The recorded seed predators of Amorpha fruticosa L., indigo bush weevils and pteromalid wasps, were the subject of laboratory and field research studies in the period from 2006 to 2011. Sample analyses were carried out on more than 30 localities in Serbia with the aim of measuring the summarized pre-dispersal and post dispersal predation preferences. The percentages of the total pre-dispersal (max≈33%) and post-dispersal re-infested material (over 95%), make these insects serious candidates for host-plant suppression. Their bionomics were monitored through continuous collection, dessection and observation of infested seeds, in correlation with environmental parameters, especially water-level fluctuations in endangered forests. [Projekat Ministarstva nauke Republike Srbije, br. TP-31070: The development of technological methods in forestry in order to attain optimal forest cover

Determining the drivers of non-native plant invasions is critical for managing native ecosystems and limiting the spread of invasive species1,2. Tree invasions in particular have been relatively overlooked, even though they have the potential to transform ecosystems and economies3,4. Here, leveraging global tree databases5–7, we explore how the phylogenetic and functional diversity of native tree communities, human pressure and the environment influence the establishment of non-native tree species and the subsequent invasion severity. We find that anthropogenic factors are key to predicting whether a location is invaded, but that invasion severity is underpinned by native diversity, with higher diversity predicting lower invasion severity. Temperature and precipitation emerge as strong predictors of invasion strategy, with non-native species invading successfully when they are similar to the native community in cold or dry extremes. Yet, despite the influence of these ecological forces in determining invasion strategy, we find evidence that these patterns can be obscured by human activity, with lower ecological signal in areas with higher proximity to shipping ports. Our global perspective of non-native tree invasion highlights that human drivers influence non-native tree presence, and that native phylogenetic and functional diversity have a critical role in the establishment and spread of subsequent invasions.

1. Biodiversity is an important component of natural ecosystems, with higher species richness often correlating with an increase in ecosystem productivity. Yet, this relationship varies substantially across environments, typically becoming less pronounced at high levels of species richness. However, species richness alone cannot reflect all important properties of a community, including community evenness, which may mediate the relationship between biodiversity and productivity. If the evenness of a community correlates negatively with richness across forests globally, then a

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Daños por heladas tardías en pino oregón, Patagonia argentina 113 BOSQUE 26(3): 113-120, 2005 NOTA TECNICA Evaluación de daños por heladas tardías en ensayos de procedencias de pino oregón introducidos en el norte de la SUMMARY The susceptibility to late frost of the seed source used for afforestations at the moment it is one of the main adaptatives characteristic limiting the increase of the planted area of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in Argentinien North Patagonia Region. In two provenances trials of this species we registered frost injury caused by absolute minimum temperature of-7º C during spring. In both sites we found significant differences among treatments. We found a strong correlation between the percentage of frost injury and seed source longitude (r = 0.86) and with seed source altitude (r = 0.75) in the trail that registered the most rigorous minimum. In this trial we found also a weaker association with nursery mean heights (r = 0.55) and the origin latitude (r = 0.44). Considering that coastal origins are those of better potential growth, selection based only growth criteria could produce an indirect selection of susceptible genotypes. Finally we recommend the simultaneous evaluation of yield and susceptibility to be able to extend the specie cultivation towards other areas with increased frost risks. RESUMEN La susceptibilidad a las heladas tardías de la fuente de semilla actualmente utilizada es una de las principales características adaptativas que limitan la ampliación del área de plantación de pino oregón (Pseudotsuga menziesii (Mirb.) Franco) en la Región Norpatagónica de la Argentina. En dos ensayos de procedencias de esta especie se registró el daño provocado por heladas de primavera de hasta-7º C de mínima absoluta. En ambos ensayos se encontraron diferencias significativas entre los tratamientos. En el ensayo en el que se registraron mínimas más rigurosas pudieron establecerse correlaciones altamente significativas entre el porcentaje de daño por heladas con la longitud (r = 0,86) y altitud (r =-0,75) del origen de la semilla, y una menor asociación con la altura media de las plantas en vivero (r = 0,55) y la latitud de origen (r = 0,44). Considerando que los orígenes costeros son los de mayor potencial de crecimiento, estos resultados indican que la selección en base a ese único criterio podría producir una selección indirecta de genotipos susceptibles. Finalmente se recomienda la evaluación simultánea de rendimien-to y susceptibilidad para extender el cultivo de la especie hacia áreas de mayor riesgo de heladas. Palabras clave: pino oregón, mejoramiento genético, ensayos de orígenes, heladas, Patagonia, Argentina.