COBALT: A STRATEGIC AND CRITICAL RESOURCE FOR INDUSTRIALIZED NATIONS, SUPPLIED BY DEVELOPING NATIONS

In 1978, the world cobalt market was abruptly thrust into a state of great uncertainty, with soaring prices, limited supply, and accelerating demand. A critical shortage threatened to develop but never really materialized. However, this situation dramatized Western nations' vulnerability to supply disruption. A number of factors, including limited natural occurrence, unfavourable market conditions, and accelerating demand for cobalt, combined to bring about these unstable conditions.
En 1978, le marché mondial du cobalt a été soudainement plongé dans un état de désorganisation, avec des prix en flèche, peu d'approvisionnement et une demande accélérée. La situation menaçait de devenir critique mais n'a jamais atteint un point dangereux. Cependant, ceci a fait ressortir combien vulnérables pouvaient être les pays occidentaux à l'interruption des ressources. Un certain nombre de facteurs parmi lesquels le nombre limité de gisements, des conditions de marché défavorables et la demande accélérée pour le cobalt se sont combinés pour créer ces conditions d'instabilité.
En 1978 el mercado mundial del cobalto se encontró abruptamente en un estado de gran incertidumbre, con precios crecientes, oferta restringida y la demanda en acelerado aumento. Aunque la amenaza de una paralizante carestía del cobalto no se materializó, esta situación sirvió para dramatizar la vulnerabilidad de los países occidentales a la interrupción del suministro de este recurso. Un número de factores tales como la limitada disponibilidad de estos recursos, las condiciones desfavorables del mercado y el crecimiento acelerado de la demanda, se combinaron para dar lugar a esta situación inestable.     

Quantifying Eradication Success: the Removal of Feral Pigs from Santa Cruz Island, California

Abstract:  A major challenge facing pest-eradication efforts is determining when eradication has been achieved. When the pest can no longer be detected, managers have to decide whether the pest has actually been eliminated and hence to decide when to terminate the eradication program. For most eradication programs, this decision entails considerable risk and is the largest single issue facing managers of such programs. We addressed this issue for an eradication program of feral pigs ( Sus scrofa ) from Santa Cruz Island, California. Using a Bayesian approach, we estimated the degree of confidence in the success of the eradication program at the point when monitoring failed to detect any more pigs. Catch-effort modeling of the hunting effort required to dispatch pigs during the eradication program was used to determine the relationship between detection probability and searching effort for different hunting methods. We then used these relationships to estimate the amount of monitoring effort required to declare eradication successful with criteria that either set a threshold for the probability that pigs remained undetected (type I error) or minimized the net expected costs of the eradication program (cost of type I and II errors). For aerial and ground-based monitoring techniques, the amount of search effort required to declare eradication successful on the basis of either criterion was highly dependent on the prior belief in the success of the program unless monitoring intensities exceeded 30 km of searching effort per square kilometer of search area for aerial monitoring and, equivalently, 38 km for ground monitoring. Calculation of these criteria to gauge the success of eradication should form an essential component of any eradication program as it allows for a transparent assessment of the risks inherent in the decision to terminate the program.     

Predicting Risk of Habitat Conversion in Native Temperate Grasslands

Abstract: Native grasslands that support diverse populations of birds are being converted to cropland at an increasing rate in the Prairie Pothole Region of North America. Although limited funding is currently available to mitigate losses, accurate predictions of probability of conversion would increase the efficiency of conservation measures. We studied conversion of native grassland to cropland in the Missouri Coteau region of North and South Dakota (U.S.A.) during 1989–2003. We estimated the probability of conversion of native grassland to cropland with satellite imagery and logistic regression models that predicted risk of conversion and by comparing the overlap between areas of high biological value and areas most vulnerable to conversion. Annualized probability of conversion was 0.004, and 36,540 ha of native grassland were converted to cropland during the period of our study. Our predictive models fit the data and correctly predicted 70% of observed conversions of grassland. Probability of conversion varied spatially and was correlated with landscape features like amount of surrounding grassland, slope, and soil productivity. Tracts of high biological value were not always at high risk of conversion. We concluded the most biologically valuable areas that are most vulnerable to conversion should be prioritized for conservation. This approach can be applied broadly to other systems and offers great utility for implementing conservation in areas with spatially variable biological value and probability of conversion.