Catálogo de publicaciones - revistas

<jats:p>Ecological history plays many roles in ecological restoration, most notably as a tool to identify and characterize appropriate targets for restoration efforts. However, ecological history also reveals deep human imprints on many ecological systems and indicates that secular climate change has kept many targets moving at centennial to millennial time scales. Past and ongoing environmental changes ensure that many historical restoration targets will be unsustainable in the coming decades. Ecological restoration efforts should aim to conserve and restore historical ecosystems where viable, while simultaneously preparing to design or steer emerging novel ecosystems to ensure maintenance of ecological goods and services.</jats:p>

<jats:p>Species invasions impose key biotic thresholds limiting the success of ecological restoration projects. These thresholds may be difficult to reverse and will have long-term consequences for restoration because of invasion legacies such as extinctions; because most invasive species cannot be eliminated given current technology and resources; and because even when controlled to low levels, invasive species continue to exert substantial pressure on native biodiversity. Restoration outcomes in the face of biological invasions are likely to be novel and will require long-term resource commitment, as any letup in invasive species management will result in the loss of the conservation gains achieved.</jats:p>

<jats:p>Pollination services underpin sustainability of restored ecosystems. Yet, outside of agri-environments, effective restoration of pollinator services in ecological restoration has received little attention. This deficiency in the knowledge needed to restore pollinator capability represents a major liability in restoration programs, particularly in regions where specialist invertebrate and vertebrate pollinators exist, such as global biodiversity hotspots. When compounded with the likely negative impacts of climate change on pollination services, the need to understand and manage pollinator services in restoration becomes paramount.</jats:p>

<jats:p>Microorganisms have critical roles in the functioning of soil in nutrient cycling, structural formation, and plant interactions, both positive and negative. These roles are important in reestablishing function and biodiversity in ecosystem restoration. Measurement of the community indicates the status of the system in relation to restoration targets and the effectiveness of management interventions, and manipulation of the community shows promise in the enhancement of the rate of recovery of degraded systems.</jats:p>

<jats:p>Ecological restoration is an activity that ideally results in the return of an ecosystem to an undisturbed state. Ecosystem services are the benefits humans derive from ecosystems. The two have been joined to support growing environmental markets with the goal of creating restoration-based credits that can be bought and sold. However, the allure of these markets may be overshadowing shortcomings in the science and practice of ecological restoration. Before making risky investments, we must understand why and when restoration efforts fall short of recovering the full suite of ecosystem services, what can be done to improve restoration success, and why direct measurement of the biophysical processes that support ecosystem services is the only way to guarantee the future success of these markets. Without new science and an oversight framework to protect the ecosystem service assets which people depend, markets could actually accelerate environmental degradation.</jats:p>

<jats:p>Arial mapping during an extreme drought has revealed the detailed plan of a major Roman city in the Venice lagoon.</jats:p>

<jats:title>Fighting for Fisheries</jats:title> <jats:p> In the debate concerning the future of the world's fisheries, some have forecasted complete collapse but others have challenged this view. The protagonists in this debate have now joined forces to present a thorough quantitative review of current trends in world fisheries. <jats:bold> Worm <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="578" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1173146">578</jats:related-article> ) evaluate the evidence for a global rebuilding of marine capture fisheries and their supporting ecosystems. Contrasting regions that have been managed for rebuilding with those that have not, reveals trajectories of decline and recovery from individual stocks to species, communities, and large marine ecosystems. The management solutions that have been most successful for rebuilding fisheries and ecosystems, include both large- and small-scale fisheries around the world. </jats:p>

<jats:title>Mapping the Neuronal Map</jats:title> <jats:p> In vertebrates, sensory information is topographically represented as a neural map in the brain. How is the neural map formed in the brain? Nearly a half-century ago, Roger Sperry proposed the “chemoaffinity” model, in which the positional cues on the target determine the axonal projection site, thereby establishing the topographic neural map. However, molecular mechanisms of topographic map formation remain controversial. <jats:bold> Imai <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="585" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1173596">585</jats:related-article> , published online 9 July; see the Perspective by <jats:bold> <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" issue="5940" page="544" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1178117">Miyamichi and Luo</jats:related-article> </jats:bold> ) now report that the topographic map is formed by axon-axon interactions before the axons reach the target. In the mouse olfactory system, the topography of the map is determined by the relative expression levels of a guidance receptor, Neuropilin-1, and its repulsive ligand, Semaphorin-3A, expressed in axons. Topographic organization occurs even in the absence of the target, the olfactory bulb. These findings require that Sperry's model, which suggests that only the targets determine the topography of neural maps, needs to be reconsidered. </jats:p>

<jats:title>Optimizing Molecular Sieve Production</jats:title> <jats:p> Microporous membranes composed of aluminosilicate minerals are known as zeolites and are often called molecular sieves because of their ability to filter or separate small molecules. The separation performance is partly governed by the selectivity for one species over another, and this can be compromised by defects, which allow for easy diffusion pathways. To create the porosity, structure-directing agents are used, which need to be removed during a long thermal treatment that can generate defects. <jats:bold> Choi <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="590" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1176095">590</jats:related-article> ) show that for the silicalite-1 system, a rapid thermal treatment significantly reduces the defect density, with corresponding improvement in the filtration of very similar species, such as xylene isomers. </jats:p>

<jats:title>Perfectly Flat?</jats:title> <jats:p> Plasmonic devices, which exploit the interactions of light with surface electrons, show great promise for applications in sensing, communications, and energy conversion. A key hindrance is the deposition of patterned metals used for plasmonics, because, as deposited, the terminal surfaces are rough and not amenable to patterning by directional dry-etching techniques. <jats:bold> Nagpal <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="594" related-article-type="in-this-issue" vol="325" xlink:href="10.1126/science.1174655">594</jats:related-article> ) use patterned silicon substrates on which they add gold, silver, or copper and then apply an epoxy layer to the deposited metal. When pulled apart, the metal separates from the silicon, where the adhesion is poorer, leaving an ultra-smooth surface. The resulting surface plasmon propagation lengths approach the theoretical values for perfectly flat films. </jats:p>