Toni Laaksonen

Toni Laaksonen
University of Turku | UTU · Department of Biology

About

230
Publications
35,111
Reads
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4,109
Citations
Introduction
I am an animal ecologist working in the fields of animal behaviour, applied ecology, conservation biology, and life history and population ecology.
Additional affiliations
September 2019 - present
University of Turku
Position
  • Professor
January 2018 - August 2019
Natural Resources Institute Finland (Luke)
Position
  • Senior Researcher
May 2011 - December 2017
University of Turku
Position
  • Lecturer

Publications

Publications (230)
Article
We investigated trophic dynamics of Hg in the polluted Baltic Archipelago Sea using established trophic magnification (TMFs) and biomagnification factors (BMFs) on a comprehensive set of bird, fish, and invertebrate species. As different ecological and ecophysiological species traits may affect trophic dynamics, we explored the effect of food chain...
Article
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The role of an alien predator in the community depends on its interaction with native predators. The absence of apex predators may facilitate outbreaks of invasive mesopredators, but the effect of apex predators may vary between species and environments. We analysed the occurrence of a common invasive mesopredator in Europe, the raccoon dog ( Nycte...
Article
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National forest inventories (NFI) in Finland provide empirical evidence for a marked increase in tree growth, total forest area, and total timber volume over the past century. Meanwhile, the assessments of threatened forest species and habitats indicate continuous degradation of biodiversity in Finnish forests. To shed light on this seeming paradox...
Article
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Certain species experience rapid population increases in human-modified and -affected environments. Conservation actions and increased wintertime food availability have led to a population increase of several large herbivorous waterbird species. In Northern Europe, this trend is opposite to the overall decrease of several smaller waterbird species....
Article
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1. In vertebrates, thyroid hormones (THs) play an important role in the regulation of growth, development, metabolism, photoperiodic responses and migration. Maternally transferred THs are important for normal early‐phase embryonic development when embryos are not able to produce endogenous THs. Previous studies have shown that variation in materna...
Preprint
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Migratory connectivity is a metric of the co-occurrence of migratory animals originating from different breeding sites, and like their spatio-temporal distributions, can vary substantially during the annual cycle. Together, both these properties affect the optimal times and sites of population censusing. We tracked taiga bean geese (Anser fabalis f...
Article
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1. Knowledge concerning spatio‐temporal distributions of populations is a prerequisite for successful conservation and management of migratory animals. Achieving cost‐effective monitoring of large‐scale movements is often difficult due to lack of effective and inexpensive methods. 2. Taiga bean goose Anser fabalis fabalis and tundra bean goose A. f...
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Telomere length and shortening rate are increasingly used as biomarkers for long-term costs in ecological and evolutionary studies because of their relationships with survival and fitness. Both early-life conditions and growth, and later-life stressors can create variation in telomere shortening rate. Studies on between-population telomere length a...
Article
Climate change influences population demography by altering patterns of gene flow and reproductive isolation. Direct mutation rates offer the possibility for accurate dating on the within-species level but are currently only available for a handful of vertebrate species. Here, we use the first directly estimated mutation rate in birds to study the...
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Background Knowledge on migration patterns and flyways is a key for understanding the dynamics of migratory populations and evolution of migratory behaviour. Bird migration is usually considered to be movements between breeding and wintering areas, while less attention has been paid to other long-distance movements such as moult migration. Methods...
Article
Human-induced mercury (Hg) contamination is of global concern and its effects on wildlife remain of high concern, especially in environmental hotspots such as inland aquatic ecosystems. Mercury (Hg) biomagnifies through the food web resulting in high exposure in apex predators, such as the white-tailed eagle (Haliaeetus albicilla), making them exce...
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Telomere length is increasingly used as a biomarker of long‐term somatic state and future survival prospects. While most studies have overlooked this aspect, biological interpretations based on a given telomere length will benefit from considering the level of within‐individual repeatability of telomere length through time. Therefore, we conducted...
