Introduction

At high altitudes most plants are long-lived and vegetative growth is abundant. Sexual reproduction may be constrained by

• low pollinator availability at low temperatures,
• a short growing season for seed ripening,
• and limiting environmental conditions for seed germination and seedling establishment.

However, without reproduction, life and its maintenance through time is not possible. Reproduction is necessary to replace inividuals dead from senescence, hazards and disturbances, and to allow for population growth. In plants, sexual reproduction is usually linked to dispersal. Dispersal is necessary for the occupation of empty patches and the colonisation of new sites.