Catherine Rich and Travis Longcore, eds.
Island Press, Washington DC,
2006, 458 pp.
$65 (hardcover), $35 (paperback)
ISBN 1559631287 (hardcover), ISBN 1559631295 (paperback)

The world at night is illuminated artificially mainly by urban lighting, but also fires, gas flares, and light-induced fisheries (www.ngdc.noaa.gov/dmsp/image/poster_world.jpg). This edited volume is the best source for the increasingly recognized environmental impact of artificial light on the living world. Artificial lighting disrupts animals by disorienting them at night, increasing their exposure to predation or conversely to abundant food sources, altering light-sensitive endocrine systems, and disrupting crepuscular and nocturnal mating, signaling, and dispersal. The best-known examples of these disruptions are confusion and mortality of migrating birds at lighted towers and buildings and the disorientation of sea turtle hatchlings returning to the sea. This is just a fraction of the ecological effects of night luminescence, of which only a small portion are documented. Fifteen chapters cover effects of artificial lighting on mammals, birds, reptiles, amphibians, fishes, invertebrates (mostly insects), and plants. The book was an outgrowth of the first and only conference on Ecological Consequences of Artificial Night Lighting, held in Los Angeles in 2002.

The volume is organized in sections based on the taxonomy of animals, plus one chapter on plants, an introduction, and a synthesis section. Each of six larger sections is punctuated by a passage about darkness and its creatures, an unusual but effective "time out" from the scientific chapters. These personal accounts are by various authors, from Thoreau to Bernd Heinrich.

The coverage of different groups is uneven. Mainly this reflects the uneven, usually deficient, attention to the effects of artificial lighting on many groups, coupled with the desire of the organizers to represent major groups even if the available information is thin. Birds and sea turtles are given extensive coverage in the reviews as in the primary literature. A few chapters are very specific, with primary data, such as chapter 6, which consists mostly of a field study of nesting godwits in Dutch wetland adjacent to street lighting.

Three chapters deal principally with insects, and several others (including those on bats and freshwater habitats) also include a significant entomological component. Attraction of insects to streetlights is reviewed in detail by Gerhard Eisenbeis; this includes new primary data contrasting different light types and catch patterns including moon phase, along with theory regarding different types of behavioral disruptions. Kenneth Frank provides an impressive review on moths including useful prescriptive recommendations regarding streetlamp types that are most and least attractive. The chapter on fireflies by James Lloyd is an overview of temperate fireflies and a case for the likely effects of artificial light on their bioluminescent signals, with an open-ended and stimulating call for more study of proposed questions. The chapter on bats by Jens Rydell is an excellent summary of a complex topic involving altered interactions with insect prey and changes in competitive interaction among predators. Marianne Moore and coauthors show that freshwater habitats are very sensitive even to diffuse lighting. For example, the vertical movements of planktonic arthropods in the lentic water column respond to very small changes in nocturnal light intensity, less than moonlight or even starlight. That these arthropods are primary consumers of algae near the surface of eutrophic urban ponds and lakes has clear ecosystem-level implications.

The introduction and synthesis chapters were both helpful but could have been meatier. Illumination units and magnitude are explained in the introduction but consistently converted to lux in the chapters. Light quality is referred to in several places in different chapters, when authors describe spectral characteristics of diffuse light or different light sources such as high-pressure sodium and mercury lamps. A review of light spectral quality as well as issues of light measurement, in addition to light intensity, would have been helpful for understanding these chapters. In the synthesis, some of the generalizations do not ring true: for instance, "Artificial night lighting is homogenizing the range of physical conditions present in natural ecosystems." This is too vague to be useful and is not borne out by the facts presented: the heterogeneity of night lighting is striking at most spatial scales.

The book clearly achieves its twin goals of raising awareness and reviewing the oft-scarce available data on night lighting's effects. A chapter or two on "what do we do now" would have been welcome. The editors and their associates at The Urban Wildlands Group and many others influenced by the conference and by this book are involved in investigating and mitigating impacts. In the book, this is limited to some general exhortation and scattered specific prescriptions such as a table elaborating the Bird-friendly Building Program to protect migrating songbirds and alteration of shoreline lighting in Florida for protection of sea turtles. The conference itself had more presentations and discussions regarding mitigation in design and modification of night lighting, focusing on darkening the night sky for astronomy, and protection of birds. The synthesis chapter could have broadened this discussion to consider the bigger picture for global trends in artificial lighting and protection of ecosystems for the future.

To my disappointment, nowhere does the book question the proposition that "outdoor night lighting accompanies (or must accompany) modern human settlements." When every motor vehicle has and must have headlights, why is street lighting required for the automobile? Gigawatts ride on the answer, gigawatts that are increasingly expensive to humans and to the environment as a whole. A separate question is whether outdoor lighting truly improves the safety of pedestrians. This evokes political controversy—and makes clear there is not one answer for every location.

"Ecological consequences of artificial night lighting" is a thought-provoking volume that many entomologists would profit from owning. I gleaned a number of ideas for future studies from this valuable book and other less tangible but beneficial thoughts on how we as humans perceive and evaluate environmental effects on animals very different from us. It is an effective and well-documented appeal for scientists and citizens to give the dark its due and to heed our impacts on its denizens, which are, in fact, all of us.

Donald C. Weber
USDA-ARS Invasive Insect Biocontrol & Behavior Laboratory
 Beltsville, Maryland

Environmental Entomology
Vol. 37, No. 5, October 2008