I'm not sure if this has been shared generally but passes are being required for a growing number of CA wildlife areas which were formerly free. I'd seen an article in the SF Chronicle a couple of weeks ago describing the new Lands Pass program, highlighting the addition of the Woodbridge (Sandhill Crane) Ecological Reserve to the program.
I was still surprised when I arrived at the Yolo Bypass Wildlife Area outside of Sacramento earlier this week to find a sign saying passes were required. There was no kiosk or other means of obtaining a pass on the spot and the phone number and Web site listed on the sign were not helpful, except to let us know that you can't get a pass the same day. Luckily, someone else in the same predicament had already spent 20 minutes discovering that the requirement didn't go into effect at Yolo until Jan. 1.
While the only locale in the Monterey Bay region covered by the Lands Pass program is Elkhorn Slough Ecological Reserve (as far as I've noticed), there's a fairly long list and you might be surprised to show up at a site you've visited before to find a pass required... and no way to obtain one when you are there. (Hunting and Fishing licenses are valid at these locations, if that applies.)
The annual Lands Pass is not expensive ($25.10 for 2018) and can be purchased online. They warn you that it takes 15 days. They are keyed to your state ID (e.g., driver's license) and you can buy only one for yourself. You need a pass for each person, not per vehicle like park passes. One-day guest passes can be purchased (in advance) for anyone else in your party.