The effects of altitude on macronutrient concentration in birch leaves (Betula Pubescens Ehrh. And B. Pendula Roth) along high-altitude gradient in Northern Urals

Abstract

Latitude and altitude affect the geographical distribution of plant communities on Earth from the equator to the poles. While latitude has influence on the horizontal distribution, the altitude confines the vertical range of plant communities, shaping the floral composition and their eco-physiological features such as macronutrients that control the growth. In this research, the effects of different altitude gradients on plant macronutrients (N, P, K, Mg, Ca, Na) content in leaves of two different birch species (Betula pubescens Ehrh. and B. pendula Roth) distributed in the Northern Urals region were investigated for two years. Tree leaves were collected in growing seasons in 2006 and 2008, and all measured macronutrients concentration levels were compared according to altitude and year, respectively. As a result, leaf concentration of N and P were increased by altitude in Downy birch (B. pubescens), while the macronutrient concentration levels were decreased in Silver birch (B. pendula) species. In addition, although concentration of N, P, and K levels changed in both species, the N concentration level was not significantly changed in two years. Moreover, N, P, K, and Mg concentration levels in the leaves of Silver birch increased from 2006 to 2008. This reason was likely due to the later start of the growing season and higher percentage of humidity in 2006. Consequently, altitude gradients played a significant role on macronutrient contents of birch species' leaves.