| Summary: | Iremel Massif today is a peak of the Southern Urals with the maximum expansion of woody vegetation into the mountain tundra. As a result, the areas occupied by mountain tundra communities are considerably reduced and, hence, the biodiversity of the alpine mountain is decreased. The goal of this study is to assess the climate-driven transformation of the alpine forest ecosystems of Iremel Massif using a suite of methods. The comparison of multi-temporal topographic maps and satellite images served to establish that over the past 60 years, the continuous limits of open forests have shifted by 5.5 m/decade to the higher altitudes and 21.6 m/decade horizontally. The area of the boundary shift of the open forest was 6.97 km2. For the first time, changes in the areas occupied by various types of woody vegetation in the study region were quantified based on landscape repeat photography and the WSL Monoplotting Tool software. On the northeastern slope of Bolshoy Iremel, over the past 40 years, the area of closed forests has increased by a factor of almost 2, the area of open forests has increased by a factor of 5, the area of sparse forests has increased by a factor of 2, and the area of plots with single trees has decreased by a factor of 4. Analysis of the age structure of Siberian juniper (Juniperus sibirica Burgsd.) revealed that substantial expansion of that species into mountain tundra communities occurred above the upper limits of open forests from 1920 to 1930 and from 1950 to 1980. The most dramatic increase in the number of trees began only after the 1990s, and it has been continuing until today. A high correlation has been found between the number of established J. sibirica shrubs and the amount of precipitation in the first months of the cold season (November-January) in the previous five years (Spearman's correlation coefficient is 0.61). © Siberian Federal University. All rights reserved. В настоящее время массив Иремель (Южный Урал) является одной из наиболее интенсивно зарастающих древесной и ...
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