The term Ecosystem was invented in 1935 by the Oxford ecologist Arthur Tansley to encompass the interactions among biotic (air, water, land, energy), and abiotic (plants, animals, and microorganisms) components of the environment at a given site.
"Any unit that includes all of the organisms (i.e, the community) in a given area interacting with the physical environment so that a flow of energy leads to clearly defined trophic structure, biotic diversity, and material cycles (i.e., exchange of materials between living and non-living parts) within the system.", (by Eugene Odum).
The boundaries of an ecosystem can be somewhat arbitrary, reflecting the interest of a particular ecologist in studying a certain portion of the landscape. However, according to Tansley’s definition, the Ecological System (or shorter Ecosystem) is a functional and dynamic complex that result from the interactions of abiotic (air, water, land, energy), biotic (plants, animals, and microorganisms) and cultural (anthropogenic) components.
The Earth’s biosphere, including the atmosphere (air), hydrosphere (water), and lithosphere (land), constitutes a process of communication and control between living components and their physical and chemical environments. An ecosystem consists of several smaller ecosystems interconnected with cycles of energy and chemical elements. All ecosystems are "open" systems in the sense that energy and matter are transferred in and out. For example, the Earth as a single ecosystem constantly converts solar energy into many organic products, increasing biological complexity over time.
One of our greatest current challenges is the preservation and safety of its integrity. Given the complexity of the ecosystem, the use of a single field measurement is not powerful to asses and to monitor large geographic areas. However, it is necessary the use of multidimensional measures in order to analyze the interconnections between sub-areas and the effects generated within and among them.
Measures and Indicators
- The Living Planet Index measures trends in the Earth’s biological diversity. Using this, the WWF builds the Living Planet Report.
- Canadian Environmental Sustainability Indicators
- Global Footprint Network
- ↑ Tansley, AG (1935). "The use and abuse of vegetational terms and concepts". Ecology 16 (3): 284–307. doi:10.2307/1930070.
- ↑ http://www.ourfutureplanet.org/topic-eco-systems. Retrieved 17, Dec. 2010.