As the others have said here, typically when you add in rules, and blocks into the Htaccess file, that can slow down how google will crawl your website content. The WP Super cache will not usually stop visitor traffic.
comparing the before, and after logs will also help. Another tips I would test would be to perhaps remove one rule, and monitoring it for a few days ,this can help to pinpoint why all of a sudden your organic visitor traffic has dropped.
I would then go ahead, and do the next step like blackcat recommended. I would also ask the person that added in these new rules, what each of them will actually do for your traffic and site performance.
I hope my answer helps you