Current Constraints and Future Directions in Estimating Coextinction

Conservation Biology (Impact Factor: 4.36). 01/2010; 24(3):682 - 690. DOI: 10.1111/j.1523-1739.2009.01398.x

ABSTRACT  Coextinction is a poorly quantified phenomenon, but results of recent modeling suggest high losses to global biodiversity through the loss of dependent species when hosts go extinct. There are critical gaps in coextinction theory, and we outline these in a framework to direct future research toward more accurate estimates of coextinction rates. Specifically, the most critical priorities include acquisition of more accurate host data, including the threat status of host species; acquisition of data on the use of hosts by dependent species across a wide array of localities, habitats, and breadth of both hosts and dependents; development of models that incorporate correlates of nonrandom host and dependent extinctions, such as phylogeny and traits that increase extinction-proneness; and determination of whether dependents are being lost before their hosts and adjusting models accordingly. Without synergistic development of better empirical data and more realistic models to estimate the number of cothreatened species and coextinction rates, the contribution of coextinction to global declines in biodiversity will remain unknown and unmanaged.Resumen: La coextinción es un fenómeno poco cuantificado, pero los resultados de modelos recientes sugieren grandes pérdidas de biodiversidad local mediante la pérdida de especies dependientes cuando los hospederos se extinguen. Hay vacíos críticos en la teoría de coextincíón, y los delineamos en un marco de referencia para dirigir la investigación futura hacia estimaciones más precisas de las tasas de coextinción. Específicamente, las prioridades más críticas incluyen la obtención de datos más precisos de los hospederos, incluyendo el estatus de amenaza de las especie hospedera; obtención de datos sobre el uso de hospederos por especies dependientes en una amplia gama de localidades, hábitats y amplitud tanto de hospederos como dependientes; desarrollo de modelos que incorporen correlaciones de extinciones no aleatorias de hospederos y dependientes, como la filogenia y atributos que incrementan la susceptibilidad a la extinción; y determinar sí los dependientes se pierden antes que sus hospederos y consecuentemente ajustar los modelos. Sin el desarrollo sinérgico de mejores datos empíricos y modelos más realistas para estimar el número de especies coamenazadas y las tasas de coextinción, la contribución de coextinción a las declinaciones globales de biodiversidad permanecerá desconocida y no podrá ser manejada.

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