Park ranger

Law enforcement: Law enforcement rangers have police powers and enforce national laws as well as park regulations. In some developing countries, the park rangers patrolling natural preserves may be heavily armed and function as paramilitary organizations against organized poachers or even guerrillas. In many other developing countries however, park rangers have law enforcement authority and do carry firearms as they seek to achieve respect for nature by building good relationships with local communities and the visiting public. In units of the U.S. National Park System, law enforcement Rangers are the primary police agency; their services may be augmented by the US Park Police, particularly in the Washington, DC and San Francisco metropolitan areas. The U.S. National Park Service also has a section of "Special Agents" who conduct more complex criminal investigations. According to U.S. Department of Justice statistics, National Park Service Law Enforcement Rangers suffer the highest number of felonious assaults, and the highest number of homicides of all federal law enforcement officers.[11] The City of New York has a uniformed division of Park Rangers called the New York City Parks Enforcement Patrol who are responsible for patrolling the city parks, pools and beaches.
Interpretation and education: Park Rangers provide a wide range of informational services to visitors. Some Rangers provide practical information—such as driving directions, train timetables, weather forecasts, trip-planning resources, and beyond. Rangers may provide interpretive programs to visitors intended to foster stewardship of the resources by the visitor as a method of resource protection. Interpretation in this sense includes (but is not limited to): guided tours about the park's history, ecology or both; slideshows, talks, demonstrations; informal contacts, and historical re-enactments. Rangers may also engage in leading more formalized curriculum-based educational programs, meant to support and complement instruction received by visiting students in traditional academic settings and often designed to help educators meet specific national and/or local standards of instruction. All uniformed rangers, regardless of their primary duties, are often expected to be experts on the resources in their care, whether they are natural or cultural.
Emergency response: Rangers are often trained in wilderness first aid and participate in search and rescue to locate lost persons in the wilderness. Many national parks require law enforcement rangers to maintain certification as Emergency Medical Responders, Emergency Medical Technicians, or Paramedics. Depending on the needs of the park where assigned, rangers may participate in high-angle rescue, swift-water rescue, may be certified scuba divers, and can become specially trained as helicopter pilots or crew members.
Firefighting: Rangers are often the first to spot forest fires and are often trained to engage in wild land firefighting and in some cases structural fire fighting. Rangers also enforce laws and regulations regarding campfires and other fires on park lands. In the face of a fire outside their control, rangers will call for help and evacuate persons from the area pending the arrival of additional firefighters.
Dispatcher: Some rangers work as park protection dispatchers, answering emergency calls and dispatching law enforcement rangers, park fire fighters or Park EMS crews by radio to emergency calls for service. Park Dispatchers provide pre-arrival instructions to callers to help them stay alive until responding units arrive. Dispatchers coordinate multi-agency responses to emergencies within the park boundaries and utilize computer systems to check for criminal histories of subjects stopped by park law enforcement rangers. Park Dispatchers typically perform other duties such as taking lost-and-found reports, monitoring CCTV surveillance cameras and fire alarms. Dispatchers are assigned to the Park Protection Division.
Scientists and scholars: Rangers are responsible for protecting the natural resources or cultural sites for which they work. This includes obtaining and preserving knowledge about the area. As such, many different types of historians and scientists are employed as rangers. Some scientific positions often filled by rangers include archaeologist, many different types of biologist, ecologist, fire scientist, geologist, hydrologist, paleontologist, soil scientist, volcanologist, etc. Rangers in these positions are expected to study, monitor, and inform others (in the form of published, peer-reviewed scientific papers as well as internally) about their findings. These people add to the knowledge dispersed in interpretive and educational programs, and provide information needed by managers and others to more effectively protect the resource.
Maintenance: Some rangers perform regular maintenance on infrastructure or equipment such as fire rings as part of their duties — especially in preparing for winter closures and spring reopenings. Rangers are often the first to discover vandalism or weather-related damage to park roads, trails and campgrounds.
Administration: In many cases administrative staff members are categorized officially as park rangers and may wear the distinct park ranger uniform while working "behind the scenes" to ensure the continued operation of the parks. These rangers may set policy for the parks, or handle park budgets, computers and technology, human resources, or other fields related to the administration of parks. In the case of management these positions are usually filled by individuals who have moved up from other field-based positions. These individuals are often heavily cross trained in order to allow for a knowledge of all other areas and duties under their authority.

Question: What does a Park Ranger do?