Ecotone Explained

eco•tone from ecology (eco; Greek οἶκος, oikos “house/dwelling”) + -tone from the Greek τόνος tonos, “tension.”

Two houses in tension: an ecotone is a border zone, where ecological systems meet and mingle, sometimes forming a new and different community of species.

 

Pacific crest ecotone. The peaks of the Cascade mountain range cast a “rain shadow” over eastern Oregon, instigating a harsh change from the wet, green, boreal forest of the west to the dry, sparse, high desert of the east. Greens and browns brightly demarcate the ecosystem transition, or ecotone, in this image acquired by the USGS Landsat 5 satellite on 27 Oct 2011. Credit, USGS Landsat and the NASA Earth Observatory.

Pacific crest ecotone. The peaks of the Cascade mountain range cast a “rain shadow” over eastern Oregon, instigating a harsh change from the wet, green, boreal forest of the west to the dry, sparse, high desert of the east.
Warm Chinook winds move wet air east from the Pacific Ocean. As the air rises against the western flank of the mountains, it cools, and releases its moisture as rain and snow. Dry air sliding down the eastern, leeward slopes heats as it compresses in the higher pressure at lower altitudes. 
Greens and browns brightly demarcate the ecosystem transition, or ecotone, in this image acquired by the USGS Landsat 5 satellite on 27 Oct 2011. Credit, Jesse Allen, Robert Simmon, and Tassia Owen,  the NASA Earth Observatory.

Ecotone is the news and outreach forum for the Ecological Society of America, featuring fresh research from our scholarly journals and around the ecological community. Visit us for news about the society and profiles of our members. Ecotone also offers analysis of government policy developments in the scientific arena.

 

Ecotones occur at edges and physical boundaries, where fresh water meets salt water and water meets land, where tides roll up and down coasts, where the fir trees of taiga forests give way to the lichen and grass of tundra and woodlands become pastures.

The term refers to the transition from one ecosystem to another, as well the stress inherent in a population at the limit of its tolerance for specific environmental conditions.

Burton Edward Livingston1 and Frederic Clements2 described the ecotone concept in the first decade of the twentieth century, when ecology was coalescing as a field of study.

 

We welcome guest submissions of timely relevant news of importance to the broad ecological community. Liza Lester, ESA’s communications officer, edits Ecotone.


  1. “Along a wavy east and west line passing through Rockford lies the “zone of tension” between societies I, II, and III on the one hand, and IV and V on the other…It may be that the climate, somewhat colder as we pass northward, has acted as a retarding factor, assisted by the fact that a good portion of these northern townships have a light surface soil, which seems unsuited for the hard wood societies in the absence of humus.”

    Livingston, Burton Edward. The Distribution of the Upland Plant Societies of Kent County, Michigan. Botanical Gazette, Vol. 35, No. 1 (Jan., 1903), pp. 36-55. [archived pdf scan in JSTOR]

  2. “The line that connects the points of accumulated or abrupt change in the symmetry is a stress line or ecotone. Ecotones are well-marked between formations, particularly where the medium changes; they are less distinct within formations. It is obvious that an ecotone separates two different series of zones in the one case, and merely two distinct zones in the other.”

    Clements, F.E. 1905. Research methods in ecology. University Publishing Company, Lincoln, NE. [full text in open library]