Population ecology

Definition

The study of how populations of organisms change in size and structure over time through the interplay of births, deaths, immigration, and emigration, and how these demographic processes are shaped by biotic and abiotic factors.

Etymology

Latin populus (people, multitude) + Greek oikos (house, household) + logos (study)

Example

Population ecologists might track how a outbreak of spruce budworm (Choristoneura fumiferana) collapses after defoliating its host trees, analyzing density-dependent mortality from starvation and parasitoid wasp attack alongside weather-driven survivorship of overwintering larvae.

Synonyms

• Autecology
• demographic ecology

Related Terms

• metapopulation
• Carrying capacity
• Life table
• r/K selection theory
• Density dependence
• Population dynamics
• community ecology

Usage Notes

Contrasts with community ecology (interactions among species) and ecosystem ecology (energy and nutrient flows). Specialists often reserve 'population ecology' for single-species studies, though the term sometimes extends to multi-population (metapopulation) systems. The field provides foundational models for pest management, conservation biology, and invasion biology—disciplines heavily reliant on insect and arachnid study systems due to their short generation times and tractable population sizes.