On the map I posted it shows the big area that the Alamogordo Interagency Dispatch Center covers. The Lincoln National Forest, Forest Supervisor's Office is located in Alamogordo, but the dispatch center handles the U.S. Forest Service, National P:ark Service, BLM, U.S. Fish and Wildlife Service, BIA and New Mexico State Forestry. In the case of other dispatch centers they usually only handle the fire management function of National Park Service units (parks, monuments, historic sites, national recreation areas, etc.) and the law enforcement dispatch is handled by the NPS. In some cases they use phone lines or VoIP to connect distant parks into some sort of wide area regional dispatch center. Close to home here in AZ, Grand Canyon NP fire management and aviation functions are dispatched by the Williams Interagency Dispatch Center, who also dispatches for the BIA agencies west of Williams. However, the park has a Public Safety Answering Point at their own emergency dispatch center in Grand Canyon Village, South Rim. It would surprise me if the "ranger" heard by lhillin is a law enforcement ranger. I haven't the foggiest of who does the law enforcement dispatching for the park units in the Alamogordo Center's area, those being Carlsbad, Guadalupe and Big Bend. I would guess that Guadalupe is dispatched by Carlsbad, who may have their own LE dispatching. Big Bend is anyone's guess.
Here is the link to the dispatch center's website.