How generalist are these forest specialists? What Sweden's avian indicators indicate

Monitoring of forest biodiversity and habitats is an important part of forest conservation, but due to the impossible task of monitoring all species, indicator species are frequently used. However, reliance on an incorrect indicator of valuable habitat can reduce the efficiency of conservation efforts. Birds are often used as indicators as they are charismatic, relatively easy to survey, and because we often have knowledge of their habitat and resource requirements. In the Swedish government's environmental quality goals, there are a number of bird species identified as being associated with 'older' and 'high natural value' forests. Here we evaluate the occurrence of four of these indicator species using data from 91 production forest stands and 10 forest reserves in southern Sweden. The bird species assessed are willow tit Poecile montanus, coal tit Periparus ater, European crested tit Lophophanes cristatus and Eurasian treecreeper Certhia familiaris. For the production stands assessed, these indicator species exhibited no significant preferences regarding forest composition and structure, indicating a wider range of habitat associations than expected. These species frequently showed territorial behavior in forest stands <60 and even 40 years of age; much younger than the 120-year threshold for 'older forest' as defined by governmental environmental goals. As almost 80% of the production stands >= 10 years old included at least one of the four indicator species, this raises questions regarding the suitability of these species as indictors of forests of high conservational value in southern Sweden. Notably, besides the four species assessed here, none of the additional indicator taxa identified by the government, were recorded in the 10 reserves. This outcome may reflect the difficulties involved in finding bird indicator species indicative of high natural values in this region. Our results highlight the importance of coupling bird surveys with quantified assessments of proximate vegetation cover

Winter bird communities in urban habitats:a comparative study between central and northern Europe

International audienc

Effects of urbanization on the breeding bird species richness in Finland: a biogeographical comparison

Cities represent the extreme of human-modified environments, with only remnants of the original habitats present. To study how increasing urbanization affects breeding bird richness ; we compiled literature data on bird assemblages at five different levels of urbanization (forest, countryside, village, small and large city centers) and along an urban gradient (park, residential area and city center in different towns) in the three ornithogeographical zones in Finland. The breeding birds were censused using the territory mapping or study plot method. The estimated number ofbreeding bird species decreased with urbanization . The highest species richness was found in the countryside (21 .8 species in a 50-pair sample) and the lowest in the large city center (7 .4 spp.) . This finding supports the widely accepted hypothesis that moderate disturbance will increase biotic diversity. The estimated number of breeding bird species was lower in the city centers (6 .8 species in a 25-pair sample) than in the urban parks (12.1 spp.) . This result points to the important role of trees and shrubs as shelter, and as nesting and feeding places. The species richness was similar at different latitudes, when the level of urbanization was the same. The great productivity (amount of food) and high predictability of resources (food available throughout the year) in the urban habitats may explain why the species richness does not decrease northwards in the urban environments

Niche Analysis and Conservation of Bird Species Using Urban Core Areas

Knowing the ecological requirements of bird species is essential for their successful conservation. We studied the niche characteristics of birds in managed small-sized green spaces in the urban core areas of southern (Kavala, Greece) and northern Europe (Rovaniemi, Finland), during the breeding season, based on a set of 16 environmental variables and using Outlying Mean Index, a multivariate ordination technique. Overall, 26 bird species in Kavala and 15 in Rovaniemi were recorded in more than 5% of the green spaces and were used in detailed analyses. In both areas, bird species occupied different niches of varying marginality and breadth, indicating varying responses to urban environmental conditions. Birds showed high specialization in niche position, with 12 species in Kavala (46.2%) and six species in Rovaniemi (40.0%) having marginal niches. Niche breadth was narrower in Rovaniemi than in Kavala. Species in both communities were more strongly associated either with large green spaces located further away from the city center and having a high vegetation cover (urban adapters; e.g., Common Chaffinch (Fringilla coelebs), European Greenfinch (Chloris chloris), Eurasian Blue Tit (Cyanistes caeruleus)) or with green spaces located closer to the city center and having high gray area cover and anthropogenic disturbance level (urban exploiters; e.g., Western Jackdaw (Corvus monedula), House Sparrow (Passer domesticus), Eurasian Magpie (Pica pica)). The eleven species that were common to both study areas similarly used the environmental variables and had similar niches, indicating that birds respond similarly to urbanization irrespective of latitude. Sixteen species in Kavala and eleven species in Rovaniemi were identified as conservation priority species, based on their niche specialization level and conservation status. The management actions proposed for the conservation of priority species will also benefit other species with similar ecological requirements and ultimately help maintain diverse bird communities in small-sized green spaces in urban core areas

Evaluation of the "safe nesting zone" hypothesis across an urban gradient:a multi-scale study

Urban areas have been considered "safe zones" for nesting birds because of low abundance of predators, and consequently low predation pressure. We studied risk of artificial ground nest predation across an urban gradient at regional (100 x 100 km) and local scales (5 x 5 km, within town) in Finland, Italy, and Spain. Risk of nest predation differed between countries, being greatest in Spain (66%), intermediate in Finland (51%), and lowest in Italy (29%). At the regional scale, risk of nest predation in Finland was lower in small villages and in forest area than in more urbanized sites. In Spain, the risk of nest predation was lower in villages than in the other habitat types. No differences in nest predation risk among habitat types were observed in Italy. At the local level, the risk of nest predation in Finland was higher within the town than in the surrounding forest. In Spain, the risk of nest predation in the surrounding forest area was as high as in the most urbanized areas. No difference in nest predation risk was observed between study plots in Italy at the local level analysis. Our results indicate that nest predation in town centers and their residential areas is similar to or higher than in villages and forest areas refuting the safe nesting zone hypothesis. Risk of nest predation also differed between residential area types within towns. Moreover, the abundance of potential nest predators differed between countries. Magpies and crows were more abundant in Finland than in Italy and Spain, whereas cats, dogs and pedestrians were less abundant in Finland than in the other countries. In Finland, risk of nest predation increased with the abundance of magpies. In Italy and Spain, risk of nest predation increased with the number of pedestrians and in Italy also with the number of cats. In all countries, the risk of nest predation increased with the visibility of the nest. According to our results, urban areas cannot be seen as "safe nesting zones". Actually, changes in nest predation pressure may cause changes in habitat selection patterns and affect bird community structure in urban environments