A new minimal medium for enterobacteria has been developed. It supports growth of Escherichia coli and Salmonella typhimurium at rates comparable to those of any of the traditional media that have high phosphate concentrations, but each of the macronutrients (phosphate, sulfate, and nitrogen) is present at a sufficiently low level to permit isotopic labeling. Buffering capacity is provided by an organic dipolar ion, morpholinopropane sulfonate, which has a desirable pK (7.2) and no apparent inhibitory effect on growth. The medium has been developed with the objectives of (i) providing reproducibility of chemical composition, (ii) meeting the experimentally determined nutritional needs of the cell, (iii) avoiding an unnecessary excess of the major ionic species, (iv) facilitating the adjustment of the levels of individual ionic species, both for isotopic labeling and for nutritional studies, (v) supplying a complete array of micronutrients, (vi) setting a particular ion as the crop-limiting factor when the carbon and energy source is in excess, and (vii) providing maximal convenience in the manufacture and storage of the medium.
Using the results of a survey of recovery plans for threatened and endangered species, we evaluated the role that Population Viability Analysis (PVA) has played in recovery planning and management of rare species in the United States. Although there was a significant increase over time in the percentage of plans presenting information on PVA and assigning recovery tasks to collect more such information, the use of PVA was still called for in less than half of the plans approved since 1991. Because scarcity of data for rare species may be limiting the application of PVA to endangered species, we also assessed how often recovery plans proposed to collect the full complement of data required to perform four general types of PVA. For most of the species in the database, proposed monitoring data would allow the simplest type of PVA method (i.e., analysis of total population counts) to be applied, but more complex PVAs would be possible for Ͻ25% of the species. We conclude with brief recommendations for how the use of PVA in endangered species recovery planning might be improved in the future.
Using the results of a survey of recovery plans for threatened and endangered species, we evaluated the role that Population Viability Analysis (PVA) has played in recovery planning and management of rare species in the United States. Although there was a significant increase over time in the percentage of plans presenting information on PVA and assigning recovery tasks to collect more such information, the use of PVA was still called for in less than half of the plans approved since 1991. Because scarcity of data for rare species may be limiting the application of PVA to endangered species, we also assessed how often recovery plans proposed to collect the full complement of data required to perform four general types of PVA. For most of the species in the database, proposed monitoring data would allow the simplest type of PVA method (i.e., analysis of total population counts) to be applied, but more complex PVAs would be possible for <25% of the species. We conclude with brief recommendations for how the use of PVA in endangered species recovery planning might be improved in the future.
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