Each National Wildlife Refuge has a somewhat individual Special Use Permit (SUP) process, but in general a SUP enables the public to engage in wildlife-related activities on a National Wildlife Refuge which would otherwise be prohibited, balancing use and conservation. SUPs are used by Refuge Managers to manage the amount and type of uses on an individual National Wildlife Refuge. Permits are also used as a contract between the Refuge Manager and the Permittee. They clearly explain what is expected of the Permittee with respect to restrictions, policies, reporting, etc., and they provide a protection to the Permittee by explaining what to expect from the Service in terms of support.
The Refuge System SUP forms can be found at http://www.fws.gov/refuges/visitors/permits.html.
Alternatively, you can link directly to the three SUP types here:
Proposed Commercial Activities may include but are not limited to activities such as non-news related photography, videography, or audiography; ecotours; recreational charter fishing. http://www.fws.gov/forms/3-1383-C.pdf
Proposed Research and Monitoring Activities may include scientific expeditions by students, universities, private institutions, or other non-Refuge System organizations. http://www.fws.gov/forms/3-1383-R.pdf . Download the additional Application Instructions specific to this form for the Pacific Reefs Refuge and Monument Complex
General and Other Activities may include but are not limited to education and outreach activities or amateur radio operations. http://www.fws.gov/forms/3-1383-G.pdf.