Eight temperate deciduous tree species, Acer rubrum L., A. saccharinum L., A. saccharum Marsh., Belluta alleghaniensis Britton., Fraxinus nigra Marsh., Quercus rubra L., Titia americana L., and Ulmus americana L. in e...Eight temperate deciduous tree species, Acer rubrum L., A. saccharinum L., A. saccharum Marsh., Belluta alleghaniensis Britton., Fraxinus nigra Marsh., Quercus rubra L., Titia americana L., and Ulmus americana L. in eastern North America, were selected to explore relationship between the northward distribution of temperate tree species and climatic factors. For each species, more than 30 sites at their north limits of distribution were obtained from their distribution maps, and 11 climatic indices at the north limits were computed. The standardized standard deviation (SD) method, which compares the magnitude of variance of climatic indices, was used to detect which climatic parameter was the most important for explaining northward distribution of these species. We presume that the climatic parameter that has the smallest variance at the north limit would be assigned as the dominant climatic factor for limiting the distribution of this species. The results derived from the standardized SD method indicated that the SD value of warmth index (WI) and/or annual biotemperature (ABT) were the smallest among the 11 climatic indices. Since both WI and ABT represent growing season temperature, it suggested that growing season temperature was the most important climatic factor for explaining the northward distribution of these temperate tree species. The relationships between several climatic indices, WI, coldness index (CI), annual precipitation (AP), annual range of temperature (ART) and humid/arid index were also analyzed. As a result, at the north limits of all these species, both WI and CI decreased with an increase of AP, and CI increased with an increase of ART. Besides growing season temperature, precipitation and climatic continentality also have influence on the northward distribution of the temperate trees in eastern North America.展开更多
Forests are the main components of terrestrial ecosystems and play an important role in the protection and construction of the national ecological security barrier. For a long time, China’s large-scale afforestation ...Forests are the main components of terrestrial ecosystems and play an important role in the protection and construction of the national ecological security barrier. For a long time, China’s large-scale afforestation had been practiced in areas with rainfall higher than the 400 mm threshold, but the issue of afforestation in high altitudes on the Tibetan Plateau remains elusive in both practical experience and theoretical exploration. It is worth thinking further about what principles should be followed in the selection of tree species and suitable altitudes for afforestation in high-altitude areas, as well as what experiences and lessons of previous afforestation efforts should be applied in high-altitude areas. As per the law of vegetation zonal distribution, this paper argues that afforestation at high altitudes should comply with the principle of vegetation zonal distribution and the low temperature limitation,and points out that afforestation is feasible only within the forest distribution area and below the altitudes of climate timberlines. Furthermore, we demonstrate the potential spatial areas of afforestation, and determine the local tree species that may be used for afforestation based on the existing problems of afforestation in eastern Tibet. In summary, afforestation in high-altitude areas of the eastern Tibetan Plateau must comply with the law of zonal vegetation distribution, focus on the upper limit of altitude and the selection of suitable tree species, and adopt only suitable native tree species.展开更多
Climate change is ranked as one of the most severe threats to global biodiversity. This global phenomenon is particularly true for reptiles whose biology and ecology are closely linked to climate. In this study, we us...Climate change is ranked as one of the most severe threats to global biodiversity. This global phenomenon is particularly true for reptiles whose biology and ecology are closely linked to climate. In this study, we used over 1,300 independent occurrence points and different climate change emission scenarios to evaluate the potential risk of changing climatic conditions on the current and future potential distribution of a rock-dwelling lizard; the velvet gecko. Furthermore, we investigated if the current extent of protected area networks in Australia captures the full range distribution of this species currently and in the future. Our results show that climate change projections for the year 2075 have the potential to alter the distribution of the velvet gecko in southeastern Australia. Specifically, climate change may favor the range expansion of this species to encompass more suitable habitats. The trend of range expansion was qualitatively similar across the different cli- mate change scenarios used. Additionally, we observed that the current network of protected areas in southeast Australia does not fully account for the full range distribution of this species currently and in the future. Ongoing climate change may profoundly affect the potential range distribution of the velvet gecko population. Therefore, the restricted habitat of the velvet geckos should be the focus of intensive pre-emptive management efforts. This management prioritization should be extended to encompass the increases in suitable habitats observed in this study in order to maximize the microhabitats available for the survival of this species.展开更多
