Field biologists and ecologists are starting to open new avenues of inquiry at greater spatial and temporal resolution, allowing them to “observe the unobservable” through the use of wireless sensor networks. Sensor networks facilitate the collection of diverse types of data (from temperature to imagery and sound) at frequent intervals—even multiple times per second—over large areas, allowing ecologists and field biologists to engage in intensive and expansive sampling and to unobtrusively collect new types of data. Moreover, real-time data flows allow researchers to react rapidly to events, thus extending the laboratory to the field. We review some existing uses of wireless sensor networks, identify possible areas of application, and review the underlying technologies in the hope of stimulating additional use of this promising technology to address the grand challenges of environmental science.

Various organic technologies have been utilized for about 6000 years to make agriculture sustainable while conserving soil, water, energy, and biological resources. Among the benefits of organic technologies are higher soil organic matter and nitrogen, lower fossil energy inputs, yields similar to those of conventional systems, and conservation of soil moisture and water resources (especially advantageous under drought conditions). Conventional agriculture can be made more sustainable and ecologically sound by adopting some traditional organic farming technologies.

The mammalian proglucagon gene encodes three related sequences, glucagon and the glucagon-like peptides 1 and 2 (GLP-1 and GLP-2), each of which has an essential role in metabolism. A family of closely related receptors mediates the physiological actions of these hormones. Intriguingly, GLP-1 has opposite functions in mammals and fish. In mammals, secretion of GLP-1 results in a reduction in blood sugar levels, whereas in fish it causes an increase. The recent release of draft genome sequences of diverse vertebrates has made it possible to examine the evolution of the receptors for these peptide hormones. Phylogenetic analysis of sequences of receptors for proglucagon-encoded hormones suggests a potential explanation for the change in function of GLP-1 between fish and mammals. I suggest that in fish, GLP-1 lost the ability to act on insulin-secreting cells and was recruited as a ligand for a duplicated glucagon receptor, resulting in a physiological action similar to that of glucagon.

The major contributor to global warming is considered to be the high levels of greenhouse gas emissions, especially carbon dioxide (CO₂), caused by the burning of fossil fuel. Thus, to mitigate CO₂ emissions, renewable energy sources such as ethanol have been seen as a promising alternative to fossil fuel consumption. Brazil was the world's first nation to run a large-scale program for using ethanol as fuel. Eventually, the United States also developed large-scale production of ethanol. In this study, we compare the benefits and environmental impacts of ethanol fuel, in Brazil and in the United States, using the ecological footprint tool developed by Wackernagel and Rees. We applied the STELLA model to gauge possible outcomes as a function of variations in the ethanol production scenario.

Critical loads are a potentially important tool for protecting ecosystems from atmospheric deposition and for promoting recovery. Exceeding critical loads for nitrogen and sulfur can cause ecosystem acidification, nitrogen saturation, and biotic community changes. Critical loads are widely used to set policy for resource protection in Europe and Canada, yet the United States has no similar national strategy. We believe that ecosystem science and resource protection policies are sufficiently advanced in the United States to establish critical loads for federal lands. Communication and interaction between federal area managers and scientists will ensure that critical loads are useful for assessing ecosystem conditions, influencing land management decisions, and informing the public about the status of natural resources. Critical loads may also be used to inform air pollution policy in the United States, regardless of whether critical loads are directly linked to air quality regulations and emissions reductions agreements, as they are in Europe.

Aldo Leopold, perhaps best known for his revolutionary and poignant essays about nature, was also an eloquent advocate during the 1930s and 1940s of the need to maintain wolves and other large carnivores in forest and range ecosystems. He indicated that their loss set the stage for ungulate irruptions and ecosystem damage throughout many parts of the United States. We have synthesized the historical record on the potential effects of wolf extirpation in the context of recent research. Leopold's work of decades ago provides an important perspective for understanding the influence of large carnivores, via trophic cascades, on the status and functioning of forest and range plant communities. Leopold's personal experiences during an era of extensive biotic changes add richness, credibility, and even intrigue to the view that present-day interactions between ungulates and plants in the United States have been driven to a large degree by the extirpation of wolves and other large carnivores.