Problems in Extinction Model Selection and Parameter Estimation

It is a vexing problem to achieve a consensus about the proper scientific way to assess population viability for habitat conservation plans. Rather than a hypothesis-testing approach, here it is proposed to select population models, estimate extinction parameters, and assess prediction uncertainty using a pragmatic, empirical Bayesian approach. The simplest usable models include the effects of population growth, r; carrying capacity, K; Allee threshold, N(A); and environmental stochasticity, v(r). Analytic predictions of expected extinction times are available for such models. Models that are more complex can be elaborated from this basis. Selection from a hierarchy of nesting population models can often be done through the evaluation of parameters. The estimation of the most important extinction parameters can be undertaken in a variety of ways. Time series can be analyzed to estimate r(d), v(r), rho, and K. Habitat models and individualistic population models may help estimate N(A) and K and demographic stochasticity. Fine-scale biogeography and climatological data may be useful in the estimation of a variety of parameters. Because it takes many years to estimate extinction parameters accurately for a given population of interest, the most efficient estimation procedures are desirable. I propose the use of prior information from an (as yet nonexistent) population biology database. The accumulation of local information through monitoring will improve our estimates allowing adaptive management. Uncertainty in the estimates will always remain, but it may be quantified by the posterior distributions. A crude example is discussed using treefrog population data. Although the motivations, beliefs, and biases of competing stakeholders will differ, a habitat conservation plan could accommodate this variation in the prior distributions. Field experience from monitoring will increasingly clear up any discrepancies between the opposing beliefs and the real ecosystem. As the world is an uncertain place and because there is no universal scientific method, there will always be controversy and surprises. The best we can do is (1) agree about our prior information, (2) agree about the strategy of model selection and parameter estimation, and (3) agree about our strategy for adaptive management. Perhaps the greatest impediment to such prior agreements for HCPs is the likely paranoia inspired by the use of unfamiliar statistical methodology. We need to train students of ecology in a more flexible and deeper understanding of statistics and philosophy of science.     

Seventy‐One Important Questions for the Conservation of Marine Biodiversity

The ocean provides food, economic activity, and cultural value for a large proportion of humanity. Our knowledge of marine ecosystems lags behind that of terrestrial ecosystems, limiting effective protection of marine resources. We describe the outcome of 2 workshops in 2011 and 2012 to establish a list of important questions, which, if answered, would substantially improve our ability to conserve and manage the world's marine resources. Participants included individuals from academia, government, and nongovernment organizations with broad experience across disciplines, marine ecosystems, and countries that vary in levels of development. Contributors from the fields of science, conservation, industry, and government submitted questions to our workshops, which we distilled into a list of priority research questions. Through this process, we identified 71 key questions. We grouped these into 8 subject categories, each pertaining to a broad component of marine conservation: fisheries, climate change, other anthropogenic threats, ecosystems, marine citizenship, policy, societal and cultural considerations, and scientific enterprise. Our questions address many issues that are specific to marine conservation, and will serve as a road map to funders and researchers to develop programs that can greatly benefit marine conservation. Setenta y Un Preguntas Importantes para la Conservación de la Biodiversidad Marina     

COAL SUBSTITUTION AND OTHER APPROACHES TO EASING THE PRESSURE ON WOODFUEL RESOURCES

The substitution of coal for charcoal in domestic use in Dakar and Dar es Salaam is not immediately feasible for technical, social and economic reasons. In the event of severe charcoal shortages, coal is the only large-scale substitute likely to be available and research should be carried out to ensure that the problems of its use and distribution are solved in advance. Coal, bottled gas, improvements in stove efficiency and charcoal manufacture are unlikely to ease the pressure on free-good wood resources unless they are associated with effective ceilings on wood exploitation. The production of charcoal for urban use should become a commercial responsibility linked with rural wood lot planting and exploitation. La substitution du charbon à la place du charbon de bois pour les usages domestiques à Dakar et à Dar es Salaam n'est pas possible dans l'immédiat pour des raisons techniques, sociales et économiques. Dans le cas de pénuries aigues en charbon de bois, le charbon est l'unique combustible de remplacement qui serait disponible sur une grande échelle et des recherches devraient être entreprises afin de s'assurer que les problèmes concernant son utilisation et sa répartition soient résolus d'avance. Le charbon, le gaz en bouteille, les améliorations dans le rendement des fourneaux et dans la fabrication du charbon de bois ne soulageront sans doute pas la pression exercée sur les ressources gratuites en bois à moins que celles-ci ne soient limitées par des plafonds concernant l'exploitation du bois. La production du charbon de bois pour les utilisations urbaines devrait être commercialement liée à un programme de plantation et d'exploitation parcellaires rurales. La substitución de carbón vegetal por carbón mineral para uso doméstico en Dakar y Dar es Salaam no es factible en forma immediata debido a razones técnicas, sociales y económicas. En caso de una escasez severa de carbón vegetal el único substituto que puede estar disponsible es el carbón mineral; en consecuencia debe investigarse para asegurar que los problemas de su uso y distribución sean resueltos con anticipación. El carbón mineral, el gas embotellado, y las mejoras en la eficiencia de las cocinas y en la fabricación del carbón vegetal tienen poca probabilidad de disminuir la demanda de un bien gratuito como es la leña a menos que esten asociados a una limitación efectiva de la explotación de los bosques. La producción del carbón vegetal para uso urbano debe ser una responsabilidad comercial ligada a la reforestación y explotación de bosques.