Jari Valkama

University of Helsinki | HY · Finnish Museum of Natural History

Understanding how weather conditions affect animal populations is essential to foresee population changes in times of global climate shifts. However, assessing year-round weather impacts on demographic parameters is hampered in migratory animals due to often unknown occurrence in space and time. We addressed this by coupling tracking and weather da...

The use of indicator species in forest conservation and management planning can facilitate enhanced preservation of biodiversity from the negative effects of forestry and other uses of land. However, this requires detailed and spatially comprehensive knowledge of the habitat preferences and distributions of selected focal indicator species. Unfortu...

Ectoparasites such as louse flies (Diptera: Hippoboscidae) have tendency for host specialization, which is driven by adaptation to host biology as well as competition avoidance between parasites of the same host. However, some louse fly species, especially in genera attacking birds, show wide range of suitable hosts. In the presented study, we have...

Climate change has ubiquitous impacts on ecosystems and threatens biodiversity globally. One of the most recognized impacts are redistributions of species, a process which can be hindered by habitat degradation. Protected areas (PAs) have been shown to be beneficial for preserving and reallocating species occurrences under climate change. Yet, stud...

Spatial synchrony between populations emerges from endogenous and exogenous processes, such as intra- and interspecific interactions and abiotic factors. Understanding factors contributing to synchronous population dynamics help to better understand what determines abundance of a species. This study focuses on spatial and temporal dynamics in the E...

We present species and sex specific body masses and wing lengths (maximum and minimum chord lengths; Fig. 1) based on the Finnish ringing database (Fig. 2). This article includes the non-passerines and corvids. The first part containing the passerines was published earlier in this same journal (Piha & Lehikoinen 2016). Measurements have been active...

Species distribution models (SDMs) can be used to predict species occurrence and to seek insight into the factors behind observed spatial patterns in occurrence, and thus can be a valuable tool in species conservation. In this study, we used MaxEnt software to explain the occurrence of a protected forest-dwelling species, the Siberian flying squirr...

Citizens’ field observations are increasingly stored in accessible databases, which makes it possible to use them in research. Citizen science (CS) complements the field work that must necessarily be carried out to gain an understanding of any of bird species’ ecology. However, CS data holds multiple biases (e.g. presence only data, location error...

Climate change is triggering adaptation by people and wildlife. The speed and magnitude of these responses may disrupt ecological equilibria and potentially cause further biodiversity losses, but this has rarely been studied. Species inhabiting human-dominated landscapes may be particularly negatively affected by human adaptations to climate change...

The summer of 2017 was cold and rainy, which resulted in poor breeding success of many Passerines and other open-nesting species, such as gulls and terns. Consequently, the number of nestlings ringed, 80 058, was lowest since 1987 (Fig. 1, Appendix 1). Quite unexpectedly, the number of full-grown birds ringed was higher than ever before: 188 916. H...

Capsule: Mark–recapture data suggest low apparent survival and sex- and population-specific site fidelity and territory turnover in adult Northern Goshawks Accipiter gentilis breeding in northern Europe. Aims: To understand how species cope with global environmental change requires knowledge of variation in population demographic rates, especially...

In the current scenario of human-induced environmental changes, boreal forest biodiversity appears to be threatened by both deforestation for timber production and climate change. A northern species which has experienced a decline due to ongoing habitat degradation in Finland is the Northern Goshawk (Accipiter gentilis), a forest-dwelling avian pre...

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...

Around the nests of many birds of prey the pressure of nest predators is decreased. This attracts other bird species to breed near nests of those birds of prey in order to benefit from protection conferred. This study examines the possible protective effect of the Northern Goshawk (Accipiter gentilis) on two of its main prey species, the Black Grou...

Habitat loss causes population declines, but the mechanisms are rarely known. In the European Boreal Zone, loss of old forest due to intensive forestry is suspected to cause declines in forest-dwelling raptors by reducing their breeding performance. We studied the boreal breeding habitat and habitat-associated breeding performance of the northern g...

Sex differences in survival have consequences to population dynamics making information on sex specific survival important. In birds, females often have lower survival than males, and one of the main mechanisms is considered to be differential reproductive investment. We studied apparent adult survival and local recruitment of a small monoga-mous s...

Context Biodiversity and ecosystem functioning underpins the delivery of all ecosystem services and should be accounted for in all decision-making related to the use of natural resources and areas. However, biodiversity and ecosystem services are often inadequately accounted for in land use management decisions. Objective We studied a boreal fores...

The cyclic population dynamics of vole and predator communities is a key phenomenon in northern ecosystems, and it appears to be influenced by climate change. Reports of collapsing rodent cycles have attributed the changes to warmer winters, which weaken the interaction between voles and their specialist subnivean predators. Using population data c...

Global climate change is a major threat to biodiversity, posing increasing pressures on species to adapt in situ or shift their ranges. A protected area network is one of the main instruments to alleviate the negative impacts of climate change. Importantly, protected area networks might be expected to enhance the resilience of regional populations...

Detailed presentation of CORINE land cover and distribution of protected areas.

