Clonal plants in disturbed mountain forests: Heterogeneity enhances ramet integration

Abstract

Clonal plants confer a range of ecologically important traits related to local heterogeneity (e.g., foraging and integration). Disturbances generally impact heterogeneity at a variety of scales, but there is a paucity of research linking disturbance, heterogeneity, and clonal plant response. Further, there is a growing need to understand how different plants respond to changing disturbance regimes if stewards want to predict ecosystem response and successfully manage public lands. Thus, we examined clonal plant response to disturbance in the Tatra Mountains (Western Carpathians, Slovakia and Poland) at both the community and population levels. We collected 30 plots (10 m × 10 m) of data from four disturbance site types (DR = windthrow and not salvaged; DS = windthrow salvaged; NF = Forest without gap; NG = forest with canopy gap) in the Western Carpathians. Collected data included cover of all species, heterogeneity metrics, soil temperature 10 cm beneath the surface and clonal connectedness data (through dye experiments on selected species). Windthrow (DR) sites that were not salvaged had the greatest heterogeneity while forest sites with full canopy cover (NF) had the least. We found distinct differences in community composition and structure among the four treatments; however, floristic clonal dominance and the type of clonal growth organ did not change but made up over 90% of cover throughout. Clonal integration was related to disturbance and heterogeneity for Calamagrostis villosa and Rubus idaeus; R. idaeus had greater distances among ramets in the more heterogenous windthrown sites. Clonal plant growth was also related to compositional richness for C. villosa, having greater numbers of ramets under higher diversity pressure. These data suggest the dominance of clonal plants in the understory of mountain spruce forests in the Tatras are responding to changes in heterogeneity through growth and integration but in a species-specific manner.