Article
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Habitat use studies provide invaluable information for the conservation of species that suffer from habitat loss or degradation. We used satellite telemetry to study the habitat use of white-tailed eagles ( Haliaeetus albicilla ) in relation to six habitat classes (artificial surfaces, agricultural areas, forests, semi-natural areas, wetlands and w...
Preprint
Full-text available
Telomere length and shortening rate are increasingly used as biomarkers for long-term costs in ecological and evolutionary studies because of their relationships with survival and fitness. Telomere length can be heritable, but both early-life conditions and later-life stressors can create variation in telomere shortening rate. Studies on between-po...
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Aim The configuration of the earth's landmasses influences global weather systems and spatiotemporal resource availability, thereby shaping biogeographical patterns and migratory routes of animals. Here, we aim to identify potential migratory barriers and corridors, as well as general migration strategies within the understudied Indo‐European flywa...
Article
Tree cavities are an essential requirement for reproduction and survival of secondary cavity nesters. Little is known, however, about how cavity distribution in space and time may limit their use during and outside of the breeding season. Using long-term (17 yr) data on the use of nest-boxes resembling tree cavities by individually marked Eurasian...
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How environmental factors influence population dynamics in long-distance migrants is complicated by the spatiotemporal diversity of the environment the individuals experience during the annual cycle. The effects of weather on several different aspects of life history have been well studied, but a better understanding is needed on how weather affect...
Preprint
Full-text available
Telomere length is increasingly used as a biomarker of long-term life history costs, ageing and future survival prospects. Yet, to have the potential to predict long-term outcomes, telomere length should exhibit a relatively high within-individual repeatability over time, which has been largely overlooked in past studies. To fill this gap, we condu...
Article
Early-life conditions are crucial determinants of phenotype and fitness. The effects of pre- and postnatal conditions on fitness prospects have been widely studied but their interactive effects have received less attention. In birds, asynchronous hatching creates challenging developmental conditions for the last-hatched chicks, but differential all...
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Many apex predator populations are recolonizing old areas and dispersing to new ones, with potential consequences for their prey species and for livestock. An increasing population of the White-tailed Eagle (Haliaeetus albicilla) has settled north of the Arctic Circle in northern Finland, mainly at two big water reservoirs but also in areas with ma...
Article
We studied the relationship between temperature and the coexistence of great tit Parus major and blue tit Cyanistes caeruleus, breeding in 75 study plots across Europe and North Africa. We expected an advance in laying date and a reduction in clutch size during warmer springs as a general response to climate warming and a delay in laying date and a...
Article
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Changing climate can modify predator–prey interactions and induce declines or local extinctions of species due to reductions in food availability. Species hoarding perishable food for overwinter survival, like predators, are predicted to be particularly susceptible to increasing temperatures. We analysed the influence of autumn and winter weather,...
Article
Specialist individuals within animal populations have shown to be more efficient foragers and/or to have higher reproductive success than generalist individuals, but interspecific reproductive consequences of the degree of diet specialisation in vertebrate predators have remained unstudied. Eurasian pygmy owls (hereafter POs) have less vole‐special...
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Aim Nest building is widespread among animals. Nests may provide receptacles for eggs, developing offspring and the parents, and protect them from adverse environmental conditions. Nests may also indicate the quality of the territory and its owner and can be considered as an extended phenotype of its builder(s). Nests may, thus, function as a sexua...
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Fluctuations in the abundance of main prey species might shape animal communities, by inducing numerical responses and dietary shifts in predators. Whether numerical responses and dietary shifts differ among individuals of different age and sex has so far gained little attention. These differences could affect how much predators consume main and al...
Article
Sulphate soils, characterised by low pH conditions, are found worldwide, and are potentially large sources of metal contamination, often exceeding industrial emissions. Metal leaching from sulphate soils has been shown to be harmful to aquatic organisms, but the cascading effect on exposure in apex avian predators has not been studied earlier. With...
Article
Natural cavities are a critical resource for non-excavating hole-nesting birds, many of which are declining in northern Europe. In the heavily managed boreal forests in Finland, cavities may be a scarce resource, but their availability to different hole-nesters has been examined in only a few studies. We studied the abundance of suitable cavities i...
