Chinook salmon (Oncorhynchus tshawytscha) are critical to subsistence and commerce in the Yukon River basin, but several recent years of low abundance have forced devastating fishery closures and raised urgent questions about causes of the decline. The Chena River subpopulation in interior Alaska has experienced a decline similar to that of the broader population. To evaluate possible factors affecting Chena River Chinook salmon productivity, I analyzed both population data and the behavior of individual fish during the summer they spend as fry drift feeding in the river. Using a stereo pair of high definition video cameras, I recorded the fine-scale behavior of schools of juvenile Chinook salmon associated with woody debris along the margins of the Chena River. I developed a software program called VidSync that recorded 3-D measurements with sub-millimeter accuracy and provided a streamlined workflow for the measurement of several thousand 3-D points of behavioral data (Chapter 1). Juvenile Chinook salmon spent 91% of their foraging attempts investigating and rejecting debris rather than capturing prey, which affects their energy intake rate and makes foraging attempt rate an unreliable indicator of foraging success (Chapter 2). Even though Chinook salmon were schooling, some were highly territorial within their 3-D school configurations, and many others maintained exclusive space-use behaviors consistent with the population regulatory effects of territoriality observed in other salmonids (Chapter 3). Finally, a twenty-year population time series from the Chena River and neighboring Salcha River contained evidence for negative density dependence and a strong negative effect of sustained high summer stream discharge on productivity (Chapter 4). The observed territoriality may explain the population's density dependence, and the effect of debris on foraging efficiency represents one of many potential mechanisms behind the negative effect of high stream discharge. In combination, these findings contribute to a statistically and mechanistically plausible explanation for the recent decline in Chena River Chinook salmon. If they are, in fact, major causes of the decline (other causes cannot be ruled out), then we can be tentatively hopeful that the population may be experiencing a natural lull in abundance from which a recovery is possible.

A global assessment of the current state of freshwater fish biodiversity and the opportunities and challenges to conservation.

Over a half century of exploration of the Earth’s space environment, it has become evident that the interaction between the ionosphere and the magnetosphere plays a dominant role in the evolution and dynamics of magnetospheric plasmas and fields. Interestingly, it was recently discovered that this same interaction is of fundamental importance at other planets and moons throughout the solar system. Based on papers presented at an interdisciplinary AGU Chapman Conference at Yosemite National Park in February 2014, this volume provides an intellectual and visual journey through our exploration and discovery of the paradigm-changing role that the ionosphere plays in determining the filling and dynamics of Earth and planetary environments. The 2014 Chapman conference marks the 40th anniversary of the initial magnetosphere-ionosphere coupling conference at Yosemite in 1974, and thus gives a four decade perspective of the progress of space science research in understanding these fundamental coupling processes. Digital video links to an online archive containing both the 1974 and 2014 meetings are presented throughout this volume for use as an historical resource by the international heliophysics and planetary science communities. Topics covered in this volume include: Ionosphere as a source of magnetospheric plasma Effects of the low energy ionospheric plasma on the stability and creation of the more energetic plasmas The unified global modeling of the ionosphere and magnetosphere at the Earth and other planets New knowledge of these coupled interactions for heliophysicists and planetary scientists, with a cross-disciplinary approach involving advanced measurement and modeling techniques Magnetosphere-Ionosphere Coupling in the Solar System is a valuable resource for researchers in the fields of space and planetary science, atmospheric science, space physics, astronomy, and geophysics. Read an interview with the editors to find out more: https://eos.org/editors-vox/filling-earths-space-environment-from-the-sun-or-the-earth

This book seeks to confront an apparent contradiction: that while we are constantly attending to environmental issues, we seem to be woefully out of touch with nature. The goal of Ecopsychology, Phenomenology and the Environment is to foster an enhanced awareness of nature that can lead us to new ways of relating to the environment, ultimately yielding more sustainable patterns of living. This volume is different from other books in the rapidly growing field of ecopsychology in its emphasis on phenomenological approaches, building on the work of phenomenological psychologists such as Maurice Merleau-Ponty. This focus on phenomenological methodologies for articulating our direct experience of nature serves as a critical complement to the usual methodologies of environmental and conservation psychologists, who have emphasized quantitative research. Moreover, Ecopsychology, Phenomenology and the Environment is distinctive insofar as chapters by phenomenologically-sophisticated ecopsychologists are complemented by chapters written by phenomenological researchers of environmental issues with backgrounds in philosophy and geology, providing a breadth and depth of perspective not found in other works written exclusively by psychologists.

