Mission Trails, from mountainbikebill.com
Yes, you read that right. Both California and U.S. Fish & Wildlife have specified which trails should be closed or curtailed; details in this piece. CA Fish & Wildlife has also frustrated the community and local government by putting a surprise roadblock on the plan for Del Mar Mesa, which just a few months ago finally looked like there was a management plan to officially open it. Conservation is great, but it seems that the agency is working against local governments and communities, not with and for them.
I suspect there is more going on between CA Fish & Wildlife and the City of San Diego than the public knows about - especially since by way of comparison, that I know of, in recent history CA F & W has not interfered this way with any Bay Area city's park planning.