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The identification of conservation areas based on systematic reserve-selection algorithms requires decisions related to both spatial and ecological scale. These decisions may affect the distribution and number of sites considered priorities for conservation within a region. We explored the sensitivity of systematic reserve selection by altering values of three essential variables. We used a 1:20,000-scale terrestrial ecosystem map and habitat suitability data for 29 threatened vertebrate species in the Okanagan region of British Columbia, Canada. To these data we applied a reserve-selection algorithm to select conservation sites while altering selection unit size and shape, features of biodiversity (i.e., vertebrate species), and area conservation targets for each biodiversity feature. The spatial similarity, or percentage overlap, of selected sets of conservation sites identified (1) with different selection units was ≤40%, (2) with different biodiversity features was 59%, and (3) with different conservation targets was ≥94%. Because any selected set of sites is only one of many possible sets, we also compared the conservation value (irreplaceability) of all sites in the region for each variation of the data. The correlations of irreplaceability were weak for different selection units (0.23 ≤ r ≤ 0.67), strong for different biodiversity features (r = 0.84), and mixed for different conservation targets (r = 0.16; 0.16; 1.00). Because of the low congruence of selected sites and weak correlations of irreplaceability for different selection units, recommendations from studies that have been applied at only one spatial scale must be considered cautiously.Resumen: La identificación deáreas de conservación basada en algoritmos de selección sistemática de reservas requiere decisiones relacionadas tanto con la escala espacial como la ecológica. Estas decisiones pueden afectar la distribución y el número de sitios considerados prioridades de conservación en una región. Exploramos la sensibilidad de la selección sistemática de reservas alterando los valores de tres variables esenciales. Utilizamos un mapa de ecosistema terrestre a escala 1:20,000 y datos de aptitud de hábitat para 29 especies amenazadas de vertebrados en la región de Okanagan en Columbia Británica, Canadá. Aplicamos un algoritmo de selección sistemática de reservas a estos datos para seleccionar sitios de conservación mientras se alteraba el tamaño y la forma de la unidad seleccionada, las características de la biodiversidad (es decir, especies de vertebrados) y los objetivos de conservación para cada característica de biodiversidad del paisaje. La similitud espacial, o porcentaje de traslapamiento, de conjuntos de sitios de conservación selectos identificada 656 Sensitivity of Systematic SelectionWarman et al. con (1) diferentes unidades de selección fue ≤40%, (2) diferentes características de biodiversidad fue 59% y (3) diferentes objetivos de conservación fue ≥94%. Debido a que cualquier conjunto de sitios seleccionado es solo uno de muchos conjuntos po...

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The morphological and physiological adaptations associated with sequestration of cardenolides by the lygaeidOncopeltus fasciatus are summarized and discussed. Cardenolides are efficiently accumulated inO. fasciatus; however, the insect does not appear to suffer any physiological cost as a result of handling large amounts of these plant toxins. Morphological adaptations of the insect include a modified integument composed of a double layered epidermis with an inner layer (the dorsolateral space) specialized for cardenolide storage. Special weak areas of the cuticle are found on both the thorax and abdomen, which rupture when the insect is squeezed, resulting in the cardenolide-rich contents of the inner epidermal layer being released onto the body surface in the form of discrete spherical droplets. Physiological adaptations include selective sequestration of food plant cardenolides, concentration of cardenolides in the dorsolateral space, passive uptake of cardenolides at the gut and dorsolateral space requiring little energy output, reabsorption of secreted cardenolides by the Malpighian tubules, high in vivo tolerance to cardenolides, and the presence of cardenolide-resistant Na,K-ATPases.

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