Mining as a catalyst of overgrazing resulting in risk of forest retreat, Erdenet Mongolia

Abstract

This paper provides information on long-term suppression of natural forest regeneration due to the livestock grazing in the vicinity of one of the world largest open-pit ore mine close the city of Erdenet in Mongolia. The area is characterized by high concentration of herder’s households where the 52% were found only up to 1 km distance from the forest edge. Forest grazing causes extensive damage to seedlings and significant reduction of their growth. Within the 30–99 cm height category, up to 61% Larix sibirica, 90% Betula platyphylla and 68% Populus tremula individuals are grazingdamaged. L. sibirica and P. tremula seedlings with heights over 99 cm were absent, and no individuals of any species were found within 136–200 cm height category. In addition to the seedlings, only 7 or more meters high L. sibirica individuals are found in the forest structure, which means the absence of successfully growing forest regeneration for at least 40 years. In 2017, the defoliation of L. sibirica, reaching locally up to 100%, occurred in the stands east of the mine. Total defoliation represents a high risk of mortality of affected individuals. The stands cannot be successfully regenerated under the conditions of current intensive grazing. Mine metal stocks are calculated to provide for at least another 25 years of mining. Over that time, neither significant population decline nor decreasing grazing pressure on forests can be expected. If effective protection measures are not implemented, there is a risk of transforming threatened forest into steppe.