Alpine plant communities differ in their seed germination requirements along a snowmelt gradient in the Caucasus

Abstract Mesoscale heterogeneity of alpine landscapes generates snowmelt gradients resulting in a distinct vegetation zonation from almost snow-free fellfields to long-lasting snowbeds. Although the vegetative trait variation along such has been intensively studied, little is known about whether and how seed germination adapted variable snowpack duration. Here, we compare niches 18 characteristic plant species occurring four communities (alpine lichen heath— Festuca varia grassland— Geranium - Hedysarum meadow—snowbed) an gradient North Caucasus (Russia). In fully factorial experiment, tested responses temperature (10/2, 14/6, 18/10, 22/14, 26/18 30/22 °C) water potential (0, − 0.2, 0.4, 0.6 0.8 MPa) gradients, reflecting full spectrum seedling establishment conditions study system. Community-specific were identified by generalised mixed model with Bayesian estimation. Our revealed that focal significantly differed their requirements for germination, whereas soil moisture was found be limiting factor entire gradient. The snowbed constrained comparatively high temperatures above 10 °C, heaths occurred under wide range experimental conditions. patterns grasslands meadows reflected intermediate position We conclude niche affected environmental filtering thus departing general syndrome.