• Animal ecology
• Aquatic ecosystems
• Biosphere
• Ecological balance
• Ecosystem services
• Human ecology
• Plant ecology
• Terrestrial ecosystems

• Ecohydrology
• Ecology
• Natural environment

• The system of interdependent complex of plant and animal populations within a particular geographic content, generally an area of uniform environmental conditions.

• Science > Natural resources

http://vocabularies.unesco.org/thesaurus/concept211