Brings together disparate conversations about wildlife conservation and renewable energy, suggesting ways these two critical fields can work hand in hand. Renewable energy is often termed simply "green energy," but its effects on wildlife and other forms of biodiversity can be quite complex. While capturing renewable resources like wind, solar, and energy from biomass can require more land than fossil fuel production, potentially displacing wildlife habitat, renewable energy infrastructure can also create habitat and promote species health when thoughtfully implemented. The authors of Renewable Energy and Wildlife Conservation argue that in order to achieve a balanced plan for addressing these two crucially important sustainability issues, our actions at the nexus of these fields must be directed by current scientific information related to the ecological effects of renewable energy production. Synthesizing an extensive, rapidly growing base of research and insights from practitioners into a single, comprehensive resource, contributors to this volume • describe processes to generate renewable energy, focusing on the Big Four renewables—wind, bioenergy, solar energy, and hydroelectric power • review the documented effects of renewable energy production on wildlife and wildlife habitats • consider current and future policy directives, suggesting ways industrial-scale renewables production can be developed to minimize harm to wildlife populations • explain recent advances in renewable power technologies • identify urgent research needs at the intersection of renewables and wildlife conservation Relevant to policy makers and industry professionals—many of whom believe renewables are the best path forward as the world seeks to meet its expanding energy needs—and wildlife conservationists—many of whom are alarmed at the rate of renewables-related habitat conversion—this detailed book culminates with a chapter underscoring emerging opportunities in renewable energy ecology. Contributors: Edward B. Arnett, Brian B. Boroski, Regan Dohm, David Drake, Sarah R. Fritts, Rachel Greene, Steven M. Grodsky, Amanda M. Hale, Cris D. Hein, Rebecca R. Hernandez, Jessica A. Homyack, Henriette I. Jager, Nicole M. Korfanta, James A. Martin, Christopher E. Moorman, Clint Otto, Christine A. Ribic, Susan P. Rupp, Jake Verschuyl, Lindsay M. Wickman, T. Bently Wigley, Victoria H. Zero

Destruction of habitat is the major cause for loss of biodiversity including variation in life history and habitat ecology. Each species and population adapts to its environment, adaptations visible in morphology, ecology, behaviour, physiology and genetics. Here, the authors present the population ecology of Atlantic salmon and brown trout and how it is influenced by the environment in terms of growth, migration, spawning and recruitment. Salmonids appeared as freshwater fish some 50 million years ago. Atlantic salmon and brown trout evolved in the Atlantic basin, Atlantic salmon in North America and Europe, brown trout in Europe, Northern Africa and Western Asia. The species live in small streams as well as large rivers, lakes, estuaries, coastal seas and oceans, with brown trout better adapted to small streams and less well adapted to feeding in the ocean than Atlantic salmon. Smolt and adult sizes and longevity are constrained by habitat conditions of populations spawning in small streams. Feeding, wintering and spawning opportunities influence migratory versus resident lifestyles, while the growth rate influences egg size and number, age at maturity, reproductive success and longevity. Further, early experiences influence later performance. For instance, juvenile behaviour influences adult homing, competition for spawning habitat, partner finding and predator avoidance. The abundance of wild Atlantic salmon populations has declined in recent years; climate change and escaped farmed salmon are major threats. The climate influences through changes in temperature and flow, while escaped farmed salmon do so through ecological competition, interbreeding and the spreading of contagious diseases. The authors pinpoint essential problems and offer suggestions as to how they can be reduced. In this context, population enhancement, habitat restoration and management are also discussed. The text closes with a presentation of what the authors view as major scientific challenges in ecological research on these species.