Directed Trends in the Shoot Number Dynamics and the Functional Traits of Plants Growing on Festuca varia Grasslands of the Teberda National Park

Abstract

The modern long-term dynamics of high-mountain communities can be influenced by either climate warming or a reduction in land use intensity. Annual counts of the shoot number of vascular plants were carried out in 1987–2019 on permanent plots located on alpine Festuca varia grasslands (Teberda National Park, Karachay-Cherkessia, Russia). Regression models simulating the shoot number dynamics used predictors such as the year (for revealing linear trends) and weather conditions, including the average temperatures and precipitation in the preceding vegetation season (July–August) and in the beginning of the current season (May–June). The number of shoots significantly increased in six species characterized by the lower average altitudes of distribution within the National Park and decreased in five high-mountain species. However, these trends were not associated with an increase in the average temperatures of the July–August period of the preceding year. Changes in weather conditions influenced fluctuations in several species independently of the direction of their dynamics. The linear trend values for one of the sample areas positively correlated with the specific leaf area, water content in leaves, and contribution of a ruderal strategy, and they negatively correlated with the contribution of a stress-tolerant strategy. The dynamics of Festuca varia grasslands was related mainly to a long-term recovery succession after grazing cessation, but not to the warming that occurred during a vegetation season. The main dominant of the community, Festuca varia Haenke, was less subjected to fluctuations and climate changes within the current amplitude, thus providing the stability of the community.