Hunting (visiting) Swedish nature reserves and national parks for worked nature reserve SMFF diplomas or just for fun is popular among Swedish hams. This is administrated by SK6AW SMFF.
On the SK6AW SMFF page is a link to "Senast aktiva" (latest active). This is of great help to see where and when and on wich band/frequency SMFF stations recently have been active. The photo below shows recent SMFF activity on my mobile phone as it was on March 13, 2014 13:18 UTC.
Another easy way to be informed about SMFF activity is by listening to an Internet SDR radio while driving. In the video clip below I am listening to a SDR radio in Holland. This is when I am near a nature reserve called Torsmyran SMFF-2331 in Nordmaling in northern Sweden.
Some of my nature reserve visits in 2014 in northern Sweden are described (photos and videos) here.