Forest-steppe transitions in central Asia are extremely sensitive ecosystems, as forests occur there at their drought limit. Therefore, stressors becoming effective in addition to drought may strongly influence the spatial distribution of ecosystems, their biodiversity and functioning. Such additional stressors include logging, fire, herbivory by insects and other small animals as well as livestock grazing.
Typical of livestock husbandry in central Asia are free-roaming animals held by nomads. The livestock primarily browses grasslands, but significantly affects tree regeneration at forest lines and even penetrates into the forest interior. Nonetheless, studies to grazing impacts on vegetation usually focus on grasslands, rather than forests. In the Altai Project, effects of livestock grazing of forests of Siberian larch are comparably studied in Kazakhstan and Mongolia within the Altai-Khangai-Sayan ecoregion. The political transformation process from the centrally planned to the market economy after the breakdown of the Soviet Union led to contrasting developments in the livestock sectors of both countries. In Kazakhstan, livestock number strongly declined and only started to recover recently, whereas livestock numbers in Mongolia increased. The investigations include studies on biodiversity, forest regeneration, stem wood formation and the livelihoods of the local populations. In addition, effects of global warming that coincide with changes of land use are studied with the help of tree-ring analyses.