NASA’s Earth Observatory
Figure 1. City lights in the United States, based on data from 2012.
The nighttime environment has historically included darkness in outdoor settings, brightened only to the degree that celestial objects and human-sourced light allowed. Human-caused lighting has increased in intensity and use over the last several decades, producing what is known as light pollution, or nuisance lighting. It is estimated that nearly 99% of the world’s skies are now deemed light-polluted, and the severity and extent of light pollution are expected to increase substantially (Cinzano 2001; fig. 1, above). A key trait of nuisance lighting is that it shines where it is not wanted (Brons et al. 2008), creating light trespass, or is deemed problematic in some other way. The U.S. National Park Service (NPS) has documented light pollution up to 200 miles (322 km) from its source in the form of sky glow: the orange or milky-gray glow characteristic of many metropolitan areas at night. Remote locations that have few or no nuisance light sources of their own can be affected by distant light sources via sky glow.>
The National Park Service has a small team of scientists dedicated to addressing what it calls “natural lightscapes.” The Night Skies Team (NST) uses science and technology to better understand the impact of anthropogenic light on the view of the celestial sky and to develop management recommendations for protection of these nighttime resources. Since its inception in 1999, the NST has expanded its scope to address the cultural, historical, ecological, and experiential (i.e., recreational) value of the night in the national parks. National Park Service management policies paralleled this change and in 2001 incorporated discussion of ecological and cultural values of natural lightscapes (natural resources and values found in the absence of human-caused light). Yet the bulk of nighttime stewardship remains focused on the celestial view and stargazing. This narrow bias may be a result of the decades of outreach by professional and amateur astronomers or the appearance of other park-related efforts and organizations. For example, the Starlight Initiative, the International Union for Conservation of Nature’s (IUCN) World Commission on Protected Areas, and the International Dark-sky Association remain focused on the view of the sky, whether on scientific, aesthetic, or cultural grounds.
A consequence of this institutional narrow focus is that a park manager may dismiss or minimize the value of the nighttime environment if the desire for stargazing is low, and overlook the wide range of other recreational activities that are linked to a naturally dark nighttime environment. Additionally, the fraction of the public that enjoys stargazing per se is likely smaller than the fraction that enjoys other nighttime recreational activities. Nighttime recreation may include other activities such as nocturnal species observation, historical or cultural learning, night fishing, camping, and night hiking (fig. 2, below). Night resources include nocturnal flora and fauna (fig. 3, below), the relative quiet of the night, and a natural dark environment. No accepted definitions of night recreation or night resources exist. This is problematic because an incompletely or incorrectly defined activity or resource cannot be properly managed, protected, or fully appreciated.
Figure 2. Camping is just one of 15 common types of night recreation that occurs in parks.
Benjamin Derge, Wikipedia Commons
Figure 3. Bioluminescent fungi are both natural and cultural night resources. Foxfire, created by such fungus, is a part of Appalachian folklore.
Empirical examinations of night resources—other than the ht sky—and night recreation are just beginning to occur from a social science perspective. A need exists to better understand the diversity of activities, experience opportunities, and use levels of night recreation in PPAs. This article presents (1) a census of night recreation activities offered in U.S. national and state parks; (2) proposed, expanded, and formalized definitions of night recreation and night resources; and (3) an assessment of opportunities, access to, and visitor participation in night recreation activities in the U.S. National Park System.
Smith, B. L., and J. C. Hallo. 2013. A system-wide assessment of night resources and night recreation in the U.S. national parks: A case for expanded definitions. Park Science 29(2):54–59.
Available at http://www.nature.nps.gov/ParkScience/archive/PDF/Article_PDFs/ParkScience29(2)FallWinter2012-2013_54-59_SmithHallo_et_al_3641.pdf.