Overwintering

Overwintering is the process by which organisms survive winter conditions when environmental resources are scarce and temperatures are low. It encompasses behavioral, physiological, and developmental strategies that enable persistence through cold periods and to resume growth or reproduction when conditions improve. Strategies vary across taxa and environments, from entering a prolonged dormancy to undertaking long-distance migration.

In plants, overwintering often involves dormancy and reduced metabolic activity. Perennials may die back to roots or storage organs such as bulbs, tubers, or rhizomes, resuming growth in spring. Some trees retain leaves and rely on hardiness or protective structures. Seed banks in the soil allow germination when conditions are favorable. Protective coverings, mulches, and insulating structures help minimize damage from frost and desiccation.

Insects and other invertebrates overwinter by overwintering as eggs, larvae, pupae, or adults, often with cryoprotectants or antifreeze compounds that lower freezing risk. Some species migrate away or seek sheltered microhabitats like leaf litter, under bark, or in soil. Vertebrates may hibernate or enter short, periodic torpor to conserve energy; others stay active but with lowered metabolic rate. Some amphibians and fish tolerate freezing of body tissues through biochemical adaptations.

Human practices include protecting overwintering crops and ornamentals with mulching, row covers, greenhouses, or cold frames, and storing seeds or transplant stock to survive winter. Understanding overwintering is important for agriculture, ecology, and conservation, as climate variability can alter the cues that trigger dormancy, migration, or emergence.