SCIENCE IS DRIVEN BY DATA. NEW TECHNOLOGIES HAVE VASTLY INCREASED THE EASE OF DATA collection and consequently the amount of data collected, while also enabling data to be independently mined and reanalyzed by others. And society now relies on scientifi c data of diverse kinds; for example, in responding to disease outbreaks, managing resources, responding to climate change, and improving transportation. It is obvious that making data widely available is an essential element of scientifi c research. The scientifi c community strives to meet its basic responsibilities toward transparency, standardization, and data archiving. Yet, as pointed out in a special section of this issue (pp. 692-729), scientists are struggling with the huge amount, complexity, and variety of the data that are now being produced. Recognizing the long shelf-life of data and their varied applications, and the close relation of data to the integrity of reported results, publishers, including Science, have increasingly assumed more responsibility for ensuring that data are archived and available after publication. Thus, Science and other journals have strengthened their policies regarding data, and as publishing moved online, added supporting online material (SOM) to expand data presentation and availability. But it is a growing challenge to ensure that data produced during the course of reported research are appropriately described, standardized, archived, and available to all. Science's policy for some time has been that "all data necessary to understand, assess, and extend the conclusions of the manuscript must be available to any reader of Science" (see www.sciencemag. org/site/feature/contribinfo/). Besides prohibiting references to data in unpublished papers (including those described as "in press"), we have encouraged authors to comply in one of two ways: either by depositing data in public databases that are reliably supported and likely to be maintained or, when such a database is not available, by including their data in the SOM. However, online supplements have too often become unwieldy, and journals are not equipped to curate huge data sets. For very large databases without a plausible home, we have therefore required authors to enter into an archiving agreement, in which the author commits to archive the data on an institutional Web site, with a copy of the data held at Science. But such agreements are only a stopgap solution; more support for permanent, community-maintained archives is badly needed. To address the growing complexity of data and analyses, Science is extending our data access requirement listed above to include computer codes involved in the creation or analysis of data. To provide credit and reveal data sources more clearly, we will ask authors to produce a single list that combines references from the main paper and the SOM (this complete list will be available in the online version of the paper). And to improve the SOM, we will provide a template to constrain its content to methods and data descriptions, as an a...

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Succession was monitored over ten years in a 10×10m plot in forest with mor humus at 1550 m in the Blue Mountains of Jamaica, following the removal in January 1975 of all aerial plant parts and some of the root material. In April 1977, August–January 1980/1 and August 1984, all woody recruits in the plot were tagged and numbered, identified and measured (height), and mapped on a 1 m grid. The height of coppice was recorded. Ten of the eleven tree species present before felling produced coppice shoots. Two individuals almost attained canopy height by 1984. Twenty tree species and three shrub species were recruited from seed; six of the tree species were normally absent from the forest. Species composition changed very little with time.The rate of seedling recruitment was greatest immediately after clearing. The overall den-sity of individuals changed little after 1977. Overall mortality of recruits was about 10% per annum. Mortality of the earliest recruits declined with time since establishment. Later recruits and individuals with poor growth had higher mortality than other plants. Mortality was not density-dependent. Growth rates of recruits were relatively slow. Only ten individuals exceeded 4 m by 1984.Recruitment rates, density, growth and species diversity were greatest in the parts of the plot where the mor humus had been removed or piled up during the initial clearance. Recruit-ment, growth and density were least, and mortality was greatest, at the edge. There was no relationship between any of these parameters and the presence of coppicing stumps.Tree species showed a clear spectrum from obligate gap-demanders to obligate shade-bearers. The persistence of gap-demanding species in this forest (in which gaps are normally rare) may be due to infrequent hurricanes, and also to a natural ability to produce basal sprouts. The succession conforms to an initial floristic composition model; it is slow, and we suggest that at least 50 years will elapse before the plot begins to resemble the undisturbed forest.

Building on a Firm Foundation Reviews 756 Global Change and the Ecology of Cities N. B. Grimm et al. 772 Urbanization and the Wealth of Nations D. E. Bloom et al.