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In addition to direct mortality, predators can have indirect effects on prey populations by affecting prey behaviour or physiology. For example, predator presence can increase stress hormone levels, which can have physiological costs. Stress exposure accelerates the shortening of telomeres (i.e. the protective caps of chromosomes) and shorter telom...
Preprint
Full-text available
Animals' life-history traits vary largely along many continuums across species and several physiological parameters have been proposed as possible mediators that drive the life-history variation, such as metabolic rates, glucocorticoids, and oxidative stress. Interestingly, thyroid hormones (THs), despite closely interacting with these physiologica...
Article
Bird populations are in continuous change in the Finnish archipelago. Some species are increasing in abundance but more are decreasing. More than half of the species, the main breeding area of which is in the archipelago, are currently red-listed in the most recent Red Data Book of Finnish bird species (Lehikoinen et al. 2019). We present short-ter...
Article
Social information can spread fast and help animals adapt in fluctuating environments. Prospecting on the breeding sites of others, a widespread behavior, can help to maximize reproduction by, for instance, settling in the same area as other successful breeders. Previous studies have shown that successful broods have the highest number of prospecto...
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Striking variation in melanin coloration within natural populations is likely due to the different fitness outcomes of alternative phenotypes in varying environmental conditions. There are two types of melanin: eumelanins yield blackish hues, whereas pheomelanins yield reddish hues. The production of eumelanins requires low levels of glutathione (G...
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Large-scale construction of wind power plants may threaten large raptors at both individual and population levels. The most efficient way to prevent the negative effects of wind power plants is to avoid building on presumably high-risk sites, which requires an understanding of the movement patterns and habitat use of vulnerable species. The White-t...
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Human‐induced climate change is expected to cause major biotic changes in species distributions and thereby including escalation of novel host‐parasite associations. Closely related host species that come into secondary contact are especially likely to exchange parasites and pathogens. Both the Enemy Release Hypothesis (where invading hosts escape...
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Hoarding behaviour (storing food for a later use) has evolved to reduce starvation risk when resources are scarce. Different age and sex classes often show differences in foraging due to experience, skills or life history strategy, but such differences in hoarding under spatio-temporally varying environmental conditions have rarely been studied in...
Article
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1.Co‐existence between great tits Parus major and blue tits Cyanistes caeruleus, but also other hole nesting taxa, constitutes a classic example of species co‐occurrence resulting in potential interference and exploitation competition for food and for breeding and roosting sites. However, the spatial and temporal variation in co‐existence and its c...
Article
Environmental shifts may induce sudden reversals in the relative quality or sexual attractiveness of mates (ecological cross‐overs) leading to non‐directional sexual selection. Studies on such ecological cross‐overs induced by environmental shifts during the non‐breeding season are particularly rare. We studied the interactive effects between non‐b...
Article
The expansion of wind energy over large areas may be accompanied by major conflicts with birds, including birds of prey. Hence, it is desirable that the space use of species known to be vulnerable to wind energy be assessed in light of current and future developments. Here, we report on the large-scale dispersal movements of pre-breeding white-tail...
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Many organisms adjust their reproductive phenology in response to climate change, but phenological sensitivity to temperature may vary between species. For example, resident and migratory birds have vastly different annual cycles, which can cause differential temperature sensitivity at the breeding grounds, and may affect competitive dynamics. Curr...
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Background Carnivores are re-establishing in many human-populated areas, where their presence is often contentious. Reaching consensus on management decisions is often hampered by a dispute over the size of the local carnivore population. Understanding the reproductive dynamics and individual movements of the carnivores can provide support for mana...
Poster
Full-text available
Hoarding behaviour evolved in few small species to reduce starvation risk, especially in response to harsh winter condition or food shortage. Some species of owls, such as Eurasian pygmy owls (Glaucidium passerinum), store prey in natural cavities or in nest-boxes. Despite storing habits of pygmy owls being already documented at the population leve...
Article
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‘Cry for help’ hypothesis predicts that attraction of predators with chemical or visual cues can decrease insect damage of plants. Visual cues involve changes in photosynthetic activity and the reflectance of leaves, and there is some evidence that birds may use these changes as foraging cues. However, changes in the visual properties of leaves hav...
