Rapid declines threaten the persistence of many marine fish. Data from more than 230 populations reveal a median reduction of 83% in breeding population size from known historic levels. Few populations recover rapidly; most exhibit little or no change in abundance up to 15 years after a collapse. Reductions in fishing pressure, although clearly necessary for population recovery, are often insufficient. Persistence and recovery are also influenced by life history, habitat alteration, changes to species assemblages, genetic responses to exploitation, and reductions in population growth attributable to the Allee effect, also known as depensation. Heightened extinction risks were highlighted recently when a Canadian population of Atlantic cod (Gadus morhua) was listed as endangered, on the basis of declines as high as 99.9% over 30 years. Unprecedented reductions in abundance and surprisingly low rates of recovery draw attention to scientists' limited understanding of how fish behavior, habitat, ecology, and evolution affect population growth at low abundance. Failure to prevent population collapses, and to take the conservation biology of marine fishes seriously, will ensure that many severely depleted species remain ecological and numerical shadows in the ecosystems that they once dominated.

Ecologists are often asked to contribute to solutions for broadscale problems. The extent of most ecological research is relatively limited, however, necessitating extrapolation to broader scales or to new locations. Spatial extrapolation in ecology tends to follow a general framework in which (a) the objectives are defined and a conceptual model is derived; (b) a statistical or simulation model is developed to generate predictions, possibly entailing scaling functions when extrapolating to broad scales; and (c) the results are evaluated against new data. In this article, we examine the application of this framework in a variety of contexts, using examples from the scientific literature. We conclude by discussing the challenges, limitations, and future prospects for extrapolation.

Invertebrate species represent more than 99% of animal diversity; however, they receive much less publicity and attract disproportionately minor research effort relative to vertebrates. Nonmarine mollusks (i.e., terrestrial and freshwater) are one of the most diverse and imperiled groups of animals, although not many people other than a few specialists who study the group seem to be aware of their plight. Nonmarine mollusks include a number of phylogenetically disparate lineages and species-rich assemblages that represent two molluscan classes, Bivalvia (clams and mussels) and Gastropoda (snails, slugs, and limpets). In this article we provide an overview of global nonmarine molluscan biodiversity and conservation status, including several case studies documenting the diversity and global decline of nonmarine mollusks. We conclude with a discussion of the roles that mollusks and malacologists should play in conservation, including research, conservation management strategies, and education and outreach.

Responsible conduct in science is more than simply a matter of following everyday ethical imperatives—not misreporting what actually happened in the lab, dealing honestly with colleagues, and so forth. Scientific responsibility arises because scientists play a special role, and that role brings obligations. In this article I maintain that scientists have an obligation to reflect on the ends of scientific research; that scientists should work for the public good, directing their efforts toward an ideal of well-ordered science; and that the ideal of well-ordered science should be understood in a global and democratic fashion.

Polar bears give birth in snow dens in midwinter and remain in dens until early spring. The survival and development of cubs is dependent on a stable environment within the maternal den. To mitigate potential disruption of polar bear denning by existing and proposed petroleum activities, we used forward-looking infrared (FLIR) viewing to try to detect heat rising from dens. We flew transects over dens of radio-collared females with FLIR imager–equipped aircraft, recorded weather conditions at each observation, and noted whether the den was detected. We surveyed 23 dens on 67 occasions (1 to 7 times each). Nine dens were always detected, and 10 dens visited more than once were detected on some flights but not on others. Four dens were never detected (17 percent), but three of those were visited only under marginal conditions. The odds of detecting a den were 4.8 times greater when airborne moisture (snow, blowing snow, fog, etc.) was absent than when it was present, and they increased 3-fold for every 1°C increase in temperature–dew point spread. The estimated probability of detecting dens in sunlight was 0. Data suggested that FLIR surveys conducted during optimal conditions for detection can produce detection rates approaching 90 percent and thus can be an important management and mitigation tool.

There are few well-documented, general ecological principles that can be applied to pressing environmental issues. When they discuss them at all, ecologists often disagree about the relative importance of different aspects of the science's original and still important issues. It may be that the sum of ecological science is not open to universal statements because of the wide range of organizational, spatial, and temporal phenomena, as well as the sheer number of possible interactions. We believe, however, that the search for general principles has been inadequate to establish the extent to which generalities are possible. We suggest that ecologists may need to reconsider how we view our science. This article lists 10 suggestions for ecology, recognizing the many impediments to finding generalizations in this field, imposed in part by the complexity of the subject and in part by limits to funding for the study of ecology.

Behavioral ecologists have advocated a greater role for behavioral research in conservation, and the contribution of behavioral study to conservation has increased dramatically. However, a review of the literature in the fields of behavioral ecology and conservation finds that half the articles that investigate behavior in conservation journals do not advance beyond the descriptive phase (compared with 14 percent in behavioral ecology journals) and that most articles in behavioral ecology journals (71 percent) are narrowly focused on questions about the adaptive value of behavior, whereas conservation biology journals include more diverse interests such as causative and developmental mechanisms (43 percent). Addressing this mismatch between the disciplines is the key to improving the utility of behavioral ecology in conservation. The solution I propose is a renewed appreciation of Tinbergen's paradigm, both in behavioral ecology, where it can encourage more pluralistic research by integrating proximate and evolutionary questions, and in conservation biology, where it can structure the advance from descriptive studies of behavior to behavioral problem solving.