I came across this term in an article from 2010 but the author provides no citation for it. I would appreciate both a definition and a brief summary of key scholars working in this subfield.
Three different anthropologists have written about discourse ecologies rather independent of each other.
1. The first mention of the term that I could find was in 1985 in an article by Michael Agar on institutional culture in Text - Interdisciplinary Journal for the Study of Discourse. He approaches discourse ecologies as a way to understand the limitations and parameters of discourse within a specific institutional context.
2. Robin Shoaps presents the term as a new term in an article published in 2009 "Ritual and (Im) Moral Voices: Locating the Testament of Judas In Sakapultek Communicative Ecology". Whereas Agar had approached discourse ecologies as the external limitations on discourse, Shoaps explores the sources, resources, and potentiality that are being tapped into by he specific discourse being considered.
3. Ato Quayson writing in 2010 in his article "Signs of the Times: Discourse Ecologies and Street Life on Oxford St., Accra" approaches the topic similarly to Shoaps. Both authors are working with a comparable process but seem unaware of each other.