Динамика населения мелких млекопитающих пирогенных сообществ в степном бору

Abstract

In 2008–2021 we studied small mammals annually using zoological ditches in the Tsasucheysky steppe pine forest (Zabaikalsky Region, Russia). Before the 2012 high-severity fire we captured small mammals in a typical pine forest, either old-growth or old-burnt sites, and after the 2012 fire—in sites of fresh primary and repeated burns as well as in survived areas. The undisturbed steppe pine forest was characterised by small numbers of mammals, dominated by Myodes rutilus. In the first-burnt sites mainly Cricetulus pseudogriseus individuals were captured during the first decade after the fire. This species also rapidly invaded the re-burnt sites; however, in the third or fourth year the small mammal community became polydominant. In the old post-fire area (more than 10 years after the fire) small mammals were most abundant and the community was more diverse. In the post-fire sites С. pseudogriseus, Lasiopodomys raddei, Sorex tundrensis and S. minutissimus were the most numerous; Alexandromys mongolicus was also common in the old burnt sites. The total number of small mammals decreased significantly only in the first year after the fire. The total abundance of small mammals in the sites of old and repeated burns was significantly higher than in the undisturbed pine forests and first burned areas. In parallel, the total numbers of small mammals in the pyrogenic and relevant preceding communities were not statistically different. The number of M. rutilus decreased and the number of C. pseudogriseus increased in the burns compared to the pine forest. Despite the changes in the composition and structure of the community, the fire led to no significant changes in the overall abundance of small mammals in the Tsasucheysky Pine Forest during the first following decade. Subsequently, when the burns became overgrown, the small mammal community became richer in both number of species and their abundance. This indicates the resilience of small mammal populations to fires in the forest-steppe and, thus, the stability of the food base for small mammal predator populations.