Luontotutkimus Solonen Oy

Helsinki, Finland

Luontotutkimus Solonen Oy

Helsinki, Finland
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Moller A.P.,University Paris - Sud | Solonen T.,Luontotutkimus Solonen Oy | Byholm P.,University of Helsinki | Huhta E.,Finnish Forest Research Institute | And 2 more authors.
Journal of Avian Biology | Year: 2012

Predators impose strong selection on their prey, regulate prey populations and engage in coevolutionary interactions with their prey. The intensity of selection and the strength of coevolutionary interactions will depend on how stringent predators are in their choice of prey. We estimated susceptibility of different species of birds to predation by two common raptors, the northern goshawk Accipiter gentilis and the Eurasian sparrowhawk A. nisus, in an agricultural landscape in Denmark and boreal forests in Finland. We estimated susceptibility to predation as the deviation of the log 10-transformed observed frequency of prey of different species from the log 10-transformed expectation based on population density during the breeding season. We found a high degree of consistency in susceptibility to predation by the goshawk in two areas in Finland. More importantly, there was significant consistency in susceptibility to predation between Denmark and Finland, albeit the degree of consistency in the goshawk was higher than in the sparrowhawk. There was considerable overlap in susceptibility to predation between goshawk and sparrowhawk in Denmark, but not in Finland, implying differences in intensity of interspecific competition as reflected by a much higher extent of goshawk predation on sparrowhawks in Denmark than in Finland. Our findings suggest that hawks impose similar selection pressures on their prey populations, and that the degree of consistency has implications for intensity of interspecific killing. © 2012 The Authors. Journal of Avian Biology © 2012 Nordic Society Oikos.


Jokimaki J.,Finnish Forest Research Institute | Jokimaki J.,Rovaniemi University of Applied science | Jokimaki J.,University of Lapland | Solonen T.,Luontotutkimus Solonen Oy
Ornis Fennica | Year: 2011

Conservation areas are important for many species associated with old forests, but most individuals still occur in commercially-used forest landscapes. We conducted three-visit breeding bird surveys in a total of 37 study squares of 1 km , and used National Forest Inventory data to evaluate habitat associations of birds linked with old forests in three geographical regions: southern, eastern and northern Finland. All study squares were located within managed forests. Out of the total of 23 pre-selected old-forest species, 12 were recorded in the study squares of all three study regions; the number of species varied between 16 and 21 among the regions. The total abundance did not significantly vary among the regions, but the abundances of many single species varied significantly among the regions. Forest-patch size was the single most important factor, positively affecting the abundance of most of the species considered. Development class affected most species in the south and east, and species associated with mature and old forest stands in general. Tree height and stand age were included into the models more often than tree species and , diameter. In general, forest patch size, developmental class, age and tree height were among the most important factors in explaining the abundance of old-forest bird species in commercially-used forests. These stand characteristics appeared particularly important for resident species and cavity nesters. Our results indicate that the responses of old-forest bird species to environmental variation in managed, forested landscapes are individualistic, and different factors may affect them in different regions. Variables included in the patch-level forest-inventory data well explained abundance variation of species associated with old forests. Our results underscore the importance of integrating national forestinventory and bird-survey data to obtain information about species habitat requirements and forest-sector related information about the effects of forestry on birds.


Solonen T.,Luontotutkimus Solonen Oy | Jokimaki J.,Finnish Forest Research Institute | Jokimaki J.,University of Lapland
Bird Conservation International | Year: 2011

We conducted three-visit surveys of 1-km2 plots and traditional Finnish single-visit line transects (considering only the 50 m wide main belt) to evaluate these methods in censusing of a predetermined set of 23 target species known to prefer old forests in three regions in Finland. The efficiency of the two methods was compared on the basis of the number of territories recorded per hour. An attempt was made to find indicators of the occurrence of suitable habitats for species preferring old forest in general, including the rarest ones, and so also largely indicating total diversity of forest bird fauna of the study area. The total number of pairs observed per hour and the abundance of sedentary bird species were significantly higher in the square surveys than in the main belt of the line transects. There were significant positive relationships between the densities of relatively abundant (density > 1.0 pairs km-2) and less abundant target species. There emerged five common forest bird species that seemed to form a suitable set of indicators of the occurrence of habitats for birds preferring old forest in the northern boreal zone: Great Spotted Woodpecker Dendrocopos major, Mistle Thrush Turdus viscivorus, Willow Tit Parus montanus, Eurasian Treecreeper Certhia familiaris, and Eurasian Bullfinch Pyrrhula pyrrhula. We concluded that sedentary species preferring old forest are good candidates for indicators to characterize some threatened aspects of forest bird diversity. © Copyright BirdLife International 2010.


