Ecology can be divided into many sub-disciplines using various criteria. Many of these fields overlap, complement and inform each other, and few of these disciplines exist in isolation. For example, methods from molecular ecology might inform the study of the population, and all kinds of data are modeled and analyzed using quantitative ecology techniques. Specialized branches of ecology include, among many others:

• applied ecology, the practice of employing ecological principles and understanding to solve real world problems (includes agroecology and conservation biology)
• biogeochemistry, effect of biota on global chemistry, and the cycles of matter and energy that transport the Earth’s chemical components in time and space
• biogeography, the study of the geographic distributions of species
• conservation ecology, which studies how to reduce the risk of species extinction
• ecological succession, which focuses on understanding directed vegetation change
• evolutionary ecology or ecoevolution which looks at evolutionary changes in the context of the populations and communities in which the organisms exist
• functional ecology, the study of the roles, or functions, that certain species (or groups thereof) play in an ecosystem
• global ecology, which examines ecological phenomena at the largest possible scale, addressing macroecological questions
• marine ecology, and aquatic ecology, where the dominant environmental milieu is water
• microbial ecology, the ecology of micro-organisms
• paleoecology, which seeks to understand the relationships between species in fossil assemblages
• restoration ecology, which attempts to understand the ecological basis needed to restore impaired or damaged ecosystems
• soil ecology, the ecology of the pedosphere
• urban ecology, the study of ecosystems in urban areas

Interdisciplinary Fields

Ecology also plays important roles in many inter-disciplinary fields:

• ecological design and ecological engineering
• ecological economics
• festive ecology
• human ecology and ecological anthropology
• social ecology, ecological health and environmental psychology

Ecology has also inspired (and lent its name to) other non-biological disciplines such as

• industrial ecology
• media ecology
• software ecology and information ecology

Finally, ecology is used to describe several philosophies or ideologies, such as

• deep ecology
• social ecology