Our purpose was to define a quantitative and expeditious method to analyze the effects of processes that influence species distribution and abundance at different organizational scales. We considered habitat loss, the breaking apart of habitat patches, and habitat structural alteration critical processes that affect species distribution and abundance. We evaluated the effects of these processes by considering the response of selected indicator species to isolation (landscape scale), patch size and edge effect (patch scale), and habitat structure (plot scale). We used broadleaf forests as our case-study ecosystem and birds as indicator species. Faunal data came from a georeferenced, long-term, breeding-bird database, and environmental data were obtained from field surveys and land-use digital cartography Birds, grouped according to their sensitivity to patch isolation, patch size, edge effect, and habitat structure, indicated how environmental conditions affected species abundance. The most sensitive group to the above-mentioned processes included the Marsh Tit (Parus palustris), Nuthatch (Sitta curopaea), and Short-toed Treecreeper (Certhia brachydactyla). We evaluated the umbrella effect of these species for the conservation of the other co-occurring birds and found that their effectiveness varied according to the criterion used to select sites for protection. Site selection based on indicator species identified forest patches with greater species abundance than an alternative criterion that chose sites based on patch isolation and size, edge effect, and.forest structure. The alternative criterion, although not as efficient as indicator species, may nevertheless be useful and effective for conservation when faunal data are lacking and guidelines for habitat management or restoration are needed. Our method is applicable to other ecosystems and taxa because the processes we considered occur in many ecosystems and may have significant effects on species from all taxonomic groups.

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Ecological networks consist of core areas connected by corridors and shielded by buffer zones. It is now largely accepted that extensive networks need to be established at different scales to conserve biodiversity. We propose using focal species to plan woodland ecological networks because such species encompass the structural and functional needs of entire ecological communities. To this end, we chose (1) the type of landscape to be conserved and (2) the suitable focal species for that task. The study area (2500 km 2 ) was north of Milan where human activity is heavy but wooded patches are mostly protected as regional parks. We used an interpreted satellite image to compare land-use patterns with the presence or abundance of focal species. This method produced "suitability maps" for focal species-woodland birds and mammalian carnivores-on which ecological corridors can be drawn as lines connecting core areas through the best available habitat in the matrix. These potential corridors are a useful guideline for implementation of a regional ecological network.Uso de Especies Focales en el Diseño de Redes de Hábitat para un Área Baja de Lombardia, Italia Resumen: Las redes ecológicas consisten de áreas núcleo conectadas por corredores y protegidas por áreas de amortiguamiento. Actualmente se acepta ampliamente que es necesario establecer redes extensas a diferentes escalas para conservar la biodiversidad. Proponemos el uso de especies focales para planear las redes ecológicas de zonas boscosas, puesto que estas especies incluyen necesidades estructurales y funcionales de comunidades ecológicas enteras. Con este fin, seleccionamos: (1) el tipo de paisaje a conservar y (2) las especies focales adecuadas para esta tarea. El área de estudio (2500 m 2 ) se encuentra al norte de Milán donde las actividades humanas son inteusas pero los parches están en su mayoría protegidas como parques regionales. Empleamos una imagen de satélite interpretada para comparar los patrones de uso del suelo con la presencia o abundancia de especies focales. Este método produjo "mapas de sostenibilidad" para especies focalesaves y mamíferos carnívoros de zonas arboladas-en los cuales se pueden dibujar corredores ecológicos como líneas que conectan áreas núcleo usando los mejores hábitats disponibles en la matriz. Estos corredores potenciales son una guía útil para la implementación de redes ecológicas regionales.

The European pond turtle, Emys orbicularis (L., 1758), is threatened throughout its distribution, prompting management of habitats and populations for conservation. Quantitative data on habitat requirements for this species are needed to better evaluate which areas are the most suitable, or what actions can improve habitat suitability. We studied relationships between the distribution and abundance of E. orbicularis and the environment by analysing water quality and features of 39 wetland and upland habitats in the Po River delta of northern Italy; visual transects and point counts were used to determine turtle presence and relative abundance. Emys orbicularis occurs more frequently and abundantly in permanent wetlands surrounded by woodlands, and its presence does not appear to be related to water eutrophication. Woodlands strongly influence adjacent wetland features and may be important for turtles' terrestrial activities such as nesting and dispersal. Habitat management and conservation plans for E. orbicularis should include protection of extensive terrestrial woodland habitat containing diverse wetland systems, to support turtle survival at different life-history stages. The requirements for wetlands and natural terrestrial habitat are difficult to meet in the currently human-dominated European lowlands; nevertheless, conservation plans for this species should take a broad-scale approach.