Habitat specialisation in plants of cold climates

Summary Plants of northern and arctic habitats possess a number of adaptations which help to counteract the disadvantages of low thermal environment. The ability to increase metabolic rates at low temperatures provides an efficient means of thermal compensation. When northern plants are exposed to warm temperatures this capacity for increased metabolic rates results in high energy losses. Dioecism with female predominant sex ratios can have advantages in increasing seed production in the arctic habitat. This advantage would not be maintained in areas of lush vegetation as inefficient pollen dispersal from the smaller number of males greatly reduces the effective breeding size of the population. Many of the adaptations in respiration, photosynthesis and reproduction found in northern and arctic plants which increase their efficiency at low temperatures place them at a disadvantage in warmer climates.