Phytoliths of temperate forest-steppe: A case study from the Altay, Russia

Phytoliths are a useful paleoproxy in arid environments. This modern analog study assessed variability of silica phytoliths in 30 species of grasses and 42 modern soil samples from eight locations in the Altaysky Kray and the Republic of Gorny Altay of Russia. Phytoliths were grouped into 25 broadly defined morphotypes based on their 3D shapes under light microscope and presumed anatomical origin within the plant. Grasses exhibited the most diverse forms. Forests, meadows, and steppes can be distinguished based on differences in proportion of various morphotypes. Steppes can be reliably identified based on high proportion of rondel phytoliths, but low presence of lobate and lanceolate forms. Meadows have high proportion of lobate and lanceolate forms. All forests have high proportion of smooth long cells and lanceolate phytoliths. Coniferous forests additionally have small presence of blocky forms with pitted surface and pores from conifers. Phytolith assemblages were also found to vary with gradients of temperature and precipitation, which could enable direct paleoenvironmental inferences from phytoliths in geological sediments from the region. However, vegetation types could not be differentiated based on the presence of particular types of trichomes, as has been suggested for other regions in Russia.