Google+ like any other social media platform and the majority of the forums out there have links marked with the nofollow attribute. Can you imagine what would happen if the links were not nofollow ones? The links from Google+ won`t pass any PageRank to your website (I know that Google stopped updating PageRank, but that doesn`t mean that PageRank doesn`t exist now) but that doesn`t mean that Google+ can`t bring you lots of traffic (targeted one if you know what you are doing). I suggest you to don`t worry too much about the nofollow links from social media, because some people suggest that it is healthy and normal to have a mix of nofollow and follow links. (if you have just follow links Google might think that you are spamming)
Google+ is a social media with no follow attribute. but google+ can increase your site's ranking by huge visitor.