Studied species of conservation concern in different classifications.

Protected area network in Finland.

Upon leaving their natal area, dispersers are confronted with unknown terrains. Species-specific perceptual ranges (i.e. the maximum distance from which an individual can perceive landscape features) play a crucial role in spatial movement decisions during such wanderings. In nocturnal animals that rely on vision, perceptual range is dramatically e...

Species inhabiting high-latitude environments are anticipated to be exceptionally vulnerable to climate change because of the greater temperature increases projected for these regions. Earlier studies based on bioclimatic envelope models and bird atlas data from 1974 to 1989 have suggested that northern-boreal bird species may face considerable ran...

Forest age structure has become younger and the amount of old forest has decreased due to intensive forestry in Northern Europe. Consequently, large forest‐dwelling hawks may lack nest sites as they need large trees to support their nests. Construction of artificial nests has been a globally adopted conservation measure to provide nest sites for se...

Population consequences of parasites in wild birds are rarely documented. One exception is the decline of British finch populations due to an epidemic caused by the protozoan parasite Trichomonas gallinae. Finch trichomonosis has recently spread from the UK to northern Europe, but its consequences for local finch populations have not been studied....

Climatic warming predicts that species move their entire distribution poleward. Poleward movement of the 'cold' side of the distribution of species is empirically supported, but evidence of poleward movement at the 'warm' distributional side is relatively scarce. Finland has, as the first country in the world, completed three national atlas surveys...

The species names (in alphabetical order), range size (RS) and weighted mean latitude (WML) of southern species in the three atlases of Finnish breeding birds (A1, A2, A3, respectively). (DOCX)

Difference in the number of atlas grid cells surveyed for each latitudinal row between atlas 1 and atlas 3 (in blue) and between atlas 2 and atlas 3 (in green). Atlas 3 is the best surveyed atlas and the red line indicates equal number of cells surveyed as in atlas 3. (TIF)

Different prey species can vary in their significance to a particular predator. In the simplest case, the total available density or biomass of a guild of several prey species might be most relevant to the predator, but behavioural and ecological traits of different prey species can alter the picture. We studied the population dynamics of a predato...

While much effort has been made to quantify how landscape composition influences the distribution of species, the possibility that geographical differences in species interactions might affect species distributions has received less attention. Investigating a predator-prey setting in a boreal forest ecosystem, we empirically show that large-scale d...

Contemporary research has documented a large number of shifts in spring phenology and changes in distribution range although the average spring temperatures have increased by only 0.3-0.6 °C over the past 100 years. Generally, earlier breeding birds have larger clutch sizes, and the advancing spring could thus potentially increase breeding success....

Parental care may be costly to parents because it decreases resources allocated to self-maintenance and may thus reduce survival and future reproductive success. An inter-sexual conflict may exist in animals with obligatory bi-parental care, such as birds of prey, in which females incubate and brood, whereas males provision food for their families....

TL and J. Valkama, Finnish Museum of Natural History, FI-00014 Univ. of Helsinki, Finland. Costs and benefits of dispersal can vary in space and time, depending on environmental factors and individual state. Plastic, condition-dependent dispersal strategies, in which individuals rely on external cues such as food abundance to adjust their dispersal...

Supplementary Figures S1-S4, Supplementary Tables S1-S6, Supplementary Methods and Supplementary References.

The ongoing climate change has improved our understanding of how climate affects the reproduction of animals. However, the interaction between food availability and climate on breeding has rarely been examined. While it has been shown that breeding of boreal birds of prey is first and foremost determined by prey abundance, little information exists...

To ensure long-term persistence, organisms must adapt to climate change, but an evolutionary response to a quantified selection pressure driven by climate change has not been empirically demonstrated in a wild population. Here, we show that pheomelanin-based plumage colouration in tawny owls is a highly heritable trait, consistent with a simple Men...

Current climate change has been found to advance spring arrival and breeding dates of birds, but the effects on autumn migration and possible responses in the distribution of wintering individuals are poorly known. To thoroughly understand the consequences of climate change for animal life histories and populations, exploration of whole annual cycl...

We studied the concordance of population trends and indices between data from (1) the Finnish Constant Effort mist-netting Scheme (CES) and (2) line transect and point count based National Bird Monitoring Scheme (NMS). Population indices of nine common passerines between 1987-2006 were calculated with log-linear Poisson modelling (TRIM). The concor...

A changing climate induces shifts in the location of biomes. Tracing such a shift may pose problems for life history traits adapted to the prior conditions, so that, e.g. the timing of reproduction and the time with sufficient resources for rearing hatchlings do not match. We show that the timing of breeding of Finnish common buzzards Buteo buteo,...

J. 2008: Survival estimates, mortality patterns, and population growth of Fennoscandian mallards Anas platyrhyn-chos. — Ann. Zool. Fennici 45: 483–495. Long-term mallard capture–recapture data from Sweden and Finland were analyzed to describe temporal mortality patterns and reasons. We used program MARK and Seber models to estimate annual survival...