Article
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Life is uncertain. To reduce uncertainty and make adaptive decisions, individuals need to collect information. Individuals often visit the breeding sites of their conspecifics (i.e., “prospect”), likely to assess conspecifics’ reproductive success and to use such information to identify high-quality spots for future breeding. We investigated whethe...
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The evolutionary purpose of a fleshy fruit is to attract seed dispersers and get the seeds dispersed by frugivorous animals. For this reason, fruits should be highly rewarding to these mutualists. However, insect herbivory can alter plant reproductive success e.g. by decreasing fruit yield or affecting the attractiveness of the fruits to mutualisti...
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In a substantial number of species, females show some development of secondary sexual characters. These traits can function as signals of individual phenotypic or genetic qualities and status to conspecifics. Individuals may benefit potentially from expressing signals or badges of status if they are reliable and honest signals of individual quality...
Article
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Mothers may affect the future success of their offspring by varying allocation to eggs and embryos. Allocation may be adaptive based on the environmental conditions perceived during early breeding. We investigated the effects of food supplementation and predation risk on yolk hormone transfer in the pied flycatcher Ficedula hypoleuca. In a food sup...
Article
The return of apex predators re-shape population densities of their prey species, creating conflicts and challenges for the conservation and management of both predator and prey populations. The population of white-tailed eagles (Haliaeetus albicilla) in the Baltic Sea has grown rapidly since the 1980s after a previous population collapse, causing...
Article
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The increase in size of human populations in urban and agricultural areas has resulted in considerable habitat conversion globally. Such anthropogenic areas have specific environmental characteristics, which influence the physiology, life history, and population dynamics of plants and animals. For example, the date of bud burst is advanced in urban...
Data
Figure S1. Intensity of urbanisation according to (A) classification by scientists. Box plots show medians, quartiles, 5‐ and 95‐percentiles, and extreme values, and (B) CORINE land cover code (red = discontinuous urban, purple = industrial or commercial units, pink = green urban sites, brown = arable land and rice field, orange = agriculture lands...
Data
Figure S2. Distribution of study plots across Europe, North Africa and the Middle East.
Data
Table S1. Summary data for study plots. See Material and methods for definitions. Table S2. Correlation matrix of explanatory variables. Table S3. Mixed linear model investigating laying date in four passerines species (CF: Collared Flycatcher, GT: Great tit and PF: Pied Flycatcher) as a function of habitat characteristics (intensity of urbanisat...
Data
Figure S3. Box plots of latitude of study plots in four passerine birds in Europe, North Africa and the Middle East.
Article
Full-text available
The increase in size of human populations in urban and agricultural areas has resulted in considerable habitat conversion globally. Such anthropogenic areas have specific environmental characteristics, which influence the physiology, life history, and population dynamics of plants and animals. For example, the date of bud burst is advanced in urban...
Article
Full-text available
To understand the consequences of ever-changing environment on the dynamics of phenotypic traits, distinguishing between selection processes and individual plasticity is crucial. We examined individual consistency/plasticity in several male secondary sexual traits expressed during the breeding season (white wing and forehead patch size, UV reflecta...
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Intraguild (IG) predation and interspecific competition may affect the settlement and success of species in their habitats. Using data on forest-dwelling hawks from Finland, we addressed the impact of an IG predator, the northern goshawk Accipiter gentilis (goshawk), on the breeding of an IG prey, the common buzzard Buteo buteo. We hypothesized tha...
Article
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The presence of poorly sited wind farms raises concerns for wildlife, including birds of prey. Therefore, there is a need to extend the knowledge of the potential human-wildlife conflicts associated with wind energy. Here, we report on the movements and habitat use of post-fledging satellite-tagged white-tailed eagles in Finland, where wind-energy...
Article
Predation risk has negative indirect effects on prey fitness, partly mediated through changes in behaviour. Evidence that individuals gather social information from other members of the population suggests that events in a community may impact the behaviour of distant individuals. However, spatially wide-ranging impacts on individual behaviour caus...