Publication Details |
Category | Text Publication |
Reference Category | Journals |
DOI | 10.1046/j.1523-1739.2003.02144.x |
Title (Primary) | Endangered species constrained by natural and human factors: the case of brown bears in northern Spain |
Author | Naves, J.; Wiegand, T.; Revilla, E.; Delibes, M. |
Source Titel | Conservation Biology |
Year | 2003 |
Department | OESA |
Volume | 17 |
Issue | 5 |
Page From | 1276 |
Page To | 1289 |
Language | englisch |
Abstract | We developed a conceptual framework for classifying habitat quality that requires the construction of separate habitat models for each key demographic feature; the framework can be applied when the factors that determine different demographic processes differ substantially. For example, survival of large carnivores is mainly determined by human-induced mortality, whereas nutritional condition determines reproductive rate. Hence, a two-dimensional habitat model built for reproduction and survival yields five hypothetical habitat categories: matrix, with no reproduction and/or very high mortality; sink, with low reproduction and high mortality; refuge, with low reproduction and low mortality; attractive sink, with high reproduction and high mortality; and source, with high reproduction and low mortality. We applied this framework to two endangered brown bear ( Ursus arctos ) populations in the Cantabrian Mountains, Spain. Our aim was to generate working hypotheses about the quality and spatial arrangement of bear habitat to analyze the present conditions of the different population nuclei and to facilitate identification of core areas of high conservation value, conflictive areas, or areas with unoccupied potential habitat. We used a geographic information system and two spatial long-term data sets on presence and reproduction and performed logistic regressions for building a two-dimensional model. The analysis reveals that both populations exist under different suboptimal conditions: the eastern population mainly occupies areas of suboptimal natural habitat and relatively low human impact, whereas the western population is located mainly in areas with high human impact but otherwise good natural quality. To test hypotheses about demographic features of the obtained habitat categories, we classified data on historic extinction in northern Spain ( fourteenth to nineteenth centuries ) with the two-dimensional model. Extinction probabilities within each habitat category confirmed the hypotheses: most extinctions occurred in matrix habitat, and the fewest occurred in source habitat. Especies Amenazadas Limitadas por Factores Naturales y Humanos: el Caso del Oso Pardo en el Norte de Espana Resumen: Desarrollamos un marco conceptual para clasificar la calidad del habitat que requiere la construccion de modelos de habitat separados para cada caracteristica demografica clave. El marco se puede aplicar cuando difieren sustancialmente los factores que determinan diferentes procesos demograficos. Por ejemplo, la supervivencia de grandes carnivoros esta determinada principalmente por mortalidad inducida por humanos, mientras que la condicion nutricional determina la tasa reproductiva. Consecuentemente, un modelo bidimensional del habitat construido para reproduccion y supervivencia produce cinco categorias hipoteticas de habitat: matriz ( sin reproduccion y/o mortalidad muy alta ), sumidero ( reproduccion baja, mortalidad alta ), refugio ( reproduccion baja, mortalidad baja ), sumidero atractivo ( reproduccion alta, mortalidad alta ) y fuente ( reproduccion alta, mortalidad baja ). Aplicamos este marco a dos poblaciones en peligro de oso pardo ( Ursus arctos ) en la Cordillera Cantabrice, Espana. Nuestra meta fue generar hipotesis de trabajo sobre la calidad y la distribucion espacial del habitat de los osos para analizar las condiciones actuales de los diferentes nucleos de poblacion, para facilitar la identificacion de areas nucleo de alto valor de conservacion, areas conflictivas o areas con habitat potencial desocupado. Utilizamos un sistema de informacion geografica y dos conjuntos de datos historicos de presencia y reproduccion y aplicamos regresiones logisticas para construir un modelo bidimensional. El analisis revela que ambas poblaciones existen bajo diferentes condiciones sub-optimas: la poblacion oriental ocupa principalmente areas de habitat natural sub-optimo y relativamente bajo impacto humano, mientras que la poblacion occidental se localiza principalmente en areas con alto impacto humano, pero por lo demas con buena calidad natural. Para evaluar las hipotesis sobre las caracteristicas demograficas de cada tipo de habitat, clasificamos datos de extinciones historicas en el norte de Espana ( siglos XIV a XIX ) con el modelo bidimensional. Las probabilidades de extincion en cada categoria de habitat confirmaron las hipotesis: la mayoria de las extinciones ocurrieron en habitat matriz y la minoria ocurrio en habitat fuente |
Persistent UFZ Identifier | https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=5089 |
Naves, J., Wiegand, T., Revilla, E., Delibes, M. (2003): Endangered species constrained by natural and human factors: the case of brown bears in northern Spain Conserv. Biol. 17 (5), 1276 - 1289 10.1046/j.1523-1739.2003.02144.x |