilla anguilla L.) were obtained in 2011 from the Comacchio lagoon (Italy). The analysis was performed in three steps: (i) correction of yellow eel data, which are affected by the fyke nets selectivity during samplings, (ii) estimation of survival curve, stock, recruitment and metamorphosis rates of the population (calibration using data from 2011) and (iii) validation of the model using the observed amount of silver eel migrating population of the next year. A bootstrap procedure was used to assess the level of uncertainty for each parameter using the 95% intervals of the highest posterior density distribution HPDD (Bayesian approach). The measured abundance of silver eels was 0.56 ind·ha^?1, while the yellow eel abundance and recruitment were estimated by the model for 2011 at 8.77 ind·ha^?1 and 5.99 ind. ha^?1 respectively. The model performance during validation was satisfactory as the observed total mass of migrating population of 2012 (3777 kg) was inside the 95% HPDD intervals (3197–3839 kg) of model's predictions. The estimated stocks and recruitment were at least ten times lower from the respective estimations of previous studies of 1989 highlighting the crucial conditions of the population. The proposed modelling approach can provide significant information about eel population conditions, facilitating the evaluation of a range of management options in the context of eel conservation plans.     

Contrasting land use legacy effects on forest landscape dynamics in the Italian Alps and the Apennines

Landscape Ecology - Land use legacies of human activities and recent post-abandonment forest expansion have extensively modified numerous forest landscapes throughout the European mountain ranges....     

A preliminary investigation of the relationship between the “moment of resistance” of the canine spine, and the frequency of traumatic vertebral lesions at different spinal levels

The aims of this work were to re-evaluate the moments of resistance (MoRs) of the vertebral column proposed by Slijper (1946) in the dog and to study the relationship between the MoRs and the frequency distribution of vertebral traumas in the same species. The spine (C2-L7) of four dogs was measured to obtain MoRs and subsequently scanned with a dual-energy X-ray absorptiometer (DXA). These findings were then analysed retrospectively the frequency distribution of canine vertebral fractures and luxations, diagnosed radiographically at a referral practice. The highest percentage of vertebral injuries affected the T9-L7 tract. This study confirmed that this segment was characterized by a rising trend of the MoR curves and presumably bore the major bending forces. The significant correlation between T9-L1 MoRs and DXA values supports the Slijper’s hypothesis suggesting the posterior thoracic region as the weakest segment of the body-axis.     

Unravelling landslide risk: soil susceptibility,agro‐forest systems and the socio‐economic profile of rural communities in Italy

Landslides are considered a form of physical soil degradation and are concentrated, especially in southern European countries, on inland and marginal rural areas. Low‐density, economically disadvantaged and poorly accessible areas are assumed to share a high landslide occurrence probability. However, an empirical verification of this assumption is still lacking for Mediterranean countries. This study investigates the spatial relation between a composite index of landslide risk and more than 100 indicators at the municipal level in Italy – a country with high landslide risk – exploring multiple territorial dimensions (population dynamics and settlements, job market and human capital, economic specialization and competitiveness, quality of life, agriculture and rural development, territory and environment). We combine nonparametric correlation, principal component analysis and hierarchical clustering, to profile municipalities according to their levels of landslide risk. The high landslide risk in certain areas of Italy is related to specific socio‐economic attributes (depopulation, ageing, tourism specialization, low density of economic activities, modest participation to the job market and crime intensity) and agro‐environmental features (low‐intensity cropping systems, natural landscapes and water resource availability).     

Susceptibility to flavescence dorée of different Vitis vinifera genotypes from north-western Italy

