Commodity risk assessment of oak logs with bark from the US for the oak wilt pathogen Bretziella fagacearum under an integrated systems approach.

The European Commission submitted to the EFSA Panel on Plant Health a Dossier by USDA proposing a systems approach to mitigate the risk of entry of Bretziella fagacearum to the EU when trading oak logs with bark from the USA. Due to the forthcoming ban of methyl bromide (MB), the Dossier indicates sulfuryl fluoride (SF) as the substitute fumigant for this commodity. After collecting additional evidence from USDA,EU NPPOs, external experts and the published literature, the Panel performed a quantitative assessment on the likelihood of pest freedom for B. fagacearum at the point of entry in the EU, comparing the proposed systems approach with those already implemented by Commission Decision 2005/359/EC. The Panel provided also a non-quantitative assessment for all risk reduction options (RROs) proposed to be undertaken in the EU, from the point of entry to processing at the sawmill. The quantitative assessment until the EU point of entry, based on experts' judgement, indicated that: i) the most effective import option remains the current one with MB (95% certainty that between 9,573 and 10,000 containers per 10,000 would be free of B. fagacearum), followed by that with SF (95% certainty that between 8,639 and 10,000 containers per 10,000 would be free of B. fagacearum) and, last, by the other existing option based on delivering white oak logs in certain periods of the year to certain regions of the EU without fumigation (95% certainty, between 7,803 and 10,000 containers per 10,000). RROs proposed to be undertaken in the EU are expected to further reduce the risk of establishment of B. fagacearum, should these RROs be regulated, correctly implemented and checked by NPPOs. A wood pathway analysis is needed to quantitatively assess the importance of each measure and to optimise regulatory actions and risk management efforts.

Substantial differences occur between canopy and ambient climate: Quantification of interactions in a greenhouse-canopy system.

Organ temperature and variation therein plays a key role in plant functioning and its responses to e.g. climate change. There is a strong feedback between organ, especially leaf, temperature and the climate within the canopy (canopy climate), which in turn interacts with the climate outside the canopy (ambient climate). For greenhouses, the determinants of this interplay and how they drive differences between canopy and ambient climate are poorly understood. Yet, as many experiments on both regular greenhouse crops and field crops are done in greenhouses, this is crucial to know. Therefore, we designed an experiment to quantify the differences between ambient and canopy climate and leaf temperature. A path analysis was performed to quantify the interactions between components of the greenhouse canopy-climate system. We found that with high radiation the canopy climate can be up to 5°C cooler than the ambient climate, while for cloudy days this was only 2°C. Canopy relative humidity (RH) was up to 25% higher compared to ambient RH. We showed that radiation is very important for these climate differences, but that this effect could be partly counteracted by turning off supplementary light (i.e. due to its indirect effects e.g. changing light distribution). Leaf temperature was substantially different, both higher and lower, from the canopy air temperature. This difference was determined by leaf area index (LAI), temperature of the heating pipe and the use of supplementary light, which all strongly influence radiation, either shortwave or thermal radiation. The difference between leaf and ambient air temperature could be decreased by decreasing the LAI or increasing the temperature of the heating pipe.

Development of a pathway model to assess the exposure of European pine trees to pine wood nematode via the trade of wood.

Pine wood nematode (PWN), Bursaphelenchus xylophilus, is a threat for pine species (Pinus spp.) throughout the world. The nematode is native to North America, and invaded Japan, China, Korea, and Taiwan, and more recently Portugal and Spain. PWN enters new areas through trade in wood products. Once established, eradication is not practically feasible. Therefore, preventing entry of PWN into new areas is crucial. Entry risk analysis can assist in targeting management to reduce the probability of entry. Assessing the entry of PWN is challenging due to the complexity of the wood trade and the wood processing chain. In this paper, we develop a pathway model that describes the wood trade and wood processing chain to determine the structure of the entry process. We consider entry of PWN through imported coniferous wood from China, a possible origin of Portuguese populations, to Europe. We show that exposure increased over years due to an increase in imports of sawn wood. From 2000 to 2012, Europe received an estimated 84 PWN propagules from China, 88% of which arose from imported sawn wood and 12% from round wood. The region in Portugal where the PWN was first reported is among those with the highest PWN transfer per unit of imported wood due to a high host cover and vector activity. An estimated 62% of PWN is expected to enter in countries where PWN is not expected to cause the wilt of pine trees because of low summer temperatures (e.g., Belgium, Sweden, Norway). In these countries, PWN is not easily detected, and such countries can thus serve as potential reservoirs of PWN. The model identifies ports and regions with high exposure, which helps targeting monitoring and surveillance, even in areas where wilt disease is not expected to occur. In addition, we show that exposure is most efficiently reduced by additional treatments in the country of origin, and/or import wood from PWN-free zones. Pathway modelling assists plant health managers in analyzing risks along the pathway and planning measures for enhancing biosecurity.