Lodenius M.,University of Helsinki | Solonen T.,Luontotutkimus Solonen Oy
Ecotoxicology | Year: 2013

Published results concerning metal levels in feathers of birds of prey were listed and evaluated. Mercury concentrations have been studied most and the background values normally vary between 0.1 and 5 mg/kg dry weight the highest concentrations being in birds from aquatic food chains. Pollution causes elevated levels of mercury in feathers. The concentrations of cadmium, copper, lead and zinc show reasonable variation between species, areas and time periods. Feathers of birds of prey have proved to be good indicators of the status of environmental heavy metal pollution. Special attention should be paid to clean sampling and preparation of samples. Interpretation of the results requires knowledge on food habit, molting and migration patterns of the species. Several species representing different food chains should be included in comprehensive monitoring surveys. Chick feathers reflect most reliably local conditions. © 2013 Springer Science+Business Media New York.


Solonen T.,Luontotutkimus Solonen Oy | Hilden M.,University of Helsinki
Ornis Fennica | Year: 2014

Urbanization and climate change are two environmental factors that have most prominently affected breeding phenology of birds during recent decades. We examined such relationships in rural, suburban and urban nest box populations of Great Tits Parus major and Blue Tits P. caeruleus in the capital region of Finland in the 1980s and 1990s. We expected that mild winters and high spring temperatures may advance the breeding season of tits, but less so in urban habitats, where breeding should in any case start earlier than elsewhere. On average, Blue Tits began egg laying a few days earlier in spring than Great Tits. Contrary to expectations, tits bred later in the urban parks of the city than in other habitats,whereas breeding was earliest in suburban areas. It seems that these intermediate habitats, in some way, offer the advantages of both rural and urban habitats. During the study period, the timing of breeding in tits showed advancing temporal trends in rural habitats, and in the Blue Tit also in urban habitats. The effect of increasing winter temperatures on laying dates was mainly minor, but a significant delay emerged in urban Great Tits. The main effect of increasing April temperatures on laying dates was a significant advancement. In urban habitats, however, the advancing effect was in Great Tits significantly stronger and in Blue Tits significantly weaker than in other habitats. The results suggest that breeding of tits may advance also with warming climate but some urban populations might be more resistant to climate change than rural ones.


Solonen T.,Luontotutkimus Solonen Oy | Ahola P.,Kolsintie 12 B
Canadian Journal of Zoology | Year: 2010

We studied dynamics of local small-mammal assemblages consisting of shrews, voles, and mice by small-scale snap trapping in each spring and autumn from 1981 to 2006 in southern Finland. Our aim was to search for relative roles of possible regulatory associations within and between species, as well as to find reflections of the effects of large-scale climatic phenomena on local populations. Preceding intraspecific densities had a dominating role in seasonal changes in small-mammal numbers. Their relationships with weather-related factors indicated by the indices of the North Atlantic Oscillation (NAO) were most pronounced during winter. Relationships with the NAO indices, increasing values of which indicate milder weather in the north, were negative in voles but positive in shrews and mice. Spring densities were governed by the largely compensatory effects of the growth rate of the preceding summer and subsequent population decline during winter in the field vole (Microtus agrestis (L., 1761)) and mice, while the effects of winter decline dominated in shrews. The bank vole (Myodes glareolus (Schreber, 1780) = Clethrionomys glareolus (Schreber, 1780)) showed decreasing winter decline, which had a considerable positive effect on population densities.


