Final answer:
Yosemite Valley was not designated as a park during the colonial era in the American colonies.
Step-by-step explanation:
The NOT a colonial era conservation effort in the American colonies was C: Yosemite Valley was designated as a park. The other options, A: Great Ponds Act of 1641, B: Massachusetts hunting regulations, and D: New York est. a closed hunting season for certain wild fowl, were all actual colonial era conservation efforts. These efforts were made to preserve natural landscapes and habitats, regulate hunting, and establish closed hunting seasons to protect wildlife.