Changes in the Diversity of the Herb-Shrub Layer of Pine Forests Caused by Severe Pollution and Fire Disturbances in the Southern Urals

We assumed that the state of the herb-shrub layer of forest communities near a large enterprise in the Southern Urals is determined not only by technogenic impact, but also by fire disturbances. The purpose of this study is to assess the diversity of the herb-shrub layer in forests polluted by the Karabash copper smelter emissions with different time passed since the last fire. We analyzed 77 geobotanical descriptions performed in polluted and unpolluted pine forests, in both versions with different time passed since the last fire (from 1 year to burned long ago or probably unburned). Diversity was assessed using: traditional diversity measures that do not take into account species heterogeneity; functional diversity parameters; and estimation of the Grime’s strategy type importance ratios. We have found that technogenic pollution is the main factor affecting the herb-shrub layer diversity. As the level of technogenic pollution increased, all diversity indicators decreased, the contribution of species with C- and S-strategy components to community formation increased, and the contribution of species with R-strategy component decreased. The effects of fire disturbance on the herb-shrub layer diversity have not been confirmed. Correlation of technogenic and pyrogenic impacts has not been found.