Endangered Species Constrained by Natural and Human Factors: the Case of Brown Bears in Northern Spain

摘要: We developed a conceptual framework for classifying habitat quality that requires the construc- tion of separate models each key demographic feature; can be applied when factors determine different processes differ substantially. For example, survival large car- nivores is mainly determined by human-induced mortality, whereas nutritional condition determines repro- ductive rate. Hence, two-dimensional model built reproduction and yields five hypothet- ical categories: matrix , with no and/or very high mortality; sink low refuge attractive source mortality. this to two endangered brown bear ( Ursus arctos ) populations in Cantabrian Mountains, Spain. Our aim was gen- erate working hypotheses about spatial arrangement analyze present conditions population nuclei facilitate identification core areas conservation value, conflictive areas, or unoccupied potential habitat. used geographic information system long-term data sets on presence performed logistic regressions building model. The analysis reveals both exist under subopti- mal conditions: eastern occupies suboptimal natural relatively human impact, western located impact but otherwise good quality. To test features obtained cate- gories, we classified historic extinction northern Spain (fourteenth nineteenth centuries) Extinction probabilities within category confirmed hypotheses: most extinctions occurred habitat, fewest Especies Amenazadas Limitadas por Factores Naturales y Humanos: el Caso del Oso Pardo en Norte de Espana Resumen: Desarrollamos un marco para clasificar la calidad que requiere con- struccion modelos separados cada caracteristica demografica clave. El se puede aplicar cuando difieren sustancialmente los factores determinan diferentes procesos demograficos. Por ejemplo, supervivencia grandes carnivoros esta determinada principalmente mortalidad inducida humanos, mientras condicion nutricional determina tasa reproductiva. Consecuentemente, modelo bidimensional construido reproduccion produce cinco categorias hipoteticas habitat: matriz (sin y/o muy alta), sumidero (reproduccion baja, refugio baja), atractivo alta, mor- talidad alta) fuente baja). Aplicamos este dos poblaciones peli- gro oso pardo Cordillera Cantabrice, Espana. Nuestra meta fue generar hipotesis trabajo sobre distribucion espacial osos analizar las condiciones actu-