Ecotrons phylogenies: an historical perspective on the development of large facilities for the conditioning of ecosystems and the measurement of their processes.

The term “ecotron “ was coined at the Botanical Institute of Montpellier in the late 50’s to describe a project of a facility to the study plant ecophysiology. An article in the September 1960 UNESCO Bulletin attributes its origin to Prof. Louis Emberger, head of this institute. However, the person who was behind the Ecotron project was Frode Eckardt, a CNRS researcher in Montpellier. In 1963 he submitted to the Montpellier University the project of an Ecotron to study the ecophysiology of plants (and not plant development as in most phytotrons at that time). F. Eckardt had spent the years 1956-1957 with Fritz Went in his Caltech, Pasadena, new Phytotron. Certainly inspired by this impressive facility for the time, F. Eckardt had the ambition to develop a facility of the same type but devoted to the study of plants responses and adaptation to the environment. He may have coined the word Ecotron on his way back from Pasadena. The term “Phytotron” came in a joking conversation between Pasadena biologists. It was constructed on the structure of “cyclotron”, the large physicists’ instrument built in 1941 in Berkeley (cyclo- from the circle used to accelerate the electrons and -tron, the end of electron). It was used at the inauguration of the Earhart Plant Research Laboratory conceived by F. Went to insist on the similarity between instruments for biologists and physicists (as costly and as important for society). Several phytotrons were then built around the world in the late 50s early 60s: in France (Gif-sur Yvette, 1961), Australia (Canberra, 1962), US (Duke University 1968), etc.

Fritz Went moved to Saint Louis, Missouri, where he built the Climatron, a large air conditioned greenhouse to display ecosystems of the world. A range of climates (from Amazonia to cool Indian uplands) were recreated without physical partitioning of the space. F. Went then moved to Reno, Nevada, to set-up an ecophysiology laboratory in the Desert Institute. His successor at this laboratory, Tim Ball and then Jay Arnone developed in the 90’s the Ecocells facility, whose principle is the same as an Ecotron.

Frode Eckardt did not succeed in building his Ecotron, but he became an international leading figure in the development of plant ecophysiology methods, especially climate controlled chambers for the measurement in natura of ecosystem gas exchanges. This was the heart of the activity of the ecophysiology laboratory of the CNRS Centre d’Etudes Phytosociologiques et Ecologiques (now Centre d’Ecologie Fonctionnelle et Evolutive) with Bernard Saugier and André Berger continuing Eckardt work. Jacques Roy was their student and then colleague. He had developed various climate-controlled and gas exchange facilities for plants and ecosystems and was given the charge to build the CNRS Ecotron in Montpellier.

Independently of these two lineages of Ecotrons (Cf scheme below), John Lawton at Imperial College in Silwood Park built an ecotron in the early 90’s. A community ecologist, John Lawton was initially interested in testing in this ecotron the role of biodiversity in ecosystem processes. This research topic that spurred by a meeting organized by Detlef Schulze and Harold Mooney in Bayreuth in 1991 with a subsequent seminal book (Biodiversity and ecosystem function, 1994, Springer). The Silwood Park Ecotron gave birth to high visibility publications but was closed in 2013 due to decreased relevance of its technical characteristics and lack of funding.

The scientific need for controlled-environment experimental facilities is still very vivid. Large sets of growth chambers exists in most major universities and agronomic institutes, for example the Duke University Phytotron, the Rothamsted controlled environment and glasshouse facilities, the New Zealand Biotron. Ecotron-like facilities with both environmental control and process measurements are being developed in several countries: the Bioklima project in Norway is in a pre-financing phase, the Leipzig iDiv ecotron project is in a designing phase in Germany and the Hasselt and Gembloux universities ecotrons projects in Belgium are in a construction phase. In France, CNRS is developing a facility complementary to the Montpellier ecotron, the ecotron IleDeFrance, with in particular the possibility to experiment with aquatic ecosystems.

Ecotrons phylogeny