Key to understanding the implications of climate and land use change on biodiversity and natural resources is to incorporate the physiographic platform on which changes in ecological systems unfold. Here, we advance a detailed classification and high-resolution map of physiography, built by combining landforms and lithology (soil parent material) at multiple spatial scales. We used only relativ...

the potassium pools of five major physiographic units of urmia region in western azarbaijan province were studied to investigate the distribution of k forms as a function of clay mineralogy and physiographic units. for this, soil samples from different horizons of ten pedons were selected and analyzed for physiochemical properties, mineralogy of clay fraction, and forms of k. analyses of xrd re...

_ ----------____-_.__________.__..____._... Introduction.-.._._..___.__.___...'_.._.._.___...___ Pleistocene and Recent deposits .......L.............. North Loup River valley near Elba._____._..___._ North Loup River valley near Burwell..__.__._.__ North Loup River valley downstream from Brewster. North Loup River valley upstream from Brewster... South Loup River valley near Cumro. ___________...

Two factors that can lead to geographic structuring in conspecific populations are barriers to dispersal and climatic stability. Populations that occur in different physiographic regions may be restricted to those areas by physical and/or ecological barriers, which may facilitate the formation of phylogeographic clades. Long-term climatic stability can also promote genetic diversification, beca...