One of the things that the Ecological Society of America does is to
issue position statements about policy issues relevant to its
members. Some of these are in response to issues raised by members
who contact ESA leadership or the Public Affairs Office. For example,
ESA has just sent a letter to the President of Nicaragua to express
concern about the proposed new Interoceanic Canal that would run
through Lake Nicaragua to connect the Atlantic and Pacific Oceans:
http://www.esa.org/esa/documents/2015/02/nicaragua-canal-letter.pdf
A list of other policy letters sent by ESA Presidents is available at:
http://www.esa.org/esa/public-affairs/esa-policy/letters-from-esa-president/
In many cases ESA members volunteer their expertise to help draft the letters.
David Inouye