Conversation so far:
What is Paul Watson's biggest environmental achievement?
Watson was a field correspondent for Defenders of Wildlife from 1976 to 1980 and a field representative for the Fund for Animals from 1978 to 1981.
What else did he achieve environmentally?
Watson also was a co-founder of Friends of the Wolf and Earthforce Environmental Society.
Did he achieve anything else environmentally?
According to The New Yorker, Watson revived the 19th-century practice of tree spiking.
Can you tell me about any further achievements environmentally?
Watson ran as an independent candidate in the 1980 Canadian Federal election in Vancouver Centre, proclaiming he wasn't a politician but an environmentalist.
Did he win that election?
He received less than 100 votes.
What did he do after the election?
Watson did work with the Green Party of British Columbia in Vancouver in the 1980s and 90s.
Did he ever hold political office?
In April 2003, Watson was elected to the board of directors of the Sierra Club for a three-year term.

Question: What did he do there?
Self-contained rewrite: What did Paul Watson do on the board of directors of the sierra club?