文摘Eight temperate deciduous tree species, Acer rubrum L., A. saccharinum L., A. saccharum Marsh., Belluta alleghaniensis Britton., Fraxinus nigra Marsh., Quercus rubra L., Titia americana L., and Ulmus americana L. in eastern North America, were selected to explore relationship between the northward distribution of temperate tree species and climatic factors. For each species, more than 30 sites at their north limits of distribution were obtained from their distribution maps, and 11 climatic indices at the north limits were computed. The standardized standard deviation (SD) method, which compares the magnitude of variance of climatic indices, was used to detect which climatic parameter was the most important for explaining northward distribution of these species. We presume that the climatic parameter that has the smallest variance at the north limit would be assigned as the dominant climatic factor for limiting the distribution of this species. The results derived from the standardized SD method indicated that the SD value of warmth index (WI) and/or annual biotemperature (ABT) were the smallest among the 11 climatic indices. Since both WI and ABT represent growing season temperature, it suggested that growing season temperature was the most important climatic factor for explaining the northward distribution of these temperate tree species. The relationships between several climatic indices, WI, coldness index (CI), annual precipitation (AP), annual range of temperature (ART) and humid/arid index were also analyzed. As a result, at the north limits of all these species, both WI and CI decreased with an increase of AP, and CI increased with an increase of ART. Besides growing season temperature, precipitation and climatic continentality also have influence on the northward distribution of the temperate trees in eastern North America.
基金The National Natural Science Foundation of China and ICIMOD Joint Research Project (41661144045)。
文摘Forests are the main components of terrestrial ecosystems and play an important role in the protection and construction of the national ecological security barrier. For a long time, China’s large-scale afforestation had been practiced in areas with rainfall higher than the 400 mm threshold, but the issue of afforestation in high altitudes on the Tibetan Plateau remains elusive in both practical experience and theoretical exploration. It is worth thinking further about what principles should be followed in the selection of tree species and suitable altitudes for afforestation in high-altitude areas, as well as what experiences and lessons of previous afforestation efforts should be applied in high-altitude areas. As per the law of vegetation zonal distribution, this paper argues that afforestation at high altitudes should comply with the principle of vegetation zonal distribution and the low temperature limitation,and points out that afforestation is feasible only within the forest distribution area and below the altitudes of climate timberlines. Furthermore, we demonstrate the potential spatial areas of afforestation, and determine the local tree species that may be used for afforestation based on the existing problems of afforestation in eastern Tibet. In summary, afforestation in high-altitude areas of the eastern Tibetan Plateau must comply with the law of zonal vegetation distribution, focus on the upper limit of altitude and the selection of suitable tree species, and adopt only suitable native tree species.
文摘Climate change is ranked as one of the most severe threats to global biodiversity. This global phenomenon is particularly true for reptiles whose biology and ecology are closely linked to climate. In this study, we used over 1,300 independent occurrence points and different climate change emission scenarios to evaluate the potential risk of changing climatic conditions on the current and future potential distribution of a rock-dwelling lizard; the velvet gecko. Furthermore, we investigated if the current extent of protected area networks in Australia captures the full range distribution of this species currently and in the future. Our results show that climate change projections for the year 2075 have the potential to alter the distribution of the velvet gecko in southeastern Australia. Specifically, climate change may favor the range expansion of this species to encompass more suitable habitats. The trend of range expansion was qualitatively similar across the different cli- mate change scenarios used. Additionally, we observed that the current network of protected areas in southeast Australia does not fully account for the full range distribution of this species currently and in the future. Ongoing climate change may profoundly affect the potential range distribution of the velvet gecko population. Therefore, the restricted habitat of the velvet geckos should be the focus of intensive pre-emptive management efforts. This management prioritization should be extended to encompass the increases in suitable habitats observed in this study in order to maximize the microhabitats available for the survival of this species.
