I'm running a 1070 at the moment, was underwhelmed by the performance in ARK (obvs it's a EA title and not really optimised or w/e). Try tweaking;
the graphics option checkboxes (one of them, maybe distance field shadowing or distance field AO, had a really noticeable difference)
Sky quality - I turn this down to much lower than the game set it IIRC, makes stuff clearer and easier to spot as well
Clutter Density/Clutter Draw distance - If you just max these out it hits your performance pretty hard I think
I'll check my settings and report back!
EDIT; I uploaded a screenshot of my settings, turned on stuff/turned up stuff until I stopped getting 60 fps (these settings (all eyeballed) got me 60-90fps averaging 70-80fps on test runs across the swamp, through the plains, past the mountain and into the forest then back again. This is on; i7 4770k @ 4.5, 16gb 2133 DDR3, GTX 1070 running off a standard SSD at 1080p