Disturbance and resource availability act differently on the same suite of plant traits: revisiting assembly hypotheses.

Understanding the mechanisms of trait selection at the scale of plant communities is a crucial step toward predicting community assembly. Although it is commonly assumed that disturbance and resource availability constrain separate suites of traits, representing the regenerative and established phases, respectively, a quantification and test of this accepted hypothesis is still lacking due to limitations of traditional statistical techniques. In this paper we quantify, using structural equation modeling (SEM), the relative contributions of disturbance and resource availability to the selection of suites of traits at the community scale. Our model specifies and reflects previously obtained ecological insights, taking disturbance and nutrient availability as central drivers affecting leaf, allometric, seed, and phenology traits in 156 (semi-) natural plant communities throughout The Netherlands. The common hypothesis positing that disturbance and resource availability each affect a set of mutually independent traits was not consistent with the data. Instead, our final model shows that most traits are strongly affected by both drivers. In addition, trait-trait constraints are more important in community assembly than environmental drivers in half of the cases. Both aspects of trait selection are crucial for correctly predicting ecosystem processes and community assembly, and they provide new insights into hitherto underappreciated ecological interactions.

The contribution of mosses to the carbon and water exchange of Arctic ecosystems: quantification and relationships with system properties.

Water vapour and CO2 exchange were measured in moss-dominated vegetation using a gas analyser and a 0.3 x 0.3 m chamber at 17 sites near Abisko, Northern Sweden and 21 sites near Longyearbyen, Svalbard, to quantify the contribution of mosses to ecosystem level fluxes. With the help of a simple light-response model, we showed that the moss contribution to ecosystem carbon uptake varied between 14 and 96%, with an average contribution of around 60%. This moss contribution could be related to the normalized difference vegetation index (NDVI) of the vegetation and the leaf area index (LAI) of the vascular plants. NDVI was a good predictor of gross primary production (GPP) of mosses and of the whole ecosystem, across different moss species, vegetation types and two different latitudes. NDVI was also correlated with thickness of the active green moss layer. Mosses played an important role in water exchange. They are expected to be most important to gas exchange during spring when leaves are not fully developed.

Supporting parents of youths with intellectual disabilities and psychopathology.

BACKGROUND: Parents of children and adolescents with both intellectual disabilities (ID) and psychopathology often experience high levels of parenting stress. To support these parents, information is required regarding the types of support they need and whether their needs are met. METHOD: In a sample of 745 youths (aged 10-24 years) with moderate to borderline ID, 289 parents perceived emotional and/or behavioural problems in their child. They were asked about their needs for support and whether these needs were met. Logistic regression analysis revealed the variables associated with both needing and receiving specific types of support. In addition, we asked those parents who had refrained from seeking support about their reasons. RESULTS: Most parents (88.2%) needed some supports, especially a friendly ear, respite care, child mental health care and information. Parents who perceived both emotional and behavioural problems in their child needed support the most. In addition, parents whose child had any of these problems before the past year, who worried most about their child and suffered from psychopathology themselves, more often needed support. Parents of children with moderate ID or physical problems especially needed 'relief care', that is, respite care, activities for the child and practical/material help. The need for a friendly ear was met most often (75.3%), whereas the need for parental counselling was met least often (35.5%). Not receiving support despite having a need for it was primarily related to the level of need. Parents who indicated to have a stronger need for support received support more often than parents who had a relatively low need for support. The parents' main reasons for not seeking support concerned their evaluation of their child's problems (not so serious or temporary), not knowing where to find support or wanting to solve the problems themselves first. CONCLUSIONS: Most parents had various support needs that were frequently unmet. Service providers should especially aim at providing information, activities, child mental health care and parental counselling. Furthermore, parents need to be informed about where and how they can obtain what kind of support. A case manager can be of help in this.