Potential impacts of climate change on Welwitschia mirabilis populations in the Namib Desert,southern Africa

Climate change is threatening natural ecosystems in the Earth, and arid regions of southern Africa are particularly exposed to further drying. Welwitschia mirabilis Hook. （Welwitschiaceae） is an unusual gymnosperm tree that is recognized as an icon of the Namib Desert, southern Africa. Many aspects of its biology were investigated in the past, with a special emphasis for its physiology and adaptations, but nothing is known about its potential sensitivity to current climate changes. In this study, we adopted an approach based on distribution data for W. mirabilis and ecological niche models for clarifying the species-climate interactions and for predicting the potential impacts of climate change on W. mirabilis populations in three well-separated sub-ranges （northern, southern and central） in northwestern Namibia, southern Africa. We evidenced that the populations occurring in the northern sub-range have peculiar climatic exigencies compared with those in the central and southern sub-ranges and are particularly exposed to the impact of climate change, which will consist of a substantial increase in temperature across the region. These impacts could be represented by demographic changes that should be detected and monitored detailedly to plan efficient measures for managing populations of this important species on the long-term scale.

Mapping the Genetic Diversity of Castanea sativa: Exploiting Spatial Analysis for Biogeography and Conservation Studies

The current distribution of forest tree species is a result of natural or human mediated historical and contemporary processes. Knowledge of the spatial distribution of the diversity and divergence of populations is crucial for managing and conserving genetic resources in forest tree species. By combining tools from population genetics, landscape ecology and spatial statistics, landscape genetics thus represents a powerful method for evaluating the geographic patterns of genetic resources at the population level. In this study, we explore the possibility of combining genetic diversity data, spatial statistic tools and GIS technologies to map the genetic divergence and diversity of 31 Castanea sativa populations collected in Spain, Italy, Greece, and Turkey. The IDW technique was used to interpolate the diversity values and divergence indices as expected hetereozygosity (He), allelic richness (Rs), private allelic richness (PRs), and membership values (Q) of each population to different clusters. Genetic diversity maps and a synthetic map of the spatial genetic structure of European chestnut populations were produced. Spatial coincidences between landscape elements and statistically significant genetic discontinuities between populations were investigated. Evidence is provided of the significance of cartographic outputs produced in the study and on their usefulness in managing genetic resources.

On-farm Conservation of Sweet Chestnut （Castanea sativa Mill.） in Andalusia

Sweet chestnut （Castanea sativa Mill.）, the only native species of Castanea genus in Europe, occupies over 12,000 ha in Andalusia （South of Spain）. From 2000 until now, we have carried out different activities focused on the location and cataloguing of the different chestnut groves in the region and the evaluation of the genetic variability contained in this germplasm. Two different types of chestnut groves were detected： one of clonal nature （varieties obtained by grafting） and another of open pollination （trees from seed）. In the first case, the aim of our study was to identify and characterise the main chestnut traditional varieties. High levels of genetic variability were detected in clonal orchards by means of morphological and molecular analysis. A total of 38 varieties were identified： 12 in Huelva and 26 in Malaga regions. Moreover, we reported data about the presence of synonymies and homonymies. Our results indicate that chestnut production in this region is a traditional system that uses varieties developed in situ, constituting a genuine system of ＇on farm＇ conservation. Nevertheless, their preservation is seriously threatened in most zones due to the varietal substitution, the low profit or the abandonment, which determines the urgent necessity to safeguard these genetic resources. Furthermore, preliminary results for chestnut populations indicated a high degree of genetic variation.

Carbon mitigation potential of different forest ecosystems under climate change and various managements in Italy

This study reviews carbon stocks and carbon dynamics in diferent types of forest land in Italy:ordinary managed forests,forest plantations,old growth forests,and trees outside forests.Forest management,combined with global environmental changes,increases the capacity of carbon uptake of ordinary managed forests.Forest plantations,particularly the ones subject to short-rotation forestry systems,potentially have high soil carbon accumulation,especially in agricultural lands.Old growth forests,recently discovered as a carbon sink,cover a significant surface area in Italy.Moreover,the trees outside forests may represent a sensible carbon stock,especially in the context of urban environments.Our study points out the management actions that can be implemented in Italy to increase the carbon stocks of different forest ecosystems,such as increasing the mean annual increment in managed forests,enhancement of the national network of old growth forests,and expansion of forest plantations in suitable areas.These aspects have important implications after the recent recognition of the Land Use,Land Use Change and Forestry sector in the EU target within the 2030 Climate and Energy Policy Framework.

Essential oils as solvents and core materials for the preparation of photo-responsive polymer nanocapsules

Light-triggered release of active ingredients from polymeric nanosized capsules can be employed in a wide range of applications, such as biomedicine, active packaging, and cosmetics. However, the preparation of core-shell polymeric nanocarriers typically involves the use of toxic organic solvents. To improve the sustainability and safety of nanocapsule applications, we demonstrate that natural essential oils can be used both as solvent and active material in light-responsive nanocapsules synthesized via miniemulsion polycondensation. The documented antimicrobial, anti-inflammatory, and antioxidant activity of essential oils enables the design of multipurpose light-responsive delivery platforms. The photo-responsive behavior of the capsules, achieved by means of photochromic azobenzene segments embedded in the capsule shell, is triggered by UV light irradiation （λmax= 360 nm）. Light-induced release kinetics of the essential oils and a fluorescent probe molecule, coumarin-6, is evaluated via UV-vis spectroscopy and spectrofluorimetry, respectively, demonstrating the efficiency and reliability of the release mechanism. Biological tests prove that the capsules are non-cytotoxic and readily internalized by cells, indicating the suitability of these smart nanocarriers for biological applications.