For marine, you may want too refer to the papers and their authors for more detailed guidance:

World Conservation Congress (2016). Increasing Marine Protected Area Coverage for Effective Marine Biodiversity Conservation Motion 53. Hawai’i: IUCN.

Asaad I, Lundquist CJ, Erdmann MV, Van Hooidonk R and Costello MJ (2018.) Designating Spatial Priorities for Marine Biodiversity Conservation in the Coral Triangle. Front. Mar. Sci. 5:400. doi: 10.3389/fmars.2018.00400

https://www.frontiersin.org/articles/10.3389/fmars.2018.00400/full

Qianshuo Zhao, Fabrice Stephenson, Carolyn Lundquist, Kristin Kaschner, Dinusha Jayathilake, Mark J. Costello (2020). Where Marine Protected Areas would best represent 30% of ocean biodiversity. IN: Biological Conservation, Volume 244, 2020, 108536, ISSN 0006-3207, https://doi.org/10.1016/j.biocon.2020.108536

(https://www.sciencedirect.com/science/article/pii/S0006320719312182)