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...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.展开更多
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 c...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.展开更多
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 g...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.展开更多
基金supported by the LifeWatch-ITA European Research Infrastructure on Biodiversity and the Project LIFE+Man For C.BD.(LIFE09 ENV/IT/000078)
文摘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.
文摘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.
文摘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.