The aim of this work was to evaluate the susceptibility to flavescence dorée (FD) of 12 Vitis vinifera cultivars grown in Piedmont, and representative of the wine-making tradition of this area. The experiments were conducted under controlled conditions to ensure constant infection pressure. Test plants were ex vitro potted vines, singly inoculated with four Scaphoideus titanus infected by FD-C phytoplasma (FDp), under greenhouse conditions. Vines were tested for FDp at 5 and 8 weeks postinoculation (wpi) and the phytoplasma load was measured in leaves and roots at 8 wpi. Within the 14 V. vinifera accessions (belonging to 12 cultivars), three susceptibility clusters were identified. Cultivars within the low susceptibility group showed low phytoplasma loads and low percentages of infected plants, suggesting a tolerant behaviour. To confirm these results, four Vitis cultivars, representing extremes of FD susceptibility from low to high, were grafted onto Kober 5BB rootstocks and inoculated with laboratory-infected S. titanus, under semi-field conditions. The transmission experiments onto grafted cuttings confirmed that susceptibility to the disease depends on the scion genotype. The data indicated that none of the tested V. vinifera genotypes are resistant to FD, although some cultivars with low susceptibility are available, and can be explored for identifying genetic traits involved in disease tolerance/resistance. Moreover, ranking Vitis genotypes for their susceptibility to FD is in itself a valuable tool to support vine growers in their decision management, by helping them to choose the most appropriate varieties according to their specific FD epidemiological contexts.     

Pathogenicity and infectivity of Phytophthora ramorum vary depending on host species,infected plant part,inoculum potential,pathogen genotype,and temperature

A total of 25 ornamental plant species representing 10 families were inoculated using three genotypes, each representing one of the genetic lineages NA1, NA2, and EU1 of the pathogen Phytophthora ramorum. Leaves were inoculated using suspensions with two zoospore concentrations and exposure at three temperatures, while stems were inoculated using agar plugs colonized by mycelia. Susceptibility was determined by measuring either the success of pathogen reisolation or lesion length caused by the pathogen. Infectivity was determined by counting sporangia in washes of inoculated leaves or stems. Results from all three pathogen genotypes combined were used to rank each of the 25 plant species for susceptibility and infectivity, while pooled results per genotype from all 25 hosts combined were employed for a preliminary comparison of pathogenicity and infectivity among genotypes. Statistical analyses showed that leaf results were affected by the concentration of zoospores, temperature, plant host, pathogen genotype, and by the interaction between host and pathogen genotype. Stem results were mostly affected by host and by the interaction between host and pathogen genotype. Hosts ranked differently when looking at the various parameters, and differences in rankings were also significant when comparing stem and leaf results. Differences were identified among the 25 hosts and the three pathogen genotypes for all parameters: results can be used for decision-making regarding regulations or selection of plants to be grown where infestations by P. ramorum are an issue.     

Changes in foliar carbon isotope composition and seasonal stomatal conductance reveal adaptive traits in Mediterranean coppices affected by drought

We estimated water-use efficiency and potential photosynthetic assimilation of Holm oak(Quercus ilex L.) on slopes of NW and SW aspects in a replicated field test examining the effects of intensifying drought in two Mediterranean coppice forests. We used standard techniques for quantifying gas exchange and carbon isotopes in leaves and analyzed total chlorophyll, carotenoids and nitrogen in leaves collected from Mediterranean forests managed under the coppice system. We postulated that responses to drought of coppiced trees would lead to differential responses in physiological traits and that these traits could be used by foresters to adapt to predicted warming and drying in the Mediterranean area. We observed physiological responses of the coppiced trees that suggested acclimation in photosynthetic potential and water-use efficiency:(1) a significant reduction in stomatal conductance(p0.01) wasrecorded as the drought increased at the SW site;(2) foliar δ13C increased as drought increased at the SW site(p0.01);(3) variations in levels of carotenoids and foliar nitrogen, and differences in foliar morphology were recorded, and were tentatively attributed to variation in photosynthetic assimilation between sites. These findings increase knowledge of the capacity for acclimation of managed forests in the Mediterranean region of Europe.     

基于方格网法的树冠体积测算方法

提出了一种基于方格网法测算树冠体积的方法。研究利用免棱镜全站仪获取树冠点云数据,建立树冠表面特征点的坐标方格网,根据方格网法计算土方量的原理来求算树冠体积,通过传统经典模型人工方法、三维激光量测法与本文算法,分别计算实验区域研究对象的体积,将结果进行对比分析,本研究提出的算法平均相对误差为4.13%,平均准确度为95.97%,且在置信度0.05下树冠体积的计算值与实测值之间的差异性为不显著,结果完全满足计算精度,其计算耗时只有传统人工量测法的1/3,成本为三维激光扫描的2%,降低了成本且提高了效率。