[Phytomass utilization and deposition of feces by ungulates on steppe pastures of eastern Mongolia].

The research investigates how the plant mass in the steppe pastures of Eastern Mongolia is utilized and how the deposition of feces by both livestock and wild animals contributes to the overall landscape. It reveals that the grazing ungulates, even at high densities, do not harm the vegetation productivity of the pastures.

Study Procedure

• The researchers estimate the amount of plant mass removed by a complex of livestock (horses, cattle, sheep, and goats) and wild ungulates (Mongolian gazelle), grazing in plain and mountain pastures of Eastern Mongolia. This is done by considering the feces deposited by these animals.

Findings

• The study shows that the total annual amount of feces reaches up to 140 kg per hectare (dry weight) at an animal density of 30 head per square kilometer. Out of this, the majority (up to 90 kg per hectare) is deposited by horses.
• The contribution of Mongolian gazelles in some pastures reaches 20-40 kg per hectare per year.
• The decomposition of feces proceeds very slowly, thereby leading to gradual accumulation of non-decomposed matter in the soil. The annual loss of their weight is only about 9-12%.
• The removal of plant mass by the complex of ungulates, calculated from the amount of feces considering their annual loss and forage digestibility, varies between 240 and 400 kg per hectare. This means 25-60% of the total aboveground plant mass is consumed by these species.

Impact of Ungulates

• The study found that horses utilize the greatest amount of plant mass of up to 200 kg per hectare. Mongolian gazelles utilize up to 86 kg per hectare per year.
• Moreover, during the growing season, ungulates remove no more than 11-16% of the total aboveground plant mass.
• The research concludes that even in high densities the combined impact of livestock and wild ungulates does not impair the productivity of vegetation in the studied pastures.