Solonen T.,Luontotutkimus Solonen Oy | Ahola K.,Tornihaukantie 8 D 72 | Karstinen T.,Juusinkuja 1
Environmental Monitoring and Assessment | Year: 2015

Voles are often considered as harmful pests in agriculture and silviculture. Then, the knowledge of their abundance may be of considerable economical importance. Commonly used methods in the monitoring of vole abundances are relatively laborious, expensive, and spatially quite restricted. We demonstrate how the mean clutch size of the tawny owl Strix aluco may be cost-effectively used to predict relative densities of voles over large areas. Besides installing a number of suitable nest boxes, this vole monitoring system primarily includes only the inspection of the nest boxes and counting the number of tawny owl eggs found two times during a few weeks period in spring. Our results showed a considerable agreement between the fluctuations in the mean clutch size of tawny owls and the late spring abundance indices of small voles (Myodes, Microtus) in our study areas in southern Finland. The mean clutch size of the tawny owl reflected spring vole abundance over the spatial range examined, suggesting its suitability for general forecasting purposes. From the pest management point of view, an additional merit of the present method is that it may increase numbers of vole-eaters that provide biological control of vole populations. © 2015, Springer International Publishing Switzerland.


The onset of breeding in boreal owls might be linked to food supply, weather conditions or both, but the relative importance of each is poorly understood. The primary goal of this study was to discuss the impact that fluctuating food supply and various climatic factors have on the timing of breeding in northern Tawny Owls Strix aluco in rural and urban environments. The timing of breeding was significantly earlier in urban territories than in rural ones. In accordance with earlier findings, very early clutches occurred mainly in urban habitats. In association with being significantly earlier in urban than in rural habitats, the breeding of Tawny Owls began earlier the higher the (autumn) vole levels and the milder the preceding winter. Owls bred earlier the more there were voles and snow simultaneously. It seems that the state of readiness to start egg laying in urban habitats is in general higher than elsewhere and therefore favourable large-scale environmental conditions may also activate breeding earlier there than in rural areas. © 2013 Dt. Ornithologen-Gesellschaft e.V.


The study upon which this article is based examined the interspecific relationships between three differentsized species, both before and during breeding, within a guild of birds of prey in southern Finland between 1997 and 2007. The study sought to examine how the territory occupancy and fledgling production of the smaller (subdominant) species was related to the vicinity of a larger (dominant) species. Inverse relationships were thought to suggest effects of potential intraguild predation. Three key relationships emerged. Firstly, the vicinity of the dominant eagle owl had no significant effect on the occupancy of nesting territories of the subdominant northern goshawk, while the fledgling production of the goshawk increased as the distance from the dominant owl species increased. Secondly, a significant positive relationship was found between the occupancy of the nearest neighbour nesting territories of the eagle owl and the tawny owl. However, the vicinity of the eagle owl had no significant effect on tawny owl reproduction. Thirdly, the occupation of tawny owl territories showed a nearly significant association with the nesting territories of the northern goshawk. However, no significant relationship was found between the vicinity of nearest neighbour nesting territories of the northern goshawk and fledgling production of the tawny owl. The results of this study suggest that depressing reflections of intraguild predation may be expected when the populations of guild members share similar nest sites or if the nest sites of subdominant members of the guild are accessible for dominant members, or in locally unstable populations of less site-tenacious species that show rapid turnover of individuals rather than in strictly site-tenacious longterm territorial species. © Tapio Solonen; Licensee Bentham Open.


PubMed | Luontotutkimus Solonen Oy
Type: Journal Article | Journal: Environmental monitoring and assessment | Year: 2015

Voles are often considered as harmful pests in agriculture and silviculture. Then, the knowledge of their abundance may be of considerable economical importance. Commonly used methods in the monitoring of vole abundances are relatively laborious, expensive, and spatially quite restricted. We demonstrate how the mean clutch size of the tawny owl Strix aluco may be cost-effectively used to predict relative densities of voles over large areas. Besides installing a number of suitable nest boxes, this vole monitoring system primarily includes only the inspection of the nest boxes and counting the number of tawny owl eggs found two times during a few weeks period in spring. Our results showed a considerable agreement between the fluctuations in the mean clutch size of tawny owls and the late spring abundance indices of small voles (Myodes, Microtus) in our study areas in southern Finland. The mean clutch size of the tawny owl reflected spring vole abundance over the spatial range examined, suggesting its suitability for general forecasting purposes. From the pest management point of view, an additional merit of the present method is that it may increase numbers of vole-eaters that provide biological control of vole populations.

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