نتایج جستجو برای: climatic
تعداد نتایج: 31884 فیلتر نتایج به سال:
Starting from traditional ideas on the climatic steering of fluvial system dynamics, it appears that there are different kinds of climatic influences on system dynamics. They vary from direct climatic forcing (like peak precipitation) to indirect (like permafrost) and partial forcing (like vegetation). Vegetation (or its absence), and not directly climate, is considered as the main cause of flu...
Mid-Pleistocene vertebrates in North America are scarce but important for recognizing the ecological effects of climatic change in the absence of humans. We report on a uniquely rich mid-Pleistocene vertebrate sequence from Porcupine Cave, Colorado, which records at least 127 species and the earliest appearances of 30 mammals and birds. By analyzing >20,000 mammal fossils in relation to modern ...
This study aims to address the effects of climatic factors (temperature, relative humidity and rainfall) on Aedes aegypti mosquito density (hereinafter called mosquito density) in the Jeddah city, Saudi Arabia. Data for climatic factors, mosquito density and dengue fever cases for the years 2004 to 2011 were collected for the study period. Descriptive and bivariate statistical analyses were con...
The extent to which species' life histories evolve to match climatic conditions is a critical question in evolutionary biology and ecology and as human activities rapidly modify global climate. GIS-based climatic data offer new opportunities to rigorously test this question. Superficially, the spadefoot toads of North America (Scaphiopodidae) seem to offer a classic example of adaptive life-his...
Based on the tree-ring growth characteristics of Erman’s birch (Betula ermanii charm.) and the relationships between it and climatic factors at elevation of 1950m, the sensitivity of tree lines in Changbai Mountain to climatic factors was assessed. The results indicated tree line forest in Changbai Mountain had an obvious sensitivity to climate factors. However, difference from other study sits...
A climatic classification for Europe suitable for pesticide fate modelling was constructed using a 3-stage process involving the identification of key climatic variables, the extraction of the dominant modes of spatial variability in those variables and the use of k-means clustering to identify regions with similar climates. The procedure identified 16 coherent zones that reflect the variabilit...
The Italian Locust, Calliptamus italicus (Linnaeus) (Orthoptera: Acrididae) , is one of the most harmful species to the grasslands in Xinjiang province, China. It attacks a variety of plants in Compositae, Chenopodiaceae and Gramineae. We used CLIMEX and ArcGIS to determine the potential geographical distribution of C. italicus in China under current and future climatic scenarios. Our analysis ...
Species climate requirements are useful for predicting their geographic distribution. It is often assumed that the niche requirements for invasive plants are conserved during invasion, especially when the invaded regions share similar climate conditions. California and central Chile have a remarkable degree of convergence in their vegetation structure, and a similar Mediterranean climate. Such ...
Interest in climatic variability on time-scales of decades to centuries has grown rapidly in the last five years. Some of this interest has been engendered by the need to gain a better understanding of natural climatic variability in order to resolve more clearly the climatic signature of enhanced greenhouse warming. However, this focus on decadal and interdecadal fluctuations in climate has al...
The combined isotopic records in the Greenland ice cores, in modern and ancient wood samples, and in marine foraminifera provide a climatic record for the Aller6d-B011ing-Younger Dryas and post-Younger Dryas Periods that is not compatible with the usual climatic interpretation of the 2H/1H ratios in the Greenland ice cores. For example, the Younger Dryas was not solely a North Atlantic event be...
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