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The American Institute of Biological Sciences dedicated this year's annual meeting to the challenge of Earth's changing climate and its effects on the environment, and the spread of infectious diseases. The conference, held in May in Arlington, Virginia, attracted more than 250 biologists, climatologists, and other scientists, as well as physicians and public health officials.
Fungi play a major role in the function and dynamics of terrestrial ecosystems, directly influencing the structure of plant, animal, and bacterial communities through interactions that span the mutualism-parasitism continuum. Only with the advent of deoxyribonucleic acid (DNA)-based molecular techniques, however, have researchers been able to look closely at the ecological forces that structure fungal communities. The recent explosion of molecular studies has greatly advanced our understanding of fungal diversity, niche partitioning, competition, spatial variability, and functional traits. Because of fungi's unique biology, fungal ecology is a hybrid beast that straddles the macroscopic and microscopic worlds. While the dual nature of this field presents many challenges, it also makes fungi excellent organisms for testing extant ecological theories, and it provides opportunities for new and unanticipated research. Many questions remain unanswered, but continuing advances in molecular techniques and field and lab experimentation indicate that fungal ecology has a bright future.
Amplification of the hydrological cycle as a consequence of global warming is forecast to lead to more extreme intra-annual precipitation regimes characterized by larger rainfall events and longer intervals between events. We present a conceptual framework, based on past investigations and ecological theory, for predicting the consequences of this underappreciated aspect of climate change. We consider a broad range of terrestrial ecosystems that vary in their overall water balance. More extreme rainfall regimes are expected to increase the duration and severity of soil water stress in mesic ecosystems as intervals between rainfall events increase. In contrast, xeric ecosystems may exhibit the opposite response to extreme events. Larger but less frequent rainfall events may result in proportional reductions in evaporative losses in xeric systems, and thus may lead to greater soil water availability. Hydric (wetland) ecosystems are predicted to experience reduced periods of anoxia in response to prolonged intervals between rainfall events. Understanding these contingent effects of ecosystem water balance is necessary for predicting how more extreme precipitation regimes will modify ecosystem processes and alter interactions with related global change drivers.
Digital three-dimensional models, besides representing helpful didactic tools, play an important role in the analysis of brain function and development. The fundamental idea of this approach is that patterns of neural connectivity and activity, pathological lesions, or gene expression are transferred into a single in silico structure: the digital atlas model. This article focuses on recent and ongoing work to build digital models of the developing Drosophila brain, which is formed by an invariant set of approximately 100 neural lineages. Lineages represent key elements in the emerging models of the fly brain: aside from their common origin, which is reflected in the shared expression of numerous developmental control genes, neurons belonging to a given lineage share many morphological characters, including axonal projection and dendritic arborization.
We determined the relative benefits for eight categories of ecosystem goods and services associated with native and restored lands across the conterminous United States. Less than 10% of most native US ecosystems remain, and the proportion that is restored varies widely by biome. Restored lands offer 31% to 93% of native land benefits within a decade after restoration, with restored wetlands providing the most economic value and deserts providing the least. Restored ecosystems that recover rapidly and produce valuable commodities return a higher proportion of total value. The relative values of the benefits provided by restoration vary both by biome and by the ecosystem goods and services of interest. Our analysis confirms that conservation should be the first priority, but that restoration programs across broad geographic regions can have substantial value. “No net loss” policies should recognize that restored lands are not necessarily equivalent to native areas with regard to estimated ecosystem benefits.
An inevitable consequence of global climate change is that altered patterns of temperature and precipitation threaten agriculture in many tropical regions, requiring strategies of human adaptation. Moreover, the process of management intensification in agriculture has increased and may exacerbate vulnerability to climate extremes. Although many solutions have been presented, the role of simple agroecological and agroforestry management has been largely ignored. Some recent literature has shown how sustainable management may improve agroecological resistance to extreme climate events. We comment specifically on a prevalent form of agriculture throughout Latin America, the coffee agroforestry system. Results from the coffee literature have shown that shade management in coffee systems may mitigate the effects of extreme temperature and precipitation, thereby reducing the ecological and economic vulnerability of many rural farmers. We conclude that more traditional forms of agriculture can offer greater potential for adapting to changing conditions than do current intensive systems.
The Cambrian explosion is an excellent example of a grand idea that has been tempered by the steady collection of data to test hypotheses. Historically, the idea of an “explosion” developed from an apparent lack of bilaterian animal fossils before a certain point in the fossil record, in contrast with a great diversity of life that seemed to appear in the Cambrian period. DNA molecular clock estimates contradict this story, however, with most dates for the divergence of major phyla predating the Cambrian by 100 million to 400 million years. The contradiction might be rectified by corrections to the clock or by discoveries of Precambrian bilaterian fossils. Although many candidates exist, no single environmental or biological explanation for the Cambrian explosion satisfactorily explains the apparent sudden appearance of much of the diversity of bilaterian animal life. Scientists' understanding of this phenomenon has been greatly amplified in recent years by better geological dating and environmental characterization, new fossil discoveries, and by a great expansion of our knowledge of developmental mechanisms and their evolutionary meaning.
Scientists and their professional societies are seeking to increase their influence in shaping policy decisions. A recent call for natural resource professional societies to endorse position statements on economic growth raises questions about how scientific societies can and should effectively contribute to policy development. Taking a stand on policy issues is akin to serving as a policy advocate. We believe that natural resource professionals can most constructively contribute to policy development by conducting rigorous research that is policy relevant and by effectively conveying the results and policy implications of that research to all parties interested in the issue. By actively engaging decisionmakers and providing information on pressing policy issues, professional societies can increase opportunities to be recognized as sources for reliable, unbiased information about natural resources and their management.
In rare circumstances, scientists have been able to revive dormant propagules from ancestral populations and rear them with their descendants to make inferences about evolutionary responses to environmental change. Although this is a powerful approach to directly assess microevolution, it has previously depended entirely upon fortuitous conditions to preserve ancestral material. We propose a coordinated effort to collect, preserve, and archive genetic materials today for future studies of evolutionary change—a “resurrection paradigm.” The availability of ancestral material that is systematically collected and intentionally stored using best practices will greatly expand our ability to illuminate microevolutionary patterns and processes and to predict ongoing responses of species to global change. In the workshop “Project Baseline,” evolutionary biologists and seed storage experts met to discuss establishing a coordinated effort to implement the resurrection paradigm.