As a suscriber of many decades to the National Geographic Magazine, I can vouch for the fact that an article about the Western Ghats appeared in the magazine in 1999. However, I do not recall any mention of Goa at all. To my recollection in was an excellent article about the bio-diversity of the Western Ghats and there were some mention of some flora and fauna that were unique to this area. If you need it, I can ask National Geographic to get me a copy of that article, if it is not available on their site.