We compared paternity assurance behaviour and related displays in high (1.6 pairs perkm2) and low (6.7 pairs per km2) density populations of the Curlew Numenius arquata breeding on arable farmland in western Finland. There was little evidence of individuals pursuing extra-pair copulations or males exhibiting paternity assurance behaviour. Furthermo...

Animals use carotenoid-pigments for coloration, as antioxidants and as enhancers of the immune system. Carotenoid-dependent colours can thus signal individual quality and carotenoids have also been suggested to mediate life-history trade-offs. To examine trade-offs in carotenoid allocation between parents and the young, or between skin coloration a...

Whether predators can limit their prey has been a topic of scientific debate for decades. Traditionally it was believed that predators take only wounded, sick, old or otherwise low-quality individuals, and thus have little impact on prey populations. However, there is increasing evidence that, at least under certain circumstances, vertebrate predat...

Trichinellosis is 1 of the most widespread parasitic zoonoses in the world and can be lethal to humans. Trichinella spp. are also parasites of considerable economic importance. Because rats may play a role in the transmission of trichinellosis to swine and farmed wild boar, 767 brown rats (Rattus norvegicus Berkenhout) from 13 Finnish waste disposa...

Offspring sex ratio may be an unpredictable component of life history that might select for behavioural plasticity in parental care. If the parents do not have such plasticity and the two sexes of offspring differ in size, individuals in a brood or litter biased towards the larger sex offspring may suffer from food shortage. Sibling sex ratio could...

Resource allocation from parents to their offspring can be modulated by inter-sexual size dimorphism. High dimorphism promotes differential costs in rearing male and female offspring and unequal competitive ability among siblings. We examined whether any of these types of biases occur in Eurasian kestrels, Falco tinnunculus, in which females are la...

We examined inter-clutch egg size variation of Eurasian kestrels Falco tinnunculus in western Finland over a period of 12 years, during which their main prey, Microtus voles, fluctuated in three-year population cycles. Females that bred twice in the area had highly repeatable egg size, and the main part of the observed variation was likely to be du...

55 pages.-- REGHAB Project: Report on Workpackage 3 – Deliverable no 5. The traditional Erringtonian view suggested that predators are generally not harmful to prey populations as they only take a doomed surplus of the prey population (Errington 1956). It was also frequently assumed that the predated individuals were ill, injured or otherwise of lo...

Hatching asynchrony is the consequence of birds initiating incubation before clutch completion. It has been suggested that variation in hatching asynchrony in owls is extensive, and therefore they should be excellent objects to study the effects of spatio-temporal variation in food abundance on this phenomenon. We examined how abundance and predict...

We examined developmental stability in mountain birch Betula pubescens ssp. czerepanovii along a strong pollution gradient in the Kola Peninsula, north‐western Russia, over a period of 8 years (1993–2000). In particular, we investigated whether climatic factors or aerial pollution could increase developmental instability, which was assessed through...

The reasons for female desertion of offspring and the evolution of predominantly male care among monogamous bird species are not clearly understood. We studied parental effort during the incubation and chick rearing periods in the Eurasian Curlew Numenius arquata in western Finland, and compared timing of brood desertion with other populations in E...

We studied age structure, seasonal variation in abundance and habitat use in the Barn Owl Tyto alba on a lowland farmland area in central Portugal during 1991-93. Abundance varied markedly throughout the year and followed a similar pattern in different years. During the breeding season owls were scarce whereas in autumn their abundance was very hig...

We studied nestbox selection, habitat quality and reproductive success of Eurasian Kestrels Falco tinnunculus during 1985–95 in western Finland. Nestboxes were termed small, intermediate or large depending on the basal area, and exposed or sheltered depending on their orientation to prevailing weather conditions. Egg-laying started earlier in the i...

We quantified the intensity of nest predation in the curlew in two arable farmland areas in western Finland, as well as nest-site characteristics associated with nest predation using data on real nests (1995-1997) and artificial nests (1996). Predation on real curlew nests was consistently higher in the area of mixed farm/woodland than in the area...

We examined the effect of heavy metal pollution on the foraging success and breeding performance of the curlew (Numenius arquata) along a documented pollution gradient from a point source, and also by comparing foraging and breeding parameters between the polluted site and two non-polluted areas. Prey biomass and abundance, and foraging success did...

Habitats selected for foraging by kestrels Falco tinnunculus breeding were examined in W Finland during 1989-1991. Voles Microtus epiroticus and M. agrestis) were the main prey. Considerable variation was found among years in the use of the main habitat, agricultural fields. The proportion of agricultural fields used as hunting habitat remained con...

We studied the reproductive investment of microtine rodents (bank vole (Clethrionomys glareolus),Microtus epiroticus andMicrotus agrestis) in western Finland under predation risk from small mustelids. During 1984–1992, the yearly mean litter size of overwintered bank voles was smaller at high least weasel and stoat densities than at low densities (...

In a single-prey loader. the load-size effect may select for transportation of large prey to the nest and consumption of small prey at capture sites. Sonerud suggested that analyses of prey items delivered by avian predators to the nest may profoundly bias the shape of functional response (FR) curves. Therefore, FR may be underestimated, if alterna...